AISI 4340 Steel, annealed, 25 mm 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), 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

Material Notes:
Annealed: heated to 810°C, furnace cooled 11°C/hr to 355°C, air cooled

Physical Properties	Metric	English	Comments
Density	7.85 g/cc	0.284 lb/in³
Mechanical Properties
Hardness, Brinell	217	217
Hardness, Knoop	240	240	Converted from Brinell hardness.
Hardness, Rockwell B	95	95	Converted from Brinell hardness.
Hardness, Rockwell C	17	17	Converted from Brinell hardness. Value below normal HRC range, for comparison purposes only.
Hardness, Vickers	228	228	Converted from Brinell hardness.
Tensile Strength, Ultimate	745 MPa	108000 psi
Tensile Strength, Yield	470 MPa	68200 psi
Elongation at Break	22 %	22 %
Reduction of Area	50 %	50 %
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	12.3 µm/m-°C	6.83 µin/in-°F	specimen oil hardened, 600°C (1110°F) temper; 20-100°C (68-212°F)
CTE, linear 20°C	12.7 µm/m-°C	7.06 µin/in-°F	specimen oil hardened, 600°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	13.7 µm/m-°C	7.61 µin/in-°F	specimen oil hardened, 600°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	14.5 µm/m-°C	8.06 µin/in-°F	specimen oil hardened, 600°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.