① Hot rolled seamless stainless steel pipe

Generally, hot rolled seamless pipes can be divided into medium and low pressure boiler steel pipes, general steel pipes, high pressure boiler steel pipes, stainless steel pipes and alloy steel pipes. The production process is as follows: checking and preparing the tube blank, heating the tube blank, piercing, sub-crown, heating the hollow tube, determining the diameter, heat treatment, straightening the finished tube, finishing, inspection and warehousing. The raw material of seamless steel tube is round tube blank, which needs to be cut by a cutting machine to grow about 1m leather, and sent to a furnace for heating by a transmission belt. The high temperature is about 1250℃, and the fuel in the pyrolysis tube is mostly acetylene or radon. After the tube blank is discharged from the furnace, it needs to be perforated, and then it is tied and rolled by three rollers. Sizing is to use a cone drill to rotate and drill the billet at high pressure to form a steel pipe.

② Cold working seamless stainless steel pipe.

Usually cold rolling is the main method, supplemented by cold drawing. About 65% seamless pipes need to be made into finished products by cold working, which promotes the development of cold working process equipment. Generally, there are three cold working processes: cold rolling process, cold drawing process and cold rolling and cold drawing combined process. More and more foreign countries use cold drawing and cold rolling combined process to produce seamless pipes.

The technological process of producing seamless stainless steel tube by cold working and cold drawing is as follows: external tube blank-cutting-heating-piercing-cutting to length-hammerhead-pickling-lubrication-drawing-annealing-cutting-water pressure-inspection-finished product. Cold-drawn seamless stainless steel pipe has the advantages of high production efficiency, convenient specification change, strong flexibility, simple equipment and production method. However, it has some defects, such as small pass variables, long production and processing time, high metal consumption and poor surface finish.

The technological process of producing seamless stainless steel tube by cold working and cold rolling is as follows: steelmaking-round steel rolling-piercing-cold drawing-cold rolling-annealing and brightening-polishing the inner surface-polishing the outer surface-acceptance inspection-warehousing and packaging. Cold rolling process can improve seamless stainless steel tube surface very well.

Quality of noodles, high production efficiency. For example, Shanghai Tianyang adopts the raw materials of domestic mainstream steel mills, through cold drawing, finishing rolling, heat treatment and pickling, and finally through 320 mesh surface polishing, it has the characteristics of high surface finish and precise size, and is suitable for high-precision ferrule connection application pipeline systems.

③ Hot extrusion seamless stainless steel pipe.

The hot extrusion process commonly used abroad is one of the hot working production processes of seamless stainless steel pipes. Compared with rolling production, the extrusion method makes the metal subject to three-dimensional compressive stress during deformation. In the best condition, not only the deformation resistance is improved, but also the internal and external surface quality of steel pipes with poor thermoplasticity is improved, which is more suitable for producing seamless stainless steel pipes with multiple specifications and small batches, such as high alloy pipes that cannot be processed by cross-rolling piercer. The process flow is as follows: tube blank peeling-cutting-drilling-chamfering-cleaning the blank-heating-reaming-heating-extruding-straightening the steel tube-shot peening-cutting off the head and tail-pickling-inspection-packaging and warehousing.

With the development of high-speed and automation, hot working has become a better processing technology for seamless stainless steel pipes, which has high economic applicability, especially for steel pipes that are difficult to deform in the production process.

Today, with the gradual acceleration of industrialization in China, there is a higher demand for seamless stainless steel pipes. Only by improving the stainless steel smelting technology and selecting a suitable production process of seamless stainless steel pipes can we ensure the production quality of seamless stainless steel pipes and enhance the economic benefits of enterprises.