Materials and Heat Treatment for SIRKEN Roller Bearings
Materials and heat treatment are crucial components and processes affecting the performance of rolling bearings. In recent years, we have significantly increased our investment in this area. Previously, material procurement and heat treatment were based on standards. Today, our process begins with skilled and qualified material selection, and heat treatment is an integral part of the product design process from the outset. We work closely with material suppliers and heat treatment plants to plan and simulate optimal material selection and the most suitable heat treatment processes for various applications.
Materials for Rolling Bearings and Rolling Bearing Components
A wide variety of materials are available for different types and applications of rolling bearings. The selection of each material requires consideration of multiple criteria. The primary factor is the performance of the rolling bearing, but factors such as economy, environmental friendliness, availability, and machinability also influence material selection. The most well-known and perhaps most widely studied steel globally is 100Cr6 (Gcr15). This steel, containing approximately 1% carbon and 1.5% chromium, has maintained a virtually unchanged chemical composition.
The quality of steel used in rolling bearings is currently listed in the international standard DIN EN ISO 683-17. This standard also provides precise information on grades, order details, chemical composition analysis, mechanical properties, and purity.
Steel is supplied in diameters up to 250 mm, available as bars or tubes. Ring sizes exceeding 250 mm in diameter are typically manufactured using forging.
The most commonly used steel types for SIRKEN bearings are the over-hardened steel series from the aforementioned DIN EN ISO standard, including 100Cr6 (Gcr15) or alloys adjusted according to wall thickness to enhance over-hardening properties. In the surface-hardening steel series, 18CrNi-Mo7-6 (20CrNi2MoA) or 19MnCr5 (20CrMn) are selected. For stainless steel components, we use X46Cr13, X65Cr14, SUS304, SUS316, SUS420, SUS440, and SUS440.
In high-temperature applications, we have validated the performance of X40CrMoV51 (4Cr5MoSiV1) or X153CrMoV12 (Cr12MoV). Both steels exhibit excellent properties over high-temperature ranges.
For rolling bearing types in spring technology, we typically use a well-researched spring steel strip, 50CrV4 or 51CrV4, similar to 100Cr6. We work closely with suppliers and renowned materials research institutes to further develop this steel. The shapes and qualities used today are the result of years of continuous collaboration. For high-temperature applications, we also use specially rolled hot-worked steel (X40CrMoV51). Typically, we use non-alloy carbon steel for pressure rings, discs, and spacers. Non-steel cages are made of brass or high-strength aluminum. All materials used must meet the relevant chemical analysis standards. For components requiring rolling, the purity of the raw materials is also a crucial criterion. All material deliveries are accompanied by corresponding certificates for documentation. Furthermore, additional inspections such as crack testing, ultrasonic testing, or similar tests can be agreed upon as needed.
In the next article, we will continue with bearing heat treatment, so please stay tuned.
