SAE 4140
SAE 4140 Grade Introduction:
SAE 4140 Alloy steel grade is a versatile alloy with good atmospheric corrosion resistance and reasonable strength. It shows good overall combinations of strength, toughness, wears resistance, and fatigue strength.
SAE 4140 Grade Application:
- Forgings for the aerospace industry
- Oil and gas industries
- Automotive industry
- Agricultural industry
- Defense industry
SAE 4140 Equivalent Grades:
| Country |
Standard |
Specification |
| USA |
ASTM A29 |
4140 |
| Germany (DIN) |
DIN 1654 |
1.6523/21NiCrMo2 |
| BS |
EN 10084 |
1.6523/21NiCrMo2-2 |
| UK (BS) |
BS 970 |
805M20 |
| Japan |
JIS G4103 |
SNCM220 |
SAE 4140 Chemical Composition:
| Standard |
Grade |
C |
Mn |
P |
S |
Si |
Cr |
Mo |
| ASTM A29 |
4140 |
0.38-0.43 |
0.75-1.00 |
0.035 |
0.040 |
0.15-0.35 |
0.8-1.10 |
0.15-0.25 |
| EN 10250 |
42CrMo4 /1.7224 |
0.38-0.45 |
0.6-0.9 |
0.035 |
0.035 |
0.4 |
0.9-1.2 |
0.15-0.30 |
| JIS G4105 |
SCM440 |
0.38-0.43 |
0.60-0.85 |
0.03 |
0.03 |
0.15-0.35 |
0.9-1.2 |
0.15-0.30 |
Mechanical Properties:
| Properties |
Metric |
Imperial |
| Tensile strength |
655 MPa |
95000 psi |
| Yield strength |
415 MPa |
60200 psi |
| Bulk modulus (typical for steel) |
140 GPa |
20300 ksi |
| Shear modulus (typical for steel) |
80 GPa |
11600 ksi |
| Elastic modulus |
190-210 GPa |
27557-30458 ksi |
| Poisson’s ratio |
0.27-0.30 |
0.27-0.30 |
Physical Properties:
| Properties |
Metric |
Imperial |
| Density |
7.85 g/cm³ |
0.284 lb/in³ |
| Melting point |
1416°C |
2580°F |
Thermal Properties:
| Properties |
Metric |
Imperial |
| Density |
7.85 g/cm³ |
0.284 lb/in³ |
| Melting point |
1416°C |
2580°F |
Forging Properties:
Forging of SAE 4140 steel should be carried out between 2200 and 1650 º F (1200 and 900 º C). The lower the finishing temperature from forging, the finer will be the grain size. This alloy steel should ideally not be forged below 1650 º F (900 º C) and should be slow cooled after forging in oil or water.
Stress Relieving:
Stress Relieving Heat to 680°C– 700°C, hold until temperature is uniform throughout the section, soak for 1 hour per 25 mm section, and cool in still air.