65Mn spring steel
 Properties of manganese to improve hardenability, φ12mm the hardenability of steel oil can, a small surface decarburization tendency than silicon, the mechanical properties after heat treatment is better than carbon steel, but overheating sensitivity and temper brittleness. As small size of flat, round spring, spring seat, spring winding, spring ring can also be produced, valve springs, clutch springs, brake springs and cold drawn steel wire cold roll coil spring.
 Has excellent overall performance, such as mechanical properties (particularly elastic limit, ultimate strength, yield ratio), bullet-proof by performance (ie, decreased resistance to elastic properties, also known as anti-relaxation properties), fatigue properties, hardenability, physical and chemical properties (heat resistance, low temperature, oxidation, corrosion, etc.). In order to meet these performance requirements, spring steel with excellent metallurgical quality (high purity and uniformity), good surface quality (surface defects and decarburization strict control), the exact shape and size.
 Use
 65Mn steel strength, hardness, elasticity and hardenability steel is higher than 65, with a thermal sensitivity and tendency to temper brittleness, water quenching have to cracking tendencies. Cutting can still be annealed, cold plastic deformation is low, poor welding. By the middle of the plate spring load, diameter 7-20mm of coil spring and spring washer. Spring ring. High wear parts, such as grinding spindle, spring chuck. Precision machine screw. Cutter. Screw on the roller bearing ring. Railroad rails, etc.
 Chemical composition
 Carbon C: 0.62 ~ 0.70
 Si Si: 0.17 ~ 0.37
 Manganese Mn: 0.90 ~ 1.20
 Sulfur S: ≤ 0.035
 Phosphorus P: ≤ 0.035
 Chromium Cr: ≤ 0.25
 Ni-Ni: ≤ 0.30
 Copper Cu: ≤ 0.25
 Mechanical properties
 Tensile strength σb (MPa): ≥ 980 (100)
 Yield strength σs (MPa): ≥ 784 (80)
 Elongation δ10 (%): ≥ 8
 Reduction of area ψ (%): ≥ 30
 Hardness: hot, ≤ 302HB; cold-drawn + heat treatment, ≤ 321HB