According to different production methods, it can be divided into hot rolled pipe, cold rolled pipe, cold drawn pipe and extruded pipe.
1. Hot-rolled stainless steel seamless pipes are generally produced on automatic rolling mills. The solid tube blank is inspected and the surface defects are removed, cut into the desired length, centered on the end face of the perforated end of the tube blank, then sent to the furnace for heating and perforated on the punch. At the same time, the perforation is continuously rotated and advanced. Under the action of the roll and the head, a cavity is gradually formed inside the tube blank, which is called a capillary tube. Then send it to the automatic pipe rolling machine to continue rolling. Finally, the whole machine is thick and thick, and the sizing machine is sizing to meet the specification. The production of hot-rolled seamless steel tubes by continuous rolling mills is a more advanced method.
2. If you want to obtain a seamless tube with smaller size and better quality, you must use cold rolling, cold drawing or a combination of the two. Cold rolling is usually carried out on a two-roll mill in which the steel pipe is rolled in an annular hole type composed of a variable-section circular hole groove and a stationary tapered head. Cold drawing is usually carried out on a single-chain or double-chain cold drawing machine of 0.5 to 100T.
3. Extrusion method The tube blank to be heated is placed in a closed extrusion cylinder, and the perforated rod moves together with the extrusion rod to extrude the extrusion from the smaller mold hole. This method can produce steel pipes with smaller diameters.
Such steel pipes can be divided into two categories: stainless steel seamless steel pipes and stainless steel welded steel pipes (with seam pipes). According to different manufacturing processes, they can be: basic types such as hot rolling, extrusion, cold drawing and cold rolling. The shape can be divided into round tubes and shaped tubes. Circular tubes are widely used, but there are also some special-shaped stainless steel tubes such as square, rectangular, semi-circular, hexagonal, equilateral triangle, and octagonal.
For steel pipes subjected to fluid pressure, hydraulic tests are carried out to check the pressure resistance and quality. No leakage, wetting or expansion is allowed under the specified pressure. Some steel pipes are also subjected to the crimping test according to the standard or the requirements of the purchaser. , flaring test, flattening test.
Seamless stainless steel pipe, also called stainless steel seamless pipe, is made of steel ingot or solid pipe blank through perforation, and then made by hot rolling, cold rolling or cold drawing. The specifications of the seamless steel pipe are expressed by the outer diameter * wall thickness in millimeters.