Research on root weldingprocess for large blunt edge of steel lined wear resistant material slurry pipeline
When welding steel lined wear-resistant material slurry pipe pipeline,only the outer steel pipe is welded,and the lining pipe material is not weldable.In order to ensure the internal forming of the outer metal pipe,the tra-ditional welding needs to process a large groove size and reserve a large assembly gap,which leads to low welding efficiency and easy wear and failure of the pipe.The root welding technology of the outer layer of steel lined slurry pipes with small gaps and large blunt edges was studied by high efficiency A-TIG welding.As a result,it was found that when welding on V-shaped grooves without assembly gaps,the active welding arc that should have shrunk will experience arc"climbing"along both sides of the groove,resulting in a sharp decrease in the penetration depth of the active TIG root welding.After reserving assembly gaps,the plasma flow line at the center of the active welding arc is distributed towards the inner side of the blunt edge,effectively improving the phenomenon of arc"climbing".Heat is more easily transmitted to the blunt edge,and fusion of the blunt edge is easier.With the increase of assem-bly gap,it is conducive to the flow of the active welding pool from edge to center,and the blunt edge is easy to fuse,but the forming effect is reduced.When the reserved gap is too large,the two sides of the blunt edge cannot fuse without filling materials.When the size of the blunt edge is 5 mm and the assembly gap is 1.2 mm,with the support of appropriate process parameters,the effect of small gap and large blunt edge is obvious.
A-TIG weldingsmall gap largelarge blunt edgeroot welding
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