Large diameter hot rolled seamless steel pipe

　　High-frequency welded pipes are generally completed by processes such as cold rolling, high-frequency welding, and forming. It is a kind of seamed pipe. Large diameter hot rolled seamless steel pipes are divided into hot-rolled seamless pipes and cold-drawn seamless pipes. Hot-rolled pipes are made by billet forging, piercing, rolling, shaping, and other processes. Generally, large-diameter and thick-walled seamless pipes adopt this form; cold-drawn pipes are cold-drawn from tube blanks, and the material strength is relatively low, and the outer and inner surfaces are smooth. Most of the small-caliber and thin-walled seamless pipes are of this kind.

　　Seamless steel pipe is a long strip of steel with a hollow section and no seams around it. Steel pipes have a hollow section and are used in large quantities as pipes for conveying fluids.

　　The high-frequency welded pipe is cold-pressed into a square tube with a certain width of steel strip and then welded by high-frequency welding. Generally, it is made by cold-rolling. The surface of the hot-rolled plate is rough, with oxides, and the thickness tolerance is not accurate. The seamless pipe is made by heating the steel billet, passing it through with a hard rod in the middle, and extruding it with a rolling roller on the outside. It is suitable for high-pressure and high-temperature conveying fluid. High-frequency welded pipes are generally passed through, cold rolling, high-frequency welding, forming, etc. The craft is complete. It is a kind of seamed pipe.

　　Seamless steel pipes are divided into hot-rolled seamless pipes and cold-drawn seamless pipes. Hot-rolled pipes are made by billet forging, piercing, rolling, shaping, and other processes. Generally, large-diameter and thick-walled seamless pipes adopt this form; cold-drawn pipes are cold-drawn from tube blanks, and the material strength is relatively low, and the outer and inner surfaces are smooth. Most of the small-caliber and thin-walled seamless pipes are of this kind.