Steel grade		C		Si	Mn		P	S	Cr		Mo		Ni
Steel name	Steel number	min.	max.	max.	min.	max.	max.	max.	min.	max.	min.	max.	min.	max.
41Cr4	1.7035	0,38	0,45	0,40	0,60	0,90	0,035	0,035	0,90	1,20	-	-	-	-
25CrMo4	1.7218	0,22	0,29	0,40	0,60	0,90	0,035	0,035	0,90	1,20	0,15	0,30	-	-
30CrMo4	1.7216	0,27	0,34	0,35	0,35	0,60	0,035	0,035	0,80	1,15	0,15	0,30	-	-
34CrMo4	1.7220	0,30	0,37	0,40	0,60	0,90	0,035	0,035	0,90	1,20	0,15	0,30	-	-
42CrMo4	1.7225	0,38	0,45	0,40	0,60	0,90	0,035	0,035	0,90	1,20	0,15	0,30	-	-
a See also 7.1.
b<0,25% Cu.

Steel grade		Minimum tensile properties
Steel name	Steel number	Yield strength (ReH) MPa				Tensile strength ( Rm) MPa				Elongation A%
		For T in mm				For T in mm				For T in mm
		T≤8	8＜T≤20	20＜T≤50	50＜T≤80	T≤8	8＜T≤20	20＜T≤50	50＜T≤80	T≤8		8＜T≤20		20＜T≤50		50＜T≤80
										l	t	l	t	l	t	l	t
41Cr4	1.7035	800	660	560	-	1000	900	800	-	11	9	12	10	14	12	-	-
25CrMo4	1.7218	700	600	450	400	900	800	700	650	12	10	14	12	15	13	16	14
30CrMo4	1.7216	750	630	520	480	950	850	750	700	12	10	13	11	14	12	15	13
34CrMo4	1.7220	800	650	550	500	1000	900	800	750	11	9	12	10	14	12	15	13
42CrMo4	1.7225	900	750	650	550	1100	1000	900	800	10	8	11	9	12	10	13	11
NOTE l = longitudinal, t = transverse.

Tolerances of Lengths: When Length equals 6000mm, Tolerances 0/+10 When 6 000 < L =12 000, Tolerances 0/+15 When > 12 000,Tolerances 0/+ by agreement Process specification and physical properties of 42CrMo steel pipe 42CrMo steel pipe, carbon content: 0.38 ～ 0.45%, silicon: 0.17 ～ 0.37%, manganese: 0.50 ～ 0.80%.

42CrMo steel pipe belongs to ultra-high strength steel, with high strength and toughness, good hardenability, no obvious tempering brittleness, high fatigue limit and multiple impact resistance after quenching and tempering treatment, and good low-temperature impact toughness.

The steel is suitable for manufacturing large and medium-sized plastic molds requiring certain strength and toughness. Its corresponding international standard organization brand: 42CrMo4 corresponds to Japanese brand: scm440 corresponds to German brand: 42CrMo4 approximately corresponds to American brand: 4140 characteristics and scope of application: high strength, hardenability, good toughness, small deformation during quenching, high creep strength and endurance strength at high temperature. It is used to manufacture forgings with higher strength and larger quenching and tempering cross-section than 35CrMo steel, such as large gear for locomotive traction, transmission gear of supercharger, rear axle, connecting rod and spring clamp with great load, drill pipe joint and fishing tool for oil deep well below 2000m, and mold for bending machine.

Sulfur s: allowable residual content ≤ 0.035% Phosphorus P: allowable residual content ≤ 0.035% Chromium (CR): 0.90 ～ 1.20% Nickel Ni: allowable residual content ≤ 0.030% Copper Cu: allowable residual content ≤ 0.030% Molybdenum (MO): 0.15 ～ 0.25% Allowable stress of 42CrMo 42CrMo allowable stress 186 ～ 310 / MPa, yield point 930 σ S / MPa, 42CrMo has high strength, hardenability, good toughness, small deformation during quenching, and high creep strength and endurance strength at high temperature. 42CrMo steel pipe is used to manufacture forgings with higher strength and larger quenched and tempered section than 35CrMo steel.

1) Critical point temperature (approximate): AC1 = 730 ° C, AC3 = 800 ° C, Ms = 310 ° C.

2) Linear expansion coefficient: temperature 20 ~ 100 ° C / 20 ~ 200 ° C / 20 ~ 300 ° C / 20 ~ 400 ° C / 20 ~ 500 ° C / 20 ~ 600 ° C, linear expansion coefficient: 11.1 × 10K/12.1 × 10K/12.9 × 10K/13.5 × 10K/13.9 × 10K14.1 × 10K。

3) Elastic modulus: temperature 20 ° C / 300 ° C / 400 ° C / 500 ° C / 600 ° C, elastic modulus 210000mpa / 185000mpa / 175000mpa / 165000mpa / 15500mpa

Hot working specification The heating temperature is 1150 ~ 1200 ° C, the starting temperature is 1130 ~ 1180 ° C, and the ending temperature is > 850 ° C, φ> 50mm, slow cooling. Normalizing specification The normalizing temperature is 850 ~ 900 ° C, and the furnace is cooled by air. High temperature tempering specification The tempering temperature is 680 ~ 700 ° C, and the furnace is cooled by air. Quenching and tempering specifications Preheating temperature 680 ~ 700 ° C, quenching temperature 840 ~ 880 ° C, oil cooling, tempering temperature 580 ° C, water cooling or oil cooling, hardness ≤ 217hbw. Specification for subcritical strengthening and toughening Quenching temperature 900 ° C, tempering temperature 560 ° C, hardness (37 ± 1) HRC Specification for induction quenching and tempering Quenching temperature 900 ° C, tempering temperature 150 ~ 180 ° C, hardness 54 ~ 60HRC.

Hot working specification The heating temperature is 1150 ~ 1200 ° C, the starting temperature is 1130 ~ 1180 ° C, and the ending temperature is > 850 ° C, φ> 50mm, slow cooling. Normalizing specification The normalizing temperature is 850 ~ 900 ° C, and the furnace is cooled by air. High temperature tempering specification The tempering temperature is 680 ~ 700 ° C, and the furnace is cooled by air. Quenching and tempering specifications Preheating temperature 680 ~ 700 ° C, quenching temperature 840 ~ 880 ° C, oil cooling, tempering temperature 580 ° C, water cooling or oil cooling, hardness ≤ 217hbw. Specification for subcritical strengthening and toughening Quenching temperature 900 ° C, tempering temperature 560 ° C, hardness (37 ± 1) HRC Specification for induction quenching and tempering Quenching temperature 900 ° C, tempering temperature 150 ~ 180 ° C, hardness 54 ~ 60HRC.