Project Description

18CrMo4 is a low carbon case hardening steel which has at least 0.9Cr%,0.15%Mo as strengthening elements as per EN10084 standard.It has good process performance ,and has high strength when temperature at 500-550 °C.The oxidation resistance is deteriorated and the creep strength is remarkably lowered when temperature exceeds 550°C.The weldability of 18CrMo4 steel is also very good, with excellent machining or cutting properties.

18CrMo4 steel

1.Supply Form & Size & Tolerance

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

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

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

18CrMo4/1.72430.15-0.21≤ 0.40.6-0.90.9-1.20.15-0.25≤ 0.025≤ 0.035
18CrMoS4/1.72440.15-0.21≤ 0.40.6-0.90.9-1.20.15-0.25≤ 0.0250.02-0.04

3.Relevant Standards


4. Mechanical Property

Diameter d mm≤ 1616-4040-100
Yield Strength Mpa≥835≥685≥590
Tensile Strength Mpa1080-1370930-1300800-1150
Elongation, %≥9≥9≥10
Reduction of area ,%≥35≥35≥40


18CrMo4 forging temperature:950 – 1100°C,cooled as slowly as possible in the air or in sand after forged.

6.Heat Treatment

  • Normalizing:  870 – 900°C,Cooling in air
  • Soft Annealing:680 – 700°C,Cooling in furnace
  • Carburizing:880-980°C
  • Core-hardening:860-900°C,oil-polymer salt bath
  • Case-hardening:780-820°C,oil-polymer salt bath
  • Carbonitriding:860-950°C
  • Tempering:150-200°C

7.Surface Hardness

  • Soft annealed(+A):Max 207HB
  • Treated to hardness range(+TH):156-207HB
  • Treated to ferrite-pearlite structure and hardness range(+FP):140-187HB
TypeDistance mm1.535791113152025303540

HRC Min3937343027242221-----
HRC Max47464542393735343129282726

HRC Min42403834312826252220---
HRC Max47464542393735343129282726

HRC Min3937343027242221-----
HRC Max44434138353331302725242322


18CrMo4 case hardening steel is widely in gear components of all kind and cog wheels. Open die steel forgings for general engineering purposes.High and medium pressure steam pipes, headers and superheaters.

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