CN104805331B - A kind of engineering machinery U-shaped material of the wear-resisting extruded zinc alloy of high-strength and high ductility and preparation method thereof - Google Patents

Abstract

The invention relates to a high-strength, high-toughness and wear-resistant extruded zinc alloy U-shaped material for engineering machinery and a preparation method thereof. Pure metals or intermediate alloys are selected according to the mass percentage of components, heated and melted in a crucible resistance furnace, and cast into ingots; the cast Homogenize the ingot at 280°C-360°C; put the homogenized ingot into the extrusion barrel of the extruder, and extrude it at 260°C-340°C; cut the extruded U-shaped material The required length is heated in a box-type resistance furnace and then quenched in water. In the invention, the high-strength, high-toughness and wear-resistant extruded zinc alloy U-shaped material is prepared through the combination of alloy component optimization and process treatment.

Description

A high-strength, high-toughness, wear-resistant extruded zinc alloy U-shaped material for construction machinery and its preparation method

technical field

The invention relates to an extruded zinc alloy profile and a preparation method, in particular to a high-strength, high-toughness and wear-resistant extruded zinc alloy U-profile for construction machinery and a preparation method, belonging to the field of new nonferrous metal material manufacturing.

Background technique

At present, U-shaped guide grooves (or guide grooves, wear-resistant plates) for domestic construction machinery are mainly made of copper alloy materials, such as aluminum bronze, tin bronze, etc., which are produced in a single piece by casting method and used after machining. Therefore, the cost of raw materials is high and the production efficiency is low.

Compared with copper alloy materials, it is made of high-aluminum-zinc alloy materials, which has low raw material costs, abundant material sources, and less energy consumption for melting. However, it is produced by casting, and the plasticity and toughness of the alloy are low (1-3% elongation).

Contents of the invention

The object of the present invention is to provide a high-strength, high-toughness and wear-resistant extruded zinc alloy U-shaped material for construction machinery and a preparation method thereof.

To achieve the above object, the present invention takes the following technical solutions:

A method for preparing a high-strength, high-toughness, wear-resistant extruded zinc alloy U-shaped material for construction machinery, comprising the following steps:

(1) According to the mass percentage of the following components, select pure metals or intermediate alloys, heat and melt them in a crucible resistance furnace and cast them into ingots: 25.0-45.0% Al, 2.0-5.0% Cu, 0.015-0.04% Mg, 0.04-0.10 %Ti, 0.008～0.02%B, 0.004～0.01%C, the balance is zinc and unavoidable impurity elements, the control range of impurity element content is: Fe≤0.1%, Pb≤0.004%, Sn≤0.002%, Cd≤ 0.003%;

(2) Homogenize the ingot at 280°C to 360°C for 3 to 12 hours;

(3) Preheat the profile extrusion die to 260°C to 320°C and install it on the extrusion machine;

(4) Put the homogenized ingot into the extrusion cylinder of the extruder, and extrude it at 260°C to 340°C;

(5) Cut the extruded profile to the required length, put it into a box-type resistance furnace, heat it to 290°C-360°C, keep it warm for 1-8 hours, and then quickly put it into water at 0°C-35°C, that is, solution treatment Carry out water quenching afterwards;

(6) After solid solution treatment and water quenching, place at room temperature and natural aging for more than two weeks to obtain the finished product.

The specific operation of step (1) is optimized: first, add electrolytic aluminum, electrolytic copper, and zinc ingots into the resistance crucible furnace, heat up and melt, and the melting control temperature is 700 ° C to 750 ° C. When the content of aluminum and copper is high, the melting control temperature is increased accordingly. . After it is completely melted, use a refining agent to remove slag and gas, and then remove the slag after standing still. Then, first add the Mg-10%Al master alloy with a preheating temperature of 200-300°C, and then add the Al-5%Ti-1%B-0.5%C master alloy with a preheating temperature of 200-300°C, or add the pre-heated Hot Mg-10%Al master alloy and Al-5%Ti-1%B-0.5%C master alloy, after the master alloy is completely melted, stir the molten metal evenly, let it stand for 10 to 15 minutes, at 620~690 ℃ poured into a round ingot. After the ingot is cooled, the surface oxide scale is removed by turning, and then it is ready for extrusion.

The ingot homogenization temperature described in step (2) is preferably 300-340°C, and the homogenization time is 3-5 hours;

The profile extrusion die described in step (3) is a flat die, and the die preheating temperature is preferably 280 to 300°C;

The extrusion temperature described in step (4) is preferably 280 to 320°C;

The solution treatment temperature of the heat treatment of the profile in step (5) is preferably 300-340°C, heat preservation for 2-4 hours, and then rapid water quenching, the water temperature is 0-35°C.

After the heat treatment of the profiles described in step (6), place them at room temperature and allow natural aging for more than two weeks to obtain finished products.

The functions of each component in the alloy of the present invention are as follows: the main function of aluminum in the alloy is to refine the structure of the alloy and improve the strength, hardness, plasticity and wear resistance of the alloy. In the extruded zinc alloy of the present invention, with the increase of the aluminum content, the strength, hardness, plasticity and wear resistance of the alloy are improved in the extruded state. In the alloy, copper is added to increase the strength, hardness and wear resistance of the alloy. Part of the copper is dissolved in the aluminum-rich α phase and the zinc-rich η phase, and the remaining copper and zinc form the CuZn ₄ intermetallic compound phase. When the copper content is 1.5%, the CuZn ₄ intermetallic compound phase is formed in the cast state. With the increase of copper content, the amount of CuZn ₄ intermetallic compound phase increases. In the as-cast state, the CuZn ₄ phase is distributed in the grain boundary or in the interstices of dendrites in the form of larger dots and strips. After extrusion, the CuZn ₄ intermetallic compound is uniformly distributed in the form of fine dots. However, when the copper content exceeds 5%, due to the formation of too many CuZn ₄ intermetallic compound phases in the structure, the plasticity and toughness of the alloy in the heat-treated state are reduced. Magnesium is an important microalloying element, which has a significant impact on the properties of the alloy. Especially in the heat treatment state, a very significant strengthening effect can be obtained by adding a small amount of magnesium. A small amount of magnesium is mainly dissolved in the aluminum-rich α phase and the zinc-rich η phase, which plays a role of solid solution strengthening. However, when the magnesium content exceeds 0.05%, the magnesium will significantly reduce the ductility and toughness of the alloy in the heat-treated state. Ti, B, and C are mainly used to refine the primary aluminum-rich α phase of the alloy to obtain a fine and uniform ingot structure. After adding Ti, B, and C to the alloy, fine TiAl ₃ phase, TiB phase TiC and other particles are formed in the alloy liquid. These fine particles serve as the crystal nuclei of the primary aluminum-rich α phase, which promotes the refinement of the primary aluminum-rich α phase in the matrix structure. , forming an equiaxed grain structure, which is conducive to improving the performance of the extruded alloy. Ti, B, C are added in the form of Al-5%Ti-1%B-0.5%C master alloy, Mg is added in the form of Mg-10%Al master alloy, and the absorption rate of alloying elements is high.

The ingot structure is not uniform in the casting state. Homogenizing the ingot before extrusion is beneficial to reduce composition segregation, obtain a relatively uniform ingot structure, and improve and enhance the process performance of extrusion forming. However, when the homogenization temperature exceeds 380°C, overburning will occur, and when the temperature is lower than 280°C, the homogenization holding time will be prolonged. Therefore, the homogenization temperature should be between 280 and 360°C. If the homogenization time is too long, grain coarsening will appear in the structure of the ingot, and due to the dissolution of CuZn ₄ phase, the number will decrease, which will affect the wear resistance of the alloy.

Studies have shown that when the extrusion temperature is lower than 260°C, the extrusion deformation resistance is greater; when it is higher than 360°C, the quality of the extruded profile is poor due to the low strength at high temperature.

The extruded profile is heat treated, that is, solution treated and water quenched, which can significantly improve the tensile strength and hardness of the alloy, and has excellent plasticity and toughness. Studies have shown that the strengthening effect is remarkable when the profile is heated to 290-360°C and kept warm for a certain period of time and then water quenched. At high temperatures, the solubility of Zn, Mg, and Cu atoms in the Al-rich α phase increases, while at low temperatures, the solubility of Zn, Mg, and Cu atoms in the Al-rich α phase decreases. When rapidly cooled, the Al-rich α phase In a supersaturated state, the strength and hardness are significantly improved. However, when the solution treatment temperature exceeds 360°C, the profile is prone to deformation due to the low thermal strength of the alloy, and cracking is prone to occur during water quenching. When the solution treatment temperature is lower than 290°C, the effect is not significant. If the holding time exceeds 8 hours, the crystal grains will be coarsened and the performance of the alloy will be reduced.

After the heat treatment of the profiles, natural aging at room temperature for more than two weeks can improve the dimensional stability.

In the invention, the high-strength, high-toughness and wear-resistant extruded zinc alloy U-shaped material is prepared through the organic combination of alloy component optimization and process treatment.

Description of drawings

Fig. 1 is the extruded zinc alloy U-shaped bar of three specifications for engineering machinery prepared by extrusion in the present invention.

detailed description

The present invention will be further described below in conjunction with a specific embodiment of a U-shaped bar with a width of 32 mm, a height of 32 mm, and a wall thickness of 8 mm.

Example 1

U profile width 32mm, height 32mm, wall thickness 8mm. Ingot size Φ120X450, extrusion cylinder diameter Φ125, extrusion ratio 19.

According to the composition ratio (mass percentage): 26.0% Al, 2.50% Cu, 0.025% Mg, 0.06% Ti, 0.012% B, 0.006% C, the balance is Zn and unavoidable impurity elements, the control range of impurity elements is: Fe≤0.1%, Pb≤0.004%, Sn≤0.002%, Cd≤0.003%.

The preparation method is as follows: Weigh electrolytic aluminum, electrolytic copper, and zinc ingots, put them into a preheated graphite crucible, and melt in a resistance furnace to control the temperature at 700°C. After it is completely melted, use a refining agent to remove slag and degas, and then stand still to remove slag. Add Mg-10%Al master alloy and Al-5%Ti-1%B-0.5%C master alloy with a preheating temperature of 200-300°C. After they are completely melted, stir the molten metal evenly and let it stand for 10 minutes. The ingot is cast by metal mold, and the pouring temperature is 630-640°C. After the ingot is cooled, the surface scale is removed by turning, and the billet is prepared for extrusion.

Homogenize the extruded billet in a box-type resistance furnace at a temperature of 300°C for 3 hours. The extrusion barrel preheating temperature is 300°C, and the mold preheating temperature is 300°C.

Put the billet into the extrusion cylinder for extrusion, the extrusion temperature is 300°C, and the extrusion speed is 25-30mm/s.

Cut the extruded profile to the required length.

Put the profile into a box-type resistance furnace, heat up to 320°C, keep it warm for 2 hours, and then quickly put it into water at 20-25°C.

Place the heat-treated profile at room temperature for natural aging for two weeks.

The mechanical properties of the profile heat treatment state are: tensile strength 530-537MPa, elongation 17-18%, Brinell hardness HB155-160.

Example 2

U profile width 32mm, height 32mm, wall thickness 8mm. Ingot size Φ120X450, extrusion cylinder diameter Φ125, extrusion ratio 19.

According to the composition ratio (mass percentage): 26.0% Al, 2.50% Cu, 0.035% Mg, 0.06% Ti, 0.012% B, 0.006% C, the balance is Zn and unavoidable impurity elements, the control range of impurity elements is: Fe≤0.1%, Pb≤0.004%, Sn≤0.002%, Cd≤0.003%.

The preparation method is as follows: Weigh electrolytic aluminum, electrolytic copper, and zinc ingots, put them into a preheated graphite crucible, and melt in a resistance furnace to control the temperature at 700°C. After it is completely melted, use a refining agent to remove slag and degas, and then stand still to remove slag. Add Mg-10%Al master alloy and Al-5%Ti-1%B-0.5%C master alloy with preheating temperature of 200℃～300℃. After all of them are melted, stir the molten metal evenly and let it stand for 10 minute. The ingot is cast by metal mold, and the pouring temperature is 630-640°C. After the ingot is cooled, the surface scale is removed by turning, and the billet is prepared for extrusion.

Homogenize the extruded billet in a box-type resistance furnace at a homogenization temperature of 360°C for 12 hours, then lower the temperature to 300°C for heat preservation. The extrusion barrel preheating temperature is 300°C, and the mold preheating temperature is 300°C.

Put the billet into the extrusion cylinder for extrusion, the extrusion temperature is 300°C, and the extrusion speed is 25-30mm/s.

Cut the extruded profile to the required length.

Put the profile into a box-type resistance furnace, heat up to 320°C, keep it warm for 2 hours, and then quickly put it into water at 20-25°C.

Place the heat-treated profile at room temperature for natural aging for two weeks.

The mechanical properties of the profile heat treatment state are: tensile strength 576-579MPa, elongation 10-11%, Brinell hardness HB170-175.

Example 3

U profile width 32mm, height 32mm, wall thickness 8mm. Ingot size Φ120X450, extrusion cylinder diameter Φ125mm, extrusion ratio 19.

According to the composition ratio (mass percentage): 26.0% Al, 3.50% Cu, 0.025% Mg, 0.06% Ti, 0.012% B, 0.006% C, the balance is Zn and unavoidable impurity elements, the control range of impurity elements is: Fe≤0.1%, Pb≤0.004%, Sn≤0.002%, Cd≤0.003%.

The preparation method is as follows: Weigh electrolytic aluminum, electrolytic copper, and zinc ingots, put them into a preheated graphite crucible, and melt in a resistance furnace to control the temperature at 700°C. After it is completely melted, use a refining agent to remove slag and degas, and then stand still to remove slag. Add Mg-10%Al master alloy and Al-5%Ti-1%B-0.5%C master alloy with preheating temperature of 200℃～300℃. After all of them are melted, stir the molten metal evenly and let it stand for 10 minute. The ingot is cast by metal mold, and the pouring temperature is 630-640°C. After the ingot is cooled, the surface scale is removed by turning, and the billet is prepared for extrusion.

Homogenize the extruded billet in a box-type resistance furnace at a temperature of 300°C for 4 hours. The extrusion barrel preheating temperature is 300°C, and the mold preheating temperature is 300°C.

Put the billet into the extrusion cylinder for extrusion, the extrusion temperature is 300°C, and the extrusion speed is 25-30mm/s.

Cut the extruded profile to the required length.

Put the profile into a box-type resistance furnace, heat up to 320°C, keep it warm for 2 hours, and then quickly put it into water at 20-25°C.

Place the heat-treated profile at room temperature for natural aging for two weeks.

The mechanical properties of the profile in the heat treatment state are: tensile strength is 540-542 MPa, elongation is 16-18%, and Brinell hardness is HB157-162.

Example 4

U profile width 32mm, height 32mm, wall thickness 8mm. Ingot size Φ120X450, extrusion cylinder diameter Φ125mm, extrusion ratio 19.

According to the composition ratio (mass percentage): 26.0% Al, 4.50% Cu, 0.025% Mg, 0.06% Ti, 0.012% B, 0.006% C, the balance is Zn and unavoidable impurity elements, the control range of impurity elements is: Fe≤0.1%, Pb≤0.004%, Sn≤0.002%, Cd≤0.003%.

The preparation method is as follows: Weigh electrolytic aluminum, electrolytic copper, and zinc ingots, put them into a preheated graphite crucible, and melt in a resistance furnace to control the temperature at 700°C. After it is completely melted, use a refining agent to remove slag and degas, and then stand still to remove slag. Add Mg-10%Al master alloy and Al-5%Ti-1%B-0.5%C master alloy whose preheating temperature is 200℃～300℃, and after they are completely melted, stir the molten metal evenly and let it stand for 10 minute. The ingot is cast by metal mold, and the pouring temperature is 640-650°C. After the ingot is cooled, the surface scale is removed by turning, and the billet is prepared for extrusion.

Homogenize the extruded billet in a box-type resistance furnace. The homogenization temperature is 360°C for 12 hours, and then lowered to 300°C. The extrusion barrel preheating temperature is 300°C, and the mold preheating temperature is 300°C.

Put the billet into the extrusion cylinder for extrusion, the extrusion temperature is 300°C, and the extrusion speed is 25-30mm/s.

Cut the extruded profile to the required length.

Put the profile into a box-type resistance furnace, heat up to 320°C, keep it warm for 2 hours, and then quickly put it into water at 20-25°C.

Place the heat-treated profile at room temperature for natural aging for two weeks.

The mechanical properties of the profile heat treatment state are: tensile strength 545-548MPa, elongation 15-16%, Brinell hardness HB160-165.

Example 5

U profile width 32mm, height 32mm, wall thickness 8mm. Ingot size Φ120X450, extrusion cylinder diameter Φ125mm, extrusion ratio 19.

According to the composition ratio (mass percentage): 30.1% Al, 3.05% Cu, 0.025% Mg, 0.06% Ti, 0.012% B, 0.006% C, the balance is Zn and unavoidable impurity elements, the control range of impurity elements is: Fe≤0.1%, Pb≤0.004%, Sn≤0.002%, Cd≤0.003%.

The preparation method is as follows: Weigh electrolytic aluminum, electrolytic copper, and zinc ingots, put them into a preheated graphite crucible, and melt in a resistance furnace to control the temperature at 730°C. After it is completely melted, use a refining agent to remove slag and degas, and then stand still to remove slag. Add Mg-10%Al master alloy and Al-5%Ti-1%B-0.5%C master alloy whose preheating temperature is 200℃～300℃, and after they are completely melted, stir the molten metal evenly and let it stand for 10 minute. The ingot is cast by metal mold, and the pouring temperature is 650～670℃. After the ingot is cooled, the surface scale is removed by turning, and the billet is prepared for extrusion.

Homogenize the extruded billet in a box-type resistance furnace with a homogenization temperature of 360°C for 6 hours, and then lower it to 300°C for heat preservation. The extrusion barrel preheating temperature is 300°C, and the mold preheating temperature is 300°C.

Put the billet into the extrusion cylinder for extrusion, the extrusion temperature is 300°C, and the extrusion speed is 25-30mm/s.

Cut the extruded profile to the required length.

Put the profile into a box-type resistance furnace, heat up to 320°C, keep it warm for 2 hours, and then quickly put it into water at 20-25°C.

Place the heat-treated profile at room temperature for natural aging for two weeks.

The mechanical properties of the profile heat treatment state are: tensile strength 545-548MPa, elongation 15-19%, Brinell hardness HB165-168.

Example 6

U profile width 32mm, height 32mm, wall thickness 8mm. Ingot size Φ120X450, extrusion cylinder diameter Φ125mm, extrusion ratio 19.

According to the composition ratio (mass percentage): 40.5% Al, 3.5% Cu, 0.025% Mg, 0.06% Ti, 0.012% B, 0.006% C, the balance is Zn and unavoidable impurity elements, the control range of impurity elements is: Fe≤0.1%, Pb≤0.004%, Sn≤0.002%, Cd≤0.003%.

The preparation method is as follows: Weigh electrolytic aluminum, electrolytic copper, and zinc ingots, put them into a preheated graphite crucible, and melt in a resistance furnace to control the temperature at 730°C. After it is completely melted, use a refining agent to remove slag and degas, and then stand still to remove slag. Add Mg-10%Al master alloy and Al-5%Ti-1%B-0.5%C master alloy whose preheating temperature is 200℃～300℃, and after they are completely melted, stir the molten metal evenly and let it stand for 10 minute. The ingot is cast by metal mold, and the pouring temperature is 670-680°C. After the ingot is cooled, the surface scale is removed by turning, and the billet is prepared for extrusion.

Homogenize the extruded billet in a box-type resistance furnace at a homogenization temperature of 360°C for 12 hours, and then lower the temperature to 300°C. The extrusion barrel preheating temperature is 300°C, and the mold preheating temperature is 300°C.

Put the billet into the extrusion barrel and extrude at a speed of 25-30mm/s.

Cut the extruded profile to the required length.

Put the profile into a box-type resistance furnace, heat up to 320°C, keep it warm for 2 hours, and then quickly put it into water at 20-25°C.

Place the heat-treated profile at room temperature for natural aging for two weeks.

The mechanical properties of the profile heat treatment state are: tensile strength 558-562MPa, elongation 16-20%, Brinell hardness HB170-175.

comparative example

The U profile is 32mm wide, 32mm high, and 8mm thick, and is gravity-cast with metal molds.

According to the composition ratio (mass percentage): 26.0% Al, 2.50% Cu, 0.025% Mg, 0.06% Ti, 0.012% B, 0.006% C, the balance is Zn and unavoidable impurity elements, the control range of impurity elements is: Fe≤0.1%, Pb≤0.004%, Sn≤0.002%, Cd≤0.003%. .

The preparation method is as follows: Weigh electrolytic aluminum, electrolytic copper, and zinc ingots, put them into a preheated graphite crucible, and melt in a resistance furnace to control the temperature at 700°C. After it is completely melted, use a refining agent to remove slag and degas, and then stand still to remove slag. Add Mg-10%Al master alloy and Al-5%Ti-1%B-0.5%C master alloy whose preheating temperature is 200℃～300℃, and after they are completely melted, stir the molten metal evenly and let it stand for 10 minute.

Metal mold gravity casting is adopted, and the pouring temperature is 630-640°C.

The mechanical properties in the casting state are: tensile strength is 385-415MPa, elongation is 1-3%, and Brinell hardness is HB115-120.

Using the same heat treatment process as the extruded profile, put the cast blank into a box-type resistance furnace, heat it up to 320°C, keep it warm for 2 hours, and then quickly put it into water at 20-25°C. The mechanical properties of heat treatment state are: tensile strength is 440-460 MPa, elongation is 1%, Brinell hardness HB130-135.

As can be seen from Comparative Example 1, compared with the casting method, the tensile strength of the U-shaped bar prepared by the extrusion method has increased by more than 15%, the elongation has increased by 17 times, and the Brinell hardness has increased by 18% in the heat-treated state. %.

Claims (4)

1. a kind of engineering machinery preparation method of the U-shaped material of the wear-resisting extruded zinc alloy of high-strength and high ductility, is characterized in that, including step such as Under：

(1) simple metal or intermediate alloy are chosen according to following ingredients mass percent, heats in crucible electrical resistance furnace and melt and pour Form ingot casting：25.0～45.0%Al, 2.0～5.0%Cu, 0.015～0.04%Mg, 0.04～0.10%Ti, 0.008～ 0.02%B, 0.004～0.01%C, balance of zinc and inevitable impurity element, impurity content control range is： Fe≤0.1%, Pb≤0.004%, Sn≤0.002%, Cd≤0.003%；

(2) ingot casting is carried out Homogenization Treatments；

(3) profile extrusion die is preheated, and on extruder；

(4) by Homogenization Treatments after ingot casting be put in the recipient of extruder, extrusion molding；

(5) extrudate is intercepted required length, is put into heating and thermal insulation in chamber type electric resistance furnace, is then put into rapidly cold water In, i.e. the laggard water-filling of solution treatment is quenched；

(6) after solution treatment water quenching, room temperature is placed, and natrual ageing obtains finished product in more than two weeks；

Ingot homogenization temperature described in step (2) is 280～360 DEG C, 3～12 hours Homogenization Treatments time；

Extrusion temperature described in step (4) is 260～340 DEG C；

Solid solution temperature described in step (5) is 290～360 DEG C, is incubated 1～8 hour, is then put into rapidly 0 DEG C～35 DEG C Water in cool down, i.e. water quenching after solution treatment.

2. preparation method of a kind of engineering machinery according to claim 1 with the U-shaped material of the wear-resisting extruded zinc alloy of high-strength and high ductility, It is characterized in that, the concrete operations of step (1) are first in electrical crucible to add electrolytic aluminium, cathode copper, zinc ingot metal, heat up molten Change, fusing 700 DEG C～750 DEG C of temperature of control, when aluminium, copper content are high, fusing control temperature is accordingly improved, and treats all fusings Afterwards, slagging-off degassing processing is carried out with refining agent, skim after standing；Then, the Mg-10% of 200～300 DEG C of preheating temperature is initially charged Al intermediate alloys, add the Al-5%Ti-1%B-0.5%C intermediate alloys of 200～300 DEG C of preheating temperature, or are simultaneously introduced The Mg-10%Al intermediate alloys and Al-5%Ti 1%B-0.5%C intermediate alloys of 200～300 DEG C of preheating, treats that intermediate alloy is complete After portion's fusing, molten metal is stirred, stand 10 to 15 minutes, circular ingot is poured at 620～690 DEG C.

3. preparation method of a kind of engineering machinery according to claim 1 with the U-shaped material of the wear-resisting extruded zinc alloy of high-strength and high ductility, It is characterized in that, the profile extrusion die described in step (3) is flat-die, and mold preheating temperature is 280～300 DEG C.

4. the U-shaped material of any one of claims 1 to 3 methods described is prepared kirsite.