Manufacturing of stainless steel seamless pipes

According to the different production methods, it can be divided into hot-rolled pipe, cold-rolled pipe, cold-drawn pipe, extruded pipe, etc.

1.1 Hot-rolled stainless steel seamless pipes are generally produced on automatic pipe rolling mills. The solid tube blank is inspected, surface defects are removed, cut to the required length, centered on the end face of the perforated end of the tube blank, then sent to a heating furnace for heating, and perforated on a punching machine. While perforating, it keeps spinning and advancing. Under the action of the roller and the plug, a cavity is gradually formed in the tube blank, which is called a capillary. Then it is sent to the automatic rolling mill to continue rolling. Finally, the wall thickness is adjusted by the whole machine, and the diameter is determined by the sizing machine to meet the specification requirements. The production of hot-rolled seamless steel pipes with continuous pipe mills is an advanced method.

1.2 If you want to obtain seamless pipes with smaller size and better quality, cold rolling, cold drawing or a combination of the two should be used. Cold rolling is usually carried out on a two-roll mill, and the steel pipe is rolled into an annular pass consisting of variable-section circular grooves and fixed conical plugs. Cold drawing is usually carried out on a 0.5.100t single-chain or double-chain cold drawing machine.

1.3-Extrusion method means that the heating tube is placed in a closed extrusion cylinder, and the perforated rod moves with the extrusion rod to extrude the extrusion from the smaller die hole. This method can produce steel pipes with smaller diameters.

This kind of steel pipe can be divided into stainless steel seamless steel pipe and stainless steel welded steel pipe (grooved pipe), which can be manufactured according to different production processes.

These basic types are: hot rolled, extruded, cold drawn and cold rolled. According to the cross-sectional shape, it can be divided into round tube and special-shaped tube. Round steel pipes are widely used, but there are also some special shapes of stainless steel pipes, such as square, rectangle, semicircle, hexagon, equilateral triangle and octagon.

A hydrostatic test will be performed on the liquid pressure of the steel pipe to test its pressure resistance and quality. If there is no leakage, wetting and expansion under the specified pressure, it is qualified. Some steel pipes will also undergo crimping tests, flaring tests and flattening tests according to standards or requirements.

Seamless stainless steel pipe, also known as stainless steel seamless pipe, is made of hot-rolled, cold-rolled or cold-drawn after perforation of steel ingot or solid tube blank. The specification of seamless steel pipe is expressed in millimeters of outer diameter or wall thickness.