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4140 Annealed (LPA) CD Steel Bar

4140 LPA steel bar is a medium Carbon, Chromium-Molybdenum steel with high hardenability. It is characterized as having excellent toughness and is known for its ability to resist high stress and high heat working conditions. Eaton Steel Bar Company stocks many diameters of 4140 LPA cold drawn steel to meet the market demand. ASTM specifications are generally applicable for 4140 LPA steel bars.

4340 cold-rolled-steel-bar

4140 LPA Cold Drawn Steel Bar Applications

Typical applications for this grade of steel include bolts, shafts, gears, couplings and tools. Ideal for applications requiring forging

Shapes and Sizes

Eaton Steel Bar Company supplies 4140 LPA cold drawn steel bar in a variety of sizes ranging from – 5/6”-6”. The shapes available for this grade include:

  • Rounds

Standard "4140 Annealed (LPA) 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 Properties for "Grade 4140 Annealed (LPA)"

Tensile strength 95,000 psi
Yield strength 60,500 psi
Elongation in 2" 15-25%
Reduction of area 45-55%
Brinell Hardness 187-197