AISI 4130 Alloy Steel | 25CrMo4 | DIN 1.7218 | SCM430

AISI 4130 is a low alloy steel which contains nominally at least 0.28% Carbon, 0.8% Chromium and 0.15% Molybdenum as strengthening agents. It has good strength ,toughness,fatigue strength,and good atmospheric corrosion resistance.Similar to 4140, it has a lower carbon level which gives 4130 improved weldability, at the expense of through thickness strength.AISI 4130 steel is usually used in the quenched and tempered condition with hardness 207-235HB.But the hardenability limitations of this grade (depth to which it will harden/obtain the specified mechanical properties after heat treatment) must always be taken into account when designing and selecting equipment.

AISI 4130 Forged round bar

1.AISI 4130 steel Supply Form & Size

Form of SupplySize(mm)Length(mm)
Round barΦ6-Φ1,0003,000-10,000
Square bar100x100-600x6003,000-6,000
Plate/SheetThickness :20-400
Flat bar/BlcoksThickness :120-800

2.Surface Finish&Tolerance

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

3.Chemical Composition&Related Specifications

25CrMo4/1.7218708A25 / 708M2530CrMoSCM430

4.Mechanical Property

Tensile Strength Mpa Yield Strength MpaElongation %Reduction of Area %Hardness HBImpact Charpy-V, -18ºC,J
60K ≥ 586  ≥ 420 ≥ 18  ≥ 35174-237 ≥ 42
75K ≥ 655 ≥ 517 ≥ 17  ≥ 35197-237  ≥ 33

5.AISI 4130 steel Forging

Preheat carefully, then raise temperature to 950-1200°C for forging. Do not forge below 950°C,material should be cooled as slowly as possible after forged.

6.Heat Treatment

  • Normalizing:880℃-900℃,Cool in air
  • Annealing:800℃-850℃,Cool in furnace
  • Hardening:870-890°C,oil quench
  • Tempering:4400-570°C, cool in still air


AISI 4130 steel can be readily machined by conventional methods. Machinability is best  in the normalized and tempered condition. Although this material may be machined in the fully heat treated condition,but machining becomes difficult when the hardness of the steel increasing.


AISI 4130 is widely used for a variety of applications in the oil and gas ,automotive, agricultural and defense industries.Typical applications:

  • Aircraft engine mounts
  • Welded tubing
  • Valve bodies
  • Pumps
  • Fittings