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HR 4140 steel bar is a medium carbon steel that has a high hardenability. This grade is also widely used for forging. 4140 hot rolled steel also has good fatigue and impact resistance after heat treating. Eaton Steel Bar Company stocks many diameters of 4140 hot rolled steel to meet the markets demand. We also supply 4140 steel bar to various industries like ATV, automotive, construction, and military.

4150 hot-rolled-steel-bar

4140 HR Steel Bar Applications

Typical applications for this grade include drill collars, pins, axles, bolts, and shafts.

Shapes and Sizes

Eaton Steel Bar Company supplies 4140 steel bar in a variety of sizes ranging from 7/16”-15”. The shapes available for this grade include:

  • Rounds

4140 Chemical Properties

Carbon .38-.45
Manganese .75-.1.0
Phosphorus (max) .035
Sulfur (max) .040


4140 Mechanical Properties

Tensile strength 100 ksi
Yield strength 60 ksi
Elongation in 2” 20% - 30 %
Reduction of area 50% - 60%
Brinell Hardness 185-210