GB/T 38715-2020 in English

This standard is applicable to high-strength magnesium alloy bars produced by extrusion process, and focuses on standardizing the technical requirements for deformed magnesium alloy products with tensile strength ≥350MPa. Compared with conventional magnesium alloy standards, there are significant improvements in the following aspects:

• Strength threshold: clearly stipulate the lower limit of room temperature tensile strength
• Alloy system: New VW series rare earth magnesium alloy grades
• Process control: Require process guarantee of extrusion ratio ≥ 6

The innovative VW series rare earth magnesium alloys in the standard (such as VW93M, VW94M) are strengthened by Gd/Y/Zn multi-components to achieve:

1. The total content of rare earth elements reaches 8-9.8%
2. Zr microalloying for grain refinement
3. Strict control of impurity elements such as Fe/Ni (≤0.02%)

Typical application case: After adopting VW84N alloy, an aerospace structural part can reduce its weight by 30% while meeting the strength requirement of 450MPa.

Key points of production process control

• Ingot quality must comply with YS/T627 standard
• Extrusion temperature must be controlled in the range of 300-400℃
• T5/T6 heat treatment requires precise control of aging parameters

Detection precautions

• Chemical composition arbitration adopts GB/T13748 method
• Macrostructure detection should pay attention to the depth of coarse grain ring
• Water immersion method is recommended for ultrasonic flaw detection