40Cr alloy structural steel
     40Cr China China GB standard steel, 40Cr steel is the most widely used mechanical manufacturing of steel. After quenching with good mechanical properties, good low temperature impact toughness and notch sensitivity. Good hardenability of steel, when quenched in water quenching to Ф28 ~ 60mm, when oil quenching hardenability to Ф15 ~ 40mm. In addition to quenching of this steel is also suitable for external cyanide and high-frequency quenching treatment. Cutting is better, when the hardness HB174 ~ 229, the relative machinability of 60%. The production of steel suitable for medium-sized plastic molds.

Basic Information
According to the standard GB / T 3077-1999 standard corresponding to the foreign: JIS G4053 ASTM A29 / ISO 683-18:1996
Chemical composition
Grade C Si Mn Cr Ni P S CU
40Cr 0.37 ~ 0.44 0.17 ~ 0.37 0.50 ~ 0.80 0.80 ~ 1.10 ≤ 0.030 ≤ 0.035 ≤ 0.035 ≤ 0.030

Mechanical properties
Blank sample size (mm): 25

    Heat treatment: the first quenching temperature (℃): 850; Coolant: Oil

     Second quenching temperature (℃): -

   Tempering heating temperature (℃): 520;

   Coolant: water, oil 40CR roundwood
    Tensile strength (σb / MPa): ≧ 980

  Yield point (σs / MPa): ≧ 785

Elongation (δ5 /%): ≧ 9

Reduction of (ψ /%): ≧ 45

  Impact absorbed energy (Aku2 / J): ≧ 47

Brinell hardness (HBS100/3000) (annealing or tempering condition): ≦ 207