2. Preparation and docking

2.1 Welding-induced deformations

Before describing the means generally used to prepare and dock parts prior to welding, we'll look at the phenomena that justify these means and give them their importance.

• What are the origins of the deformations produced by a welding operation?

  The welding arc must melt the edges to be welded, and the filler metal if present. It therefore generates a field of high, localized temperatures. These two cumulative factors in turn generate a field of stresses as soon as the heat source appears.

  Thermal stresses are very high. In the case of welding, they far exceed the elastic limit of the material being welded.

  A simple way of estimating...