Xingcheng Special Steel Achieves Full-Chain China Production and Green Upgrade for Third-Generation Hub Bearing Steel

At the Steel Industry Science and Technology Innovation Conference held on January 30, 2026, CITIC Special Steel Co., Ltd. (hereinafter referred to as "CITIC Special Steel") showcased its major technological breakthrough in the field of high-end wheel hub bearing steel. Tan Liang, Deputy Director of the R&D Department of the company's Bar and Wire Rod Research Institute, systematically introduced the company's independent R&D achievements and industrialization progress of "third-generation and above high-load-resistance, long-life wheel hub bearing steel," marking that my country has broken free from import dependence in this key automotive basic material field and entered a new stage of green and low-carbon development.

Targeting Three Core Components, Implementing Precise Technological Breakthroughs

As a key component of the automotive driving system, wheel hub bearings endure high loads and high-frequency alternating stresses for extended periods, placing extremely stringent requirements on material performance. CITIC Special Steel has formulated differentiated R&D strategies for its three core components—flanges, inner rings, and steel balls—achieving full-category coverage:

Wheel Hub Flanges: As the main load-bearing structure, they must balance lightweighting and high strength. The team employed a microalloying design, combined with non-uniform temperature controlled rolling and cooling, and directional rolling processes, to significantly reduce the anisotropy of the steel, improving overall mechanical properties and fatigue life by over 15%. It is also compatible with various heat treatment paths, including quenching and tempering and online normalizing.

Bearing inner ring: Although small in size, it is the most vulnerable part, requiring extremely high purity and carbide uniformity. Through innovative technologies such as converter oxidation to remove titanium, low-temperature primary refining, and ultra-low oxygen smelting, the team successfully controlled the oxygen content in the steel to ≤5ppm, titanium ≤10ppm, and calcium ≤2ppm. Combined with a novel spheroidizing annealing process, a highly homogenized microstructure was achieved (spheroidization grade 2-3, network carbides ≤2.5), providing a stable matrix for subsequent processing.

Steel balls: Previously a bottleneck restricting domestic production, relying heavily on imports. Facing the industry's prevailing approach of using energy-intensive electroslag remelting or ingot casting processes, CITIC Special Steel took a different approach, adhering to a green continuous casting and rolling route, pioneering a high-efficiency, low-carbon manufacturing channel for bearing steel wire rods used in steel balls. By establishing a "hardness difference" control system (≤15HV) and an inclusion size model (single particle ≤10μm), the company effectively solves the problems of early pitting corrosion and fatigue fracture, meeting the ultra-long lifespan requirements under tens of thousands of alternating loads per minute.

Green Intelligent Manufacturing Leads Industry Transformation

In addition to performance breakthroughs, CITIC Special Steel is simultaneously advancing the construction of a low-carbon manufacturing system. The company has built China's first national-level "near-zero carbon emission electric arc furnace" demonstration line, employing a short-process smelting method using green electricity and pure scrap steel. Carbon emissions per ton of steel are less than 150 kg, a reduction of over 90% compared to the traditional long-process method. This approach not only responds to the national "dual-carbon" strategy but also provides downstream industries with green raw materials that meet international carbon footprint standards.

Furthermore, the company is collaborating with leading bearing manufacturers to jointly develop next-generation near-net-shape bearing steel products—possessing higher surface quality, better dimensional accuracy, and higher purity—aiming to further improve the first-pass yield of components, reduce manufacturing costs, and support the reliability goals of the entire vehicle lifecycle.

From "Follower" to "Leader": Industry experts point out that CITIC Special Steel's technological achievement not only fills the gap in domestic high-end wheel bearing materials, but also restructures the industry's technological roadmap with green processes, breaking the traditional perception that "high performance must be energy-intensive." With the promotion and application of the new generation of products, the security and competitiveness of my country's automotive basic component supply chain will be substantially enhanced.