GB/T 24595-2020 in English
SUPERSEDEDHot-rolled steel bars for quenched and tempered automobile crankshafts
- Issued on:2020-03-06
- Implemented on:2020-10-01
- File Format:PDF
- Delivery:Via email within 1~3 business days
Price(USD)：
$140.00
$136.00
$136.00
《GB/T 24595-2020汽车调质曲轴用热轧钢棒》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
Background of Standard Revision and Technological Evolution
GB/T 24595-2020 is a special standard for steel used in key automotive components. It has carried out a comprehensive technical upgrade of the 2009 version to meet the special requirements of crankshafts under high temperature and high pressure conditions. It mainly responds to the following industry needs:
- To adapt to the trend of lightweight engines, the diameter limit of hot-rolled steel bars is increased to 200mm
- Improve material purity and increase control of hydrogen content (≤0.0002%) and oxygen content (≤0.0020%)
- Optimize alloy design, delete 40CrA/42CrMoA grades, and adjust element limits such as P/S
Analysis of key technical requirements
5.1 Chemical composition control
| Elements | 2009 version | 2020 version | Significance of adjustment |
|---|---|---|---|
| P | ≤0.035% | ≤0.025% | Reduce cold brittleness tendency |
| S | ≤0.035% | ≤0.025% | Improve fatigue performance |
| Cr | 0.80~1.10% | 0.85~1.25%(42CrMo) | Enhance hardenability |
5.5 End hardenability requirements
Use Jominy test to ensure the hardness gradient in the core of the material:
- HRC of 42CrMoS steel J9 needs to reach 50~58
- Add precise control of quenching temperature tolerance ±5℃
- Clear normalizing treatment process parameters (860~880℃)
Implementation and application suggestions
Key points of quality control
- Ultrasonic testing: Diameter ≤130mm according to Grade A standard, >130mm according to Grade B
- Banded structure: Adopt the new rating method of GB/T34474.1, limit level 3
- Surface treatment: Defect removal depth and diameter correlation control (see Table 6)
Sample only — not a preview of GB/T 24595-2020
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