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CN-122007195-A - Die and process for hot extrusion molding of high-magnesium-content aluminum alloy thin-wall part

CN122007195ACN 122007195 ACN122007195 ACN 122007195ACN-122007195-A

Abstract

The invention discloses a die and a process for hot extrusion molding of an aluminum alloy thin-wall part with high magnesium content. The die body is provided with a flow guide cavity and a working belt, the cross section shapes of the flow guide cavity and the working belt are identical and are I-shaped, a flow guide groove connecting the flow guide cavity and the working belt is a conical groove, and the working belt is a variable-length working belt with three typical positions. The process comprises the following steps of (1) processing an aluminum alloy cast ingot, (2) preheating an extrusion die, heating the cast ingot by adopting an induction heating mode, controlling the temperature of a tail section of the cast ingot to be higher than that of a head section, (3) pushing the cast ingot to pass through the die by a pushing rod of an extruder after the tail section and the head section of the cast ingot are arranged in front, and finally forming, (4) carrying out online strong wind cooling on the extruded thin-wall part profile, and (5) standing the cooled thin-wall part profile for at least 7 days at room temperature, and carrying out two-stage aging treatment. The thin-wall profile obtained according to the invention has low density and has high surface quality, high dimensional accuracy and excellent comprehensive properties.

Inventors

  • ZHU KAI
  • LI YANAN
  • LIU HONGWEI
  • YU MINGYANG
  • LI YING
  • SHI GUOHUI
  • LIU QILONG
  • LI CHANGLIN
  • GAO GUANJUN
  • LI XIWU
  • YAN HONGWEI
  • XIONG BAIQING
  • ZHANG YONGAN
  • LI ZHIHUI
  • YAN LIZHEN
  • WEN KAI

Assignees

  • 有研工程技术研究院有限公司

Dates

Publication Date
20260512
Application Date
20260206

Claims (13)

  1. 1. A die for hot extrusion forming of an aluminum alloy thin-wall part with high magnesium content is characterized in that a die body is provided with a flow guide cavity and a working belt, the flow guide cavity and the working belt are identical in section shape and are I-shaped, a flow guide groove connecting the flow guide cavity and the working belt is a conical groove, the taper angle is 2-4 degrees, the working belt is a variable-length working belt with three typical positions, the length of a contact surface of a first typical position of the working belt is 5.9-6.5 mm, the length of a contact surface of a second typical position is 4.7-5.2 mm, and the length of a contact surface of a third typical position is 2.9-3.2 mm.
  2. 2. The differential speed control operating band die for a thin-walled member according to claim 1, wherein the thinnest wall thickness of the thin-walled member is 1.6mm.
  3. 3. The differential speed controlled working tape die for thin-walled articles according to claim 1 or 2 wherein the length of the contact surface at the first typical position of the working tape is 6.0mm, the length of the contact surface at the second typical position is 5.0mm, and the length of the contact surface at the third typical position is 3.0mm.
  4. 4. The differential speed controlled working tape die for thin-walled articles according to claim 1 or 2 wherein the die is prepared by additive manufacturing, and the die steel powder comprises the following elements ：C 0.35～0.55％、Si 0.01～0.15％、Mn 1.50～2.90％、Cr 4.50～5.70％、Mo 0.6～0.90％、P≤0.025％、S≤0.015％、Nb 0.03～0.04％、N 0.03～0.05％、Al 0.05～0.09％, in weight percent, the balance being Fe and unavoidable impurities.
  5. 5. A process for hot extrusion molding of a novel high-magnesium-content aluminum alloy thin-wall part by using the die as claimed in any one of claims 1 to 4, wherein the aluminum alloy consists of 6.0 to 9.9wt% of Mg, 1.1 to 3.01wt% of Zn, 0.1 to 1.15wt% of Si, at least one element Mn, cu, zr, sc, ti with a total content of not more than 0.8wt%, and the balance of Al and unavoidable impurities, and the process comprises the following steps: (1) Processing into aluminum alloy ingots according to the component compositions of the aluminum alloy; (2) Preheating an extrusion die, heating an ingot by adopting an induction heating mode, and controlling the temperature of the tail section of the ingot to be higher than that of the head section; (3) Placing the ingot subjected to induction heating into an extrusion barrel, wherein a tail section and a head section of the ingot are arranged at the front side, a push rod of the extrusion machine pushes the ingot to pass through a die, and finally forming, wherein the extrusion temperature is 380-520 ℃, the push rod speed of the extrusion machine is 0.2-1.4 mm/s, the temperatures of the extrusion barrel and the die are 440-500 ℃, and the outlet temperature is 350-390 ℃; (4) Carrying out on-line strong wind cooling on the extruded thin-wall part profile, wherein the final cooling temperature is 30-50 ℃, and the cooling speed is 2-8 ℃ per second; (5) And standing the cooled thin-wall piece section for at least 7 days at room temperature, and performing two-stage aging treatment, wherein the first-stage aging system is kept at 50-110 ℃ for 2-96 h, and the second-stage aging system is kept at 120-230 ℃ for 2-12 h.
  6. 6. The process according to claim 5, wherein the aluminum alloy is composed of at least one of Mg 6.5-7.8 wt%, zn 1.5-2.8 wt%, si 0.15-0.5 wt%, and Mn, cu, zr, sc, ti element having a total content of not more than 0.6wt%, the balance being Al and unavoidable impurities.
  7. 7. The process according to claim 5, wherein in the step (2), boron nitride powder is added as a lubricant when the extrusion die is preheated to 150 to 200 ℃.
  8. 8. The process of claim 5, wherein in step (2), the difference between the temperature of the head section and the temperature of the tail section of the ingot to be extruded is 20-90 ℃.
  9. 9. The process of claim 5, wherein in step (3), the extrusion temperature is 450-515 ℃, the extruder ram speed is 0.5-1.2 mm/s, the extruder barrel and die temperature is 440-500 ℃, and the outlet temperature is 420-495 ℃.
  10. 10. The process according to claim 5, wherein in the step (4), the final cooling temperature is 30-40 ℃, the wind speed is 40-60 m/s, the nozzle height is 50-80 mm, the angle between the nozzle and the profile horizontal plane is 30-45 °, and the cooling speed is 2-8 ℃.
  11. 11. The process of claim 5, wherein in step (5), the first stage aging regime is maintained at a temperature of 50 to 80 ℃ for 4 to 18 hours and the second stage aging regime is maintained at a temperature of 175 to 215 ℃ for 6 to 12 hours.
  12. 12. The novel high-magnesium-content aluminum alloy thin-wall part is characterized in that the novel high-magnesium-content aluminum alloy thin-wall part is prepared by the process of any one of claims 5-11, no cracking phenomenon occurs, the surface roughness is 0.4-1.2 mu m, and the bending radian of each 1m thin-wall part section bar is less than 3 degrees.
  13. 13. The novel high-magnesium-content aluminum alloy thin-wall part according to claim 12, wherein the density of the aluminum alloy thin-wall part profile is less than or equal to 2.68g/cm 3 , the L-direction tensile strength is more than or equal to 435MPa, the elongation after breaking is more than or equal to 12%, and the peeling corrosion grade is not lower than EA grade.

Description

Die and process for hot extrusion molding of high-magnesium-content aluminum alloy thin-wall part Technical Field The invention relates to the technical field of extrusion processing of thin-wall parts, in particular to a die and a process for hot extrusion forming of an aluminum alloy thin-wall part with high magnesium content. Background With the rapid development of the fields of aerospace, rail transit and the like, the demands for special aluminum alloy extrusion profiles of thin-wall parts, special-shaped parts and the like are gradually increased. The aluminum alloy profile is used as a key component, and high surface quality, high dimensional accuracy and excellent comprehensive performance are required. At present, the traditional alloy is adopted to prepare the thin-wall part section, the weight is difficult to be effectively lightened due to the limitation of density and comprehensive performance, the energy is saved, the consumption is reduced, and the material cost is relatively high. Patent document CN116065066B discloses a light high-strength corrosion-resistant aluminum alloy material and a preparation method thereof, wherein a novel Al-Mg-Zn-Si alloy with high magnesium content is provided, the novel Al-Mg-Zn-Si alloy has the advantages of low cost, low density, corrosion resistance and the like, and the thin-wall part profile prepared by adopting the novel series of alloy can further save energy and reduce cost. However, because the wall thickness of the extrusion blank is thinner and the shape is asymmetric, the novel high-magnesium-content Al-Mg-Zn-Si alloy has large deformation resistance, is sensitive to an extrusion temperature window and the like, and the phenomena of twisting, bending, waviness, fracture, vehicle tightness, rough surface, unqualified mechanical property and the like of the thin-wall section are easily generated in the extrusion process. Disclosure of Invention The invention aims to provide a die and a process for hot extrusion molding of an aluminum alloy thin-wall part with high magnesium content, so that the density of the alloy thin-wall section is less than or equal to 2.65g/cm 3, and the alloy thin-wall section has high surface quality, high dimensional accuracy and excellent comprehensive performance. In order to achieve the above purpose, the present invention adopts the following technical scheme: The die for hot extrusion forming of the high-magnesium-content aluminum alloy thin-wall part comprises a flow guide cavity and a working belt, wherein the flow guide cavity and the working belt are identical in section shape and are I-shaped, a flow guide groove connecting the flow guide cavity and the working belt is a conical groove, the taper angle is 2-4 degrees, the working belt is a variable-length working belt with three typical positions, the length of a contact surface of a first typical position of the working belt is 5.9-6.5 mm, the length of a contact surface of a second typical position of the working belt is 4.7-5.2 mm, and the length of a contact surface of a third typical position of the working belt is 2.9-3.2 mm. Preferably, the thinnest wall thickness of the thin-walled member is 1.6mm. Preferably, the length of the contact surface of the first typical position of the working belt is 6.0mm, the length of the contact surface of the second typical position is 5.0mm, and the length of the contact surface of the third typical position is 3.0mm. Preferably, the mold is prepared by an additive manufacturing method, and the mold steel powder comprises the following elements ：C 0.35～0.55％、Si 0.01～0.15％、Mn 1.50～2.90％、Cr 4.50～5.70％、Mo 0.6～0.90％、P≤0.025％、S≤0.015％、Nb 0.03～0.04％、N 0.03～0.05％、Al 0.05～0.09％, in percentage by weight, and the balance of Fe and unavoidable impurities. The process for hot extrusion molding of the novel high-magnesium-content aluminum alloy thin-wall part by using the die is characterized by comprising the following components of 6.0-9.9wt% of Mg, 1.1-3.01wt% of Zn, 0.1-1.15wt% of Si, at least one of Mn, cu, zr, sc, ti elements with the total content not exceeding 0.8wt% and the balance of Al and unavoidable impurities, wherein the process comprises the following steps: (1) Processing into aluminum alloy ingots according to the component compositions of the aluminum alloy; (2) Preheating an extrusion die, heating an ingot by adopting an induction heating mode, and controlling the temperature of the tail section of the ingot to be higher than that of the head section; (3) Placing the ingot subjected to induction heating into an extrusion barrel, wherein a tail section and a head section of the ingot are arranged at the front side, a push rod of the extrusion machine pushes the ingot to pass through a die, and finally forming, wherein the extrusion temperature is 380-520 ℃, the push rod speed of the extrusion machine is 0.2-1.4 mm/s, the temperatures of the extrusion barrel and the die are 440-500 ℃, and the outlet temperature is 350