Pipes of special steels are produced by the method of centrifugal casting, hot rolling or by folding the sheet with subsequent welding. The manufacturing method is largely determined by the properties of the raw material and its processing capabilities.
Advantages of use
As a product of steels with a high content of alloying components, this type of pipe is valuable due to its improved qualities: wear resistance, plasticity of the material, resistance to oxidation and corrosion under the influence of aggressive and chemically active media, ability to withstand significant internal and external loads.
Pipe sub-structures made of thermally hardened carbon steels show themselves well in areas with sharp differences and high operating temperatures. Pipes made of 12Kh1MF heat-resistant steel are used at operating temperatures in the range of 540-580 degrees. These pipes show a long service life at elevated temperatures and find application in the creation of heat exchanger bundles, pipelines for supplying superheated steam, devices operating at high pressure. The use of pipes from special steels is justified due to their long service life and unique properties of specific alloys.
Depending on the field of application and the nature of the steel used in the manufacture of steel, the pipes are divided into 3 types:
Pipes of steels resistant to corrosion for work in moderately aggressive environments. This species is most common both in industry and in everyday life.
Pipes made of heat-resistant steels. Kind of products that are not subject to corrosion in high temperature and most aggressive environments. Can be used in chemical industries.
Pipes made of heat-resistant steels. Their use guarantees good mechanical strength under high temperature conditions.
By the method of manufacturing pipes are divided into seamless and welded. Welded, in turn, are straight and spiral.
Areas of distribution
These types of products are used in areas using aggressive environments with increased operating temperatures. They can act as elements of piping of boilers and heat exchange equipment, used in systems with high internal pressure to transport petroleum products, acids and alkalis, refrigerants.
Communications in installations of the chemical industry, as a rule, are assembled from pipes based on austenitic steels. This subspecies of stainless chrome-nickel steels is the most common and universal. About 60-70% of rolled products use this material. The food industry at the present stage almost does not do without pipes from special steels. This is due to the high requirements for hygienic transport and storage. These products are easy to clean, do not oxidize on contact with food, do not saturate it with toxic substances, unlike plastic.
Constructional dimensions, permissible deviations and materials used in the manufacture are regulated for pipes of special steels according to GOST 8632-78, GOST 8731-74, GOST 3262-75 and separate industry standards.
The diameters and wall thicknesses range from 0.5 to 159 mm and from 0.2 to 10 mm, respectively. The most common steel grades are 12Х18Н10Т, 08Х18Н10Т, ПТ-7М, 09Г2С, Ст20, СТ45.