With the continuous development of my country's economic construction, the demand for stainless steel pipes, especially seamless stainless steel pipes (seamless pipes) is gradually increasing, which has a good development prospect. Due to its corrosion resistance, toughness and good formability, seamless pipes have a wide range of application values in the daily necessities industry, light industry, heavy industry and building decoration industry. Round steel pipes are more common in the market, and there are also some seamless stainless steel pipes such as equilateral triangles, squares, and rectangles.
①Hot-rolled seamless stainless steel pipe
Hot-rolled seamless pipes can generally be divided into medium and low pressure boiler steel pipes, general steel pipes, high pressure boiler steel pipes, stainless steel pipes, alloy steel pipes, etc. The production process is: inspection and preparation of tube blanks - heating tube blanks - perforation - sub-crown - heating of waste tubes - determining diameter - heat treatment - straightening finished tubes - finishing - inspection - storage. The raw material of the seamless steel pipe is a round tube blank, which needs to be cut by a cutting machine to a length of about 1m, and sent to a furnace for heating through a transmission belt. After the tube blank is released, it needs to be perforated, and then it is continuously tied and three-rolled. Sizing is to use a conical drill to rotate the billet under high pressure to form a steel pipe.
②Cold-worked seamless stainless steel pipe
Usually, cold rolling is the main method, and cold drawing is supplemented. About 65% of seamless pipes need to be cold-worked into finished products, which promotes the development of cold-working process equipment. There are three general cold working processes: cold rolling process, cold drawing process and combined cold rolling and cold drawing process. More foreign countries use the combined process of cold drawing and cold rolling to produce seamless pipes.
The process flow of cold working and cold drawing to produce seamless stainless steel pipe is: external tube blank-cutting-heating-piercing-cutting-to-length-hammer-pickling-lubrication-drawing-annealing-cutting-head-water pressure-checking-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 defects such as small pass variable, long production and processing time, high metal consumption, and poor surface finish.
The process flow of cold working and cold rolling to produce seamless stainless steel pipe is: steel making - round steel rolling - perforation - cold drawing - cold rolling - annealing and brightening - polishing inner surface - polishing outer surface - acceptance inspection - storage and packaging. Cold rolling process can well improve seamless stainless steel tube table
The surface quality is high, and the production efficiency is high. For example, Shanghai Tianyang adopts the raw materials of domestic mainstream steel mills, passes through cold drawing and finishing rolling, heat treatment and pickling process, and finally undergoes 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. system.
③Hot extrusion seamless stainless steel tube
The hot extrusion process commonly used abroad is one of the hot processing production processes of seamless stainless steel pipes. Compared with rolling production, the extrusion method subjects the metal to three-dimensional compressive stress during deformation. In the best state, it not only improves the deformation resistance, but also improves the inner and outer surface quality of the steel pipe with poor thermoplasticity, which is more suitable for the production of multi-specification and small batch seamless stainless steel pipes, such as high-alloy pipes that cannot be processed by skew rolling piercing machines, etc. . The technological process is: tube blank peeling - cutting - drilling - chamfering - cleaning blank - heating - reaming - heating - extrusion - straightening steel pipe - shot peening - cutting head and tail - pickling - inspection - packaging and storage.
With the development of high speed and automation, hot working has become a better processing technology for seamless stainless steel pipes, with high economic applicability, especially for steel pipes that are difficult to deform in the production process.
Today, with the gradual acceleration of the industrialization process in my country, there is a higher demand for seamless stainless steel pipes. Only by improving the stainless steel smelting technology and comprehensively considering the production scale and capital investment of the enterprise, a more suitable seamless stainless steel pipe production process is selected. In order to ensure the production quality of seamless pipes and improve the economic benefits of enterprises.
