When using roll surfacing flux for roll protection, heat input must be strictly controlled.This not only guarantees the mechanical properties of the welded joints, but also prevents the generation of cracks.Next, a small edition will introduce a way to reduce the stress of the weld!
1. Increase the size of arc-initiating and arc-extinguishing plates appropriately
People often do not understand the importance of arc-starting plates enough.They believe that the purpose of the arc extinguishing plate is only to draw the arc pit out of the weld during arc closure.Sometimes they just find a piece of steel plate to spot weld on the cylinder.Others make the arc-starting plate very small and save steel, making it a true arc-starting plate.These practices are very incorrect.In order to avoid affecting the chemical composition of the weld metal, uniform base material should be used for the arc-initiating and arc-extinguishing plates.The shape and size of the groove should also be the same as the base material.Due to the limitation of positioning welding and other reasons, long butt joint of flat plate is prone to end cracks.For plates less than 25 mm in thickness, slotted lead-out plates are recommended.The dimensions of the arc-initiating and arc-extinguishing plates should be determined by their length to ensure that the weld metal of the workpiece has the appropriate shape and width at both ends of the joints to support the required flux.
2. Attention should be paid to the assembling, positioning and welding of arc initiation plates and the rational groove form.
Generally, the length and thickness of the positioning weld should be no less than 80% of the width and thickness of the arc initiation plate. Continuous welding, not simple spot welding, is required.On both sides of the longitudinal seam, manufacturers of medium-thick plates and roll-coated flux should ensure that the seam is thick enough and, if necessary, roll-surfacing flux manufacturers should make certain grooves.
What's a good roll?