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4340 Hot Rolled SBQ Bar

Hot rolled 4340 steel bar is a nickel-chromium-molybdenum medium carbon alloy steel that is known for its toughness. This steel grade also has good ductility and high strength. Hot rolled 4340 bar has good impact, and wear resistance in the hardened condition. This grade is often used because it provides hardenability and strength that other steel grades cannot provide. Eaton Steel Bar Company stocks many diameters of 4340 hot rolled steel to meet the market demands. We also supply 4340 steel bar to various industries like aerospace, automotive, and tooling.

4340 hot-rolled-steel-bar


Typical applications for this grade include:

  • Axle shafts
  • Heavy duty shafting
  • Mine drilling parts


Eaton Steel Bar Company can meet the following specifications for this grade:

  • ASTM A29
  • ASTM A322

Shapes and Sizes

Eaton Steel Bar Company supplies 4340 steel bar in a variety of sizes ranging from 1/2”-15”. The shapes available for this grade include:

  • 4340 Hot Rolled Round Bar

***Minimum Total Quantity Per Order is 10,000 lbs.***

Estimate Your Order Weight


Standard "4340 Grade" Chemical Composition

Carbon 0.38-0.43
Manganese 0.60-0.80
Phosphorus (max) 0.035
Sulfur (max) 0.040
Silicon 0.15-0.35
Nickel 1.65-2.00
Chromium 0.70-0.90
Molybdenum 0.20-0.30


Estimated Mechanical Property Ranges for "Grade 4340"

Tensile strength (psi) 105,000 - 115,000
Yield strength (psi) 75,000 - 85,000
Elongation in 2” (%) 20 - 30
Reduction of area (%) 35 - 45
Brinell Hardness (BHN) 210 - 240