Introduction

The ideal piping system would be a single piece of pipe, so formed, shaped, sized, and directed as to contain or convey the fluid required by the process in which it is involved. For most systems this cannot be. Changes in size, shape, direction, and operating conditions usualiy preclude such a fabrication. Joints become necessary. Piping systems usuaily must be made of many different components, and the joints that connect them must be as strong and serviceable as the components themselves. Therefore, engineers and mechanics should try to apply those joining methods which most nearly meet the conditions of one-piece fabrication and also allow for necessary assembly, erection, maintenance, and operation.

Most of the austenitic stainless steels are readily weIdable when the proper procedures and techniques are followed. They can be joined by most of the fusion welding processes, and good pipe welders can adapt very quickly from carbon steel or low alloy steel to stainless steel. Orbiting pipe welding machines are also very adaptable to these materials.

The instructions in these recommended practices can be put to use by any competent pipe welder in any good shop or field site. Reasonable care is required, as in any pipe welding operation; however, careful adherence to the procedure requirements will usually produce excellent welds in stainless steel piping and tubing.