42CrMo , 4140, SCM440, 42CrMo4 High Tensile Steel Bar
42CrMo is a Chinese standard chromium-molybdenum high strength steel with good hardenability and toughness. This steel usually adopts quenching after tempering as the heat treatment solution. After tempering, it has relatively high fatigue and impact resistance and no obvious temper brittleness.
42CrMo/4140 has good mechanical properties and machinability, mainly in the form of plate and round rod. In the processing industry, the 42CrMo plate for the mold processing production, the 42CrMo round rod for mechanical direct processing parts.
42CrMo bar and plate is mainly used for manufacturing important structural parts working under high load such as hydraulic shafts, transmission gear, supercharger gear, engine cylinder; Spring clip, oil drill pipe clamp first class parts. In the mold manufacturing industry, 42CrMo is also suitable for large and medium-sized plastic molds with certain strength and toughness.
The corresponding material of 42CrMo steel as per the European Union, Japan, Germany and the United States standards respectively are: 42CrMo4, SCM440, 42CrMo4, 4140. In most situation they can be alternative materials, unless there is a special note or used for special purpose. Their differences are mainly existed in chemical elements, details showed as follows:
| Standard | Material | C | Si | Mn | Cr | Mo | P | S |
| GB/T 3077 | 42CrMo | 0.38~0.45 | 0.17~0.37 | 0.50~0.80 | 0.90~1.20 | 0.15~0.25 | ≤0.035 | ≤0.035 |
| ASTM A322 | 4140 | 0.38~0.43 | 0.15~0.35 | 0.75~1.00 | 0.80~1.10 | 0.15~0.25 | ≤0.035 | ≤0.040 |
| JIS G4053 | SCM440 | 0.38~0.43 | 0.15~0.35 | 0.60~0.90 | 0.90~1.20 | 0.15~0.30 | ≤0.030 | ≤0.030 |
| DIN 17200 | 42CrMo4
(1.7225) |
0.38~0.45 | ≤0.40 | 0.60~0.90 | 0.90~1.20 | 0.15~0.30 | ≤0.035 | ≤0.030 |