AISI 4340 Steel, oil quenched 800°C (1470°F), 650°C (1200°F) temper, 50 mm (2 in.) round

Subcategory: AISI 4000 Series Steel; Ferrous Metal; Low Alloy Steel; Medium Carbon Steel; Metal

Key Words: alloy steels, UNS G43400, AMS 5331, AMS 6359, AMS 6414, AMS 6415, ASTM A322, ASTM A331, ASTM A505, ASTM A519, ASTM A547, ASTM A646, MIL SPEC MIL-S-16974, B.S. 817 M 40 (UK) B.S. 817 M 40 (UK), SAE J404, SAE J412, SAE J770, DIN 1.6565, JIS SNCM 8, IS 1570 40Ni2Cr1Mo28, IS 1570 40NiCr1Mo15

Component    Wt. % C 0.37 - 0.43   Cr 0.7 - 0.9   Fe 96

Component    Wt. % Mn 0.7   Mo 0.2 - 0.3   Ni 1.83

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

Physical Properties	Metric	English	Comments
Density	7.85 g/cc	0.284 lb/in³
Mechanical Properties
Hardness, Brinell	269	269
Hardness, Knoop	294	294	Converted from Brinell hardness.
Hardness, Rockwell B	99	99	Converted from Brinell hardness.
Hardness, Rockwell C	27	27	Converted from Brinell hardness.
Hardness, Vickers	284	284	Converted from Brinell hardness.
Tensile Strength, Ultimate	931 MPa	135000 psi
Tensile Strength, Yield	834 MPa	121000 psi
Elongation at Break	20.5 %	20.5 %
Reduction of Area	62.5 %	62.5 %
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	50 %	50 %	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	2.48e-005 ohm-cm	2.48e-005 ohm-cm	20°C (68°F)
Electrical Resistivity at Elevated Temperature	2.98e-005 ohm-cm	2.98e-005 ohm-cm	100°C (212°F)
Electrical Resistivity at Elevated Temperature	5.52e-005 ohm-cm	5.52e-005 ohm-cm	400°C (750°F)
Electrical Resistivity at Elevated Temperature	7.97e-005 ohm-cm	7.97e-005 ohm-cm	600°C (1110°F)
Thermal Properties
CTE, linear 20°C	10.4 µm/m-°C	5.78 µin/in-°F	specimen oil hardened, 630°C (1110°F) temper; -150-20°C (-240-68°F)
CTE, linear 20°C	11.2 µm/m-°C	6.22 µin/in-°F	specimen oil hardened, 630°C (1110°F) temper; -100-20°C (-150-68°F)
CTE, linear 20°C	12.4 µm/m-°C	6.89 µin/in-°F	specimen oil hardened, 630°C (1110°F) temper; 20-200°C (68-390°F)
CTE, linear 250°C	12.6 µm/m-°C	7 µin/in-°F	1.88% Ni, normalized, tempered; 21-260°C (70-500°F)
CTE, linear 250°C	13.6 µm/m-°C	7.56 µin/in-°F	specimen oil hardened, 630°C (1110°F) temper; 20-400°C (68-750°F)
CTE, linear 500°C	13.7 µm/m-°C	7.61 µin/in-°F	1.88% Ni, normalized and tempered; 21-540°C (70-1000°F)
CTE, linear 500°C	13.9 µm/m-°C	7.72 µin/in-°F	1.90% Ni, quenched, tempered; 21-540°C (70-1000°F)
CTE, linear 500°C	14.3 µm/m-°C	7.94 µin/in-°F	specimen oil hardened, 630°C (1110°F) temper; 20-600°C (68-1110°F)
Specific Heat Capacity	0.475 J/g-°C	0.114 BTU/lb-°F	Typical 4000 series steel
Thermal Conductivity	44.5 W/m-K	309 BTU-in/hr-ft²-°F	Typical steel

References for this datasheet.