40Cr Alloy Structural Steel

Description:
40Cr is under the standard of GB/T 3077-1999 in China, 40Cr steel is one of the most widely used steel in machinery manufacturing field. After quenching and tempering, 40Cr has good comprehensive mechanical properties, good low temperature impact toughness and low notch sensitivity. its hardenability is good , when water quench hardening can reach to Ф 28 ~ 60 mm, when oil quenching hardening can reach to Ф 15 ~ 40 mm. In addition, except quenching and tempering, it also fits for cyanide and high frequency quenching process. Has good machinability, when hardness is HB174 ~ 229, the relative cutting machining is 60%. The steel is suitable for manufacturing to medium-sized plastic mold.

Equivalent grades:
JIS SCr440
DIN 1.7045
DIN 41Cr4/42G4
BS 41Cr4
SS 2245
ASTM 5140
ISO 41Cr4
Chemical composition

GRADE C% Si% Mn% P% S% Cr% Cu% Ni%
40Cr 0.37-0.44 0.17-0.37 0.50-0.80 0.035 0.035 0.80-1.10 0.03 0.03
Mechanical properties

GRADE Tensile Strength min Yield Strength min Elongation min. contraction min impact min Hardness Max
σb/M Pa σs/M Pa δ5/% ψ/% Aku2/J HBS
40Cr 980 785 9 45 47 207

Heat treatment:
AC3= 780 C
Normalizing: 850 C, oil cooling, hardness 179~229HBS
Softening treatment: 740~760 C, holding 4~6 hours, slow cool at 5~10℃/h, cool to under 600 C,
Air cooling.

Application:
Widely used as Gear, sleeve, shaft, spindle, spindle, pin, connecting rod, crankshaft, screws.