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Alloy Steel Round Bar 4340 Normalized Cold Finish has high strength, toughness, wear resistance, and fatigue strength. It can be machined in all states other than hardened and it is easily welded. Additionally, 4340 can be cold worked easily in the annealed state. It is typically used in military aircraft, automotive systems, hydraulic parts, machine tools, and a steel crankshafts.

shape Image

Dimension Name


Alloy 4340
Temper Normalized
Diameter 0.375
Max Length 144
MTR Availability Yes
Full Length true
Material Alloy Steel
Shape Bar-Round
Custom Cut Warehouse 1
Material Specifications

This material meets the following specs: ASTM -A29, ASTM -A322, AMS -6415, ASTM -A108, AMS -6484, AMS/MIL -S-5000

Weight/Lineal Foot

0.38 pounds
Please note that this data is to be used ONLY FOR REFERENCE, NOT FOR DESIGN, and by using it,you agree that any decisions you make regarding materials for your project are at your own discretion.

Mechanical Properties

Property Value
Brinell hardness  363
Rockwell Hardness B Scale 100
Elongation Typical % 12
Density g/cm^3 8
Melting Point °F 2580 - 2650
Modulus of Elasticity KSI x 10^3 29
Specific Heat BTU/lb-°F (32-212F) 0 min
Thermal conductivity BTU-in/hr-ft^2-°F 309
Ultimate KSI 190
Yield KSI 120
Ultimate shear strength KSI 110
Reduction of Area  36

Chemistry Information: 4340 Alloy Steel

Element Percentage
C 0.37 - 0.43
Cr 0.8
Fe 96
Mn 0.7
Ni 1.83
P 0.035 max
S 0.04 max
Si 0.23
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