AN IMPROVED METHOD OF COLD WIRE ADDITION IN LONG STEM BUTT WELDING OF PRESSURE VESSELS

摘要

Accordingly there is provided in one aspect of the invention, an improved method of cold wire addition for pressure vessels joints in a single/tandem submerged are welding process. In a second aspect, the invention provides an improved method of cold wire addition in a welding process for hardfacing of dissimilar fillers in a two-wire submerged are welding process The invention provides a new configuration of the wire feeder, which enables feeding of multi wire simultaneously in the same wire feeder in different feed rate for different current rating. This new wire feeder substantially enhances the production rate as compared to the conventional submerged arc welding process. An integral shaft is designed and interfaced with the available DC wire feeder for coupling the additional wire feeder for feeding the cold wire in the arc cavity in SAW process. With this new wire feeder the cold wire addition can be provided in both direction of welding. This results additional weld deposit with same in-put heat energy available in the arc zone. Additional power source and control system is not required for this new design of wire feeder. This new wire feeder can be interfaced with the existing type of SAW machine. According to the invention, single weld pool is created in which the required weld chemistry is obtained by the use of three wires of same chemistry.