SCM440 & SCM440H : Thép hợp kim
* Standard : JIS G4105-1979
* Equivalent Grades: : GB 42CrMoA, JIS SCM440, ASTM 4140, 4142, DIN 42CrMo4, 42CrMoS4.
SCM440 is medium carbon chromium molybdenum alloy steel, which is an alloy steel containing chromium and molybdenum. It has the advantages of stable composition, low harmful elements, high steel purity, small decarburization layer and few surface defects. It is easy to be spheroidized and has low cold cracking rate. It is usually hardened and tempered. The ultimate tensile strength is 850-1000 Mpa. This material achieves a very good balance between strength, toughness and wear resistance. The chromium content of the alloy provides good hardness permeability, and the molybdenum element imparts average hardness and high strength.
SCM440 reacts well in heat treatment and it is easy to process under heat treatment conditions. This material provides many desirable properties such as good strength and wear resistance, excellent toughness, good ductility and resistance to high-temperature stresses.
This material is widely used in the production of high-strength steel fasteners, such as engines, molds, motors, gears, transmission parts, shafts, gears, arms, cold forged parts, screws and other products.
* Shapes : Round, Hexagon, Flat, Square, Profile.
* Surface Finish : Cold drawn, Hot rolled, Bright, Polished, Centerless Grinding (CG), Chamfered.
* Available size range :
Bar |
ØRound bars Cold drawn : 2mm ~ 55mm Hot Rlooed : 32mm ~ 90mm ØSquare bars : 3mm ~ 45mm ØFlat Bar : 3mm ~ 65mm ØHexagonal bars : 3mm ~ 50mm |
· Available Length : 2meter ~ 5.8 meter |
* Chemical Composition :
SCM440
SCM440H
* Mechanical properties
Tensile strength (kgf/mm²): ≧100
Yield strength (kgf/mm²): ≧85
Elongation (%): ≧12
Cross section reduction rate (%): ≧45
Impact value (J/cm2): ≧6
* Conditions of heat treatment
Annealing: 830℃ Furnace Cooling
Normalization: 830~880℃ Air Cooling
Hardening: 830~880℃ Oil Cooling
Tempering: 530~630℃ Rapid Cooling
* Criterion for heat treating conditions revise:
Ac: 750~790℃
Ar: 740~690℃
Ms: 310℃