The steel grades used are
High quality carbon structural steel, and the steel grades are 20g, 20mng and 25mng; Alloy structural steel 15mog, high pressure pipe. 20mog, 12crmog, 15CrMoG, 12CR2MOG, 12crmovg, 12Cr3MoVSiTiB, etc; In addition to ensuring chemical composition and mechanical properties, 1Cr18Ni9 and 1cr18ni11nb high-pressure pipes commonly used in rusty heat-resistant steel shall be subject to hydrostatic test, flaring and flattening test one by one. Steel pipes shall be delivered in heat treated condition. In addition, there are certain requirements for the microstructure, grain size and decarburization layer of the finished steel pipe. Seamless steel pipe for geological drilling and petroleum drilling control; In order to explore the underground rock structure, groundwater, oil, natural gas and mineral resources, drilling rigs are used to drill wells. Oil and gas exploitation is inseparable from drilling. Seamless steel pipe for geological drilling control and oil drilling is the main equipment for drilling, mainly including core outer pipe, core inner pipe, casing, drill pipe, etc. As the drilling pipe needs to work at the depth of several thousand meters, the working conditions are extremely complex, the drill pipe bears the stress effects of tension, compression, bending, torsion and unbalanced impact load, and is also worn by mud and rock. Therefore, the pipe must have sufficient strength, hardness, wear resistance and impact toughness, The steel for steel pipe is represented by "DZ" (Geological Chinese Pinyin prefix) plus a number to represent the steel yield point. The commonly used steel grades are 45mnb and 50Mn of dz45; 40Mn2 and 40mn2si of dz50; 40mn2mo and 40mnvb of dz55; 40mnmob of DZ60 and 27mnmovb of dz65. Steel pipes are delivered in heat-treated condition.Petroleum cracking pipe
Seamless pipe for furnace pipe, heat exchanger pipe and pipeline in petroleum refinery. It is usually made of high-quality carbon steel (10, 20), alloy steel (12CrMo, 15CrMo), heat-resistant steel (12cr2mo, 15cr5mo) and stainless steel (1Cr18Ni9, 1Cr18Ni9Ti). In addition to the chemical composition and various mechanical properties of the steel pipe, it is also necessary to ensure the hydrostatic, flattening, flaring and other tests, as well as the surface quality and nondestructive testing. Steel pipes shall be delivered under heat treatment.Stainless steel pipe
All kinds of stainless steel hot-rolled and cold-rolled stainless steel pipes are widely used in petroleum and chemical equipment pipes and stainless steel structural parts for various purposes. In addition to ensuring chemical composition and mechanical properties, all steel pipes used to bear fluid pressure shall be qualified in hydrostatic test. Various special steel pipes shall be guaranteed according to the specified conditions. High pressure seamless steel pipe is a kind of seamless pipe. The manufacturing method is the same as that of seamless pipe, but there are strict requirements for the steel grade used in the manufacture of steel pipe. According to the service temperature, it is divided into general boiler tube and high-pressure boiler tube. ① The service temperature of high-pressure seamless steel pipe is below 450 ℃, and the domestic pipe is mainly made of No. 10 and No. 20 carbon steel hot-rolled pipe or cold drawn pipe. ② High pressure seamless steel pipe is often in high temperature and high pressure conditions. The pipe will be oxidized and corroded under the action of high temperature flue gas and steam. The steel pipe is required to have high lasting strength, high anti-oxidation and corrosion performance and good structural stability. ① High pressure seamless steel pipe is mainly used to manufacture water wall pipe, boiling water pipe, superheated steam pipe, superheated steam pipe for locomotive boiler, large and small smoke pipe and arch brick pipe. ② High pressure seamless steel pipe is mainly used to manufacture superheater pipe, reheater pipe, air duct, main steam pipe, etc. of high-pressure and ultra-high-pressure boilers in power plants.
(3) Alloy steel pipes imported from Germany are mainly 34CrMo4 and 12CrMoV. This kind of steel pipe has good high-temperature performance and is often used as steel pipe for high-temperature boiler. (4) There are many alloy pipes imported from Japan, with specifications of 426.012mm 5 ~ 8m; 152.48.0mm12m; 89.110.0mm6m; 101.610.0mm12m; 114.38.0mm6m; 127.08.0mm9m, etc. Implement Japanese industrial standard jisg3458, and the steel grade is stpa25. This kind of steel pipe is often used as supporting superalloy pipe.