Stainless Steel: W
This describes the condition of a stainless steel that, having been welded or otherwise thermally processed, now has chromium carbide particles present in the grain boundaries. In this condition the steel becomes susceptible to corrosion as the matrix areas around the carbide are depleted in chromium and cannot form the protective oxide film.
Whitworth Thread, BSP, BSP Thread
British Standard Pipe Thread, also called Whitworth Thread, with 14 threads per inch.