40Cr hot rolled steel round bars

40Cr alloy structural steel has higher tensile strength, yield strength and hardenability than No. 40 steel, but its weldability is limited and there is a tendency to form cracks. 40Cr is a medium carbon modulated steel, cold heading die steel. The steel is moderately priced and easy to process. After proper heat treatment, certain toughness, plasticity and wear resistance can be obtained. Normalizing can promote the spheroidization of the structure and improve the cutting performance of the blank with a hardness less than 160HBS. Tempering at a temperature of 550~570℃, the steel has the best comprehensive mechanical properties. The hardenability of this steel is higher than that of 45 steel, and it is suitable for surface hardening treatment such as high frequency quenching and flame quenching. After quenching and tempering, 40Cr steel is used to manufacture mechanical parts under medium load and medium speed, such as car steering knuckles, rear half shafts and gears, shafts, worms, spline shafts, top sleeves on machine tools, etc.; after quenching and After tempering at medium temperature, it is used to manufacture parts that bear high load, impact and medium speed work, such as gears, spindles, oil pump rotors, sliders, collars, etc.; after quenching and low temperature tempering, it is used to manufacture parts that bear heavy loads and low impact And parts with wear resistance and the solid thickness on the cross section below 25mm, such as worms, spindles, shafts, collars, etc.; after quenching and tempering and high-frequency surface quenching, they are used to produce high surface hardness and wear resistance. Parts with great impact, such as gears, sleeves, shafts, main shafts, crankshafts, spindles, pins, connecting rods, screws, nuts, intake valves, etc. In addition, this steel is suitable for manufacturing various transmission parts for carbonitriding, such as gears and shafts with larger diameters and good low temperature toughness.

Chemical composition

C(％)	0.37～0.44	Si(％)	0.17～0.37	Mn(％)	0.50～0.80	P(％)	≤0.030
S(％)	≤0.030	Cr(％)	0.80～1.10

Mechanical Properties

The mechanical properties of annealed GB 40CR alloy steel are outlined in the table below

Tensile	Yield	Bulk modulus	Shear modulus	Poisson’s ratio	Izod Impact
KSI	KSI	KSI	KSI		ft.lb
76900	55800	20300	11600	0.27-0.30	84.8

 

Heat treatment Related

• Annealing of 40CR Alloy structural steel

Slowly heated to 850 ℃ and allow enough times, let the steel to be thoroughly heated, Then cool slowly in the furnace. The 40CR alloy steel will get MAX 250 HB （Brinell hardness）.

• Hardening of 40CR Alloy structural steel

Heated slowly to 880-920°C, Then after adequate soaking at this temperature quench in oil. Temper as soon as tools reach room temperature.

 

Equivalent Of 40Cr alloy Structure Steel

USA	Germany	China	Japan	France	England	Italy	Poland	ISO	Austria	Sweden	Spain
ASTM/AISI/UNS/SAE	DIN,WNr	GB	JIS	AFNOR	BS	UNI	PN	ISO	ONORM	SS	UNE
5140 / G51400	41Cr4 / 1.7035	40Cr	SCr440	42C4	530A40 / 530M40			41Cr4		2245

 

Applications

GB 40CR steel is widely used for a variety of applications in the used in the automotive and engineering industries for toolholders and other such components. Typical applications such as valve bodies, pumps and fittings, Shaft, the high load of wheel, bolts, double-headed bolts, gears, etc
 

Regular size and Tolerance

Steel round bar: Diameter Ø 5mm – 3000mm

Steel plate: Thickness 5mm – 3000mm x Width 100mm – 3500mm

Steel Hexagonal bar: Hex 5mm – 105mm

Others 40CR have not specified size, pls contact our experienced sales team.