Grade 65Mn Steel High Carbon Spring Steel Properties, Specification, Equivalent
GB 65Mn Steel
65Mn steel is a Chinese GB standard spring steel grade, Manganese (Mn) improves hardenability, so the strength, hardness, elasticity and hardenability are higher than that of 65# steel, but it has overheat sensitivity and temper brittleness. Water quenching tends to form cracks. The annealed state has good machinability, low cold deformation plasticity, and poor weldability.
65Mn high carbon steel is mainly used in the manufacture of various small-section flat springs, round springs, clockwork, etc. It can also be used to manufacture spring rings, valve springs, shock absorbers, clutch reeds and brake springs.
65Mn Datasheet
Below is material AISI 65Mn spring steel datasheet including chemical composition, properties and heat treatment, etc.
Chemical Composition
The table below lists 65Mn high carbon steel chemical composition based on heat analysis.
| Chemical Composition, % | |||||||||
| Standard | Grade | C | Si | Mn | P, ≤ | S, ≤ | Cr, ≤ | Ni, ≤ | Cu, ≤ |
| GB/T 1222 | 65Mn | 0.62-0.70 | 0.17-0.37 | 0.90-1.20 | 0.030 | 0.030 | 0.25 | 0.35 | 0.25 |
65Mn Material Properties
Density: 7.85 g/cm3
| Mechanical Properties | ||||||
| Standard | Grade | Tensile Strength, MPa, ≥ | Yield Strength, MPa, ≥ | Elongation, %, ≥ | Reduction in Area, %, ≥ | Brinell Hardness, HBW, ≤ |
| GB/T 1222 | 65Mn | 980 | 785 | 8.0 | 30 | 302 |
Notes: Bars with a diameter and side length of not more than 80 mm and flat steels with a thickness of not more than 40 mm.
Heat Treatment Specification
| Heat Treatment | ||||
| Standard | Grade | Quenching temperature, °C | Quenching medium | Tempering temperature, °C |
| GB/T 1222 | 65Mn | 830 ± 20 | Oil | 540 ± 20 |
Annealing process: Annealing temperature (860 ± 10) °C, heat preservation for 45-60min, furnace cooling to (750 ± 10) °C, heat preservation for 3-3.5h, and furnace cooling to 650-660 °C, then cooling out of the furnace or slow cooling in a heat preservation pit.
65Mn Spring Steel Equivalent
65Mn steel is considered to be equivalent to AISI SAE 1065, and some people also compare 65Mn with AISI/SAE 1075, 1095, 5160; JIS SK5 (SK85) and Chinese 8Cr13Mov, so the table below lists the difference of chemical composition for your reference.
65Mn vs 1065, 1075, 1095, 5160, SK5 and 8Cr13Mov in chemical composition
| Chemical Composition % | ||||||||||
| Grade | C | Si | Mn | P (≤) | S (≤) | Cr | Ni (≤) | Cu (≤) | Mo | V |
| 65Mn | 0.62-0.70 | 0.17-0.37 | 0.90-1.20 | 0.030 | 0.030 | ≤ 0.25 | 0.35 | 0.25 | – | – |
| 1065 | 0.60-0.70 | 0.60-0.90 | 0.040 | 0.050 | – | – | (0.20) | – | – | |
| 1075 | 0.70-0.80 | 0.40-0.70 | 0.040 | 0.050 | – | – | (0.20) | – | – | |
| 1095 | 0.90-1.03 | 0.30-0.50 | 0.040 | 0.050 | – | – | (0.20) | – | – | |
| 5160 | 0.56-0.61 | 0.15-0.35 | 0.75-1.00 | 0.035 | 0.040 | 0.70-0.90 | – | (0.30) | – | – |
| SK5 | 0.80-0.90 | 0.10-0.35 | 0.10-0.50 | 0.030 | 0.030 | 0.30 | 0.25 | 0.25 | – | – |
| 8Cr13Mov | 0.70-0.80 | 1.00 | 1.00 | 0.040 | 0.030 | 13.00-14.50 | 0.60 | 0.10-0.30 | 0.10-0.25 | |
