65Mn65Mn, manganese improves hardenability and can be quenched in oil for steel with a diameter of 12mm. Its surface decarburization tendency is smaller than that of silicon steel, and its comprehensive mechanical properties after heat treatment are better than carbon steel, but it has overheating sensitivity and temper brittleness. Used for small-sized flat and round springs, seat cushion springs, spring springs, as well as spring rings, valve springs, clutch springs, brake springs, and cold drawn steel wire cold coil springs.
characteristic
Manganese improves hardenability, and steel with a diameter of 12mm can be quenched in oil. The surface decarburization tendency is smaller than that of silicon steel, and the comprehensive mechanical properties after heat treatment are better than those of carbon steel, but it has overheating sensitivity and tempering brittleness. Used for small-sized flat and round springs, seat cushion springs, spring springs, as well as spring rings, valve springs, clutch springs, brake springs, and cold drawn steel wire cold coil springs.
Has excellent comprehensive performance, such as mechanical properties (especially elastic limit, strength limit, yield to strength ratio), anti elastic reduction performance (i.e. anti elastic reduction performance, also known as anti relaxation performance), fatigue performance, hardenability, physical and chemical properties (heat resistance, low temperature resistance, oxidation resistance, corrosion resistance, etc.). In order to meet the above performance requirements, spring steel has excellent metallurgical quality (high purity and uniformity), good surface quality (strict control of surface defects and decarburization), precise shape and size.
purpose
The strength, hardness, elasticity, and hardenability of 65Mn steel plate are higher than those of 65 # steel, and it has a tendency to overheat and temper brittleness. Water quenching has a tendency to form cracks. The machinability of the annealed state is still acceptable, the cold deformation plasticity is low, and the weldability is poor. Plate springs subjected to moderate loads, spiral springs with a diameter of 7-20mm, and spring washers Spring ring. High wear resistant parts, such as grinding machine spindles and spring clamps. Precision machine tool screw. Cutting knife. The collar on the spiral roller bearing. Railway rails, etc.
chemical composition 
Chemical composition of 65Mn spring steel:
Carbon C: 0.63-0.65
Silicon Si: 0.19-0.22
Manganese Mn: 0.98-1.1
Sulfur S: ≤ 0.01
Phosphorus P: ≤ 0.014
Chromium Cr: ≤ 0.2
Nickel Ni: ≤ 0.02
Copper Cu: ≤ 0.05
National standard 65Mn spring steel chemical composition:
Carbon C: 0.62-0.70
Silicon Si: 0.17-0.37
Manganese Mn: 0.90-1.20
Sulfur S: ≤ 0.035
Phosphorus P: ≤ 0.035
Chromium Cr: ≤ 0.25
Nickel Ni: ≤ 0.30
Copper Cu: ≤ 0.25
Mechanical properties (thickness less than 3.0mm)
Tensile strength σ b (MPa): 825~925
Yield strength σ s (MPa): 520~690
Elongation rate δ 10 (%): 14~21.5
Shrinkage rate of cross-section (%): not less than 10
Hardness:
Hot rolling hardness: 240~270HB
Cold rolled soft hardness: 190~220HB
Cold rolled hard hardness: 300~340HB
Heat treatment hardness: 38~60HRC
Heat treatment
Quenching at 830 ℃± 20 ℃, oil cooling; Tempering at 540 ℃± 50 ℃ (± 30 ℃ if necessary).
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* 1250 * C/hot coil/hot plate
50Mn (2.0-16) * 1250 * C/hot coil/hot plate
65Mn (2.0-16) * 1010/1250 * C/hot coil/hot plate
Theoretical weight calculation formula for 65Mn:
Board: Length * Width * Height * Density/10000=KG
Rod: radius * radius * 3.14 * density/100000=KG

 
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