Application of Low-Carbon Steel Shot in Brake Disc Manufacturing: From Strengthening to Cost Reduction

The oxide scale and rust adhering to brake disc castings after molding are key obstacles affecting subsequent machining accuracy. Through high-speed blasting, low-carbon steel shot effectively removes these contaminants, restoring the metal's original appearance. Compared with high-carbon steel shot, it exhibits stronger plastic deformation capability and a lower breakage rate, making it particularly suitable for cleaning precision castings like brake discs, which have high surface morphology requirements. This prevents abrasive fragments from embedding into the substrate and compromising material purity.

Brake discs endure severe thermal-mechanical alternating loads during service, making them prone to thermal fatigue cracking. Using low-carbon steel shot for Shot Peening on the friction surface of brake discs induces plastic deformation in the surface layer and generates compressive residual stress. This stress layer effectively counteracts the tensile stress generated during operation, significantly delaying the initiation and propagation of fatigue cracks. Relevant process data indicate that after optimized shot peening followed by forced air cooling and normalizing treatment, the surface compressive residual stress of brake discs can reach above 300 MPa, and the failure rate due to thermal cracking on the friction surface is reduced by more than 30%.

In heat treatment strengthening processes, low-carbon steel shot is often applied to brake discs at elevated temperatures (e.g., near the Curie temperature) to refine surface grains while leveraging its high service life (with an Ervin life of up to 3,000–3,500 cycles) to achieve low consumption in mass production. Practical application data show that compared with conventional domestic steel shot, high-quality low-carbon alloy shot can reduce consumption by approximately 50%, significantly lowering the unit processing cost.