34CrMo4 steel is a heat treatable steel which contains at least 0.9%Cr,0.15%Mo as strengthening elements which is similiar like Chinese grade 35CrMo.It has good repeated impact resistance,good fatigue properties in alternating bend stress,but poor in weldability,this steel grade can be welded only with suitable procedure.This material is generally used in the quenched and tempered condition.
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 Finish | Tolerance |
Black For Forged condition | (0,+5mm) |
Black For Rolled condition | (0,+1mm) |
Rough Turned | (0,+3mm) |
Grinding | Best h9 |
Polished | Best h11 |
Peeled | Best H11 |
Cold Drawn | Best H11 |
2.Chemical Composition
Grade | C | Si | Mn | Cr | Mo | P | S |
34CrMo4/1.7220 | 0.3-0.37 | ≤ 0.4 | 0.6-0.9 | 0.9-1.2 | 0.15-0.3 | ≤ 0.025 | ≤ 0.035 |
34CrMoS4/1.7226 | 0.3-0.37 | ≤ 0.4 | 0.6-0.9 | 0.9-1.2 | 0.15-0.3 | ≤ 0.025 | 0.02-0.04 |
3.Relevant Standards
USA | UK | China | France |
4135/4137 | 708A37 | 35CrMo | 34CD4 |
4. Mechanical Property
Diameter d mm | ≤ 16 | 16-40 | 40-100 | 100-160 | 160-250 |
Thickness t mm | < 8 | 8-20 | 20-60 | 60-100 | 100-160 |
Yield Strength Mpa | ≥800 | ≥650 | ≥550 | ≥500 | ≥450 |
Tensile Strength Mpa | 1000-1200 | 900-1100 | 800-950 | 750-900 | 700-850 |
Elongation, % | ≥11 | ≥12 | ≥14 | ≥15 | ≥15 |
Reduction of area ,% | ≥45 | ≥50 | ≥55 | ≥55 | ≥60 |
impact,J | ≥40 | ≥45 | ≥45 | ≥45 | |
Hardness,HB | 298-359 | 271-331 | 240-286 | 225-271 | 213-253 |
5.Forging
34CrMo4 forging temperature:900 – 1100°C
6.Heat Treatment
- Normalizing: 850 – 880°C,Cooling in air
- Soft Annealing:650 – 680°C,Cooling in furnace,maximum hardness 223HB
- Hardening:830 – 890°C,Quenching in oil or water
- Tempering:540 – 680°C,Cooling in air
7.Application
34CrMo4 heat treatable steel with a typical tensile strength of 800 – 1100N/mm². For automotive and aircraft components with high toughness as crankshafts, axles, axle journals, tyres,gears and any components subject to fatigue stresses.