【BRIEF INTRODUCTION】Seamless pipe is a type of welded steel pipe that is manufactured using hot working methods such as perforation and hot rolling. If necessary, hot worked pipes can be further cold worked to the desired shape

Seamless pipe is a type of welded steel pipe that is manufactured using hot working methods such as perforation and hot rolling. If necessary, hot worked pipes can be further cold worked to the desired shape, size, and performance. At present, seamless pipes are widely used in petrochemical production equipment.

According to different production methods, seamless pipes can be divided into cold rolled pipes, hot rolled pipes, extruded pipes, cold drawn pipes, etc.: 1. Hot rolled seamless steel pipes are generally produced on automatic rolling mills. After inspecting and removing surface defects, the solid tube blank is cut into the required length centered on the end face of the perforated end of the tube blank, and then sent to the heating furnace for heating and perforated on the piercing machine. Rotate continuously while piercing. Under the action of the roller and the plug, a cavity is gradually formed inside the tube blank, called a capillary. Then it is fed into an automatic pipe rolling machine for continuous rolling, and the diameter is determined using a sizing machine. The wall thickness is leveled using a homogenizer to meet the standard requirements. 2. Use cold rolling, cold drawing, or a combination of both methods. Better quality and smaller size seamless pipes can be obtained. Cold rolling is usually carried out on a two roll rolling mill, where steel pipes are rolled in an annular pass composed of fixed conical plugs and variable cross-section annular grooves. 3. The extrusion method involves placing the heated tube blank in a closed extrusion cylinder, and the perforated rod moves with the extrusion rod to extrude the extruded part from the smaller mold hole. This method can produce seamless pipes with smaller diameters.

Seamless pipe usage: 1. Seamless pipes are widely used. Mainly used as pipes or structural components for conveying fluids, universal seamless pipes are rolled from low alloy structural steel, ordinary carbon structural steel, or alloy structural steel. 2. Supplied according to different purposes and mechanical properties; Supplied according to chemical composition; Supply according to hydraulic test. The first two types of steel pipes supplied should also undergo hydraulic testing, such as those used to withstand liquid pressure. 3. Special purpose seamless pipes include seamless pipes for boilers, seamless pipes for petroleum, and seamless pipes for geological purposes.

Seamless pipe types: 1. According to different production methods, seamless steel pipes can be divided into cold rolled pipes, hot pipes, cold drawn pipes, and extruded pipes. 2. Divided by shape, there are irregular pipes and circular pipes. In addition to square and rectangular pipes, there are also semi circular pipes, elliptical pipes, hexagonal pipes, triangular pipes, convex pipes, plum shaped pipes, etc. 3. According to different materials, it can be divided into carbon structural pipes, ordinary carbon structural pipes, alloy structural pipes, low alloy structural pipes, stainless steel pipes, etc. 4. According to special purposes, there are boiler pipes, geological pipes, oil pipes, etc.

Seamless pipe according to GB/T8162-87: 1. Specification: The outer diameter of the heat pipe is 32-630mm, and the wall thickness is 2.5-75mm; The outer diameter of cold rolled (cold drawn) pipes is 5-200 millimeters, and the wall thickness is 2.5-12 millimeters. 2. Appearance quality: The inner and outer surfaces of the steel pipe should be free of cracks, wrinkles, folds, layering, hairlines, and scars. These defects should be removed, and the wall thickness and outer diameter should not exceed negative deviation after removal. 3. The two ends of the steel pipe should be cut at right angles and burrs should be removed. Steel pipes with a wall thickness greater than 20mm are allowed to be cut by gas cutting and hot sawing.