SEAMLESS FLUX CORED WIRE FOR ARC WELDING AND ITS MANUFACTURE

摘要

PURPOSE:To prevent the defects of an arc being deflected and a welding bead becoming irregular at the welding time using the wire that constrains the gap existing between outer pipe and inner pipe forming a wire by the angle in the circumferential direction to less than specified angle in case of manufacturing a seamless flux cored wire for arc welding. CONSTITUTION:An inner pipe wire 2 is manufactured by forming a hoop stock 1 in a circular sectional shape by forming it in U shape and after filling a welding flux F in the inner side thereof. A hoop stock 3 is simultaneously formed in U shape and after putting the inner pipe wire 2 therein is formed in a circular sectional shape and the seamless flux cored wire of double pipe structure is made by welding the seam thereof. This is subjected to wire drawing to reduce the diameter and worked in a fine wire. The angle delta in the circumferential direction of the gap formed between the inner and outer pipes is restrained at <=30 deg. or the wire adhering the inner and outer pipes without any gap is manufactured by taking the outer diameter degressive the of the inner pipe 2 in the range of 5-20% and the back tension for the inner pipe in the range of 5-50% of the rupture load of the inner pipe at this wire drawing time.