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When your application demands tight tolerances and consistent roundness, undersized or inconsistent balls cause vibration, premature wear, and costly downtime. Engineers, machinists, and precision assembly technicians working on bearings, valves, pumps, and linear guides need steel balls they can trust to spec every time. These GCR15 solid steel balls are manufactured to ABEC G5 grade, delivering the dimensional accuracy and surface finish that demanding applications require.
Each ball is made from GCR15 bearing steel (equivalent to AISI 52100 / 100Cr6), a high-carbon chromium alloy known for its hardness, wear resistance, and fatigue strength. Available diameters range from 1.0mm (0.039 in) to 18.256mm (0.719 in), covering both metric and inch-series sizes. Balls are supplied in bulk counts from 10 PCS to 1000 PCS depending on diameter, making them suitable for both prototyping and production runs.
Typical use cases include replacement balls for deep-groove ball bearings and angular contact bearings, check valve seats in hydraulic and pneumatic systems, precision jig and fixture components, and load-bearing elements in linear motion assemblies. Long-tail search terms this product addresses: GCR15 steel ball 52100 equivalent, G5 grade bearing balls metric, solid chrome steel balls bulk, precision steel balls for bearings replacement.
Manufactured to ISO 3290 Grade 5 tolerances — spherical deviation typically ≤0.13 µm — for smooth, low-noise operation in precision bearings and instruments.
High-carbon chromium alloy (GCR15, equivalent to AISI 52100 / DIN 100Cr6) delivers hardness typically 60–66 HRC and excellent fatigue life under cyclic loading.
54 diameter options from 1.0mm to 18.256mm, including both metric and inch-series sizes (e.g., 1.588mm = 1/16", 3.175mm = 1/8", 6.35mm = 1/4", 9.525mm = 3/8", 12.7mm = 1/2").
Available in packs from 10 PCS to 1000 PCS (quantity options vary by diameter), so you can order exactly what your project or production run requires.
The chromium content in GCR15 steel provides moderate corrosion resistance and significantly extends service life compared to standard carbon steel balls in lubricated environments.
Dimensionally consistent balls suitable as direct replacements in standard bearing housings — match the ball diameter to your bearing's ball complement specification for a drop-in fit.
| Material | GCR15 Bearing Steel (equiv. AISI 52100 / 100Cr6) |
|---|---|
| Grade | G5 (ISO 3290) |
| Diameter Range | 1.0mm – 18.256mm (0.039" – 0.719") |
| Hardness | Typically 60–66 HRC |
| Surface Finish (Ra) | See variant options |
| Spherical Deviation | ≤0.13 µm (G5 grade) |
| Quantity per Pack | 10 / 20 / 30 / 50 / 100 / 150 / 200 / 300 / 400 / 500 / 600 / 1000 PCS (varies by diameter) |
| Finish | Bright / polished (uncoated) |
| Application | Ball bearings, check valves, linear guides, precision fixtures |
| Weight per Pack | See variant options |
Check your bearing's datasheet or measure the existing balls with a micrometer. The ball diameter must match the bearing's ball complement specification exactly. Common inch-series equivalents in this range: 1.588mm = 1/16", 3.175mm = 1/8", 4.763mm = 3/16", 6.35mm = 1/4", 7.938mm = 5/16", 9.525mm = 3/8", 12.7mm = 1/2", 15.875mm = 5/8".
G5 refers to ISO 3290 Grade 5, which specifies the maximum allowable deviation from a perfect sphere (≤0.13 µm) and diameter variation between balls in a set. Lower grade numbers indicate tighter tolerances. G5 is suitable for precision bearings, instruments, and applications where noise, vibration, and runout must be minimized.
GCR15 (AISI 52100) is the industry-standard bearing steel, with typical hardness of 60–66 HRC after heat treatment. It offers excellent fatigue strength under cyclic compressive loading, making it suitable for radial and thrust load applications in standard bearing designs. For extreme shock loads or corrosive environments, consult your application's load rating and consider stainless or ceramic alternatives.
GCR15 / 52100 bearing steel contains approximately 1.3–1.65% chromium, which provides moderate corrosion resistance compared to plain carbon steel. They perform well in lubricated environments but are not stainless. For wet, acidic, or outdoor environments without lubrication, consider stainless steel (AISI 440C) balls instead. Applying a light oil or grease coating during storage and use will extend service life.
Yes. GCR15 solid steel balls are widely used as check valve seats in hydraulic and pneumatic systems. Verify the ball diameter matches your valve seat bore, and confirm compatibility with the fluid media — GCR15 is suitable for mineral oils and most hydraulic fluids but may not be appropriate for highly corrosive or aqueous media without additional protection.
For bearing replacement, count the number of balls in your bearing's complement (typically 6–12 balls per bearing depending on size). Order at least one full complement plus 10–20% extra for inspection rejects. For production runs, bulk packs (400–1000 PCS) offer a lower per-unit cost. For prototyping or single-unit repair, smaller packs (10–50 PCS) minimize waste.
This listing includes both pure metric diameters (e.g., 1.0mm, 2.0mm, 3.0mm) and inch-fraction equivalents expressed in mm (e.g., 1.588mm = 1/16", 6.35mm = 1/4", 9.525mm = 3/8"). If your bearing or application specifies an inch fraction, locate the corresponding mm value in the variant selector. Both types are manufactured to the same G5 grade standard.
