35CrMnSiA low alloy high strength steel, the heat has good mechanical properties, high strength and sufficient toughness, hardenability, weldability (preheat), formability are good, but the corrosion resistance and low antioxidant properties, usually after isothermal quenching and tempering or use [1]. High strength quenched and tempered structural steel. With high strength and toughness, high hardenability, cold plastic deformation moderate, good cutting performance. There is a tendency to temper brittleness, transverse impact toughness poor. Better welding performance, but when the thickness is greater than 3mm, should be preheated to 150 ℃, post-weld heat treatment is required. After quenching general use