Plate edge preparation

Plate edge preparation is the bevelling and cleaning of plate edges to form the weld groove before butt welding, setting the included angle, root face, and root gap that control penetration and weld metal volume. Thin plate uses a square edge; thicker plate uses single-V, double-V, or X (double-bevel) grooves to reach full penetration while limiting weld metal and distortion. Edges are cut by plasma, laser, oxy-fuel, or machined, and ground free of scale, rust, oil, and moisture, since contamination raises porosity and diffusible hydrogen. The groove geometry is fixed by the qualified WPS; IACS Rec. 47 sets the tolerances on bevel angle, root face, and fit-up gap.