Specification 1. High strength and toughness. 2. High hardenability and the oil critical hardening is diameter 15~70mm. 3. Good machinability and the cold plastic deformation is medium. Application 1. It is used at quenched and tempered condition,can be used in carburizing steel which need high strenght in the centre. 2. For making large cross section and Work under high stress condition conditioning parts.Like shaft and high load handwheel; bolt; stud;wheel gear etc. 3. For making welding parts; board;welding structure;high pressure pipe in the chemical industry. 4. For making temperature under 450°Cs fastener in the steam turbine, boiler manufacturing. Chemical composition NAME C Si Mn P S Cr 1.7035 0.28-0.33 0.20-0.35 0.40-0.60 0.035 0.030 0.80-1.10 Similar grade GB AISI/ASTM DIN JIS 40Cr 5140 1.7035 SCr440