24 July 2021 Gear Steel Bar
SNCM420H Gear Steel Bar
SNCM420H belongs to JIS standard: JIS G 4052-2003 alloy structural steel, with high hardenability, no temper brittleness, good weldability, low tendency to form cold cracks, machinability And good cold strain plasticity. Generally used in quenched and tempered or carburized and quenched state, it is often used to manufacture gears in the engine and transmission system of small and medium-sized cars and tractors; it can also manufacture carburized parts and cyanide parts that require high core performance, such as oil drilling And the claws and cone bodies of roller cone bits used in metallurgical open-pit mines.
SNCM420H contains molybdenum, besides having good comprehensive performance, it can withstand certain temperature. Used to manufacture geared whole-rotor internal combustion engine connecting rod and valve section forgings for steam turbines.
Chemical composition(mass fraction)(wt.%) :
| C(％) | Si(％) | Mn(％) | P(％) | S(％) | Cr(％) | Ni(％) | Mo(％) |
|---|---|---|---|---|---|---|---|
| 0.17-0.23 | 0.15-0.35 | 0.40-0.70 | Max 0.030 | Max 0.030 | 0.35-0.65 | 1.55-2.00 | 0.15-0.35 |
Mechanical properties:
| Yield Rp0.2(MPa) | Tensile Rm(MPa) | Impact KV (J) | Elongation A (%) | Reduction in cross section on fracture Z (%) | As-Heat-Treated Condition | HBW |
|---|---|---|---|---|---|---|
| 949 (≥) | 281 (≥) | 44 | 13 | 23 | Solution and Aging, Annealing, Ausaging, Q+T,etc | 334 |
Physical properties:
| Property | Density kg/dm3 | Temperature T °C/F | Specific heat J / kgK | Thermal conductivity W/mK | Electric resistance µΩ·cm |
|---|---|---|---|---|---|
| 441 (≥) | 271 (≥) | 34 | 12 | 14 | Solution and Aging, Annealing, Ausaging, Q+T,etc |
| Temp. °C/°F | Creep strain limit (10000h) (Rp1,0) N/mm2 | Creep rupture strength (10000h) (Rp1,0) N/mm2 | - | - | - |
| 657 | 898 | 587 | - | - | - |