Views: 0 Author: Site Editor Publish Time: 2026-09-24 Origin: Site
Low carbon steel balls are a practical option for cost-sensitive mechanical components, but the material name does not tell you whether the ball has been hardened. Two balls made from the same low-carbon grade can arrive in very different supply conditions.
A ball supplied without case hardening and a carburized, hardened ball should not be purchased under the same description. The second has a hardened outer region while retaining a comparatively softer core. That difference affects wear, deformation and the inspection requirements.
During carburizing, carbon diffuses into the outer region of the steel. Subsequent hardening and tempering establish the required hardened condition. Carburizing and hardening belong to the same manufacturing route, but they are not the same operation.
The finished ball has a hard outer region over a lower-carbon core. The change is within the steel itself; the case is not a coating applied to the ball.
This arrangement provides a wear-resistant surface without making the entire section behave like through-hardened steel. It does not mean that the core is unaffected by heat treatment, or that every case-hardened ball has the same core hardness.
For the available grades and supply options, see our low carbon steel balls product page.
A case-depth requirement belongs with a ball diameter. It should not be transferred unchanged from one size to another.
The same layer thickness occupies a different proportion of a small ball and a large one. Ball diameter, heat-treatment response and the intended core condition therefore need to be considered together.
RISHENG’s published case-depth range is a reference for review, not a size-by-size acceptance table. Without a confirmed schedule, it would be misleading to assign a layer depth to each diameter.
The application also matters. A ball running in a shaped track has different contact conditions from the same ball loaded against a relatively flat surface. Load distribution, the mating material and repeated contact affect the suitability of the selected case and core structure.
If a different hardening condition is required, review the component selection separately. Our high carbon steel balls page covers the through-hardened option.
The low-carbon product page lists a reference case-depth range of approximately 0.4–1.1 mm, depending on ball diameter. It does not provide a diameter-by-diameter schedule or identify that range as effective case depth.
| Item | What needs to be agreed |
| Effective case depth | The distance to a specified hardness threshold, under the applicable test procedure |
| Total case depth | The extent of the altered surface layer, determined using an agreed method and endpoint |
| Core hardness | The hardness measured at a defined interior location; a separate characteristic |
Effective case-depth evaluation commonly uses a prepared cross-section and a series of hardness measurements taken inward from the surface. The measured hardness profile is assessed against the defined threshold.
Preparation matters. Sectioning and polishing must preserve the edge and avoid altering the material being examined. The test procedure also controls factors such as indentation spacing, test force and measurement location.
For an order requiring case-depth verification, agree on these report items:
| Peport Item | What is helps the buyer verify |
| Part number, drawing revision and lot reference | Which delivery the result represents |
| Ball diameter and tested condition | Whether the specimen matches the ordered component |
| Section and measurement location | Where the profile was evaluated |
| Hardness method, test force and threshold | How the depth was determined |
| Individual results and calculated depth | Whether the acceptance limits were met |
| Sample quantity and acceptance rule | How the inspected samples represent the lot |
Yes. Surface hardness and the depth of the hardened layer describe different characteristics. A surface result alone does not establish the hardness profile beneath it.
No. The appropriate requirement depends on ball diameter, contact conditions, the intended core and case structure, and processing considerations. Specify a justified depth requirement rather than requesting the deepest possible layer.
No. A cutting tool must still pass through the hardened outer region. If drilling, forming or other subsequent processing is the priority, review the required supply condition before ordering. See our annealed steel balls page for that option.
No. Precision grade and heat-treatment requirements are separate. The order should identify the required geometry and hardened condition.
No. Case hardening is not a corrosion-protection coating. Storage, handling and the service environment still require suitable protection.
