Nevertheless, mechanically mounted joints are delicate to residual and thickness stresses because of dissimilar metals and temperature alterations. The confront on the stub end conforms to the gasket confront in the flange. It really is utilised where sections of piping should be dismantled rapidly and simply for inspection or substitute. http://jasperbewzz.bloggerswise.com/100038/everything-about-valves-and-fittings