Welded fittings are welded on to the piping system where as pressure fitting uses National Pipe Thread (NPT) to connect to the pipe. 90° weld elbows are used to change the direction of fluid or gas flow in pipes by 90 degrees.

Hex bushings are used to reduce the size of female threads from a larger to a smaller diameter. Hex Bushings are threaded fittings that have male threads on the outside and female threads on the inside with a hex head used to tighten the fitting into the threaded opening. Merchant steel fittings are designed with Dryseal Taper Threads (NPTF) for more critical applications. NPTF Dryseal threads produce a mechanical seal by the mating and slight crushing of the threads when a wrench is applied to tighten the fittings.