A process of joining two pipe sections together using a heat source to melt the pipes, and allowing the melted plastic form each pipe to amalgamate, and then letting the joint cool to form a hard plastic again Special equipment is usually required to provide the heat for an effective butt weld The most commonly butt welded material are polypropylene and polyethylene
A technique for joining segments of metal rail or pipe in which segments aligned end to end are electronically charged, producing an electric arc that melts and welds the ends of the segments, yielding an exceptionally strong and smooth joint. Also called flash welding