China Xingtai Steel Develops New Heating Control Method for Bearing Steel, Effectively Reducing Shrinkage Cavities in Hot-Rolled Billets

Recently, the State Intellectual Property Office disclosed a new process patent jointly applied by Hebei Xinggang Technology Co., Ltd. and Xingtai Iron and Steel Co., Ltd. The technology aims to improve the shrinkage defects that occur during the hot rolling of bearing steel, thereby improving the quality of finished steel products and reducing the subsequent processing risks caused by material defects.

The name of the patent applied this time is "A Control Process for Improving the Shrinkage Defects of Hot-rolled Bearing Steel Billets", the publication number is CN119859742A, and the submission time is February 2025. At present, the technology has entered the public stage, marking another important step for the company in the field of high-quality special steel production.

Technical background and problem orientation

In the production process of bearing steel, shrinkage holes are prone to occur in hot-rolled billets. Such internal defects not only affect the density of the material, but may also cause hidden dangers to the performance of the final product. Especially in the application scenarios of high-load and high-precision operation, such quality problems may cause serious safety problems in use.

In response to this problem, Xinggang combined its own production experience and developed a set of optimized heating control processes based on existing equipment conditions, which can effectively reduce the risk of shrinkage hole formation without adding new hardware investment.

Process key points analysis

The process adopts a combination of "two-stage heating + uniform heating". Different operating parameters are set according to the initial temperature of the billet:

For billets with an initial temperature of ≥500℃, the first stage heating temperature is set between 800 and 1000℃. The entire heating process is controlled within 5 to 6 hours, and no idle step is set during the heating process to ensure continuity;

When the initial temperature of the billet is lower than 500℃, it is first slowly cooled to room temperature and then heated in stages. At this time, the heating temperature in the first stage is controlled between 500 and 800℃, and the total heating time is extended to 6 to 7 hours. At the same time, auxiliary steel billets are placed in front and behind the furnace to keep the charging gapless and uninterrupted.

Through the above control means, the uniformity of the internal structure of the steel billet can be effectively improved, the shrinkage cavity can be suppressed, and the product qualification rate can be improved.

Implementation advantages and industry value

The biggest highlight of this technology is to make full use of the existing production line resources and achieve stable improvement of product quality by optimizing the heating rhythm and steel loading method. Compared with traditional practices, this method is more flexible and practical, and is suitable for production needs under various working conditions.

In addition, since additional equipment investment is avoided, enterprises can complete process upgrades at a lower cost, which has good promotion prospects. For manufacturers of high-quality steel such as bearing steel, this improvement will help enhance market competitiveness and promote the development of products to high-end.

Conclusion

With the continuous improvement of the manufacturing industry's requirements for material performance, refined and efficient production processes have become an important direction for the development of the industry. The new method for controlling shrinkage holes in hot-rolled bearing steel billets launched by Xinggang is a technical exploration in response to market demand, and also provides new ideas and solutions for improving the quality of domestic special steels.