Same standard, different smelting

GCr15 and AISI 52100 (and DIN 100Cr6, JIS SUJ2) specify essentially the same chemistry: ~1% carbon, 1.3-1.6% chromium. There is no meaningful "grade difference" between the designations - the real quality spread comes from how the steel is smelted:

What a buyer should specify

• Smelting route (require vacuum degassing minimum) and EN 10204 3.1 material certificate
• Non-metallic inclusion rating to ISO 4967 / ASTM E45 (ask for the report, not a claim)
• Hardness after heat treatment: HRC 61-65 for rings and balls
• Structural audit: our factory profile lists metrology and heat-treatment equipment available for customer audits

KMK practice

KMK Bearing buys vacuum-degassed GCr15 from major Chinese mills for all standard product and offers ESU material for high-reliability programs. Every batch ships with material certificates and hardness records on request.

For corrosive or insulated applications, move to ceramic or stainless options instead of premium chrome steel.

Ready to source? Request a quotation or email kevin@sinoti.com - drawings, samples and OEM/ODM projects welcome. MOQ from 1 piece for prototypes.

Source: KMK Bearing