DIN 34CrMo4 Alloy Steel | AISI 4135

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

Standard	C	Si	Mn	P	S	Cr	Mo
DIN 17200	0.3-0.37	≤ 0.4	0.6-0.9	≤0.035	≤0.03	0.9-1.2	0.15-0.3
SEW 550	0.3-0.37	≤ 0.4	0.5-0.8	≤0.035	≤0.035	0.9-1.2	0.15-0.3
EN10250	0.3-0.37	≤ 0.4	0.6-0.9	≤0.035	≤0.035	0.9-1.2	0.15-0.3
EN10083	0.3-0.37	≤ 0.4	0.6-0.9	≤0.025	≤0.035	0.9-1.2	0.15-0.3

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

Grade	Quenching		Tempering Temperature,ºC
Grade	Temperature,ºC	Hardness,HRC	150ºC	200ºC	300ºC	400ºC	500ºC	550ºC	600ºC	650ºC
34CrMo4	850ºC	>55	55	53	51	43	34	32	28	24

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-mm	Type	1.5	3	6	7	9	11	13	15	20	25	30	35	40	45	50
MIN	+H	49	49	48	45	42	39	36	34	30	28	27	26	25	24	24
MAX	+H	57	57	57	56	55	54	53	52	48	45	43	41	40	40	39
MIN	+HH	52	52	51	49	46	44	42	40	36	34	32	31	30	29	29
MAX	+HH	60	60	59	58	58	57	57	56	55	52	51	49	48	46	45
MIN	+HL	49	49	48	45	42	39	36	34	30	28	27	26	25	24	24
MAX	+HL	54	54	54	52	51	49	47	46	42	39	38	36	35	35	34