36CrNiMo4 / 1.6511 Steel – EN 10250

36CrNiMo4 / 1.6511 Steel Manufacturer and Exporter,supplied with round,square,flat,block,and shaft etc.

36CrNiMo4 / 1.6511 is defined as a heat treatable and low alloy steel which has 0.8% Cr, 0.2% Mo and 1.8% Ni as strengthening alloy elements.Compared with AISI 4140,it has higher strength and toughness,also it has very good fatigue resistance, wear resistance and atmospheric corrosion resistance.36CrNiMo4 / 1.6511 is generally supplied in hardened and tempered condition with the tensile range of 930 – 1080 Mpa ,hardness 280-320HB.Pre hardened and tempered 4340 can be further surface hardened by flame or induction hardening and by nitriding.

36CrNiMo4 / 1.6511 Steel Supply Form & Size & Tolerance

Supply Form	Size(mm)	Process	Tolerance
Round	Φ6-Φ100	Cold Drawn	Bright/Black	Best H11
	Φ16-Φ350	Hot Rolled	Black	-0/+1mm
			Peeled/ground	Best H11
	Φ90-Φ1000	Hot Forged	Black	-0/+5mm
			Rough Turned	-0/+3mm
Flat/Square/Block	Thickness :120-800	Hot Forged	Black	-0/+8mm
	Width:120-1500		Rough Machined	-0/+3mm

Remark:Tolerance can be customized as per requests

36CrNiMo4 / 1.6511 Steel Chemical Composition per EN 10250-3

GRADE	NUMBER	C	Si	Mn	P	S	Cr	Mo	Ni
36CrNiMo4	1.6511	0.32-0.40	≤ 0.40	0.50-0.80	≤ 0.035	≤ 0.035	0.90-1.20	0.15-0.30	0.90-1.20

36CrNiMo4 / 1.6511 Steel Physical Property

Density g/cm3	7.85
Melting point °C	1427
Poisson’s ratio	0.27-0.30
Machinability (AISI 1212 as 100% machinability)	50%
Thermal expansion co-efficient µm/m°C	12.5
Thermal conductivity W/(m.K)	44.5
Modulus of elasticity 10^3 N/mm^2	210
Electric resistivity Ohm.mm2 /m	0.19
Specific heat capacity J/(kg.K)	460
Modulus of elasticity 10^3 N/mm2	100 ℃	200 ℃	300 ℃	400 ℃	500 ℃
	205	195	185	175	165
Thermal expansion 10^6 m/(m.K)	100 ℃	200 ℃	300 ℃	400 ℃	500 ℃
	11.1	12.1	12.9	13.5	13.9

36CrNiMo4 / 1.6511 Steel Mechanical Property

Mechanical Condition	T	U	V	W	X	Y	Z
Ruling Section (mm)	150	100	63	30	30	30	30
Tensile Strength Mpa	850-1000	930-1080	1000-1150	1080-1230	1150-1300	1230-1380	>1550
Yield Strength,Mpa	≥665	≥740	≥835	≥925	≥1005	≥1080	≥1125
Elongation %	≥13	≥12	≥12	≥11	≥10	≥10	≥5
Izod Impact J	≥54	≥47	≥47	≥41	≥34	≥24	≥10
Charpy Impact J	≥50	≥42	≥42	≥35	≥28	≥20	≥9
Brinell Hardness HB	248-302	269-331	293-352	311-375	341-401	363-429	>444

36CrNiMo4 / 1.6511 Steel High Temperature Strength

For quenched and tempered heavy forgings
Diameter mm	Yield strength MPa
	20 ℃	100 ℃	200 ℃	250 ℃	300 ℃	350℃	400℃
≤250	590	549	510	481	441	412	371
250-500	540	505	471	451	412	383	353
500-750	490	466	441	422	392	363	343

36CrNiMo4 / 1.6511 Steel Forging

Forging temperature should be carried out between 1150℃-1200℃,The lower the forging-ending temperature ,the finer the grain size .hold suitable time for the steel to be thoroughly heated before forge, but don’t forge below minimum forging temperature 850°C. 36CrNiMo4 / 1.6511 Steel has good forging characteristics,but crack is easily occured when improper cooling way after forged,so it  should be cooled as slowly as possible in still air or in sand after forged.

36CrNiMo4 / 1.6511 Steel Normalizing

Normalizing is used to refine the structure of forgings that might have cooled non-uniformly after forged,and considered as a conditioning treatment before final heat treatment.Normalizing temperature for 36CrNiMo4 / 1.6511 Steel should be carried out between 850℃-880℃. hold suitable time for the steel to be thoroughly heated to complete the ferrite to austenite transformation.Cool in still air.

36CrNiMo4 / 1.6511 Steel Annealing

Full annealing is recommended  for 36CrNiMo4 / 1.6511 Steel before machining, 36CrNiMo4 / 1.6511 Steel should be carried our at a nominal temperature of 830℃-850℃,hold suitable time for the steel to be thoroughly heated, then furnace cooling to 610℃ at a rate of 11℃ per hour, finally air cooling.

36CrNiMo4 / 1.6511 Steel Hardening

This heat treatment will obtain martensite structure after quenched.It will  increase the surface hardness and strength.36CrNiMo4 / 1.6511 Steel should be carried out between 830℃-865℃, hold suitable time for the steel to be thoroughly heated, soak for 10-15 minutes per 25 mm section, oil quench is recommended.Tempering should be followed  immediately after quenched.

36CrNiMo4 / 1.6511 Steel Tempering

36CrNiMo4 / 1.6511 Steel should be in the heat treated or normalized and heat treated condition before tempering.Tempering is usually carried out to relieve stresses from the hardening process, but primarily to obtain the required  hardness and mechanical properties. The actual tempering temperature will be chosen to meet the required properties.it is usually carried out at 450℃- 660℃,hold until temperature is uniform throughout the section, soak for 1 hour per 25 mm of section, and cool in still air.Tempering between 250℃-450℃ is not avoided as tempering within this range will seriously reduce the impact value,result in temper brittleness.

36CrNiMo4 / 1.6511 Steel Application

36CrNiMo4 / 1.6511 Steel is often used in preference to AISI 4140 at the higher strength levels because of its better hardenability and improved CVN impact toughness.

Typical applications include:Heavy-duty axles, shafts, heavy-duty gears,spindles, pins, studs, collets, bolts, couplings,sprockets, pinions, torsion bars, connecting rods,crow bars, conveyor parts,forged hydraulic,forged steel crankshafts etc.