Spring steel 55Si2MnB
Characteristics and scope of application: Silicon and manganese improve elastic strength and yield ratio, enhance hardenability, resistance to tempering stability and relaxation stability, and have low sensitivity to overheating. However, they have a greater tendency to decarbonize, especially when the silicon and carbon content is high, carbon is prone to graphitization, making the steel brittle. Used as damping plate springs and coil springs for automobiles, tractors, and locomotives, as well as cylinder safety valve springs. It can also be used as heat-resistant springs for temperatures below 250 ℃.
The performance is similar to 55Si2Mn steel, but the hardenability is higher. The critical hardenability diameter in oil is about 90-180mm, and the fatigue strength is significantly improved. Usage: Suitable for manufacturing steel plate springs with medium and small cross-sections, such as front and rear auxiliary steel plate springs on automobiles.
chemical composition
Carbon C: 0.52~0.60
Sulfur S: ≤ 0.035
Phosphorus P: ≤ 0.035
Chromium Cr: ≤ 0.35
Nickel Ni: ≤ 0.35
Copper Cu: ≤ 0.25
Silicon Si: 1.50~2.00
Manganese Mn: 0.60-0.90
mechanical property 
Tensile strength σ b (MPa): ≥ 1274 (130)
Yield strength σ s (MPa): ≥ 1176 (120)
Elongation rate δ 10 (%): ≥ 6
Shrinkage rate of cross-section (%): ≥ 30
Hardness: Hot rolled, ≤ 302HB; Cold drawing+heat treatment, ≤ 321HB
Heat treatment process
Heat treatment specification: Quenching at 870 ℃± 20 ℃, oil cooling; Tempering at 480 ℃± 50 ℃ (± 30 ℃ if necessary).
Metallographic structure: tempered martensite. Delivery status: Hot rolled steel is delivered in a heat-treated or non heat-treated state, while cold drawn steel is delivered in a heat-treated state.
1. The company has established long-term and stable cooperative relationships with multiple well-known steel mills at home and abroad, all of which provide original material certification
2. Wholesale and retail, with favorable prices, superior quality (large quantities are preferred), and timely and fast delivery
3. Wide channels, sufficient supply of goods, and business scope covering all parts of the country, can meet the needs of customers in various regions
Sincerely welcome new and old customers from all walks of life to call and inquire about and negotiate business at any time. Our high-quality products and reasonable prices will definitely meet your requirements!
Welcome new and old customers to call for consultation and negotiation.