SAE 8620
SAE 8620 Grade Introduction:
SAE 8620 Alloy Steel is a low alloy nickel, chromium, molybdenum case hardening steel, generally supplied in the as-rolled condition with a maximum hardness HB 255max. SAE 8620 alloy steel offers high external strength and good internal strength, making it highly wear-resistant. SAE 8620 steel has a higher core strength than grades 8615 and 8617.
SAE 8620 alloy steel is flexible during hardening treatments, thus enabling improvement of case/core properties. Prehardened and tempered (uncarbonized) 8620 can be further surface hardened by nitriding but will not respond satisfactorily to flame or induction hardening due to its low carbon content. SAE 8620 alloy steel is suited for applications that require a combination of toughness and wear resistance. This grade is commonly supplied in a round bar.
SAE 8620 Grade Application:
- Camshafts
- Fasteners
- Gears
- Chains/chain pins
SAE 8620 Equivalent Grades:
| Standard |
USA |
DIN |
BS |
BS |
JAPAN |
| Specification |
ASTM A29 |
DIN 1654 |
EN 10084 |
BS 970 |
JIS G4103 |
| Grade |
8620 |
1.6523/21NiCrMo2 |
1.6523/21NiCrMo2-2 |
805M20 |
SNCM220 |
SAE 8620 Chemical Composition:
| Standard |
Grade |
C |
Mn |
P |
S |
Si |
Ni |
Cr |
Mo |
| ASTM A29 |
8620 |
0.18-0.23 |
0.7-0.9 |
0.035 |
0.040 |
0.15-0.35 |
0.4-0.7 |
0.4-0.6 |
0.15-0.25 |
| DIN 1654 |
1.6523/21NiCrMo2 |
0.17-0.23 |
0.65-0.95 |
0.035 |
0.035 |
≤0.40 |
0.4-0.7 |
0.4-0.7 |
0.15-0.25 |
| EN 10084 |
1.6523/21NiCrMo2-2 |
0.17-0.23 |
0.65-0.95 |
0.025 |
0.035 |
≤0.40 |
0.4-0.7 |
0.35-0.70 |
0.15-0.25 |
| JIS G4103 |
SNCM220 |
0.17-0.23 |
0.6-0.9 |
0.030 |
0.030 |
0.15-0.35 |
0.4-0.7 |
0.4-0.65 |
0.15-0.30 |
| BS 970 |
805M20 |
0.17-0.23 |
0.6-0.95 |
0.040 |
0.050 |
0.1-0.4 |
0.35-0.75 |
0.35-0.65 |
0.15-0.25 |
Mechanical Properties:
| Property |
Metric |
Imperial |
| Tensile strength |
530 MPa |
76900 psi |
| Yield strength |
385 MPa |
55800 psi |
| Elastic modulus |
190-210 GPa |
27557-30458 ksi |
| Bulk modulus (typical for steel) |
140 GPa |
20300 ksi |
| Shear modulus (typical for steel) |
80 GPa |
11600 ksi |
| Poisson’s ratio |
0.27-0.30 |
0.27-0.30 |
Physical Properties:
| Property |
Metric |
Imperial |
| Density |
7.85 g/cm³ |
0.284 lb/in³ |
Thermal Properties:
| Property |
Metric |
Imperial |
| Thermal conductivity |
46.6 W/mK |
323 BTU in/hr.ft².°F |
Forging Properties:
SAE 8620 alloy steel is forged at a start temperature of around 2250ºF (1230ºC) down to approximately 1700ºF(925ºC.) prior to the hardening heat treatment or carburizing. The alloy is air cooled after forging.
Stress Relieving:
Heat to 630°C – 650°C, hold until temperature is uniform throughout the section, soak for 1 hour per 25mm section, and cool in still air.