34CrMo4 / 35CrMo is used as important structural parts working under high load, such as transmission parts of vehicles and engines; The rotor, main shaft and transmission shaft with heavy load of turbo generator, the large section part 34CrMo4 is used to manufacture forgings with higher strength and larger quenching and tempering section than 35CrMo steel, such as large gear for locomotive traction, booster transmission gear, rear shaft, connecting rod and spring clamp with great load. 34CrMo4 can also be used for drill pipe joints and fishing tools in oil deep wells below 2000m.34CrMo4 Gas Cylinder Pipe, mainly used in automobile gas cylinder installation, fire protection, medical fields, industry equipment, etc.
The carbon equivalent value CEQ of 35CrMo steel is 0.72%. It can be seen that the weldability of this material is poor, and its hard tendency is large during welding. The hot crack and cold crack tendency of the heat affected zone of 35CrMo alloy pipe will be large. Especially when welding in the quenched and tempered state, the cold crack tendency of the heat affected zone will be very prominent. Therefore, on the basis of selecting appropriate welding materials and reasonable welding methods, higher pre welding preheating temperature Under the condition of strict process measures and proper interpass temperature control, the purpose of product welding can be achieved.
