AISI 8740 Steel, oil quenched 830°C (1525°F), 595°C (1100°F) temper, 100 mm (4 in.) round

Subcategory: AISI 8000 Series Steel; Ferrous Metal; Low Alloy Steel; Medium Carbon Steel; Metal

Close Analogs: AISI 8740H

Key Words: DIN 1.6546, UNI 40 NiCrMo 2 KB, B.S. Type 7, ASTM A331, ASTM A505, ASTM A519, MIL-SPEC MIL-S-6049, SAE J404, SAE J412, SAE J770, UNS G87400, AMS 6322, AMS 6323, AMS 6325, AMS 6327, AMS 6358, ASTM A322

Component    Wt. % C 0.38 - 0.43   Cr 0.5   Fe 97

Component    Wt. % Mn 0.88   Mo 0.25   Ni 0.55

Component    Wt. % P Max 0.035   S Max 0.04   Si 0.23

Material Notes:
Post oil quenched hardness 42 HRC surface, 37 HRC half-radius, 36 HRC center

Physical Properties	Metric	English	Comments
Density	7.85 g/cc	0.284 lb/in³
Mechanical Properties
Hardness, Brinell	248	248
Hardness, Knoop	272	272	Converted from Brinell hardness.
Hardness, Rockwell B	98	98	Converted from Brinell hardness.
Hardness, Rockwell C	23	23	Converted from Brinell hardness.
Hardness, Vickers	261	261	Converted from Brinell hardness.
Tensile Strength, Ultimate	855 MPa	124000 psi
Tensile Strength, Yield	670 MPa	97200 psi
Elongation at Break	20.5 %	20.5 %	in 50 mm
Modulus of Elasticity	205 GPa	29700 ksi	Typical for steel
Bulk Modulus	140 GPa	20300 ksi	Typical for steel.
Poisson's Ratio	0.29	0.29	Calculated
Machinability	65 %	65 %	annealed and cold drawn. Based on 100% machinability for AISI 1212 steel.
Shear Modulus	80 GPa	11600 ksi	Typical for steel
Electrical Properties
Electrical Resistivity	2.34e-005 ohm-cm	2.34e-005 ohm-cm	Typical steel
Thermal Properties
Specific Heat Capacity	0.475 J/g-°C	0.114 BTU/lb-°F	Typical steel
Thermal Conductivity	46.6 W/m-K	323 BTU-in/hr-ft²-°F	Typical steel

References for this datasheet.