GB/T 3086-2019 in English

Interpretation of Technical Specifications for High Carbon Chromium Stainless Bearing Steel

1. Standard Background and Revision Highlights

GB/T 3086—2019 "High Carbon Chromium Stainless Bearing Steel" was issued in 2019, replacing the old version of the standard in 2008.

• Added classification by final use of steel (see 3.2)
• Clarified the allowable deviation of steel wire diameter (see 5.1.2)
• Tightened the requirements for sulfur and nickel content in chemical composition (see Table 4, Table 3 of 2008 edition)

2. Technical Features of Standard

Case study: Taking G95Cr18 as an example, the chemical composition C is increased from 0.75-1.00% to 0.90-1.00%, and the sulfur content requirement is tightened from ≤0.030% to ≤0.020%. This change significantly improves the wear resistance and service life of the material.

3. Recommendations for the implementation of the standard

In practical applications, special attention should be paid to the following aspects:

• Chemical composition control: Ensure that the sulfur and nickel contents meet the requirements to avoid degradation of material performance due to excessive impurities.
• Metallurgical process selection: Electroslag remelting technology is recommended, and other methods can be negotiated if necessary.
• Surface quality inspection: Focus on the depth of surface defects of cold-drawn round steel and steel wire to ensure compliance with the requirements of GB/T 3207 standard.

This standard has added new non-destructive testing requirements (see 6.11), especially the ultrasonic testing part. It is recommended to pay special attention to the ultrasonic flaw detection results of steel with a diameter ≥ 60mm during the procurement process.