In many high pressure and high temperature applications, the valve body is welded directly into the pipeline. Welded end connections (see Figure 35) are leak-tight at all pressures and temperatures. Welded end connections are economical in first cost; however, valves with welded ends are difficult to remove from the pipeline for service. Socket-weld ends are common for smaller valve sizes (through 2-inch) and butt-weld ends are standard for 2-1/2 inch and larger valve bodies.
