What type of joint is not used for connecting pipes without welding?

A welded joint is not used for connecting pipes without welding because, by definition, it requires the fusion of materials through melting and joining them together using heat. This process creates a permanent bond that is integral to the structure of the pipes. Instead of allowing for a removable connection, welded joints are ideal for applications where a strong, permanent, and leak-proof seal is needed, such as in high-pressure systems.

On the other hand, mechanical joints, slip joints, and compression joints are specifically designed to provide non-permanent connections. Mechanical joints typically utilize components such as bolts or clamps to hold pipes together, allowing for easy disassembly. Slip joints allow for adjustment in pipe length by sliding one pipe into another, making them useful for applications requiring flexibility and change. Compression joints employ a fitting that compresses around the pipe, forming a seal without the need for welding, thus enabling easy assembly and disassembly. Each of these types allows for maintenance and repair, unlike welded joints which create a fixed assembly.