The SS 304 Welded Pipe is stronger and is made from strips or plates of the same grade of material. The material has good general corrosion resistance and is used in general corrosive services. The high heat tolerance of the material makes it applicable in boiler and heat exchanger applications such as the ASTM A312 TP304 ERW Pipe. The different specifications cover pipes for different application requirements and the A312 specification is for welded and seamless pipes of high temperature and high pressure vessel applications such as boilers. The ASME SA 312 Grade 304 Square Pipe another such pipe that comes in square shape.