1.6523 case hardening steel

1. AISI 8620 Steel | 1.6523 | 21NiCrMo2 | SNCM220

1.6523 Nickel–Chrome–Moly Carburising Steel

1.6523 has a high case toughness and above average core toughness due to the nickel content.

2. 1.6523 Steel Specification and Relevant Standards

Country USA DIN BS BS Japan
Standard ASTM A29 DIN 1654 EN 10084 BS 970 JIS G4103
Grades 8620 1.6523/
21NiCrMo2		 1.6523/
20NiCrMo2-2		 805M20 SNCM220

3. 1.6523 Steels & Equilvalents 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/
20NiCrMo2-2		 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 0.15-0.3
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

4. 1.6523 Steel Mechanical Properties

Density (lb / cu. in.) 0.283
Specific Gravity 7.8
Specific Heat (Btu/lb/Deg F – [32-212 Deg F]) 0.1
Melting Point (Deg F) 2600
Thermal Conductivity 26
Mean Coeff Thermal Expansion 6.6
Modulus of Elasticity Tension 31

Properties 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
Izod Impact 115 J 84.8 ft.lb
Hardness, Brinell 149 149
Hardness, Knoop (converted from Brinell hardness) 169 169
Hardness, Rockwell B (converted from Brinell hardness) 80 80
Hardness, Vickers (converted from Brinell hardness) 155 155
Machinability (hot rolled and cold drawn, based on 100 machinability for AISI 1212 steel) 65 65

5. Forging of Material 1.6523 Steel

1.6523 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.

6. 1.6523 Applications

Additionally, it is the most widely used carburizing alloy steel. Typical uses include: gears, cranks, shafting, axles, bushings, heavy duty pins, bolting, springs, hand tools,and many other machinery parts.