According to different production methods, it can be divided into hot-rolled tubes, cold-rolled tubes, cold-drawn tubes, extruded tubes, etc.
1.1. Hot-rolled stainless steel seamless pipes are generally produced on automatic pipe rolling mills. The solid tube is inspected and cleaned of surface defects, cut to the required length, centered on the perforated end of the tube, and then sent to the heating furnace for heating, and then pierced on the punching machine. When the perforation continues to rotate and advance at the same time, under the action of the roller and the plug, a cavity is gradually formed inside the tube blank, which is called a capillary tube. And then sent to the automatic rolling mill to continue rolling. Finally, the whole wall thickness is uniformed by the whole machine, and the diameter is sizing by the sizing machine to meet the specification requirements. It is a more advanced method to produce hot-rolled seamless steel pipes using continuous pipe rolling mills.
1.2. If you want to obtain seamless pipes of smaller size and better quality, cold rolling, cold drawing, or a combination of the two methods must be used. Cold rolling is usually carried out on a two-high rolling mill. The steel pipe is rolled in an annular pass formed by a variable cross-section circular hole groove and a stationary tapered plug. Cold drawing is usually performed on a single-chain or double-chain cold drawing machine of 0.5 to 100T.
1.3. The extrusion method is to put the heated tube blank in a closed extrusion cylinder, and the perforated rod and the extrusion rod move together to extrude the extruded part from the smaller die hole. This method can produce steel pipes with smaller diameters.
This kind of steel pipe can be divided into two categories: stainless steel seamless steel pipe and stainless steel welded steel pipe (seam pipe).
It is: hot-rolled, extruded, cold-drawn and cold-rolled. These basic types can be divided into round pipes and special-shaped pipes according to the cross-sectional shape. Round steel pipes are widely used, but there are also some square, rectangular, and semi-circular pipes. , Hexagonal, equilateral triangle, octagonal and other special-shaped stainless steel pipes.
For steel pipes subjected to fluid pressure, hydraulic tests must be carried out to check their pressure resistance and quality, and no leakage, wetting or expansion under the specified pressure is qualified. Some steel pipes are also subject to crimping tests according to the standard or the buyer’s requirements. , Flaring test, flattening test.
Seamless stainless steel pipes, also called stainless steel seamless pipes, are made of steel ingots or solid pipe billets through perforation to make capillary tubes, and then hot-rolled, cold-rolled or cold-rolled. The specifications of seamless steel pipes are expressed in millimeters of outer diameter * wall thickness.
With the implementation of my country's reform and opening policy, the national economy has achieved rapid growth, and a large number of urban residential buildings, public buildings and tourist facilities have been constructed, which put forward new requirements for the supply of hot water and domestic water. In particular, people are paying more and more attention to water quality issues, and their requirements are constantly increasing. Due to its corrosiveness, galvanized steel pipe will gradually withdraw from the stage of history under the influence of relevant national policies. Plastic pipes, composite pipes and copper pipes have become common pipe materials for piping systems. However, in many cases, stainless steel pipes are more advantageous, especially thin-walled stainless steel pipes with a wall thickness of only 0.6～1.2mm in high-quality drinking water systems, hot water systems, and water supply systems that put safety and hygiene in the first place. It is safe, reliable, hygienic and environmentally friendly, economical and applicable. It has been proved by domestic and foreign engineering practice to be one of the new, energy-saving and environmentally-friendly pipes with the best comprehensive performance for the water supply system. It is also a very competitive water supply pipe. Comparable role.
In the building water supply piping system, as the galvanized steel pipe has ended a hundred years of glorious history, various new plastic pipes and composite pipes have been developed rapidly, but various pipes still have some shortcomings to varying degrees, which are far from being fully adapted to water supply pipes. Department’s needs and the country’s requirements for drinking water and related water quality. Therefore, relevant experts predict: Building water supply pipes will eventually return to the era of metal pipes. According to foreign application experience, thin-walled stainless steel pipe is recognized as one of the pipes with the best comprehensive performance among the metal pipes.