4340 Steel: Highly Loaded Shafts

4340 is a nickel-chromium-molybdenum alloy steel. Material reference.

Highly Loaded Shafts

Consider it for a demanding shaft or pin only after defining load spectrum, section size and failure criterion. Comparing grades by a single advertised tensile strength hides differences in heat treatment, toughness and the fatigue effect of notches or surface damage.

Manufacturing and acceptance checks

Put the required final condition, hardness and any toughness test on the drawing. Review thread roots, fillets, grinding and plating with the process supplier. Ask for traceability through heat treatment and define whether the acceptance test represents the surface, mid-radius or core of the controlling section.

Compare related options

• 4130 Steel
• 42CrMo Steel

Reference and scope

Baosteel: structural and spring steel grade families provides material or specification background. The checks above are purchasing guidance; final acceptance values must come from the agreed grade, product specification and condition.

Send a drawing and material requirements for review. Include quantity, critical dimensions and the inspection evidence required with delivery.