24 July 2021 Gear Steel Bar
SCM440H Gear Steel Bar
SCM440 is a commonly steel grade which used for the production of high-strength fasteners and gears. The product has the advantages of stable composition, low harmful elements, high steel purity, small decarburization layer, and few surface defects. It is easy to perform spheroidizing annealing and cooling during use. The upsetting cracking rate is low, the heat treatment quality is stable, and the hardness is uniform.
It is widely used in engines, molds and other industries. It can replace with 42CrMo in China and 42CrMo4 in Germany. It belongs to medium hardenability steel, has good strength and good comprehensive mechanical properties after heat treatment, good manufacturability, and high yield rate. The maximum operating temperature is 427℃. Can be used as a steam turbine fastener.
Chemical composition:
| C | Si | Mn | P | S | Cr | Mo |
|---|---|---|---|---|---|---|
| 0.38 - 0.45 | max 0.4 | 0.6 - 0.9 | max 0.025 | max 0.035 | 0.9 - 1.2 | 0.15 - 0.3 |
Mechanical properties:
| Nominal diameter (mm): | to 16 | 16 - 40 | 40 - 100 | 100 - 160 | 160 - 250 | 250 - 330 | 330 - 660 |
|---|---|---|---|---|---|---|---|
| Rm - Tensile strength (MPa) (+QT) | 1100-1300 | 1000-1200 | 900-1100 | 800-950 | 750-900 | 700 | 600 |
| Nominal thickness (mm): | 0.3 - 3 | ||||||
| Rm - Tensile strength (MPa) (+A) | 620 | ||||||
| Rm - Tensile strength (MPa) (+AC) | 630 | ||||||
| Nominal thickness (mm): | to 8 | 8 - 20 | 20 - 50 | 50 - 80 | |||
| Rm - Tensile strength (MPa) (+QT) | 1100 | 1000 | 900 | 800 | |||
| Rm - Tensile strength (MPa) (+C) | 720 | ||||||
| Rm - Tensile strength (MPa) (+LC) | 670 | ||||||
Equivalent Grade:
| EU EN | USA - | Germany DIN,WNr | Japan JIS | France AFNOR | England BS | Italy UNI | Spain UNE | China GB | Sweden SS | Finland SFS | Russia GOST | Inter ISO |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 42CrMo4 (1.7225) | 4140 4142 | 42CrMo4 | SCM440H | 42CD4 | 708M40 CFS11 | 42CrMo4 | 40CrMo4 F1252 | 42CrMo | 2244 | 42CrMo4 | 35KHM 38KHM | 42CrMo4 |
Advantage and Application:
- Good hardenability, deep hardening can be carried out, instead of surface hardening of anti-saw locks on the market
- Less tendency to temper brittleness
- Good high temperature processability, beautiful after processing
- Good welding
- The shock absorption performance is good, there will be a sense of rebound when the hammer hits it, and the violent damage cannot be carried out.