65Mn spring steel strip is a high-carbon, high-manganese (approx. 0.65% C, 0.90-1.20% Mn) cold-rolled steel known for high strength, hardness, and excellent elasticity. It is commonly used for manufacturing springs, clips, saw blades, and machine parts, often in quenched and tempered conditions. It offers high wear resistance but is susceptible to corrosion, requiring proper maintenance.
| Material Grade | S50C/65MN/C75/SK2/SK4/SK5 |
| Dureté | 42-52HRC |
| Largeur | 6mm-400mm |
| Épaisseur | 0.12mm-3.0mm |
| Surface | Polished bright/yellow/blue/, Grey blue/Natural |
| Bord | Round/slit |
| Application | Auto part/Flat Blade/Clips/Shoes metal accessories/Springs/Tools/Blades |
65 minutes bande d'acier à ressort is a medium carbon Manganese (Mn) alloy spring steel widely used in China. Its name indicates an average carbon content of 0.65% and a higher manganese content (1.00-1.30%). After proper heat treatment, it offers excellent elasticity, strength, and wear resistance.
| Spring Steel Strip Parameter | Specification / Value |
|---|---|
| Material Standard | GB/T 1222 (China) / AISI 1566 (similar int’l grade) |
| Key Characteristics | High elasticity, good hardenability, moderate price |
| Applications principales | Flat/round springs, clutch discs, brake springs, wear-resistant parts |
1. 65Mn Spring Steel Strip Chemical Composition (GB/T 1222)
| Élément | C (Carbon) | Mn (Manganese) | Si (Silicon) | P (Phosphorus) | S (Sulfur) |
|---|---|---|---|---|---|
| Contenu (%) | 0.62 – 0.70 | 0.90 – 1.20 | 0.17 – 0.37 | ≤ 0.035 | ≤ 0.035 |
2. Mechanical Properties (After Heat Treatment)
| Propriété | Typical Value |
|---|---|
| Tensile Strength (Rm) | ≥ 980 MPa |
| Yield Strength (Rp0.2) | ≥ 785 MPa |
| Elongation (A) | ≥ 8% |
| Dureté (HRC) | 38 – 60 (depends on tempering) |
Heat Treatment Process
The performance of 65Mn is fully realized through quenching and tempering:
- Quenching: Heat to 830°C ± 10°C, then cool rapidly in oil. This results in a very hard but brittle martensitic structure.
- Tempering: Reheat the quenched steel to a temperature between 370°C – 500°C, then cool. This step reduces brittleness and achieves the desired combination of strength and elasticity.
- Higher tempering temperatures (e.g., 450-500°C) yield lower hardness (HRC 38-45) but higher elasticity, ideal for springs.
- Lower tempering temperatures (e.g., 370-420°C) yield higher hardness (HRC 45-50+) and better wear resistance, suitable for tools and wear parts.
Spring Steel Strip Supply Conditions & Applications
- Cold-Rolled Hardened Strip: Supplied in a hard state (high strength), suitable for directly stamping small, low-precision springs.
- Annealed (Soft) Strip: Supplied in a soft state for ease of machining or forming before final heat treatment.