As a low alloy structural steel, 34CrMo4 steel contains Cr and Mo as alloy strengthening elements as per German standard DIN 17200.

34CrMo4 steel has high lasting strength and creep strength at high temperature, good impact toughness at low temperature, good hardenability and medium machinability.

34CrMo4 steel is usually used after quenched and tempered condition.It is often used as an important structural part working under high load, such as the transmission parts of vehicles and engines,the rotor,main shaft,and heavy-load transmission shaft of a turbo-generator, large gears for locomotive traction,supercharger transmission gears,rear shafts,connecting rods and spring clips that are heavily loaded, etc.

34CrMo4 Forged round steel with QT condition

34CrMo4 STEEL CHEMICAL COMPOSITION

StandardCSiMnPSCrMo
DIN 172000.3-0.37≤ 0.40.6-0.9≤0.035≤0.030.9-1.20.15-0.3
SEW 5500.3-0.37≤ 0.40.5-0.8≤0.035≤0.0350.9-1.20.15-0.3
EN102500.3-0.37≤ 0.40.6-0.9≤0.035≤0.0350.9-1.20.15-0.3
EN100830.3-0.37≤ 0.40.6-0.9≤0.025≤0.0350.9-1.20.15-0.3

34CrMo4 STEEL RELATED STANDARD & EQUIVALENT GRADE

China | GB 3077: 35CrMo

USA | ASTM A29: 4135/4137

France:34CD4

UK | BS970:708M32

Italy:35CrMo4

34CrMo4 STEEL PHYSICAL PROPERTY

Density, g/cm3 7.87
Melting point,℃ 1403
Specific heat capacity,(0~100℃),J/(kg.k) 561(100℃)
Linear expansion coefficient,10^-6/k 12.5(0-100℃)
Poisson’s ratio 0.286
Elastic Modulus,Mpa 217000
Shear modulus,Mpa 84000
Thermal conductivity,W/(m.K) 47.73(105℃)

34CrMo4 STEEL FORGING

  • Initial Forging Temperature:1150℃
  • Final Forging Temperature:850℃
  • Heating Rate:Strictly control the heating speed, which should be uniform and stable to prevent cracking caused by improper heating.
  • Forging Ratio:above 4:1
  • Post-Forging Treatment:34CrMo4 steel should be slowly cooling in sand after forged.Also, annealing after forging is also recommended.

34CrMo4 STEEL HEAT TREATMENT

Critical Temperature for Heat Treatment of 34CrMo4 Steel

  • Ac1:755℃
  • Ac3:800℃
  • Ar1:695℃
  • Ar3:750℃
  • Ms:271℃

Temperature Selection for Conventional Heat treatment for 34CrMo4 Steel

  • Annealing:820 – 840°C,Cooling in furnace
  • Normalizing:830-860°C,air cooling
  • Quenching:830-870°C,Medium:Water,Oil
  • Tempering:540-680°C

34CrMo4 Steel Mechanical Property with Quenched and Tempered Condition

Tensile Strength
Mpa
Yield Strength
Mpa
Elongation
%
Reduction of Area
%
Impact Charpy-V
J
≥1000≥850≥12≥45≥80

34CrMo4 Steel Tempering Temperature Vs Hardness

GradeQuenchingTempering Temperature,ºC
Temperature,ºC Hardness,HRC150ºC 200ºC 300ºC 400ºC 500ºC 550ºC 600ºC 650ºC
34CrMo4850ºC >555553514334322824

Jominy Quenching Test Curve For 34CrMo4 Steel

Jominy Quenching Test Curve For 34CrMo4 Steel

Quenching at 850°C

X:Distance from quenched end,in mm

Y:Hardness,HRC

1: HH level

2: HL level

3: H level

HRC-mmType1.5367911131520253035404550
MIN+H494948454239363430282726252424
MAX575757565554535248454341404039
MIN+HH525251494644424036343231302929
MAX606059585857575655525149484645
MIN+HL494948454239363430282726252424
MAX545454525149474642393836353534

Guideline value Curve for 34CrMo4 Steel Mechanical Property

34crmo4 steel Mechanical property reference curve

X:Tempering temperature,oC

Y:Tensile and Yield Strength,Mpa

Z:Elongation and Reduction in  area,%

WHAT WE SUPPLY FOR 34CrMo4 STEEL

Hot Forged Round bar:Φ80-Φ1000mm

Hot Rolled  Round bar:Φ16-Φ130mm

Hot Forged Square bar: Max Thickness:500mm

Flat bar/Blcoks:Thickness :120-800mm ,Width:120-1500mm

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