A335 P12 A369 FP12 A213 T12 high pressure steel pipe quality assurance
15CrMoG steel pipe is a kind of seamless steel pipe, and its performance is much higher than that of ordinary seamless steel pipe. Because this kind of steel pipe contains more Cr, its high temperature resistance, low temperature resistance and corrosion resistance can not be compared with other seamless steel pipes, so alloy pipe is widely used in petroleum, chemical industry, electric power, boiler and other industries.
The principle of hydrogen purification by 15CrMoG steel pipe is that when the hydrogen to be purified is introduced into one side of 15CrMoG steel pipe at 300-500 ℃, hydrogen is adsorbed on the wall of 15CrMoG steel pipe. Due to the lack of two electrons in the 4D electron layer of palladium, it can form unstable chemical bonds with hydrogen (the reaction between palladium and hydrogen is reversible). Under the action of palladium, hydrogen is ionized into protons with a radius of 1.5 × 1015m, while the lattice constant of palladium is 3.88 × 10-10m (at 20 ℃), it can pass through the 15CrMoG alloy steel pipe. Under the action of palladium, protons combine with electrons and re form hydrogen molecules, which escape from the other side of the 15CrMoG alloy steel pipe. On the surface of 15CrMoG alloy steel pipe, the undissociated gas cannot pass through, so 15CrMoG alloy steel pipe can be used to obtain high-purity hydrogen.
Although palladium has unique permeability to hydrogen, pure palladium has poor mechanical properties, easy oxidation at high temperature and low recrystallization temperature, which is easy to deform and embrittle 15CrMoG steel pipe. Therefore, pure palladium cannot be used as permeability membrane. Adding an appropriate amount of IB and VIII elements to palladium to make palladium alloy can improve the mechanical properties of palladium. 11. Seamless steel pipe for automobile half axle sleeve (gb3088-82) is a high-quality carbon structural steel and alloy structural steel hot-rolled seamless steel pipe for manufacturing automobile half axle sleeve and drive axle housing. In palladium alloy, silver accounts for about 20-30%, and the content of other components (such as gold, etc.) is less than 5%.
① The two digits at the beginning of the steel grade represent the carbon content of the steel, expressed as a few thousandths of the average carbon content, such as 40Cr.
② The main alloying elements in steel, except for individual microalloyed elements, are generally expressed in a few percent. When the average alloy content is less than 1.5%, generally only the element symbol is marked in the steel grade, but the content is not marked. However, if it is easy to be confused under special circumstances, the number "1" can also be marked after the element symbol, such as steel grades "12CrMoV" and "12Cr1MoV". The chromium content of the former is 0.4-0.6%, and that of the latter is 0.9-1.2%, and the other components are all the same. When the average content of alloy elements is ≥ 1.5%, ≥ 2.5%, ≥ 3.5%... The content shall be indicated after the element symbol, which can be expressed as 2, 3, 4... Etc. For example, 18Cr2Ni4WA.
③ Vanadium V, titanium Ti, aluminum Al, boron B, rare earth RE and other alloy elements in the steel belong to microalloyed elements. Although the content is very low, they should still be marked in the steel grade. For example, in 20mnvb steel. 0.07-0.12% for vanadium and 0.001-0.005% for boron.
④ High quality steel shall be marked with "a" at the end of the steel grade to distinguish it from general high quality steel.
⑤ For alloy structural steel for special purpose, the steel grade is preceded by (or suffix) to represent the symbol of the purpose of the steel. For example, 30CrMnSi steel for riveting screw is represented as ml30crmnsi.
Alloy pipe and seamless pipe have both relations and differences, and can not be confused. Alloy pipe is a kind of seamless pipe. Although it can not be mixed, seamless pipe includes alloy pipe.
Alloy pipe is defined as steel pipe according to the production material (i.e. material). As the name suggests, it is a pipe made of alloy; Seamless pipe is defined according to the production process of steel pipe (seamless seam). What is different from seamless pipe is seamless pipe, including straight seam welded pipe and spiral pipe.
