What are the two main categories of manufactured steel piping?

The correct answer identifies the two main categories of manufactured steel piping as seamless and welded. Seamless piping is produced without any joints or welds, which gives it strong structural integrity and allows for high-pressure applications. This type of pipe is typically made by extruding the steel, resulting in a continuous length of material.

On the other hand, welded piping is made by taking flat plates of steel that are rolled and welded together. This process allows for the production of longer lengths of pipe at a lower cost, but the welded seam can introduce potential weaknesses compared to seamless pipes.

The distinction between seamless and welded piping is crucial for applications where pressure and structural integrity are concerns, as each type has unique properties that make it suitable for different uses in various industrial applications.