Features and application: a high hardenability, non-temper brittleness, very good weldability, cold crack formation tendency of small, machinability and good cold plastic strain. Usually quenched and tempered or case hardening state used for the manufacture of corrosive media and in non-working temperature lower than centigrade 250 , the medium containing a mixture of nitrogen and hydrogen in the high pressure of work and a variety of fasteners, higher carburizing parts, such as gears, shafts and so on.

Chemical Composition: Carbon C: 0.17 ~ 0.24 ,Si Si: 0.17 ~ 0.37 ,Manganese Mn: 0.40 ~ 0.70 ,S S: to allow the residual content ≤ 0.035 ,P P: ≤ 0.035 to allow the residual content ,Chromium Cr: 0.80 ~ 1.10
,Ni-Ni: ≤ 0.030 to allow the residual content ,Copper Cu: ≤ 0.030 to allow the residual content ,Mo Mo: 0.15 ~ 0.25

Mechanical Properties:
Tensile strength σb (MPa): ≥ 885 (90)
Yield strength σs (MPa): ≥ 685 (70)
Elongation δ5 (%): ≥ 12
Impact energy Akv (J): ≥ 78
Impact toughness αkv (J/cm2): ≥ 98 (10)
Hardness: ≤ 197HB