Four types of industrial steel pipe type structure
According to the specified wall thickness, there are two kinds of ordinary steel pipes and thick steel pipes. The steel pipes are divided into two types according to the pipe end form: threaded and unthreaded. The main categories of industrial classification are:
Low and medium pressure boiler seamless steel pipe:
It is made of high-quality carbon structural steel (mainly made of 10 and 20 steel) hot-rolled or cold-rolled seamless steel pipe to ensure chemical composition and mechanical properties. It also needs to be tested by water pressure, crimping, flaring and flattening. Hot rolling is delivered in a hot rolled state, and cold rolling is delivered in a heat treated state. There are also certain requirements for the microstructure, grain size and decarburization layer of the finished steel pipe.
High pressure boiler steel pipe:
It is mainly used for the manufacture of high-quality carbon structural steel, alloy structural steel and stainless steel heat-resistant steel seamless pipes for steam boiler pipes such as high pressure and above. These boiler tubes undergo oxidation and corrosion under the action of high temperature and high pressure. Therefore, the steel pipe is required to have high durability, high oxidation resistance and good structural stability.
High-quality carbon structural steel has 20G., 20MnG., 25MnG;
Alloy structural steel: 15MoG., 20MoG., 12CrMoG., 15CrMoG, 12Cr2MoG, 12CrMoVG., 12Cr3MoVSiTiB, etc.;
Rust heat resistant steel: 1Cr18Ni9, 1Cr18Ni11Nb
Geological drilling and seamless steel pipe for oil drilling control
In order to find out the conditions of underground rock formation, groundwater, oil, natural gas and mineral resources, drilling wells are used. It mainly includes core outer tube, core inner tube, casing and drill pipe. Because the drilling pipe is deep enough to work in a depth of several kilometers, the working conditions are extremely complicated, and the drill pipe is subjected to stress such as tension, pressure, bending, torsion and unbalanced impact load, and is also subject to mud and rock wear. Therefore, the pipe is required. Must have sufficient strength, hardness, wear resistance and impact toughness. Steel for steel pipes is expressed by the "DZ" plus the number one representing the yield point of the steel.
Commonly used steel grades are 45MnB.50Mn of DZ45; 40Mn2.40Mn2Si of DZ50; 40Mn2Mo.40MnVB of DZ55; and 27MnMoVB of 40MnMoB.DZ65 of DZ60.
Petroleum cracking tube:
Furnace tubes for petroleum refineries. Seamless tubes for heat exchanger tubes and pipes.
It is made of high quality carbon steel (10.20), alloy steel (12CrMo.15CrMo), heat resistant steel (12Cr2Mo.15Cr5Mo) and stainless steel (1Cr18Ni9.1Cr18Ni9Ti).