GCr15 (GB/T 18254) is a high-carbon chromium bearing steel engineered for rolling contact, with properties tailored for long service life:
Hardness: 61–65 HRC after quenching (830–860°C) and tempering (150–180°C), ensuring extreme wear resistance in ball and roller bearings.
Tensile strength: ≥1500 MPa, though bearings rely more on fatigue strength (≥300 MPa for 10⁶ cycles) to withstand repeated loading.
Microstructure: Fine, uniform carbide distribution (carbide size ≤3 μm) to prevent stress concentration and spalling-a common failure mode in bearings.
Dimensional stability: Low residual stress after heat treatment, maintaining tight tolerances (±0.001mm for 10mm diameter balls) critical for smooth operation.
Its chemistry (1.00–1.10% C, 1.30–1.65% Cr) promotes carbide formation, while strict P/S limits (≤0.025% each) enhance toughness. GCr15 is equivalent to AISI 52100 (USA) and DIN 100Cr6 (Germany), widely used in automotive wheel bearings, industrial motors, and machine tool spindles. Made-in-China listings highlight it as "GCr15 Bearing Steel Round Bar-High Precision."
These detailed insights highlight how round steel's composition, properties, and standards align with global industrial needs, from construction to precision engineering, ensuring reliability across diverse applications.