42CrMo Steel: Large Sections and Final Condition

42CrMo is a chromium-molybdenum structural-steel designation used in Chinese specifications. Material reference.

Large Sections and Final Condition

For a large shaft, ask whether the proposed stock and treatment can meet requirements at the controlling section, not only at the surface. A commercial comparison with 4140 does not authorize substitution without checking the contracted specification and certificate.

Manufacturing and acceptance checks

Identify the radial and axial test locations, final hardness range, impact requirements if specified and ultrasonic acceptance where needed. Agree the roughing, treatment and finishing sequence before fixing machining allowances. Record which acceptance values apply to the finished part rather than the incoming billet.

Compare related options

• 40Cr Steel
• 4340 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.