Alloy Steel 4340

Grade Summary: Alloy Steel 4340 can obtain much deeper harden-ability than 4100 series steel. High strength in heavy sections is possible with maximum toughness and ductility. This material has a high fatigue/tensile ratio and maintains strength, ductility, and toughness at relatively high temperatures. Also has excellent non-distorting properties for an alloy steel.

Typical Applications: Crank shafts, axle shafts, dies, subs, gear shafts, gears, mine drilling parts, oil well fishing tools and parts, etc.

Available products:

• Round Bar

Typical Chemical Analysis:

1. * C – .38/.43 Max. *Mn – .60/.90 *P – .035 Max. *S – .04 Max.
2. *Si – .15/.35 *Cr – .70/.90 *Mo – .20/.30 *Ni – 1.65/2.00

Typical Mechanical Properties**