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4140 & 4150 Alloy

Typical Properties

AISI 4140 and 4150 is a medium carbon, chromium-molybdenum alloy steel. This steel is offered in a wide range of conditions including but not limited to: cold drawn annealed, hot roll heat treated, heat treated turned ground and polished. Typical tensile strength ranges from 114,000 PSI (Annealed Condition) up to 156,000 PSI (Pre-Hard, Quench and Tempered Condition). AISI 4140 and 4150 steels offer a high resistance to fatigue, improved toughness, impact resistance, and torsional strength.

Not all AISI 4140 and 4150 materials are made to the same standards. Material purchased from Specialty Steel is also Machine Straightened and Stress Relieved.

General welding, machining and additional thermal treatment data is available. Contact our office for details.

4140 Chemistry
C C Si P S Cr Mo
.38-.43 .75-1.00 .15-.35 .035 max .040 Max .80-1.10 .15-.25
4150 Chemistry
C C Si P S Cr Mo
.48-.53 .75-1.00 .15-.35 .035 max .040 Max .80-1.10 .15-.25
stainless round bar thumb

4140/4150 Heat Treated Turned Ground and Polished

Hardness 269/341 BHN ​​

Turned Ground & Polished Finish


Metric Availability

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