Precision Gcr15 Steel Ball Bearing G10 HRC63 Replacement Bearings 0.8mm to 9mm

Measure the existing balls with a micrometer or refer to the bearing manufacturer's datasheet. The ball diameter is listed in the bearing's internal geometry specification. Match the measured diameter to the nearest available size in this listing. For inch-fractional bearings, cross-reference the decimal equivalent (e.g., 1/4 in = 6.35 mm) against the available options.

G10 is an ISO 3290 precision grade indicating a diameter tolerance of ±0.25 µm and a sphericity deviation of ≤0.25 µm. It is suitable for most machine-tool spindles, precision instruments, and general industrial bearings. Applications requiring tighter tolerances (G5 or G3) — such as ultra-precision grinding spindles — should specify a higher grade.

The balls are through-hardened to HRC 60–65 via a controlled heat-treatment process. At this hardness level, plastic deformation under normal rolling-contact loads is negligible. Gcr15 / AISI 52100 is the industry-standard material for bearing balls precisely because of its combination of surface hardness and core toughness.

Gcr15 chrome steel provides moderate corrosion resistance compared to carbon steel, but it is not stainless. For humid, wet, or chemically exposed environments, apply a light rust-inhibiting oil after installation, or consider stainless steel balls (AISI 440C) for those specific conditions. For standard indoor mechanical applications, no additional treatment is required.

Yes, provided the diameter matches the OEM specification. Bearing balls are standardised components; the critical parameters are diameter, grade, and material. These G10 Gcr15 balls meet the material and dimensional standards used by major bearing manufacturers. Always verify the ball count and diameter from the bearing's technical datasheet before ordering.

Packing quantities are set per variant: smaller diameters (0.8 mm–6.3 mm) come in 300-piece packs, mid-range sizes (6.35 mm–7.5 mm) in 200-piece packs, and larger sizes (7.938 mm–9 mm) in 100-piece packs. Each variant is a separate SKU, so you can add multiple diameter variants to your cart independently to build a mixed-size stock order.

Gcr15 (AISI 52100) chrome steel offers higher hardness (HRC 60–65) and superior fatigue life under rolling contact compared to standard 440C stainless (typically HRC 58–62). Choose Gcr15 for high-load, high-cycle applications where corrosion is not a primary concern. Choose stainless steel when the operating environment involves moisture, food contact, or chemical exposure that would corrode chrome steel.