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Important factors affecting the mechanical properties of 6000 series aluminum alloy
- Dec 29, 2018 -

6063, 6063A, 6A02, 6061 aluminum alloys are mostly used in the production of construction materials, industrial materials, furniture materials, ladder materials. Most customers have higher and higher requirements for tensile strength and elongation of special-purpose products. Therefore, based on years of practical experience, how to obtain better mechanical properties of commonly used 6-series aluminum alloys is as follows:

1) Chemical composition of aluminum alloy ingot

6063 and 6063A are alloys with Mg2Si as the strengthening phase. Therefore, the content of the strengthening phase should be determined first. Generally, when the amount of Mg2Si is in the range of 0.71%----1.03%, the tensile strength is approximately linear with the increase of Mg2Si. The improvement, but the deformation resistance is also improved, the processing becomes difficult, but when the amount of Mg2Si is less than 0.72%, the tensile strength value may not meet the standard requirement for products with a small extrusion coefficient (less than or equal to 30). When the amount of Mg2Si exceeds 0.9%, the plasticity of the alloy tends to decrease. After determining the amount of the strengthening phase, the content of Mg is determined. Mg is a flammable metal, and there is burning during the smelting operation. When determining the control range of Mg, the error caused by burning is considered, but it cannot be too wide. In order to avoid the uncontrolled performance of the alloy, the fluctuation range of Mg should be within 0.04%, the T5 profile should be 0.47--0.53%, and the T6 profile should be 0.57----0.60%. When the range of Mg is determined, the Mg/Si ratio can be used to determine silicon. Si can form compounds with other elements such as AlFeSi, so Si should be supplemented by 0.09---0.13% on the original basis, and Mg/Si should be controlled at 1.18- --Between -1.32. The amount of Mg2Si in 6061 and 6A02 alloys should be controlled at about 1.4%. To enhance the elongation, the content of Cu is about 0.2---0.4%. Its Vickers hardness is greater than or equal to 15

2) Homogenization of aluminum alloy ingot

The homogenization treatment can improve the plasticity of the ingot, improve its process performance, improve the anisotropy of the product, and eliminate the residual stress inside the metal.

3) Aluminum extrusion temperature and speed

6063, 6063A its quenching temperature should not be lower than 500 degrees, so the extrusion temperature is generally controlled at 470---490 degrees, 6061, 6A02 its delivery state is generally T6, quenching temperature is slightly higher than 6063 about 510----520 degree. The specific extrusion temperature and extrusion speed should be properly adjusted according to the wall thickness, extrusion characteristics and mold condition of the profile, and adhere to the principle of high temperature and low speed, low temperature and high speed extrusion. However, its outlet temperature must not be lower than the product quenching temperature.

4) Aluminum profile quenching effect

Quenching is to preserve the Mg2Si dissolved in the base metal at high temperature after rapid cooling to room temperature after being discharged from the mold. The cooling rate is often proportional to the content of the strengthening phase, and the quenching sensitivity is increased, which is 0.8 in Mg2Si. % of 6063 alloy, from 454 degrees to 204 degrees of critical cooling temperature range, the minimum cooling rate is 38 degrees / minute, while the 6061 alloy containing 1.4% Mg2Si cooling rate in the above critical cooling temperature range should not be less than 65 Degrees/minute, therefore, 6063 can be quenched by air-cooling, and 6061 must be quenched with water. Uniform and good quenching effect can effectively improve the mechanical properties of the product.

5) Aluminum profile artificial aging

6063, 6061 alloy profiles have a tensile strength equal to or greater than 140 MPa in the extruded state, and artificial aging within 8 hours after rapid cooling to room temperature can increase the tensile strength to above 240 MPa, artificial aging Generally use 190---200 degrees insulation for 1--2 hours. 6061, 6A02 generally use 180---190 degrees to maintain 4--6 hours. (Specifically according to the profile wall thickness, chemical composition and order requirements)

In the aluminum profile production management process, the above extrusion process parameters are effectively controlled, and good mechanical properties can be obtained. 6063 and 6063A can ensure that the Vickers hardness is greater than or equal to 12.6061, 6A02, and the Vickers hardness can be greater than or equal to 15. And to meet the requirements of various products to a large extent.