TPT July 2012

Welding

Welding – latest developments

Photo: Migatronic (Denmark), see story on page 90

Tubular steel should be welded so as to develop the maximum strength at the connections. This directive has informed tube welding practice since the beginning and still applies to all its methods, from a workbench vice-hold operation through shielded metal arc (stick) welding, GMAW, GTAW, and on to whatever processes the future may hold for this already highly evolved technology.

To stipulate “maximum strength at the connections” may state the obvious. But what a number and variety of demands it imposes on the weld: soundness, smoothness, even contour, freedom from undercutting and arc strikes, total absence of gaps or unwelded areas between the members being joined, high impact toughness, receptivity to coating, and many more.

Another truism with a long reach holds that welding is expensive, and extra weld metal does not improve the quality of the structure. That is the province of sound welding practice and procedures – of the kind that are routine to the contributors to this section of Tube & Pipe Technology .