CN113862518A

CN113862518A - Aluminum-rich zinc-based coating material for reducing liquid metal embrittlement during hot forming and preparation method thereof

Info

Publication number: CN113862518A
Application number: CN202110518498.0A
Authority: CN
Inventors: 吴广新; 丁成发; 马征; 张捷宇
Original assignee: SHANGHAI UNIVERSITY
Current assignee: SHANGHAI UNIVERSITY
Priority date: 2021-05-12
Filing date: 2021-05-12
Publication date: 2021-12-31

Abstract

The invention discloses an aluminum-rich zinc-based coating material capable of reducing the brittleness caused by liquid metal in a hot forming process and a preparation method thereof. Zn-Al-Mg alloy coating, the composition of which is calculated by mass percentage, Al is 0.2-5%, Mg≤2.5%, Si is 0-2%, Ti is 0-1%, RE is 0-3%, wherein RE is at least one element in La and Ce, and the rest is Zn and some unavoidable impurity content. In the present invention, coating materials with different element contents are prepared for 22MnB5 steel sheets, and the materials of the present invention are tested by the preparation of coating-hot dipping experiment, the austenitization treatment, the microstructure observation of the coating and the steel sheet, and the hot-stretching test of the steel sheet, respectively. Inhibiting liquid metal embrittlement and high corrosion resistance, it can effectively solve the problem of liquid metal embrittlement, corrosion resistance of the coating and hot dip plating of high-strength steel plates coated with aluminum-rich zinc-based coatings during hot stamping. Oxidation of the bath during the process.

Description

Aluminum-rich zinc-based coating material for reducing brittleness of liquid metal in hot forming process and preparation method thereof

Technical Field

The invention relates to a coating material and a preparation method thereof, in particular to a coating material for inhibiting brittleness of liquid metal generated in the hot stamping forming process of a high-strength steel plate, a preparation method thereof, corrosion resistance of a coating and oxidation resistance of a coating liquid in the hot dip coating process.

Background

The high-strength steel plate is easy to have the problems of poor shape, high processing load, large rebound quantity and the like in the traditional cold forming processing process, and the use of high-strength steel is greatly limited.

Based on this, a new thermoforming technique is gradually developed. The appearance of the hot forming technology solves the problems that the ultrahigh-strength plate is poor in shape, high in forming load and large in resilience amount during cold processing, and the problems caused by cold forming can be well solved due to the fact that the tonnage of a press is low, the forming performance is good and the size of parts is accurate after forming under the hot forming condition.

Despite such great advantages, thermoforming techniques still suffer from limitations in practical production. Conventional non-plated stamped parts cause decarburization and oxidation peeling of the surface of the stamped steel sheet during heating. Decarburization reduces the strength of the steel sheet surface. The oxidation peeling increases the friction degree of the stamping part in the die, shortens the service life of the die, and the like, and limits the application of the hot forming technology in the actual industrial production.

To solve the problems in the hot stamping process, several plating techniques on hot stamped steel have been developed.

The Al-Si coating contains 90 wt.% of Al and 7-10 wt.% of Si, and the balance of the Al-Si coating also contains some impurities. The Al-Si coating has better performance due to the higher melting point of the iron-aluminum-silicon compoundThe high-temperature oxidation resistance of the Al-Si plating layer can prevent the oxidation and decarburization of the surface of the steel plate, and meanwhile, the Al-Si plating layer has good corrosion resistance, so that the Al-Si plating layer is widely applied to the manufacture of hot stamping parts at present. After the austenitizing treatment of keeping the temperature of 880-950 ℃ for 5min, Fe and Fe are sequentially formed on the Al-Si coating from the junction of the matrix to the surface of the coating due to the mutual diffusion of coating elements₃Al layer, ferrite layer, Fe₂Al₅Layer, Fe₂Al₅And FeAl₃And the like, but because the iron-aluminum compound and the iron-aluminum-silicon phase are both brittle phases, the plating layer is easy to crack during hot stamping.

GI (galvanization), GA (galvanineal) coatings are called zinc-based coatings. GI. The GA coating is originally developed to enable the coating to have sacrificial protective performance, the GI coating is a pure zinc coating, and the GA coating is an alloyed coating obtained by heating the pure zinc coating at 480-520 ℃. GI. The GA coating has good metal appearance and formability, excellent shielding and cathodic protection performances, good welding performance and coating performance, and is harmless to human bodies. GI. The austenitizing process of the GA coating steel plate is mainly a mutual diffusion process of Fe and Zn elements, the coating of the GI plate after hot stamping is mainly an Fe-Zn intermetallic compound, and the coating of the GA plate after hot stamping is mainly a solid solution of Fe. In producing GI coatings, about 0.2 wt.% Al is typically added to the zinc bath in order to initially form a layer of Fe between the bath and the substrate during immersion plating₂Al₅-Zn_xAnd a suppression layer for suppressing the formation of a brittle Fe-Zn intermetallic phase and changing the formability of the plating layer at room temperature deformation. In the production of GA coatings, the amount of A1 added to the zinc bath is generally 0.14 wt.%, and the lower A1 content does not result in a continuous layer of Fe₂Al₅The inhibition layer is easy to generate Fe-Zn intermetallic phase between the coating and the substrate. However, in the hot stamping process of the GI and GA coatings, the liquid zinc usually has a problem of brittleness, that is, the liquid zinc permeates into an austenite matrix and causes the matrix to crack, which seriously affects the use performance of the product.

Although the plating layer on the surface of the steel sheet can solve some problems in the hot stamping process, new other problems are introduced, such as the high temperature of the steel sheet during the hot forming process, which is much higher than the melting point of some element substances in the plating layer, and inevitable melting and volatilization during the hot forming process.

The Al-Si based coating can generate cracks in the coating in the hot forming process; the zinc-based coating can melt and volatilize zinc in the hot stamping forming process, the zinc is melted into liquid metal and enters a steel plate matrix in a penetration mode, and the steel plate is easy to break when external stress is applied. At present, how to solve or inhibit the problem of metal brittleness caused by reducing liquid zinc is in urgent need of solving. Therefore, it is necessary to develop a plating layer for hot forming to prevent the embrittlement of the liquid metal.

The patent technology with patent document publication number CN111155044A discloses a method for improving the surface quality of zinc-aluminum-magnesium coated steel and a zinc-aluminum-magnesium coating, wherein the Al content is 1.5-2.0% by weight, the mass ratio of Mg to Al is 1.2-1.6: 1.5-2.0, the temperature of a steel matrix put into a zinc pot is more than or equal to 470 ℃, the proportion relationship between Al and Mg elements is controlled to reduce the proportion of eutectic structures in coating tissues by controlling the proportion relationship between the Al and Mg elements, so that the volume percentage of the eutectic structures in the coating tissues is less than or equal to 30%, and meanwhile, the eutectic structures in the coating tissues are distributed in a net shape. But still can not effectively overcome the contact between the molten liquid zinc affected by high temperature and the steel plate matrix, so that the brittle fracture of the steel plate matrix can be generated during hot forming, the forming quality of the steel is affected, and the application of the steel is limited.

Disclosure of Invention

In order to solve the problems of the prior art, the invention aims to overcome the defects in the prior art and provide an aluminum-rich zinc-based plating layer material for reducing brittleness of liquid metal in a hot forming process and a preparation method thereof. The proportional relation between Al and Mg elements is controlled, so that a continuous MgAl layer can be formed in the immersion plating process₂O₄An oxide to protect the plating solution from further oxidation; meanwhile, an Fe-Al alloy layer can be formed in the hot dip coating process, and because the Fe-Al alloy layer can inhibit the contact of liquid zinc melted by high temperature and a steel plate matrix in the hot forming process, the brittle failure of the steel plate matrix can be avoided in the hot forming process; the addition of Si element can form Mg with good corrosion resistance with Mg element₂Si phase, thereby further improving the corrosion resistance of the plating; the addition of Ti element has good effect of refining the crystal grains of the plating layer; the addition of RE element can improve the surface quality of the plating layer, reduce the viscosity of the plating solution, improve the fluidity of the plating solution and improve the corrosion resistance of the plating layer.

In order to achieve the purpose, the invention adopts the following technical scheme:

an aluminum-rich zinc-based coating material for reducing brittleness of liquid metal in a hot forming process is a Zn-Al-Mg alloy, a Zn-Al-Mg-Si alloy, a Zn-Al-Mg-Ti alloy, a Zn-Al-Mg-Si-Ti alloy, a Zn-Al-Mg-RE alloy, a Zn-Al-Mg-Si-RE alloy, a Zn-Al-Mg-Ti-RE alloy or a Zn-Al-Mg-Si-Ti-RE alloy, and has the following components in percentage by weight: al: 0.2-5.0%; mg is less than or equal to 2.5 percent; si: 0 to 2.0 percent; ti: 0 to 1.0 percent; RE: 0-3.0%, and the balance of Zn and inevitable impurities; wherein RE is any one element or the combination of two elements of La and Ce.

Preferably, the aluminum-rich zinc-based plating material for reducing brittleness of liquid metal in the hot forming process comprises the following components in percentage by weight: zn: 90.0-95.0%; al: 0.2-5.0%; mg is less than or equal to 2.5 percent; si: 0 to 2.0 percent; ti: 0 to 1.0 percent; RE: 0 to 3.0% and the balance of inevitable impurities.

Preferably, the invention provides an aluminum-rich zinc-based plating material for reducing brittleness of liquid metal in a hot forming process, which is characterized in that: the concrete components and weight percentages are as follows: al: 0.2-1.4%; mg is less than or equal to 2.5 percent; si: 0 to 2.0 percent; ti: 0 to 1.0 percent; RE: 0-3.0%, and the balance of Zn and inevitable impurities.

Preferably, the invention provides an aluminum-rich zinc-based plating material for reducing brittleness of liquid metal in a hot forming process, which is characterized in that: the concrete components and weight percentages are as follows: al: 2.1-5.0%; mg is less than or equal to 2.5 percent; si: 0 to 2.0 percent; ti: 0 to 1.0 percent; RE: 0-3.0%, and the balance of Zn and inevitable impurities.

Preferably, in the invention, in the process of forming the aluminum-rich zinc-based coating on the surface of the steel, an Fe-Al inhibition layer and continuous MgAl are formed₂O₄An oxide layer.

Preferably, in the invention, in the process of forming the aluminum-rich zinc-based coating on the surface of the steel, Mg and Zn are formed into Mg₂Zn₁₁And MgZn₂Phase (1); or Si element and Mg element form Mg₂A Si phase.

The invention relates to a preparation method of an aluminum-rich zinc-based coating material for reducing brittleness of liquid metal in a hot forming process, which comprises the following steps:

a. the preparation process of the hot-dip plating solution comprises the following steps:

a-1, preparing an aluminum-rich zinc-based plating material:

the preparation method comprises the following steps of weighing the following elements and the weight percentages thereof required for preparing the aluminum-rich zinc-based plating material, and mixing the following alloy raw materials in percentage by weight: the content of Al is controlled to be 0.2-5 wt.%, the content of Mg is controlled to be 0-2.5 wt.%, the content of Si is controlled to be 0-2 wt.%, the content of Ti is controlled to be 0-1 wt.%, the content of RE element is controlled to be 0-3 wt.%, and the balance is Zn and inevitable impurities;

under the protection of a covering agent, smelting alloy raw materials in a smelting furnace according to the proportion of the alloy raw materials to obtain an alloy melt of a composite system alloy coating, pouring the alloy melt into a mold, and cooling and molding to prepare an aluminum-rich zinc-based coating material for later use;

a-2, preparing a hot plating solution:

putting the aluminum-rich zinc-based plating material prepared in the step a-1 into a zinc pot, and melting to form hot plating solution;

b: and (3) hot dip coating process:

b-1, polishing the steel to be treated by using 400-2000 # abrasive paper to remove an oxide layer on the surface of the steel;

b-2, preparing an alkaline aqueous solution, putting the alkaline aqueous solution into a constant-temperature water bath kettle for heat preservation, and removing oil stains on the surface of the steel by using the prepared alkaline aqueous solution;

b-3, preparing an acidic aqueous solution, and putting the steel into the acidic aqueous solution for acid washing to remove rust on the surface of the steel;

b-4, after the acid cleaning in the step b-3 is finished, taking out the steel, cleaning the steel with deionized water and absolute ethyl alcohol in sequence, and then drying the steel to obtain the steel with a clean surface;

b-5, conveying the steel material subjected to the step b-4 into a reducing atmosphere furnace for reduction treatment, wherein the reducing temperature is not lower than 630 ℃, and the reducing atmosphere is N₂/H₂Mixed atmosphere of H in mixed atmosphere₂The volume content is not less than 10 vol.%, and the surface of the steel is continuously subjected to reduction treatment for 5-10 min;

b-6, after the step b-5 is finished, soaking the steel mining into the molten hot plating solution prepared in the step a for hot dipping, wherein the hot dipping time is 3-15 s;

b-7, after the hot dip coating process of the step b-6 is completed, cooling the steel, and immediately cooling the steel after the steel is extracted from the hot dip coating liquid to obtain an aluminum-rich zinc-based coating formed on the surface of the steel.

Preferably, in the step a-1, a series of intermediate alloy raw materials are prepared, and then the intermediate alloy raw materials are smelted according to the alloy raw material proportion to obtain an alloy melt of the composite system alloy coating; the preparation method of each intermediate alloy raw material comprises the following steps:

(1) preparing an Al-Mg intermediate alloy:

(1-1) adopting an Al block, and then adding a covering agent to prevent the oxidation of a metal material in the melting process;

(1-2) starting to heat up to 700-900 ℃, preserving heat until the Al blocks are completely melted, then starting to gradually add the Mg blocks, stirring, treating with argon, and cooling to room temperature to obtain an Al-Mg intermediate alloy;

(2) preparing an Al-Si intermediate alloy:

(2-1) adopting an Al block, and then adding a covering agent to prevent the oxidation of a metal material in the melting process;

(2-2) starting to heat up to 700-900 ℃, preserving heat until the Al blocks are completely melted, then starting to gradually add the Si blocks, stirring, treating with argon, and cooling in a furnace to room temperature to obtain an Al-Si intermediate alloy;

(3) preparing an Al-Ti intermediate alloy:

(3-1) adopting an Al block, and then adding a covering agent to prevent the oxidation of the metal material in the melting process;

(3-2) starting to heat up to 700-900 ℃, preserving the heat until the Al blocks are completely melted, then gradually adding the Ti blocks, stirring, treating with argon, and cooling in a furnace to room temperature to obtain an Al-Ti intermediate alloy;

(4) preparing an Al-RE intermediate alloy:

(4-1) adopting an Al block, and then adding a covering agent to prevent the oxidation of the metal material in the melting process;

(4-2) heating to 700-900 ℃, preserving heat until the Al blocks are completely melted, then gradually adding RE blocks, stirring, treating with argon, and cooling to room temperature to obtain the Al-RE intermediate alloy, wherein the RE blocks are any one material of La and Ce or a mixture material of La and Ce.

Preferably, in the step a-1, the following steps are adopted in the preparation process of the aluminum-rich zinc-based plating material:

a-1-1, putting the weighed Zn blocks into a crucible, and then adding a covering agent to prevent the oxidation of Zn in the melting process;

a-1-2, putting the crucible into a resistance furnace, starting heating, raising the temperature to 700-900 ℃, keeping the temperature at 700-900 ℃ for at least 2 hours after the Zn blocks are completely melted, then starting adding the Al-Si intermediate alloy prepared in the step (2), keeping the temperature for at least 0.5 hour, and stirring to obtain a Zn-Al-Si alloy melt; then adding the Al-Mg intermediate alloy prepared in the step (1) into the prepared Zn-Al-Si alloy melt, simultaneously adding the Al-Ti intermediate alloy prepared in the step (3) into the Zn-Al-Si alloy melt, so that the Al-Mg intermediate alloy and the Al-Ti intermediate alloy are simultaneously melted in the Zn-Al-Si alloy melt, preserving heat for at least 1h, and stirring to obtain a Zn-Al-Mg-Si-Ti alloy melt; then adding the Al-RE intermediate alloy prepared in the step (4) into the prepared Zn-Al-Mg-Si-Ti alloy melt, preserving the heat for at least 0.5h, and stirring to obtain a Zn-Al-Mg-Si-Ti-RE alloy coating alloy melt; and pouring the alloy melt into a mold for cooling and molding to prepare the aluminum-rich zinc-based plating alloy material.

Preferably, the covering agent comprises the following components in percentage by weight: 50 wt.% of CaCl₂45 wt.% NaCl, 5 wt.% KCl, the covering agent is a solid powder which is uniformly mixed, wherein CaCl is added₂Is subjected to dehydration treatment in advance.

Compared with the prior art, the invention has the following obvious and prominent substantive characteristics and remarkable advantages:

1. according to the invention, Al and Mg elements with different contents are added into the traditional zinc-based plating solution, so that the content ratio of the Al and Mg elements is controlled, and a Fe-Al inhibition layer is further formed to inhibit the brittle fracture phenomenon caused by the penetration of liquid zinc into a steel plate in the hot forming process; meanwhile, a layer of continuous MgAl can be formed on the surface of a molten pool in the immersion plating process by controlling the content ratio of Al and Mg elements₂O₄An oxide to protect the plating solution from further oxidation;

2. the Mg element added in the invention can form Mg with good corrosion resistance with Zn element₂Zn₁₁And MgZn₂Phase, thereby further improving the corrosion resistance of the plating layer;

3. the added Si element can form Mg with good corrosion resistance with Mg element₂Si phase, thereby further improving the corrosion resistance of the plating;

4. the Ti element is added to have good effect of refining the crystal grains of the coating;

5. the addition of RE element can improve the surface quality of the plating layer, reduce the viscosity of the plating solution, improve the fluidity of the plating solution and improve the corrosion resistance of the plating layer.

Drawings

FIG. 1 is a microstructure and energy spectrum scan of a Zn-0.2 wt.% Al-1.0 wt.% Mg coating in accordance with an embodiment of the present invention.

FIG. 2 is a microstructure and energy spectrum scan of a Zn-3.5 wt.% Al-1.8 wt.% Mg coating and a microstructure of the coating in accordance with the second embodiment of the present invention.

FIG. 3 is a graph showing the infiltration suppression mechanism of example one Zn-0.2 wt.% Al-1.0 wt.% Mg and example two Zn-3.5 wt.% Al-1.8 wt.% Mg.

Detailed Description

The above-described scheme is further illustrated below with reference to specific embodiments, which are detailed below:

the first embodiment is as follows:

in this example, an aluminum-rich zinc-based coating material that reduces embrittlement of liquid metals during hot forming is a Zn-Al-Mg alloy having the following composition and weight percent: al: 0.2 percent; mg: 1.0 percent; zn: 98.8 wt.%, the balance being unavoidable impurities.

The preparation method of the aluminum-rich zinc-based coating material for reducing brittleness of liquid metal in the hot forming process comprises the following steps:

the preparation method comprises the following steps of weighing the following elements required by preparing the aluminum-rich zinc-based plating material and the weight percentage of the elements: the preparation method comprises the following steps of preparing an aluminum-rich zinc-based coating material by using the following preparation process steps:

a-1, preparing an aluminum-rich zinc-based plating material:

the adopted covering agent comprises the following components in percentage by weight: 50 wt.% of CaCl₂45 wt.% NaCl, 5 wt.% KCl, the covering agent is a solid powder which is uniformly mixed, wherein CaCl is added₂The method is characterized in that the method comprises the following steps of (1) dehydrating in advance, and preparing an intermediate alloy raw material in advance:

(1) preparing an Al-Mg intermediate alloy:

(1-2) starting to heat up to 700 ℃, preserving heat until the Al blocks are completely melted, then starting to gradually add the Mg blocks, stirring, treating with argon, and cooling to room temperature to obtain an Al-Mg intermediate alloy;

(2) preparing an aluminum-rich zinc-based plating material:

firstly, putting weighed Zn blocks into a crucible according to the element composition and the weight percentage thereof required for preparing the aluminum-rich zinc-based plating material, and then adding a prepared covering agent;

secondly, putting the crucible into a resistance furnace, heating to enable the temperature to reach 700 ℃, keeping the temperature at 700 ℃ for at least 2 hours after the Zn blocks are completely melted, then adding the Al-Mg intermediate alloy prepared in the step (1) according to the element composition and the weight percentage thereof required for preparing the aluminum-rich zinc-based plating material, keeping the temperature for at least 0.5 hour, stirring to obtain a Zn-Al-Mg alloy melt, pouring the Zn-Al-Mg alloy melt into a mold, and cooling and molding to prepare the aluminum-rich zinc-based plating material;

a-2, preparing a hot plating solution:

b: and (3) hot dip coating process:

b-5, conveying the steel material subjected to the step b-4 into a reducing atmosphere furnace for reduction treatment, wherein the reducing temperature is set to 630 ℃, and the reducing atmosphere is N₂/H₂Mixed atmosphere of H in mixed atmosphere₂The volume content of (2) is 10 vol.%, and the surface of the steel is continuously subjected to reduction treatment for 5 min;

b-6, after the step b-5 is finished, soaking the steel mining into the molten Zn-Al-Mg hot plating solution prepared in the step a for hot dipping for 3 s;

b-7, after the hot dip coating process of the step b-6 is completed, cooling the steel, immediately cooling the steel by water at the temperature of 20-30 ℃ after the steel is extracted from the hot plating solution, and thus obtaining the aluminum-rich zinc-based coating formed on the surface of the steel.

Experimental test analysis:

the coated base material piece was taken out of the cooling water to obtain the desired Zn-0.2 wt.% Al-1.0 wt.% Mg rich aluminum based zinc based coating material. The embodiment solves the problems that the liquid zinc permeates into the steel plate matrix to cause the brittle failure of the steel plate in the hot forming process of the high-strength steel aluminum-rich zinc-based coating, provides excellent corrosion resistance and prevents hot-dip liquid from being oxidized. By adding Al and Mg elements into the plating solution, the content ratio of the Al and Mg elements is controlled, and a Fe-Al inhibition layer is formed to inhibit the brittle fracture phenomenon caused by the penetration of liquid zinc into the steel plate in the hot forming process; meanwhile, a layer of continuous MgAl can be formed on the surface of a molten pool in the immersion plating process by controlling the content ratio of Al and Mg elements₂O₄An oxide to protect the plating solution from further oxidation; and Mg is formed by adding Mg element and reacting with Zn element in the plating solution in the hot dipping process₂Zn₁₁And MgZn₂And the corrosion resistance of the plating layer is further improved. The microstructure and energy spectrum scan of the Zn-0.2 wt.% Al-1.0 wt.% Mg aluminum rich zinc-based coating are shown in fig. 1.

The heat treatment method of the aluminum-rich zinc-based coating material comprises the following steps:

in order to obtain the liquid zinc infiltration condition of the coating of the hot-dip plated steel plate under the heat treatment process, the steel plate is placed into a vertical resistance furnace for heat treatment experiment, and the heat treatment temperature is 400-930 ℃. The specific experimental steps are as follows:

step 1: cutting a 22MnB5 steel plate sample into 15mm multiplied by 15mm in a linear mode, and processing a round hole with the diameter of 3mm at a position 3mm away from the edge to be used for tying an experimental sample;

step 2: heating the vertical furnace to 930 ℃, measuring the position corresponding to the temperature in the hearth, and placing a graphite crucible filled with water below the vertical furnace;

and step 3: putting a sample tied with the high-temperature alloy wire into a position corresponding to the temperature in the furnace body from the top of the vertical resistor furnace, and reaching the corresponding temperature according to the corresponding time in the measured temperature curve;

and 4, step 4: and after the heat treatment time is up, opening a furnace door below the vertical furnace, cutting off the alloy wires above, and putting the sample into a crucible for water cooling to finish water quenching.

A method for detecting the infiltration condition of liquid zinc after heat treatment of an aluminum-rich zinc-based plating material in the embodiment comprises the following steps:

step 1: taking each group of samples after heat treatment, and cutting the samples into a size suitable for a sample holder of a scanning electron microscope by using a linear cutting instrument;

step 2: bonding each group of cut samples on a scanning electron microscope sample base by using a conductive adhesive, and observing the cross section of a coating of the heat-treated sample by using a scanning electron microscope (SEM + EDS) equipped with an X-ray energy spectrometer;

and step 3: determining the phase composition of the cutting section of the plating neutralization sample by adopting an X-ray diffractometer (XRD), and scanning at the speed of 8 DEG/min;

and 4, step 4: observing element distribution of a cutting section of a coating and a sample by adopting Electron Probe Microanalysis (EPMA);

and 5: analyzing the surface chemical components of the cut section of the coating neutralization sample layer by adopting a glow discharge emission atomic spectrometer (GDMS);

step 6: and (3) observing the finer texture structure of the cut section of the plating and sample by using a Transmission Electron Microscope (TEM).

A method for detecting the mechanical property of a steel plate after heat treatment of the aluminum-rich zinc-based plating material comprises the following steps:

in order to obtain the cracking behavior of the substrate of the hot-dip coated steel plate in the hot forming process, a Gleeble 3500 thermal simulation testing machine is adopted to carry out a uniaxial thermal tensile test on the steel plate, and the specific experimental steps are as follows:

step 1: heating the heat-treated steel plate to a target temperature of 930 ℃ in a Gleeble 3500 thermal simulation testing machine at a heating rate of 10 ℃/s, preserving the heat for 30s, and then preserving the heat for 0.5s^-1Strain rate of 40% strain;

step 2: after the strain is finished, quenching the steel plate at a cooling speed of over 60 ℃/s by using compressed air so as to obtain a martensite structure with ultrahigh strength;

and step 3: carrying out hot stretching on the steel plate along the rolling direction, breaking the steel plate after the hot stretching is finished, analyzing the breaking morphology of the steel plate, obtaining a crack sample of the steel plate, and identifying and analyzing the morphology and microstructure of the crack in the crack sample;

and 4, step 4: preparing a hot-dip plated steel plate hot tensile sample into a crack sample by adopting a metallographic sample preparation method, and analyzing the appearance and microstructure of the crack after grinding and polishing the sample;

and 5: observing the morphology and the structure of the cracks by using a scanning electron microscope (SEM + EDS) equipped with an X-ray energy spectrometer;

step 6: observing the element distribution of the coating and the substrate at the cracks by adopting Electron Probe Microanalysis (EPMA);

and 7: cutting and analyzing the microstructure of the interface between the coating and the substrate at the crack by using a double-beam Focused Ion Beam (FIB) and a field emission transmission electron microscope (FE-TEM);

and 8: and analyzing the elongation and tensile strength of the steel plate coated with the aluminum-rich zinc-based plating layer after hot dip plating by combining a stress-strain curve provided on a Gleeble 3500 thermal simulation testing machine.

The zinc-based coating rich in aluminum is plated on a hot stamping steel plate, so that the problems of decarburization and oxidation peeling of the surfaces of some steel plates in the hot stamping forming process can be solved, and the corrosion resistance of the steel plate can be improved. In the embodiment, a layer of continuous MgAl can be formed on the surface of a molten pool in the immersion plating process by adjusting the content of Al in the plating solution and controlling the proportional relation between Al and Mg elements₂O₄Oxide compoundTo protect the plating solution from further oxidation; meanwhile, an Fe-Al alloy layer can be formed in the hot dip coating process, and because the Fe-Al alloy layer can inhibit the contact of liquid zinc melted by high temperature and a steel plate matrix in the hot forming process, the brittle failure of the steel plate matrix can be avoided in the hot forming process; meanwhile, the coating has good corrosion resistance.

Example two:

this embodiment is substantially the same as the first embodiment, and is characterized in that:

in this example, an aluminum-rich zinc-based coating material that reduces embrittlement of liquid metals during hot forming is a Zn-Al-Mg alloy having the following composition and weight percent: al: 3.5 percent; mg: 1.8 percent; the balance of Zn and inevitable impurities.

a-1, preparing an aluminum-rich zinc-based plating material:

(1) preparing an Al-Mg intermediate alloy:

(2) preparing an aluminum-rich zinc-based plating material:

a-2, preparing a hot plating solution:

b: and (3) hot dip coating process:

Experimental test analysis:

the coated base material piece was taken out of the cooling water to obtain the desired Zn-3.5 wt.% Al-1.8 wt.% Mg rich aluminum based zinc based coating material. The embodiment solves the problems that the liquid zinc permeates into the steel plate matrix to cause the brittle failure of the steel plate in the hot forming process of the high-strength steel aluminum-rich zinc-based coating and provides excellent corrosion resistance. By adding Al and Mg elements into the plating solution, the content ratio of the Al and Mg elements is controlled, and a Fe-Al inhibition layer is formed to inhibit the brittle fracture phenomenon caused by the penetration of liquid zinc into the steel plate in the hot forming process; meanwhile, a layer of continuous MgAl can be formed on the surface of a molten pool in the immersion plating process by controlling the content ratio of Al and Mg elements₂O₄An oxide to protect the plating solution from further oxidation; and Mg is formed by adding Mg element and reacting with Zn element in the plating solution in the hot dipping process₂Zn₁₁And MgZn₂And the corrosion resistance of the plating layer is further improved. The microstructure and energy spectrum scanning pattern and the coating structure morphology pattern of the Zn-3.5 wt.% Al-1.8 wt.% Mg aluminum-rich zinc-based coating are shown in figure 2. The Mg element added in the embodiment can form Mg with good corrosion resistance with Zn element₂Zn₁₁And MgZn₂Thereby further improving the corrosion resistance of the plating layer.

The zinc-based coating rich in aluminum is plated on a hot stamping steel plate, so that the problems of decarburization and oxidation peeling of the surfaces of some steel plates in the hot stamping forming process can be solved, and the corrosion resistance of the steel plate can be improved. In the embodiment, the proportional relation between Al and Mg elements is controlled by adjusting the content of Al in the plating solution aiming at the plating layerNot only can form a layer of continuous MgAl on the surface of a molten pool in the immersion plating process₂O₄An oxide to protect the plating solution from further oxidation; meanwhile, an Fe-Al alloy layer can be formed in the hot dip coating process, and because the Fe-Al alloy layer can inhibit the contact of liquid zinc melted by high temperature and a steel plate matrix in the hot forming process, the brittle failure of the steel plate matrix can be avoided in the hot forming process; meanwhile, the coating has good corrosion resistance. The Mg element added in the embodiment can form Mg with good corrosion resistance with Zn element₂Zn₁₁And MgZn₂Thereby further improving the corrosion resistance of the plating layer. Fig. 3 is a diagram illustrating an infiltration inhibition mechanism of Zn-0.2 wt.% Al-1.0 wt.% Mg and Zn-3.5 wt.% Al-1.8 wt.% Mg in example 1 according to the present invention, which is obtained by preparing a 22MnB5 steel sheet with coating materials having different element contents, and testing the coating materials through a hot dip coating test, an austenitizing treatment, a texture observation of the coating and the steel sheet, and a hot tensile test of the steel sheet, respectively, to prove that the zinc-based coating materials in the example are effective in solving the problems of embrittlement of liquid metal during hot press forming, corrosion resistance of the coating, and oxidation of the coating solution during hot dip coating of a high-strength steel sheet coated with an Al-rich zinc-based coating.

Example three:

this embodiment is substantially the same as the previous embodiment, and is characterized in that:

a-1, preparing an aluminum-rich zinc-based plating material:

(1) preparing an Al-Mg intermediate alloy:

(1-2) starting to heat up to 900 ℃, preserving heat until the Al blocks are completely melted, then starting to gradually add the Mg blocks, stirring, treating with argon, and cooling to room temperature to obtain an Al-Mg intermediate alloy;

(2) preparing an aluminum-rich zinc-based plating material:

a-2, preparing a hot plating solution:

b: and (3) hot dip coating process:

b-5, conveying the steel material subjected to the step b-4 into a reducing atmosphere furnace for reduction treatment, wherein the reducing temperature is set to 630 ℃, and the reducing atmosphere is N₂/H₂Mixed atmosphere of H in mixed atmosphere₂The volume content of (2) is 10 vol.%, and the surface of the steel is continuously subjected to reduction treatment for 10 min;

b-6, after the step b-5 is finished, soaking the steel mining into the molten Zn-Al-Mg hot plating solution prepared in the step a for hot dipping for 15 s;

The zinc-based coating rich in aluminum is plated on a hot stamping steel plate, so that the problems of decarburization and oxidation peeling of the surfaces of some steel plates in the hot stamping forming process can be solved, and the corrosion resistance of the steel plate can be improved. In the embodiment, a layer of continuous MgAl can be formed on the surface of a molten pool in the immersion plating process by adjusting the content of Al in the plating solution and controlling the proportional relation between Al and Mg elements₂O₄An oxide to protect the plating solution from further oxidation; meanwhile, an Fe-Al alloy layer can be formed in the hot dip coating process, and because the Fe-Al alloy layer can inhibit the contact of liquid zinc melted by high temperature and a steel plate matrix in the hot forming process, the brittle failure of the steel plate matrix can be avoided in the hot forming process; meanwhile, the coating has good corrosion resistance. The embodiment can add Mg elementForm Mg with good corrosion resistance with Zn element₂Zn₁₁And MgZn₂Thereby further improving the corrosion resistance of the plating layer.

Example four:

in this example, an aluminum-rich zinc-based coating material that reduces embrittlement of liquid metals during hot forming is a Zn-Al-Mg alloy having the following composition and weight percent: al: 5.0 percent; mg: 2.5 percent; the balance of Zn and inevitable impurities.

a-1, preparing an aluminum-rich zinc-based plating material:

(1) preparing an Al-Mg intermediate alloy:

(2) preparing an aluminum-rich zinc-based plating material:

a-2, preparing a hot plating solution:

b: and (3) hot dip coating process:

The zinc-based coating rich in aluminum is plated on a hot stamping steel plate, so that the problems of decarburization and oxidation peeling of the surfaces of some steel plates in the hot stamping forming process can be solved, and the corrosion resistance of the steel plate can be improved. In the embodiment, a layer of continuous MgAl can be formed on the surface of a molten pool in the immersion plating process by adjusting the content of Al in the plating solution and controlling the proportional relation between Al and Mg elements₂O₄An oxide to protect the plating solution from further oxidation; meanwhile, an Fe-Al alloy layer can be formed in the hot dip coating process, and because the Fe-Al alloy layer can inhibit the contact of liquid zinc melted by high temperature and a steel plate matrix in the hot forming process, the brittle failure of the steel plate matrix can be avoided in the hot forming process; meanwhile, the coating has good corrosion resistance. The Mg element added in the embodiment can form Mg with good corrosion resistance with Zn element₂Zn₁₁And MgZn₂Thereby further improving the corrosion resistance of the plating layer.

Example five:

in this example, an aluminum-rich zinc-based coating material that reduces embrittlement of liquid metals during hot forming is a Zn-Al-Mg alloy having the following composition and weight percent: al: 1.4 percent; mg: 1.0 percent; the balance of Zn and inevitable impurities.

a-1, preparing an aluminum-rich zinc-based plating material:

(1) preparing an Al-Mg intermediate alloy:

(2) preparing an aluminum-rich zinc-based plating material:

a-2, preparing a hot plating solution:

b: and (3) hot dip coating process:

In the embodiment, the zinc-based plating layer material with the functions of inhibiting liquid metal embrittlement and high corrosion resistance is prepared by adjusting the content of Al and the content of Mg in the plating solution as main parts and controlling the content ratio of Al and Mg elements. In the embodiment, a layer of continuous MgAl can be formed on the surface of a molten pool in the immersion plating process by adjusting the content of Al in the plating solution and controlling the proportional relation between Al and Mg elements₂O₄An oxide to protect the plating solution from further oxidation; meanwhile, an Fe-Al alloy layer can be formed in the hot dip coating process, and because the Fe-Al alloy layer can inhibit the contact of liquid zinc melted by high temperature and a steel plate matrix in the hot forming process, the brittle failure of the steel plate matrix can be avoided in the hot forming process; meanwhile, the coating has good corrosion resistance. The Mg element added in the embodiment can form Mg with good corrosion resistance with Zn element₂Zn₁₁And MgZn₂Thereby further improving the corrosion resistance of the plating layer.

Example six:

in this example, an aluminum-rich zinc-based coating material that reduces embrittlement of liquid metals during hot forming is a Zn-Al-Mg alloy having the following composition and weight percent: al: 2.1 percent; mg: 1.0 percent; the balance of Zn and inevitable impurities.

a-1, preparing an aluminum-rich zinc-based plating material:

(1) preparing an Al-Mg intermediate alloy:

(2) preparing an aluminum-rich zinc-based plating material:

a-2, preparing a hot plating solution:

b: and (3) hot dip coating process:

b-6, after the step b-5 is finished, soaking the steel material into the molten Zn-Al-Mg hot plating solution prepared in the step a for hot dipping for 3 s;

Example seven:

in this example, an aluminum-rich zinc-based coating material that reduces embrittlement of liquid metals during hot forming is a Zn-Al-Mg-Si alloy having the following composition and weight percent: al: 3.5 percent; mg: 1.8 percent; si: 2.0 percent; the balance of Zn and inevitable impurities.

the preparation method comprises the following steps of weighing the following elements required by preparing the aluminum-rich zinc-based plating material and the weight percentage of the elements: the content of Al was 3.5 wt.%, the content of Mg was 1.8 wt.%, and the ratio of Si: 2.0 percent; the balance of Zn and inevitable impurities including Zn blocks, Al blocks, Mg blocks and Si blocks, and then preparing the aluminum-rich zinc-based plating material by adopting the following preparation process steps:

a-1, preparing an aluminum-rich zinc-based plating material:

(1) preparing an Al-Mg intermediate alloy:

(2) preparing an Al-Si intermediate alloy:

(3) preparing an aluminum-rich zinc-based plating material:

secondly, putting the crucible into a resistance furnace, starting heating to enable the temperature to reach 700 ℃, keeping the temperature at 700-900 ℃ for at least 2h after the Zn blocks are completely melted, then starting adding the Al-Si intermediate alloy prepared in the step (2), keeping the temperature for at least 0.5h, and stirring to obtain a Zn-Al-Si alloy melt; and (2) adding the Al-Mg intermediate alloy prepared in the step (1) into the prepared Zn-Al-Si alloy melt, melting the Al-Mg intermediate alloy in the Zn-Al-Si alloy melt, preserving heat for at least 1h, stirring to obtain a Zn-Al-Mg-Si alloy melt, pouring the alloy melt into a mold, cooling and molding to obtain the aluminum-rich zinc-based coating alloy material.

a-2, preparing a hot plating solution:

putting the aluminum-rich zinc-based coating material prepared in the step a-1 into a zinc pot, and melting to form a Zn-Al-Mg-Si hot plating solution;

b: and (3) hot dip coating process:

b-6, after the step b-5 is finished, soaking the steel mining into the molten Zn-Al-Mg-Si hot plating solution prepared in the step a for hot dipping for 3 s;

In the embodiment, the zinc-based plating material which inhibits the embrittlement of the liquid metal and has high corrosion resistance is prepared by adjusting the content of Al and the content of Mg in the plating solution as main components and controlling the content ratio of Al and Mg elements. In the embodiment, a layer of continuous MgAl can be formed on the surface of a molten pool in the immersion plating process by adjusting the content of Al in the plating solution and controlling the proportional relation between Al and Mg elements₂O₄An oxide to protect the plating solution from further oxidation; meanwhile, an Fe-Al alloy layer can be formed in the hot dip coating process, and because the Fe-Al alloy layer can inhibit the contact of liquid zinc melted by high temperature and a steel plate matrix in the hot forming process, the brittle failure of the steel plate matrix can be avoided in the hot forming process; meanwhile, the coating has good corrosion resistance. The Mg element added in the embodiment can form Mg with good corrosion resistance with Zn element₂Zn₁₁And MgZn₂Phase, thereby further improving the corrosion resistance of the plating layer; the addition of Si element can form Mg with good corrosion resistance with Mg element₂Si phase, thereby further improvingCorrosion resistance of the plating layer.

Example eight:

in this example, an aluminum-rich zinc-based coating material that reduces embrittlement of liquid metals during hot forming is a Zn-Al-Mg-Ti alloy having the following composition and weight percent: al: 3.5 percent; mg: 1.8 percent; ti: 1.0 percent; the balance of Zn and inevitable impurities.

the preparation method comprises the following steps of weighing the following elements required by preparing the aluminum-rich zinc-based plating material and the weight percentage of the elements: the content of Al was 3.5 wt.%, the content of Mg was 1.8 wt.%, and the ratio of Ti: 1.0 percent; the balance of Zn and inevitable impurities including Zn blocks, Al blocks, Mg blocks and Ti blocks, and then preparing the aluminum-rich zinc-based coating material by adopting the following preparation process steps:

a-1, preparing an aluminum-rich zinc-based plating material:

(1) preparing an Al-Mg intermediate alloy:

(2) preparing an Al-Ti intermediate alloy:

(2-2) starting to heat up to 700-900 ℃, preserving the heat until the Al blocks are completely melted, then gradually adding the Ti blocks, stirring, treating with argon, and cooling in a furnace to room temperature to obtain an Al-Ti intermediate alloy;

(3) preparing an aluminum-rich zinc-based plating material:

secondly, putting the crucible into a resistance furnace, starting heating to enable the temperature to reach 700 ℃, and obtaining a Zn melt after the Zn blocks are completely melted; then adding the Al-Mg intermediate alloy prepared in the step (1) into the prepared Zn melt, simultaneously adding the Al-Ti intermediate alloy prepared in the step (2) into the Zn melt, melting the Al-Mg intermediate alloy and the Al-Ti intermediate alloy in the Zn-melt at the same time, preserving heat for at least 1h, stirring to obtain a Zn-Al-Mg-Ti alloy melt, pouring the alloy melt into a mold, and cooling and molding to prepare an aluminum-rich zinc-based coating alloy material;

a-2, preparing a hot plating solution:

putting the aluminum-rich zinc-based coating material prepared in the step a-1 into a zinc pot, and melting to form a Zn-Al-Mg-Ti hot plating solution;

b: and (3) hot dip coating process:

b-5, sending the steel material which is subjected to the step b-4 into a reducing atmosphere furnace for reduction treatment, wherein the reducing temperature is set asAt 630 ℃ in a reducing atmosphere of N₂/H₂Mixed atmosphere of H in mixed atmosphere₂The volume content of (2) is 10 vol.%, and the surface of the steel is continuously subjected to reduction treatment for 5 min;

b-6, after the step b-5 is finished, soaking the steel mining into the molten Zn-Al-Mg-Ti hot plating solution prepared in the step a for hot dipping for 3 s;

In the embodiment, the zinc-based plating material which inhibits the embrittlement of the liquid metal and has high corrosion resistance is prepared by adjusting the content of Al and the content of Mg in the plating solution as main components and controlling the content ratio of Al and Mg elements. In the embodiment, a layer of continuous MgAl can be formed on the surface of a molten pool in the immersion plating process by adjusting the content of Al in the plating solution and controlling the proportional relation between Al and Mg elements₂O₄An oxide to protect the plating solution from further oxidation; meanwhile, an Fe-Al alloy layer can be formed in the hot dip coating process, and because the Fe-Al alloy layer can inhibit the contact of liquid zinc melted by high temperature and a steel plate matrix in the hot forming process, the brittle failure of the steel plate matrix can be avoided in the hot forming process; meanwhile, the coating has good corrosion resistance. The Mg element added in the embodiment can form Mg with good corrosion resistance with Zn element₂Zn₁₁And MgZn₂Phase, thereby further improving the corrosion resistance of the plating layer; the addition of Ti element has good effect of refining the crystal grains of the plating layer.

Example nine:

in this example, an aluminum-rich zinc-based coating material that reduces embrittlement of liquid metals during hot forming is a Zn-Al-Mg-Si-Ti alloy having the following composition and weight percent: al: 3.5 percent; mg: 1.8 percent; si: 2.0 percent; ti: 1.0 percent; the balance of Zn and inevitable impurities.

the preparation method comprises the following steps of weighing the following elements required by preparing the aluminum-rich zinc-based plating material and the weight percentage of the elements: the content of Al was 3.5 wt.%, the content of Mg was 1.8 wt.%, and the ratio of Si: 2.0 percent; ti: 1.0 percent; the balance of Zn and inevitable impurities, including Zn blocks, Al blocks, Mg blocks, Si blocks and Ti blocks, and then preparing the aluminum-rich zinc-based coating material by adopting the following preparation process steps:

a-1, preparing an aluminum-rich zinc-based plating material:

(1) preparing an Al-Mg intermediate alloy:

(2) preparing an Al-Si intermediate alloy:

(3) preparing an Al-Ti intermediate alloy:

(4) preparing an aluminum-rich zinc-based plating material:

secondly, putting the crucible into a resistance furnace, starting heating to enable the temperature to reach 700 ℃, keeping the temperature at 700 ℃ for at least 2 hours after the Zn blocks are completely melted, then starting to add the Al-Si intermediate alloy prepared in the step (2), keeping the temperature for at least 0.5 hour, and stirring to obtain a Zn-Al-Si alloy melt; then adding the Al-Mg intermediate alloy prepared in the step (1) into the prepared Zn-Al-Si alloy melt, simultaneously adding the Al-Ti intermediate alloy prepared in the step (3) into the Zn-Al-Si alloy melt, melting the Al-Mg intermediate alloy and the Al-Ti intermediate alloy in the Zn-Al-Si alloy melt at the same time, preserving heat for at least 1h, stirring to obtain a Zn-Al-Mg-Si-Ti alloy melt, pouring the alloy melt into a mold, cooling and molding to obtain the aluminum-rich zinc-based plating alloy material;

a-2, preparing a hot plating solution:

putting the aluminum-rich zinc-based coating material prepared in the step a-1 into a zinc pot, and melting to form a Zn-Al-Mg-Si-Ti hot plating solution;

b: and (3) hot dip coating process:

b-6, after the step b-5 is finished, soaking the steel into the molten Zn-Al-Mg-Si hot plating solution prepared in the step a for hot dipping for 3 s;

In the embodiment, the zinc-based plating material which inhibits the embrittlement of the liquid metal and has high corrosion resistance is prepared by adjusting the content of Al and the content of Mg in the plating solution as main components and controlling the content ratio of the Al and the Mg elements. In the embodiment, the proportion relation between Al and Mg elements is controlled by adjusting the content of Al in the plating solution aiming at the plating layer, so that the plating can be carried out in the immersion plating processThe surface of the molten pool can form a continuous MgAl layer₂O₄An oxide to protect the plating solution from further oxidation; meanwhile, an Fe-Al alloy layer can be formed in the hot dip coating process, and because the Fe-Al alloy layer can inhibit the contact of liquid zinc melted by high temperature and a steel plate matrix in the hot forming process, the brittle failure of the steel plate matrix can be avoided in the hot forming process; meanwhile, the coating has good corrosion resistance. The Mg element added in the embodiment can form Mg with good corrosion resistance with Zn element₂Zn₁₁And MgZn₂Phase, thereby further improving the corrosion resistance of the plating layer; the addition of Si element can form Mg with good corrosion resistance with Mg element₂Si phase, thereby further improving the corrosion resistance of the plating; the addition of Ti element has good effect of refining the crystal grains of the plating layer.

Example ten:

in this example, an aluminum-rich zinc-based coating material that reduces embrittlement of liquid metals during hot forming is a Zn-Al-Mg-La alloy having the following composition and weight percent: al: 3.5 percent; mg: 1.8 percent; la: 3.0 percent; the balance of Zn and inevitable impurities.

the preparation method comprises the following steps of weighing the following elements required by preparing the aluminum-rich zinc-based plating material and the weight percentage of the elements: the content of Al was 3.5 wt.%, the content of Mg was 1.8 wt.%, and the content of La was 3.0 wt.%; the balance of Zn and inevitable impurities including Zn blocks, Al blocks, Mg blocks and La blocks, and then preparing the aluminum-rich zinc-based plating material by adopting the following preparation process steps:

a-1, preparing an aluminum-rich zinc-based plating material:

the adopted covering agent comprises the following components in percentage by weight: 50 wt.% of CaCl₂45 wt.% NaCl, 5 wt.% KCl, the covering agent is a solid mixed uniformlyPowder in the form of CaCl₂The method is characterized in that the method comprises the following steps of (1) dehydrating in advance, and preparing an intermediate alloy raw material in advance:

(1) preparing an Al-Mg intermediate alloy:

(2) preparing an Al-La intermediate alloy:

(2-2) starting to heat up to 700-900 ℃, preserving heat until the Al blocks are completely melted, then gradually adding the La blocks, stirring, treating with argon, and cooling in a furnace to room temperature to obtain an Al-La intermediate alloy;

(3) preparing an aluminum-rich zinc-based plating material:

secondly, putting the crucible into a resistance furnace, heating to enable the temperature to reach 700 ℃, keeping the temperature at 700 ℃ for at least 2 hours after the Zn blocks are completely melted, adding the Al-Mg intermediate alloy prepared in the step (1) into the prepared Zn melt according to the element composition and the weight percentage thereof required for preparing the aluminum-rich zinc-based plating material, keeping the temperature for at least 1 hour, and stirring to obtain a Zn-Al-Mg alloy melt; then adding the Al-La intermediate alloy prepared in the step (2) into the prepared Zn-Al-Mg alloy melt, preserving the heat for at least 0.5h, and stirring to obtain a Zn-Al-Mg-La alloy coating alloy melt; pouring the alloy melt into a mould for cooling and forming to prepare the alloy material of the zinc-based plating layer rich in aluminum;

a-2, preparing a hot plating solution:

putting the aluminum-rich zinc-based plating material prepared in the step a-1 into a zinc pot, and melting to form a Zn-Al-Mg-La hot plating solution;

b: and (3) hot dip coating process:

b-6, after the step b-5 is finished, soaking the steel into the molten Zn-Al-Mg-La hot plating solution prepared in the step a for hot dipping for 3 s;

In the embodiment, the Zn-Al-Mg-La alloy coating is prepared by adjusting the Al content and the Mg content in the coating solution mainly and controlling the content proportion between Al and Mg elements, the coating materials with different element contents are prepared for a 22MnB5 steel plate, and the preparation of the coating, hot dipping experiment, austenitizing treatment, observation of the structure of the coating and the steel plate and detection of the hot stretching experiment of the steel plate respectively prove that the zinc-based coating material effectively solves the problem that the high-strength steel plate coated with the aluminum-rich zinc-based coating is formed by hot stampingThe problem of brittleness of liquid metal in the process, the corrosion resistance of a plating layer and the problem of oxidation of plating solution in the hot dipping process. In the embodiment, a layer of continuous MgAl can be formed on the surface of a molten pool in the immersion plating process by adjusting the content of Al in the plating solution and controlling the proportional relation between Al and Mg elements₂O₄An oxide to protect the plating solution from further oxidation; meanwhile, an Fe-Al alloy layer can be formed in the hot dip coating process, and because the Fe-Al alloy layer can inhibit the contact of liquid zinc melted by high temperature and a steel plate matrix in the hot forming process, the brittle failure of the steel plate matrix can be avoided in the hot forming process; meanwhile, the coating has good corrosion resistance. The Mg element added in the embodiment can form Mg with good corrosion resistance with Zn element₂Zn₁₁And MgZn₂Phase, thereby further improving the corrosion resistance of the plating layer; the La element is added, so that the surface quality of the plating layer can be improved, the viscosity of the plating solution is reduced, the fluidity of the plating solution is improved, and the corrosion resistance of the plating layer can be improved. In the embodiment, the same amount of Ce element can be used to replace La element, or half of La element used to replace Ce element is used according to mass calculation, which can also improve the surface quality of the plating layer, reduce the viscosity of the plating solution, improve the fluidity of the plating solution, and improve the corrosion resistance of the plating layer. According to the above examples, this example enables the preparation of a Zn-Al-Mg-Si-La alloy, a Zn-Al-Mg-Ti-La alloy or a Zn-Al-Mg-Si-Ti-La alloy by adding La, or preparing Zn-Al-Mg-Si-Ce alloy, Zn-Al-Mg-Ti-Ce alloy or Zn-Al-Mg-Si-Ti-Ce alloy, or preparing a Zn-Al-Mg-Si-La-Ce alloy, a Zn-Al-Mg-Ti-La-Ce alloy or a Zn-Al-Mg-Si-Ti-La-Ce alloy, and also can realize the preparation of the zinc-based coating material which can inhibit the liquid metal from causing brittleness and has high corrosion resistance.

The embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made according to the purpose of the invention, and any changes, modifications, substitutions, combinations or simplifications made according to the spirit and principle of the technical solution of the present invention should be replaced with equivalents as long as the object of the present invention is met, and the technical principle and the inventive concept of the present invention are not departed from the scope of the present invention.

Claims

1. a kind of aluminum-rich zinc-based coating material that reduces liquid metal brittleness in hot forming process, is characterized in that, it is Zn-Al-Mg alloy, Zn-Al-Mg-Si alloy, Zn-Al-Mg- Ti alloy, Zn-Al-Mg-Si-Ti alloy, Zn-Al-Mg-RE alloy, Zn-Al-Mg-Si-RE alloy, Zn-Al-Mg-Ti-RE alloy or Zn-Al-Mg alloy -Si-Ti-RE alloy with the following composition and weight percentage: Al: 0.2-5.0%; Mg≤2.5%; Si: 0-2.0%; Ti: 0-1.0%; RE: 0-3.0%, the rest is Zn and inevitable impurities; wherein RE is any one element or a combination of two elements in La and Ce.

2. The aluminum-rich zinc-based coating material for reducing liquid metal embrittlement during hot forming according to claim 1, characterized in that: the specific composition and weight percentage are as follows: Zn: 90.0-95.0%; Al: 0.2-5.0% ; Mg≤2.5%; Si: 0-2.0%; Ti: 0-1.0%; RE: 0-3.0%, and the rest are inevitable impurities.

3. The aluminum-rich zinc-based coating material for reducing liquid metal embrittlement during hot forming according to claim 1, characterized in that: the specific composition and weight percentage are as follows: Al: 0.2-1.4%; Mg≤2.5%; Si : 0-2.0%; Ti: 0-1.0%; RE: 0-3.0%, and the rest are Zn and inevitable impurities.

4. The aluminum-rich zinc-based coating material for reducing liquid metal embrittlement during hot forming according to claim 1, characterized in that: the specific composition and weight percentage are as follows: Al: 2.1-5.0%; Mg≤2.5%; Si : 0-2.0%; Ti: 0-1.0%; RE: 0-3.0%, and the rest are Zn and inevitable impurities.

5. The aluminum-rich zinc-based coating material for reducing brittleness caused by liquid metal in the hot forming process according to claim 1 is characterized in that: in the formation of the aluminum-rich zinc-based coating on the steel surface, an Fe-Al inhibitory layer and a continuous layer are formed. MgAl ₂ O ₄ oxide layer.

6. The aluminum-rich zinc-based coating material for reducing the brittleness caused by liquid metal in the hot forming process according to claim 1 is characterized in that: in the aluminum-rich zinc-based coating formed on the steel surface, Mg element and Zn element are formed to form Mg ₂ Zn ₁₁ and MgZn ₂ phase; or Si element and Mg element form Mg ₂ Si phase.

7. a preparation method of the aluminum-rich zinc-based coating material that reduces the brittleness caused by liquid metal in the hot forming process according to claim 1, is characterized in that, comprises the steps:

a. Preparation process of hot-dip bath:

a-1. Preparation of aluminum-rich zinc-based coating materials:

The raw materials are weighed and prepared according to the following element compositions and their weight percentages required for the preparation of aluminum-rich zinc-based coating materials. The content of Mg is controlled between 0-2.5wt.%, the content of Si is controlled between 0-2wt.%, the content of Ti is controlled between 0-1wt.%, and the content of RE element is controlled between 0-3wt.%. %, the balance is Zn and inevitable impurities;

Under the protection of the covering agent, in the smelting furnace, according to the ratio of the alloy raw materials, the alloy raw materials are smelted to obtain the alloy melt of the composite alloy coating, which is poured into the mold to cool and form to make the aluminum-rich zinc-based coating material. spare;

a-2. Preparation of hot-dip bath:

Putting the aluminum-rich zinc-based coating material prepared in the step a-1 into a zinc pot, and melting to form a hot-dip bath;

b: Hot dip coating process:

b-1. Grind the steel to be treated with 400-2000# sandpaper to remove the oxide layer on the surface of the steel;

b-2. Prepare an alkaline aqueous solution, and put the alkaline aqueous solution into a constant temperature water bath to keep warm, and use the prepared alkaline aqueous solution to remove the oil stain on the surface of the steel;

b-3. Prepare an acidic aqueous solution, put the steel into the acidic aqueous solution, and carry out pickling to remove the rust on the surface of the steel;

b-4. After completing the pickling in step b-3, take out the steel, wash with deionized water and dehydrated ethanol successively, and blow dry to obtain steel with clean surface;

b-5. The steel material that has completed the step b-4 is sent to the reduction atmosphere furnace for reduction treatment, the reduction temperature is set to not lower than 630°C, the reduction atmosphere is an N ₂ /H ₂ mixed atmosphere, and in the mixed atmosphere H The volume content of ₂ is not less than 10vol.%, and the surface of the steel is continuously reduced for 5-10min;

b-6. After completing the step b-5, the steel is immersed in the molten hot-dip bath prepared in the step a, and hot-dip plating is performed, and the hot-dip plating time is 3-15s;

b-7. After completing the hot-dip plating process in step b-6, the steel is cooled, and the steel is removed from the hot-dip bath, and then water-cooled immediately to obtain an aluminum-rich zinc-based coating formed on the surface of the steel. .

8. The method for preparing an aluminum-rich zinc-based coating material that reduces brittleness caused by liquid metal during hot forming according to claim 7, wherein in the step a-1, a series of master alloy raw materials are prepared, and then The master alloy raw materials are smelted according to the ratio of the alloy raw materials to obtain the alloy melt of the composite alloy coating; the steps of the preparation method of each master alloy raw material are as follows:

(1) Preparation of Al-Mg master alloy:

(1-1) Using Al block, then adding a covering agent to prevent oxidation of the metal material in the melting process;

(1-2) Start heating up to 700-900°C, keep the temperature until the Al blocks are completely melted, then start to gradually add Mg blocks, and stir, and after being treated with argon gas, the furnace is cooled to room temperature to obtain an Al-Mg master alloy ;

(2) Preparation of Al-Si master alloy:

(2-1) Using Al block, then adding a covering agent to prevent oxidation of the metal material in the melting process;

(2-2) Begin to heat up until 700-900°C, keep the temperature until the Al blocks are completely melted, then start to gradually add Si blocks, and stir, and then after being treated with argon gas, the furnace is cooled to room temperature to obtain Al-Si master alloy ;

(3) Preparation of Al-Ti master alloy:

(3-1) Using Al block, then adding a covering agent to prevent oxidation of the metal material in the melting process;

(3-2) Start to heat up until 700-900°C, keep the temperature until the Al blocks are completely melted, then start to gradually add Ti blocks, and stir, and then after the treatment of argon, the furnace is cooled to room temperature to obtain Al-Ti master alloy ;

(4) Preparation of Al-RE master alloy:

(4-1) Using Al block, then adding a covering agent to prevent oxidation of the metal material in the melting process;

(4-2) Begin to heat up until 700-900°C, keep the temperature until the Al blocks are completely melted, then start to gradually add RE blocks, add stirring, and then after treatment with argon, the furnace is cooled to room temperature to obtain Al-RE master alloy , where the RE block is any one of La and Ce or a mixture of La and Ce.

9 . The method for preparing an aluminum-rich zinc-based coating material that reduces brittleness caused by liquid metal during hot forming according to claim 8 , wherein in the step a-1, the aluminum-rich zinc-based coating material is In the preparation process, the following steps are used:

a-1-1. Put the weighed Zn block into the crucible, and then add a covering agent to prevent the oxidation of Zn during the melting process;

a-1-2. Put the crucible into the resistance furnace, start heating, make the temperature rise to 700～900℃, wait for all the Zn blocks to melt, keep at 700～900℃ for at least 2h, and then start adding in the step ( 2) the Al-Si master alloy prepared in, then heat preservation for at least 0.5h and stirring to obtain a Zn-Al-Si alloy melt;

Then, the Al-Mg master alloy prepared in the step (1) is added to the prepared Zn-Al-Si alloy melt, and the Al-Mg master alloy prepared in the step (3) is also added to the Zn-Al-Si alloy melt. The Al-Ti master alloy is obtained by melting the Al-Mg master alloy and the Al-Ti master alloy in the Zn-Al-Si alloy melt at the same time. Ti alloy melt;

Then, the Al-RE master alloy prepared in step (4) is added to the prepared Zn-Al-Mg-Si-Ti alloy melt, kept for at least 0.5 h, and stirred to obtain Zn-Al-Mg-Si -Ti-RE alloy coating alloy melt; the alloy melt is poured into a mold to cool and form to make an aluminum-rich zinc-based coating alloy material.

10. The preparation method of the aluminum-rich zinc-based coating material that reduces the brittleness caused by liquid metal in the hot forming process according to any one of claims 7-9, wherein the composition ratio of the covering agent is: 50wt. % CaCl ₂ , 45 wt. % NaCl, 5 wt. % KCl, the covering agent is a uniformly mixed solid powder, wherein the CaCl ₂ has been dehydrated in advance.