Both 42CrMo and 42CrMoA are Chinese GB standard high strength alloy steels, 42CrMoA is the main material for threaded bar and bolt Anyang Longteng Heat Treatment Material Co.,Ltd.
Please noted, Anyang Longteng’s 42CrMoA is special ordered with our own technical requirements, short for “LT 42CrMoA” in below article:
STANDARD: GB/T 3077-2015
CLASSIFICATION & CODE:
Steel should be divided into the following three types acc. to metallurgical quality:
1) High quality steel;
2) Senior high quality steel (“A” added)
3) Extremely high quality steel (“E” added)
Chemical composition acc.to Anyang Longteng Technical requirements
| C | Si | Mn | P | S | Cr | Mo | |
| 42CrMoA | 0.38-0.45 | 0.17-0.37 | 0.50-0.8 | ≤0.02 | ≤0.02 | 0.9-1.2 | 0.15-0.25 |
Note: total value of P+S should not more than 0.03
GB/T 3077 requirements：
| P | S | Cu | Cr | Ni | Mo | |
| no higher than | ||||||
| 42CrMo | 0.03 | 0.03 | 0.3 | 0.3 | 0.3 | 0.1 |
| 42CrMoA | 0.02 | 0.02 | 0.25 | 0.3 | 0.3 | 0.1 |
| 42CrMoE | 0.02 | 0.01 | 0.25 | 0.3 | 0.3 | 0.1 |
It is known that the content of sulfur and phosphorus in the steel will bring great damage to steel material’s performance and strength. “A” in 42CrMoA refers to sernior high quality steel with less impurities, higher properties.
Acid corrosion LP structure level
| Ingot Segregation | Central Loosening | Ordinary Loodening | Ordinary Point Segregation | Edge Pont Segregation | |
| no higher than | |||||
| 42CrMo | 3 | 3 | 3 | 1 | 1 |
| 42CrMoA | 2 | 2 | 2 | not permitted | |
| LT42CrMoA | 1.5 | 1.5 | 1.5 | ||
| 42CrMoE | 1 | 1 | 1 | ||
Inclusion types and qualification
| Group A | Group B | Group C | Group D | Ds | |||||
| Thick | Fine | Thick | Fine | Thick | Fine | Thick | Fine | ||
| 42CrMo | ≤3.0 | ≤2.5 | ≤3.0 | ≤2.0 | ≤2.0 | ≤1.5 | ≤2.0 | ≤1.5 | — |
| LT42CrMoA | ≤2.0 | ≤1.5 | ≤2.0 | ≤1.5 | ≤2.0 | ≤1.5 | ≤2.0 | ≤1.5 | ≤2.0 |
| 42CrMoE | ≤2.5 | ≤2.0 | ≤2.5 | ≤1.5 | ≤1.5 | ≤1.0 | ≤1.5 | ≤1.0 | |
Post time: Nov-21-2020