Steel Tube Knowledge: Where is the difference between seamless steel tubes and welded steel tubes? 1. Appearance, seamless steel pipe and welded steel pipe difference in the welded pipe wall with welded ribs, and seamless. 2. The seamless pipe pressure is higher, the welded pipe is generally about 10 MPa, and the welded pipe is now seamless. 3. Seamless steel pipe is formed once in rolling. Welded steel tubes need to be rolled after welding, and are generally spiral welded and straight welded. Better performance is better, of course, the price is higher. The pipe knowledge is shared by.