SUS440C: Bearing Surfaces and Final Inspection

SUS440C is a high-carbon martensitic stainless grade. Material reference.

Bearing Surfaces and Final Inspection

For a bearing component, the required surface integrity and dimensional stability are as important as the alloy label. A generic hardness value cannot establish fatigue life or suitability for a particular lubricant and environment. Separate material qualification from finished bearing performance.

Manufacturing and acceptance checks

Specify stock quality, final treatment, hardness and any stabilization required by the design. Define race or contact-surface geometry, roughness and defect acceptance after grinding. Ask for traceability through treatment and inspect the finished component; an incoming bar certificate alone does not qualify a bearing surface.

Compare related options

• SUS440B
• SUS410

Reference and scope

Daido: JIS stainless grade identities and chemistry 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.