CN115261850B - Laser cladding material for non-oxidation heat treatment furnace and manufacturing method - Google Patents

Abstract

The invention relates to the technical field of laser cladding, in particular to a laser cladding metal material for a furnace roller of an oxidation-free heat treatment furnace and a manufacturing method thereof. The invention provides a laser cladding material of an oxidation-free heat treatment furnace, which comprises the following components in percentage by mass with the balance of ：C：0.03%-0.1%,Si：1.9%-2.8%,Mn：0.3%-0.8%,Cr：12%-15.5%,W：2%-4.5%,Mo：18.5%-25%,Ni：10%-15%,Fe：10.5%-18.8%,Co. And the material is applied to a preparation process of a laser cladding material cladding furnace roller of an oxidation-free heat treatment furnace. The material has good thermal shock resistance, good wear resistance, good anti-nodulation performance and good stability; the process solves the problem of nodulation of the furnace roller.

Description

Laser cladding material for non-oxidation heat treatment furnace and manufacturing method

Technical Field

The invention relates to the technical field of laser cladding, in particular to a laser cladding metal material for a furnace roller of an oxidation-free heat treatment furnace and a manufacturing method thereof.

Background

The roller hearth heat treatment furnace is core equipment of a steel rolling heat treatment process, and is used for realizing a flexible heat treatment system and meeting the heat treatment requirements of different steel grades. The roller hearth type heat treatment furnace has the advantages of good heat treatment quality, high yield, flexible temperature regulation, easy realization of mechanical and automatic operation, production cost reduction and the like. The non-oxidation (radiant tube) heat treatment furnace is an important form of a roller hearth type heating furnace, nitrogen with high purity is introduced into the furnace as protective gas, oxidation and decarburization of steel plates in the furnace are reduced to the greatest extent, the furnace is used for normalizing, quenching and tempering heat treatment of the steel plates, and the newly built and reconstructed high-quality production line adopts the non-oxidation roller hearth type heat treatment furnace. The running of steel sheet in the stove is transported through the stove roller, and the stove roller adopts hollow roller to have no water-cooling, because the high temperature abominable operating mode roller hearth heat treatment furnace ubiquitous stove roller nodulation, leads to the steel sheet lower surface to have the roll mark, causes the steel sheet to repair in a large scale, even scrapps seriously and influences product surface quality. Therefore, the problem of furnace roller nodulation has seriously affected normal production, and has also plagued industrial furnace companies and iron and steel enterprises.

Factors causing the nodulation of the furnace roller of the heat treatment furnace comprise a plurality of factors such as the material of the furnace roller, a medium, the surface quality of the steel plate, a heat treatment process, a production schedule and the like, and the nodulation problem is solved by adjusting the process in the current production and use. Firstly, the shot blasting quality of the steel plate is improved, and the entrainment of oxide scales is reduced; on the other hand, the furnace roller nodulation time is slowed down by reasonably arranging the furnace charging process. In recent years, the materials of furnace rollers have been studied, and at present, the materials are commonly used as 4Cr25Ni20Si2, 3Cr24Ni7N, 3Cr24Ni7NRe and the like, but the problem of nodulation is not solved. Meanwhile, a method for manufacturing furnace roller nodulation by compounding is also developed successively, wherein the method comprises the following steps: graphite sleeve roller, ceramic core spray roller, alloy steel spray roller, but current compound manufacturing should show serious mismatch in the medium plate heat treatment furnace. New materials and a composite process are needed to be researched aiming at the heat treatment furnace rollers of non-oxidation heat treatment furnaces, especially for medium and thick plates, so that the problem of nodulation is solved.

The laser cladding is a metal material surface modification technology, and the working principle is that a high-energy laser beam is used for adding a metal material to the surface of a matrix, so that the surface modification of the matrix material is realized, the metallurgical bonding is realized, and meanwhile, the cladding layer can obtain excellent performance due to rapid cooling and rapid heating. Compared with surfacing, thermal spraying and centrifugal casting have the advantages of high bonding strength, good organization property, convenient automation control and the like, and are widely applied to the fields of electric power, metallurgy, aerospace, military, automobiles and the like. The key point of the laser cladding preparation is the design of materials, which directly determines the mechanical property and the use effect of the cladding layer. The existing material can not meet the mechanical property and technological property requirements of the furnace roller of the heating furnace, and needs to be further researched.

Disclosure of Invention

The invention provides a metal material for a non-oxidation heat treatment furnace roller, which has the following properties on the surface of the heat treatment furnace roller prepared by laser cladding: (1) The composite coating has good thermal shock resistance, and is stable and fatigue-resistant and free from falling off when the temperature is increased and decreased in the production process of the heating furnace; (2) The wear resistance is good, and the requirement of long-term continuous production is met without abrasion marks affecting the quality of the steel plate; (3) The good anti-nodulation performance is achieved, the roller surface is smooth and clean and free of foreign matters, and the surface quality of the steel plate is guaranteed; (4) Has good stability and no degradation of performance in a service cycle at high temperature.

The invention provides a laser cladding material for meeting the performance requirement of a non-oxidation heat treatment furnace roller, and the mass percentage of elements of the material is ：C：0.03%-0.1%,Si：1.9%-2.8%,Mn：0.3%-0.8%,Cr：12%-15.5%,W：2%-4.5%,Mo：18.5%-25%,Ni：10%-15%,Fe：10.5%-18.8%,Co percent and the balance is.

The invention provides a preparation process of a laser cladding material cladding furnace roller of an oxidation-free heat treatment furnace, which mainly comprises the following operation steps:

(1) Cleaning the surface of the substrate material of the furnace roller to be clad by adopting alcohol;

(2) Preheating the furnace roller matrix material before cladding after the alcohol is evaporated, wherein the preheating temperature is 210-280 ℃;

(3) Firstly polishing and removing surface rust by adopting an angle grinder after preheating a furnace roller matrix material to be clad, polishing and removing foreign matters and an oxide film, and reducing the reflection of the surface on laser;

(4) Weighing reasonable component powders according to a proportion, drying and cooling, wherein the drying temperature is 80-150 ℃ and the drying time is 1-2 hours;

(5) Cladding laser cladding powder on the surface of a metal substrate by using laser, wherein the laser wavelength is as follows: 1060 microns, power: 2100W-3000W, circular spot diameter: 2.5mm-3.6mm, a distance of 10-15mm from the focal point, and a scanning speed: 9mm/s-25mm/s, powder feeding speed: 14-25g/min; the powder is fed by pneumatic coaxial feeding.

Further, in the step 5, the laser cladding parameters are as follows: power: 2500W, circular spot diameter: 3mm, a distance of 10mm from the focal point, scanning speed: 15mm/s, powder feeding speed: 17g/min.

Furthermore, in the step 5, the laser cladding mode is cladding by combining a fiber laser with a pneumatic coaxial powder feeding mode.

Furthermore, the laser cladding in the step 5 needs to be performed twice, and the specific operation method is as follows:

(1) The first time adopts 45 degrees with the roller axis, carries out first layer laser cladding along the roller surface, adopts zero lap joint mode to carry out equidistant cladding,

(2) And polishing the surface after cladding by adopting a steel wire brush after cladding the first layer, and removing oxide films and splashed material residues after cladding the surface.

(3) Preheating the surface of the first layer laser cladding roller to 230-245 DEG C

(4) And cladding the second layer in the direction opposite to the first cladding direction by adopting an angle of 45 degrees with the roller axis to obtain a diamond-shaped crossed cladding morphology.

(5) Grinding the furnace roller subjected to secondary laser cladding to obtain high-low diamond grids with regularly distributed roller surfaces;

(6) And detecting the organization performance of the regularly distributed high-low diamond lattice roll surface material.

Compared with the prior art, the invention has the beneficial technical effects.

The material is characterized in that cobalt-based alloy is adopted as a parent phase of the material, cobalt austenite has the most excellent high-temperature strength and stability in three parent phases of iron, cobalt and nickel, and the cobalt austenite keeps enough strength within the use temperature of 450-950 ℃ of a heating furnace and does not decline in the performance in the use process. The material is added with a large amount of molybdenum, tungsten and silicon elements in cobalt base to obtain a metal compound Laiff phase reinforced austenite base body with a certain volume ratio, and the Laiff phase structure is a hexagonal close-packed crystal structure, so that the material is very stable from room temperature to eutectic temperature, and the material structure is guaranteed to have very good high-temperature wear resistance. The material of the invention is added with a large amount of iron, and the material structure performance is regulated by combining nickel, so that the stability of austenite is greatly improved, the toughness is improved, and the thermal shock resistance of the furnace roller in the heating and cooling processes of the heat treatment furnace is maintained. The cobalt-based alloy design contains very high content of chromium to obtain good oxidation resistance at high temperature, but inert gases such as nitrogen are introduced into the non-oxidation heating furnace to serve as protective gas, but the content of chromium is 12% -15.5%, on one hand, chromium with the content can form a chromium oxide film with a protective effect, and the chromium oxide film can be supplied by chromium elements after long-time working; meanwhile, the chromium content is limited to be near the critical value of oxide film formation, so that the oxide film with a certain thickness is formed to form isolation between the roller surface and the nodulation foreign matter. Because the activity between the oxides is very low at high temperature, diffusion and reaction are not easy to occur, but diffusion and adhesion are easy to occur between the metal and the oxide; meanwhile, a large amount of hard phases are distributed on the cobalt-based austenite to ensure that the material has good high-temperature strength at high temperature, and a laser cladding process is combined to obtain a fine and segregation-free uniform structure to ensure that the roll surface has no any indentation defect, so that an oxide film with an isolation function is well supported by a substrate to solve the problem of surface nodulation.

Drawings

FIG. 1 is a topography after laser cladding a first layer, a second time, and a lap joint.

Fig. 2 shows a tissue topography of the example 1 material.

FIG. 3 is a graph of hardness of case 1 materials.

Fig. 4 shows a tissue topography of the example 2 material.

Figure 5 is a graph of hardness of the example 2 material.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

The invention also provides a laser cladding implementation process for cladding the furnace roller by adopting the material, which can meet the requirement of laser cladding of furnace roller materials such as 4Cr25Ni20Si2, 3Cr24Ni7N, 3Cr24Ni7NRe and the like.

Example 1.

The furnace roller of 4Cr25Ni20Si2 material is subjected to laser cladding. The mass percentages of the selected material elements are as follows: c:0.03%, si:1.9%, mn:0.3%, cr:12%, W:2%, mo:25%, ni:10%, fe:18.8%, the balance Co.

The laser manufacturing process comprises the following steps of firstly cleaning the surface of a furnace roller made of 4Cr25Ni20Si2 material by adopting industrial alcohol, preheating the furnace roller matrix material after the alcohol is evaporated, wherein the preheating temperature is 210 ℃, and polishing by adopting an angle grinder after preheating; and then drying the laser cladding material at the temperature of 80 ℃ for 2 hours. Cladding is carried out by adopting a fiber laser combined with a pneumatic coaxial powder feeding mode, and the technological parameters are as follows: power: 2500W, circular spot diameter: 3mm, a distance of 10mm from the focal point, scanning speed: 15mm/s, powder feeding speed: 17g/min. The method comprises the steps of carrying out cladding twice in the direction shown in fig. 1, carrying out first-layer laser cladding on the roller surface in an arrow manner by adopting a spiral line at an angle of 45 degrees with the central axis of the roller as shown in the left sketch of fig. 1, carrying out equidistant cladding in a zero lap joint manner, carrying out polishing on the surface after cladding by adopting a steel wire brush after the first-layer cladding, and removing oxide films and splashed material residues after the surface cladding. And then preheating the roll surface for the second time to 230 ℃, cladding the second layer according to a spiral line by adopting the reverse direction forming an angle of 45 degrees with the roll axis, wherein the cladding direction is shown in the middle diagram of fig. 1, the cladding process parameters adopt the same parameters, the diagram morphology shown in the rightmost side of fig. 1 is obtained after cladding, the diamond-shaped crossed cladding morphology is obtained, and the high-low diamond grids with regular distribution of the roll surface can be obtained after grinding. The material is subjected to tissue performance detection, the tissue morphology of the material is shown in figure 2, a large number of hard phases of intermetallic compounds are formed in the tissue as shown in the figure, the hard phases are uniformly distributed in the tissue, and the hardness of the obtained material is high and uniform as shown in figure 3.

The furnace roller manufactured according to the embodiment realizes good metallurgical bonding of the laser cladding layer and the furnace roller matrix, has no defects and pores larger than 20 microns in the inside of the structure, has fine and uniform structure grains and uniform hardness, obtains excellent use effect compared with centrifugally cast heat-resistant steel, and has good anti-nodulation performance.

Example 2.

And carrying out laser cladding on the furnace roller made of the 3Cr24Ni7NRe material. The mass percentages of the selected material elements are as follows: c:0.1%, si:2.8%, mn:0.8%, cr:15.5%, W:4.5%, mo:18.5%, ni:15%, fe:10.5% of Co and the balance.

The laser manufacturing method comprises the following steps of firstly cleaning the surface of a furnace roller made of a 3Cr24Ni7NRe material by adopting industrial alcohol, preheating a furnace roller matrix material after the alcohol is evaporated, wherein the preheating temperature is 280 ℃, and polishing by adopting an angle grinder after preheating; and then drying the laser cladding material at 150 ℃ for 1h. The fiber laser is adopted for pneumatic coaxial powder feeding for cladding, and the laser cladding parameters are as follows: power: 2100W, circular spot diameter: 2.5mm, a distance of 10mm from the focal point, scanning speed: 25mm/s, powder feeding speed: 25g/min; the method comprises the steps of carrying out cladding twice in the direction shown in fig. 1, carrying out first-layer laser cladding on the roller surface in an arrow manner by adopting a spiral line at an angle of 45 degrees with the roller axis as shown in a left sketch of fig. 1, carrying out equidistant cladding in a zero lap joint manner, carrying out polishing on the surface after cladding by adopting a steel wire brush after the first-layer cladding, and removing oxide films and splashed material residues after the surface cladding. And then preheating the roller surface for the second time to 245 ℃, and cladding the second layer according to a spiral line by adopting the opposite direction forming an angle of 45 degrees with the roller axis, wherein the shape of the second layer is shown as the diagram on the rightmost side of the figure 1 after cladding, and the diamond-shaped crossed cladding shape is obtained. After grinding, high-low diamond grids with regularly distributed roll surfaces can be obtained, and the anti-nodulation capability of the surface structure pair can be further improved, because the nodulation of the heat treatment furnace roll and the temperature rise of the contact surface have a great relationship. The material is subjected to tissue performance detection, the tissue state of the material is shown in fig. 4, a large amount of hard phases of intermetallic compounds are formed in the tissue as shown in the figure, the hard phases are uniformly distributed in the tissue, and the hardness of the obtained material is high and uniform as shown in fig. 5.

The furnace roller manufactured according to the embodiment realizes good metallurgical bonding of the laser cladding layer and the furnace roller matrix, has no defects and pores larger than 20 microns in the inside of the structure, has fine and uniform structure grains and uniform hardness, obtains excellent use effect compared with centrifugally cast heat-resistant steel, and has good anti-nodulation performance.

Example 3

And carrying out laser cladding on the furnace roller made of the 3Cr24Ni7N material. The mass percentages of the selected material elements are as follows: c:0.03%, si:1.9%, mn:0.3%, cr:12%, W:2%, mo:25%, ni:10%, fe:18.8%, the balance Co.

The laser manufacturing method comprises the following steps of firstly cleaning the surface of a furnace roller made of a 3Cr24Ni7N material by adopting industrial alcohol, preheating a furnace roller matrix material after the alcohol is evaporated, wherein the preheating temperature is 250 ℃, and polishing by adopting an angle grinder after preheating; and then drying the laser cladding material at the temperature of 125 ℃ for 1 h. The fiber laser is adopted for pneumatic coaxial powder feeding for cladding, and the laser cladding parameters are as follows: power: 3000W, circular spot diameter: 3.6mm, 15mm from focal distance, scan speed: 9mm/s, powder feeding speed: 14g/min; the method comprises the steps of carrying out cladding twice in the direction shown in fig. 1, carrying out first-layer laser cladding on the roller surface in an arrow manner by adopting a spiral line at an angle of 45 degrees with the roller axis as shown in a left sketch of fig. 1, carrying out equidistant cladding in a zero lap joint manner, carrying out polishing on the surface after cladding by adopting a steel wire brush after the first-layer cladding, and removing oxide films and splashed material residues after the surface cladding. And then preheating the roll surface for the second time to 2450 ℃, and cladding the second layer according to a spiral line by adopting the opposite direction forming an angle of 45 degrees with the roll axis, wherein the shape of the second layer is shown in the right-most diagram of FIG. 1 after cladding, and the diamond-shaped crossed cladding shape is obtained. After grinding, high-low diamond grids with regularly distributed roll surfaces can be obtained, and the anti-nodulation capability of the surface structure pair can be further improved, because the nodulation of the heat treatment furnace roll and the temperature rise of the contact surface have a great relationship. The material is subjected to tissue performance detection, so that a large number of hard phases of intermetallic compounds are formed in the tissue, the hard phases are uniformly distributed in the tissue, and the hardness of the material is high and uniform.

The furnace roller manufactured according to the embodiment realizes good metallurgical bonding of the laser cladding layer and the furnace roller matrix, has no defects and pores larger than 20 microns in the inside of the structure, has fine and uniform structure grains and uniform hardness, obtains excellent use effect compared with centrifugally cast heat-resistant steel, and has good anti-nodulation performance.

Claims (5)

1. The laser cladding material of the non-oxidation heat treatment furnace is characterized by comprising ：C：0.03%-0.1%,Si：1.9%-2.8%,Mn：0.3%-0.8%,Cr：12%-15.5%,W：2%-4.5%,Mo：18.5%-25%,Ni：10%-15%,Fe：10.5%-18.8%,Co percent of components in percentage by mass as follows.

2. The laser cladding material of an oxidation-free heat treatment furnace according to claim 1, wherein the preparation process of the material cladding furnace roller mainly comprises the following operation steps:

(1) Cleaning the surface of the substrate material of the furnace roller to be clad by adopting alcohol;

(2) Preheating the furnace roller matrix material before cladding after the alcohol is evaporated, wherein the preheating temperature is 210-280 ℃;

(3) The furnace roller matrix material to be clad is preheated and then polished by an angle grinder to remove surface rust,

(4) Weighing reasonable component powders according to a proportion, drying and cooling, wherein the drying temperature is 80-150 ℃ and the drying time is 1-2 hours;

(5) Cladding laser cladding powder on the surface of a metal substrate by using laser, wherein the laser wavelength is as follows: 1060 microns, power: 2100W-3000W, circular spot diameter: 2.5mm-3.6mm, a distance of 10-15mm from the focal point, and a scanning speed: 9mm/s-25mm/s, powder feeding speed: 14-25g/min.

3. The laser cladding material of the non-oxidizing heat treating furnace according to claim 2, wherein the laser cladding parameters in the step 5 are: power: 2500W, circular spot diameter: 3mm, a distance of 10mm from the focal point, scanning speed: 15mm/s, powder feeding speed: 17g/min.

4. The laser cladding material of the non-oxidation heat treatment furnace according to claim 2, wherein the laser cladding mode in the step 5 is cladding by adopting a fiber laser combined with a pneumatic coaxial powder feeding mode.

5. The laser cladding material of the non-oxidation heat treatment furnace according to claim 2, wherein the laser cladding in the step 5 is performed twice, and the specific operation method is as follows:

(1) Carrying out first layer laser cladding along the roller surface at 45 degrees with the roller axis for the first time, and carrying out equidistant cladding in a zero lap joint mode;

(2) Polishing the surface after cladding by adopting a steel wire brush after cladding the first layer, and removing oxide films and splashed material residues after cladding the surface;

(3) Preheating the surface of the roller subjected to the first layer of laser cladding to 230-245 ℃;

(4) Cladding the second layer in the direction opposite to the first cladding direction by adopting an angle of 45 degrees with the roller axis to obtain a diamond-shaped crossed cladding morphology;

(5) Grinding the furnace roller subjected to secondary laser cladding to obtain high-low diamond grids with regularly distributed roller surfaces;

(6) And detecting the organization performance of the regularly distributed high-low diamond lattice roll surface material.