Materials and process steps of high-pressure seamless pipes
High-pressure seamless steel pipes and high-pressure boiler tubes are a type of boiler tube and belong to the category of seamless steel pipes. The manufacturing method is the same as that of seamless pipes, but there are strict requirements on the type of steel used to manufacture steel pipes. High-pressure boiler tubes are often in high temperature and high pressure conditions when used. High-pressure boiler tubes are mainly used to manufacture superheater pipes, reheater pipes, gas guide pipes, main steam pipes, etc. of high-pressure and ultra-high-pressure boilers.
High-pressure seamless pipes are actually high-pressure boiler tubes. Because high-pressure seamless pipes are usually used in pipes of high-temperature and high-pressure boilers, they are also called boiler pipes. Although the above two pipes are called differently, they are actually one and both belong to the category of seamless steel pipes. The manufacturing process is no different from that of seamless steel pipes. However, due to its special working environment, it has high requirements on the materials used. High-pressure seamless pipes are mainly used to bear a certain temperature and pressure of liquids, but the liquids transported are also divided into many types. Because of different uses, the materials of high-pressure seamless pipes will be different, but what are the specific materials?
The manufacturing process of seamless pipes is divided into hot rolling and cold drawing, and in the cold drawing process, they are divided into two types of pipes: special-shaped pipes and round pipes, so the same is true for high-pressure seamless pipes.
Hot rolling process steps
The overall process of hot rolling is to heat the round tube billet to a certain temperature, and then perform perforation treatment. The next step is three-roller oblique rolling, continuous rolling or extrusion process, followed by tube removal, sizing, cooling to form a billet tube, straightening, and finally water pressure test, marking and storage.
Cold drawing process
The round tube billet is still heated to a perforated temperature, perforated, and then headed, annealed, pickled, copper plated. The next step is cooling treatment. It needs to be cooled multiple times. The billet tube formed after cooling must also be heat treated and straightened. It can also be marked and stored after water pressure test.
Introduction to some materials of high-pressure seamless steel pipes
Because high-pressure seamless pipes refer to a type of seamless pipes, in this category, as long as they can withstand high temperature and high pressure, and use seamless pipe technology, they are all high-pressure seamless pipes. It's just that the materials are different and the environments they can adapt to are also different.
GB5310-2008 seamless steel pipe is the high-pressure boiler pipe mentioned above. However, this type of high-pressure boiler pipe is mainly used in boilers in power stations, such as high-pressure and high-temperature resistant pipes. The materials used for this type of pipe are 15CrMoG, 20G, and 12Cr1MoVG.
GB3087-2008 seamless steel pipe belongs to the category of low- and medium-pressure boiler seamless steel pipes. Generally speaking, this seamless steel pipe is also a high-pressure seamless pipe. This type of steel pipe is mainly used for some pipelines for transporting medium and low-pressure fluids in boilers in industry and life. The materials used are 10 and 20 steel.
GB6479-2000 seamless steel pipe belongs to the seamless pipe used in high-pressure fertilizer equipment, that is, the part of fertilizer equipment that needs to transport high-pressure fluids. The materials used are 16Mn, 12Cr2Mo, 20, and 12CrMo.
GB3093-1986 seamless steel pipe is a high-pressure seamless pipe specially used in diesel engines. It is mainly used for high-pressure injection oil pipes inside diesel engines. The material used is 20A.
From the above several high-pressure seamless pipes, some are used in boilers, some are used in chemical equipment, and some are used in engines. Of course, the materials of high-pressure seamless pipes for different purposes are obviously different. Therefore, when using high-pressure seamless pipes, please pay attention to the applicable environment of each pipe to avoid affecting the service life of the machine.