AISI 4140 | |
Category | Steel |
Class | Alloy steel |
Type | Standard |
Common Names | Chromium-molybdenum steel |
Designations |
France: AFNOR 40 CD 4 , AFNOR 42 CD 4 Germany: DIN 1.7225 Italy: UNI 38 CrMo 4 KB , UNI 40 CrMo 4 , UNI G 4O CrMo 4 Japan: JIS SCM 4 , JIS SCM 4 H Sweden: SS 2244 United Kingdom: B.S. 708 A 42 , B.S. 708 M 40 , B.S. 709 M 40 United States: AMS 6378 , AMS 6379 , AMS 6381B , AMS 6382 , AMS 6382G , AMS 6390 , AMS 6390A , AMS 6395 , ASTM A322 , ASTM A331 , ASTM A505 , ASTM A519 , ASTM A547 , ASTM A646 , MIL SPEC MIL-S-16974 , SAE J404 , SAE J412 , SAE J770 , UNS G41400 |
Composition | |
Element | Weight % |
C | 0.38-0.43 |
Mn | 0.75-1.00 |
P | 0.035 (max) |
S | 0.04 (max) |
Si | 0.15-0.30 |
Cr | 0.80-1.10 |
Mo | 0.15-0.25 |
Mechanical Properties | |
Properties | Conditions | ||
T (°C) | Treatment | ||
Density (×1000 kg/m3) | 7.7-8.03 | 25 | |
Poisson's Ratio | 0.27-0.30 | 25 | |
Elastic Modulus (GPa) | 190-210 | 25 | |
Tensile Strength (Mpa) | 655.0 | 25 | annealed at 815°C more |
Yield Strength (Mpa) | 417.1 | ||
Elongation (%) | 25.7 | ||
Reduction in Area (%) | 56.9 | ||
Hardness (HB) | 197 | 25 | annealed at 815°C more |
Impact Strength (J) (Izod) |
54.5 | 25 | annealed at 815°C more |
Thermal Properties | |
Properties | Conditions | ||
T (°C) | Treatment | ||
Thermal Expansion (10-6/ºC) | 12.3 | 20-100 more | oil hardened, tempered 600°C |
Thermal Conductivity (W/m-K) | 42.7 | 100 more | |
Specific Heat (J/kg-K) | 473 | 150-200 more |
Electric Properties | |