How a chamber shell is rolled, welded and checked

Every chamber starts as flat steel plate. The plate is cut to the developed length of the hull drawing, then rolled against a template that matches the finished diameter. If the curvature is off by a few millimetres, the door frame will not sit flat, so the template check happens before any welding. Seams are welded in stages rather than in one pass, which keeps heat distortion manageable on a thin wall. After welding, seams are ground and the shell goes back on the jig so the door frame and viewing port can be aligned together. This is also when we photograph the internal seam for the buyer's file. Before assembly the shell is pressure-checked and recorded. The record, the material certificates we hold and the electrical summary are released to qualified buyers on request, and the applicable scope follows the registration and certificates actually held in the destination market.