AISI 52100 Chrome Steel Bearing Balls

Chrome steel balls are commonly used as bearing balls and are usually made from high-carbon chromium bearing steel. ‘Chrome steel’ describes the material; ‘bearing ball’ describes the application. Bearing balls can also be made from materials such as 440C stainless steel. Specify the material designation, diameter and precision grade together when ordering.

These are different concepts. The chromium in chrome steel is an alloying element in the steel; the name does not indicate chrome plating. A chrome-plated ball has an additional chromium coating on its substrate. A bright appearance alone cannot distinguish them. Specify the material and coating requirements separately.

Within the same acceptance system, G5 generally has stricter requirements than G10 for form deviation, dimensional consistency and surface roughness. Select the grade according to the drawing and assembly requirements. BOYA supplies G10 precision chrome steel balls, with G5 available on request through our manufacturing partners. Provide material, diameter, grade and quantity for a specification-based quotation.

Nominal diameter identifies the ball size. Precision grade covers requirements such as dimensional consistency, form deviation and surface roughness. Hardness is a separate property of the material and its treatment. G10 does not mean a diameter of 10 mm or a universal diameter tolerance of ±10 μm. Specify these requirements separately for quotation and acceptance.

These are common high-carbon chromium bearing steel designations from different standards systems, with closely corresponding compositions. Similar composition does not mean that every quality requirement is identical, so unconditional substitution should not be assumed. Specify the material designation, material standard and inspection documents. Confirm technical equivalence before accepting a substitute.

One inch is exactly 25.4 mm. 5/32″ = 3.96875 mm, 3/16″ = 4.7625 mm and 1/4″ = 6.35 mm. Common website labels are 3.9688, 4.7625 and 6.35 mm. State whether the inch or metric dimension governs. Rounded values do not replace the drawing dimension and tolerance.

The displayed GCr15 G10 lot reports record surface roughness as Ra in μm. Our manufacturing partner uses a SURFCOM NEX 001SD2-12 roughness instrument. Recorded readings and inspection dates are shown by diameter in the lot inspection section. State the roughness metric, limit and any measurement conditions required for your order.

The production records supplied for the three displayed G10 lots link the finished-ball lot to its raw-material heat number. BOYA coordinates the inspection and quality documentation requirements for your order. Specify any required material documents and lot identification at enquiry stage.