How to reduce welding tensile stress when welding with welding flux for roll pre protected roll surfacing
The heat input must be strictly controlled when welding with roll surfacing flux. This not only ensures the mechanical properties of the welded joint, but also prevents the generation of cracks. Next, Xiaobian brings the method of reducing welding tensile stress!
1. Appropriately increase the size of arc striking plate and arc extinguishing plate
People often don't know enough about the importance of arc striking plate. They think that the function of the arc extinguishing plate is only to lead the arc pit out of the weldment when the arc is stopped. Sometimes they just find a piece of steel to spot weld the cylinder. Others make the run on plate very small, save steel and become a real run on plate. These practices are very wrong. In order to avoid affecting the chemical composition of weld metal, the material with uniform base metal should be used for arc striking plate and arc extinguishing plate. The shape and size of the groove shall also be the same as that of the base metal. Due to the limitation of tack welding and other reasons, the long butt joint of flat plate is easy to produce end cracks. For plates with thickness less than 25 mm, slotted lead out plates are recommended. The size of arc striking plate and arc extinguishing plate shall be determined according to the length to ensure that the weld metal of workpiece has proper shape and width at both ends of joint to support the required flux.
2. Pay attention to the assembly, positioning and welding of arc striking plate and reasonable groove form
In general, the length and thickness of the positioning weld should not be less than 80% of the width and thickness of the arc striking plate. Continuous welding is required instead of simple spot welding. On both sides of the longitudinal seam, the manufacturer of medium plate and roller coated flux shall ensure that the welding seam has enough thickness, and if necessary, the manufacturer of roller surfacing flux shall make a certain groove.