1. Appearance;
Welded steel pipe have a welding line on the inner wall but seamless have no.
2. Pressure; Pressure of seamless pipe is higher. Generally welded pipe is around 10 MPa, and have welded pipe seamless process.
3.Welded pipe is completed by cold rolling system, high frequency welding, molding process etc. It ia a kind of seam steel pipe.
Seamless steel tube contains hot-rolled seamless pipe and cold drawn seamless tube. Hot rolled tube has process as forging, piercing, rolling, plastic, etc. Generally, large diameter and thick wall seamless tube adopts this form; Cold drawn tube is made of cold-drawn tube billet, forming, material strength is relatively low, smooth appearance both outside and internal. Small diameter and thin wall seamless tube adopt this process mostly.
