Project Description

42CrMo4 is a heat treatable steel which contains at least 0.9%Cr,0.15%Mo as strengthening elements.After quenched and tempered, It obtains high strength, good low-temperature impact toughness with a typical tensile strength of 900 -1200 N/mm2.42CrMo4 steel has better performance than 34CrMo4 steel due to the higher carbon and chromium content.Similar to AISI 4140,only a little difference in Mn,Cr content.This material also has good machinability,good wear-resistance,but the temper brittleness is not obvious,and poor in weldability.

42CrMo4 forged flat bar

1.Supply Form & Size & Tolerance

Hot rolled bar:Φ6-Φ130mm,Length:3000-10000mm

Hot Forged round bar:Φ130-Φ1000mm,Length:3000-10000mm

Plate/Sheet:Thickness :20-400mm xWidth:80-1000mm,Length:2000-6000mm

Flat bar/Blcoks:Thickness :120-800mm xWidth:120-1500mm,Length:2000-6000mm

Surface FinishBlack-Forged Black-Rolled Turned   GrindingPolishedPeeledCold Drawn
Tolerance(0,+5mm)(0,+1mm)(0,+3mm)Best h9Best h11Best H11Best H11

2.Chemical Composition

42CrMo4/1.72250.38-0.45≤ 0.40.6-0.90.9-1.20.15-0.3≤ 0.025≤ 0.035
42CrMoS4/1.72270.38-0.45≤ 0.40.6-0.90.9-1.20.15-0.3≤ 0.0250.02-0.04

3.Relevant Standards


4. Mechanical Property

Diameter d mm≤ 1616-4040-100100-160160-250
Thickness t mm< 88-2020-6060-100 100-160
Yield Strength Mpa≥900≥750≥650≥550≥500
Tensile Strength Mpa1100-13001000-1200900-1100800-950750-900
Elongation, %≥10≥11≥12≥13≥14
Reduction of area ,%≥40≥45≥50≥50≥55


42CrMo4 forging temperature:900 – 1100°C ,cooling as slowly as possible in still air or in sand after forged.

6.Heat Treatment

  • Normalizing:  850 – 880°C,Cooling in air
  • Soft Annealing:680 – 720°C,Cooling in furnace
  • Stress relieve:450-650°C,Cooling in air
  • Hardening:820 – 880°C,oil or water quench
  • Tempering:540 – 680°C,Cooling in air

7.Surface Hardness

  • Treated to improve shearability (+S):Max 255HB
  • Soft annealed (+A):Max 241HB
  • Pre Quenched and tempered:280-320HB
  • Flame or induction hardening:Min 53HRC
NORMAL HARDENABILITY +H (850°C - hardness HRC – distance mm)
Distance mm1.5357911131520253035404550
HRC Min535352514943403734323130302929
HRC Max616161606059595856535148474645


42CrMo4 has high strength and wear-resistance,widely used in many industries.

Components with high strength and toughness for tools, automotive parts,mechanical engineering, armament components,such as geer wheels,pinions,connecting rods,parts for mechanical engineering.

Statically and dynamically stressed components for vehicles, engines and machines. For parts of larger cross-sections, crankshafts,gears

Get a Quote