CN-121976067-A - Preparation method of high-performance 6-series aluminum alloy forging based on semi-solid pretreatment and mist cooling-oil cooling combined quenching

Abstract

The invention relates to the technical field of aluminum alloy forging preparation, in particular to a high-performance 6-series aluminum alloy forging preparation method based on semi-solid pretreatment and mist cooling-oil cooling combined quenching, which comprises the following steps of smelting; the method comprises the steps of carrying out ultrasonic treatment to a semi-solid temperature after melt cooling, standing for solidification, carrying out heat preservation treatment to an ingot, carrying out hot die forging to the ingot after heat preservation treatment, carrying out compound quenching to a forging piece, carrying out first-stage rapid cooling by water mist, then carrying out second-stage slow cooling by oil cooling, and carrying out aging treatment to the cooled forging piece. The precipitation behavior of the second phase particles is regulated and controlled by adopting a process of mist cooling and oil cooling, the residual stress in the forge piece is reduced, the alloy strength is improved, and the synergistic effect of fine grain strengthening and solid solution strengthening is fully exerted.

Inventors

• ZHANG HAO
• MO YUFEI
• ZHOU WEIDONG
• LIU FANGZHEN
• LIU CHAO
• LI DONG

Assignees

• 山东宏桥轻量化科技有限公司
• 山东宏畅轻合金有限公司

Dates

Publication Date

20260505

Application Date

20260202

Claims (7)

1. 1. The preparation method of the high-performance 6-series aluminum alloy forging based on semi-solid pretreatment and mist cooling-oil cooling combined quenching is characterized by comprising the following steps of: Smelting, wherein the smelting alloy comprises the following components: 0.8-1.3wt.% of Si, 1.2-1.7wt.% of Mg, less than or equal to 0.5wt.% of Cu, less than or equal to 0.3wt.% of Fe, less than or equal to 0.15wt.% of Mn, less than or equal to 0.15wt.% of Cr, less than or equal to 0.1wt.% of Ti, less than or equal to 0.2wt.% of other impurities, and the balance of Al; step two, after the melt is cooled, carrying out ultrasonic treatment to reach a semi-solid temperature, and standing for solidification; step three, carrying out heat preservation treatment on the cast ingot; step four, performing hot die forging on the ingot subjected to heat preservation treatment; step five, carrying out compound quenching on the forge piece, firstly adopting water mist to carry out first-stage rapid cooling, and then adopting oil cooling to carry out second-stage slow cooling; and step six, aging the cooled forging.
2. 2. The method for preparing the high-performance 6-series aluminum alloy forging based on semi-solid pretreatment and mist cooling-oil cooling combined quenching as claimed in claim 1, wherein in the second step, the ultrasonic vibration starting temperature is 660-690 ℃, and the semi-solid temperature is 580-620 ℃.
3. 3. The method for preparing the high-performance 6-series aluminum alloy forging based on semi-solid pretreatment and mist cooling-oil cooling combined quenching as claimed in claim 2, wherein in the third step, the heat preservation temperature is 450-500 ℃ and the heat preservation time is 0.5-1 h.
4. 4. The method for preparing the high-performance 6-series aluminum alloy forging based on semi-solid pretreatment and mist cooling-oil cooling composite quenching according to claim 3, wherein in the step four hot die forging, the temperature of an ingot is preheated to 450-550 ℃ for 1-3 hours, the temperature rising rate is 5-15 ℃ per minute, the die temperature is 300-400 ℃ and the forging rate is 3-15 mm/s.
5. 5. The method for preparing the high-performance 6-series aluminum alloy forging based on semi-solid pretreatment and mist-oil cooling composite quenching as claimed in claim 4, wherein in the fifth step, the rapid cooling termination temperature of the first stage is 260-280 ℃, the cooling time is 10-30 s, the water mist temperature is 10-25 ℃, and the cooling rate is 9-20 ℃ per second.
6. 6. The method for preparing a high-performance 6-series aluminum alloy forging based on semi-solid pretreatment and mist cooling-oil cooling combined quenching as claimed in claim 5, wherein in the fifth step, the slow cooling termination temperature of the second stage is 175-185 ℃, the cooling time is 50s-70s, the quenching oil temperature is 70-80 ℃, and the cooling rate is 0.5-5 ℃ per second.
7. 7. The method for preparing the high-performance 6-series aluminum alloy forging based on semi-solid pretreatment and mist cooling-oil cooling combined quenching as claimed in claim 6, wherein in the sixth step, the aging temperature is 160-220 ℃ and the time is 2-5 h.

Description

Preparation method of high-performance 6-series aluminum alloy forging based on semi-solid pretreatment and mist cooling-oil cooling combined quenching Technical Field The invention relates to the technical field of aluminum alloy forging preparation, in particular to a preparation method of a high-performance 6-series aluminum alloy forging based on semi-solid pretreatment and mist cooling-oil cooling combined quenching. Background The 6-series aluminum alloy is widely applied to the fields of automobiles, rail transit and the like by virtue of the good plasticity, strength, corrosion resistance and the like. The prepared parts are formed by forging or extrusion, and the mechanical properties of the parts are improved by a heat treatment process of solution treatment, quenching and artificial aging, so that the parts meet a worse service environment. However, element segregation is an inherent problem in conventional manufacturing techniques, and dendrite segregation, second phase particle agglomeration and relatively coarse grain structure inherent in conventional cast and forged billets are difficult to eliminate even after sufficient plastic deformation and solution treatment. The microscopic defects not only directly limit the strength and toughness of the material, but also become stress concentration points, and obviously damage the fatigue performance and long-term service reliability of the material. Disclosure of Invention The invention aims to overcome the defects of the conditions, and aims to provide a preparation method of a high-performance 6-series aluminum alloy forging based on semi-solid pretreatment and mist cooling-oil cooling combined quenching, which has simple process and excellent tensile strength and elongation. The aim of the invention is achieved by the following technical scheme: a preparation method of a high-performance 6-series aluminum alloy forging based on semi-solid pretreatment and mist cooling-oil cooling combined quenching comprises the following steps: Smelting, wherein the smelting alloy comprises the following components: 0.8-1.3wt.% of Si, 1.2-1.7wt.% of Mg, less than or equal to 0.5 wt wt.% of Cu, less than or equal to 0.3wt.% of Fe, less than or equal to 0.15wt.% of Mn, less than or equal to 0.15wt.% of Cr, less than or equal to 0.1wt.% of Ti, less than or equal to 0.2wt.% of other impurities, and the balance of Al. Step two, after the melt is cooled, carrying out ultrasonic treatment to reach a semi-solid temperature, and standing for solidification; step three, carrying out heat preservation treatment on the cast ingot; step four, performing hot die forging on the ingot subjected to heat preservation treatment; step five, carrying out compound quenching on the forge piece, firstly adopting water mist to carry out first-stage rapid cooling, and then adopting oil cooling to carry out second-stage slow cooling; and step six, aging the cooled forging. Further, in the second step, the ultrasonic vibration starting temperature is 660-690 ℃, and the semi-solid temperature is 580-620 ℃. Further, in the third step, the heat preservation temperature is 450-500 ℃ and the heat preservation time is 0.5-1 h. Further, in the step four hot die forging, firstly, the temperature of the cast ingot is preheated to 450-550 ℃ for 1-3 hours, the temperature rising rate is 5-15 ℃ per minute, the die temperature is 300-400 ℃, and the forging rate is 3-15 mm/s. Further, in the fifth step, the rapid cooling termination temperature of the first stage is 260 ℃ to 280 ℃, the cooling time is 10s to 30s, the water mist temperature is 10 ℃ to 25 ℃, and the cooling rate is 9 ℃ per second to 20 ℃ per second. Further, in the fifth step, the second stage is slowly cooled to a termination temperature of 175 ℃ to 185 ℃ for a cooling time of 50s to 70s, a quenching oil temperature of 70 ℃ to 80 ℃ and a cooling rate of 0.5 ℃ per s to 5 ℃ per s. Further, in the sixth step, the aging temperature is 160 ℃ to 220 ℃ and the time is 2 hours to 5 hours. Compared with the prior art, the invention has the beneficial effects that: According to the preparation method of the high-performance 6-series aluminum alloy forging based on semi-solid pretreatment and mist cooling-oil cooling combined quenching, mg, si, cu, fe, mn and other elements are added, so that compared with the traditional 6-series aluminum alloy, the preparation method has the advantages that the content of Mg element is improved, the preparation process conditions are adjusted, the solid solubility of Mg in primary alpha-Al is improved, the precipitation behavior and uniformity distribution of second-phase particles are controlled, and the strength and plasticity of the alloy are improved. Specifically, the semi-solid pulping process is adopted to obviously refine primary alpha-Al grains, so that the stress concentration effect in the deformation process is relieved. The solid solution of Mg element is promoted by heat preservation treatment, st