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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.

4140 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

Standard "4140 Grade" Chemical Composition

Carbon 0.38-0.43
Manganese 0.75-1.00
Phosphorus (max) 0.035
Sulfur (max) 0.040
Silicon 0.15-0.35
Chromium 0.80-1.10
Molybdenum 0.15-0.25


Estimated Mechanical Property Ranges for "Grade 4140"

Tensile strength (psi) 95,000 - 105,000
Yield strength (psi) 65,000 - 75,000
Elongation in 2” (%) 20 - 30
Reduction of area (%) 35 - 45
Brinell Hardness (BHN) 200 - 230