GB/T 38807-2020 in English
VALIDGeneral specification for super austenitic stainless steels
- Issued on:2020-06-02
- Implemented on:2020-12-01
- File Format:PDF
- Delivery:Via email within 1~3 business days
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《GB/T 38807-2020超级奥氏体不锈钢通用技术条件》由TC183（全国钢标准化技术委员会）归口，TC183SC16（全国钢标准化技术委员会特殊钢分会）执行，主管部门为中国钢铁工业协会。
Introduction
Core technical requirements of the standard
| Technical dimensions | Characteristics of super austenitic stainless steel | Comparison with conventional austenitic stainless steel |
|---|---|---|
| PREN value | ≥40（Cr+3.3(Mo+0.5W)+16N） | 18-35 |
| Chemical composition | High Cr(20-26%), Mo(5-8%), N(0.1-0.6%) | Cr16-20%, Mo0-3%, N≤0.1% |
| Mechanical properties | Tensile strength ≥600MPa, elongation ≥35% | Tensile strength ≥515MPa |
Key indicators implementation points
1. Corrosion resistance control:The standard requires intergranular corrosion test through GB/T4334-2020 E method. In actual application, please note:
- The solution treatment temperature needs to be controlled in the range of 1100-1200℃
- The cooling rate needs to be guaranteed to be ≥55℃/min to avoid σ phase precipitation
2. Ultrasonic testing alternative:For steel bars with a diameter of ＞200mm, the GB/T4162 standard can be used for full-section scanning, and the defect amplitude should be lower than 50% of the DAC curve.
Typical application scenarios
Take S31254 steel as an example, its performance in seawater desalination equipment:
- Pitting rate in 90℃ seawater environment <0.01mm/year
- Stress corrosion threshold ≥250MPa
- The service life of heat exchanger pipes can reach 3 times that of conventional 316L
Technology evolution analysis
This standard is mainly upgraded compared with the previous version:
- Three new high tungsten nitrogen alloy grades such as S31266
- PREN calculation formula introduces tungsten element correction factor 0.5
- Non-metallic inclusion rating adopts the new version of GB/T10561-2005 atlas
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