15CrMo boiler tube

15CrMo boiler tube is based on high-quality carbon structural steel, and one or several alloying elements are appropriately added to improve the mechanical properties, toughness and hardenability of steel. Products made of this type of steel usually require heat treatment (normalizing or quenching and tempering); the parts and components made of such steel usually need to undergo quenching and tempering or surface chemical treatment (carburizing, nitriding, etc.),

surface Quenching or high-frequency quenching and other treatments. Therefore, according to the chemical composition (mainly carbon content), heat treatment process and use, this type of steel can be roughly divided into three types: carburizing, quenching and tempering and nitriding.

Classification of high pressure boiler tubes:

(1) High-quality carbon structural steel grades are 20G, 20MnG, and 25MnG.
(2) Alloy structural steel grades 15MoG, 20MoG, 12CrMoG, 15CrMoG, 12Cr2MoG, 12CrMoVG, 12Cr3MoVSiTiB, etc.
(3) The commonly used 1Cr18Ni9 and 1Cr18Ni11Nb boiler tubes with rust and heat-resistant steels should be subjected to hydrostatic tests, flaring and flattening tests one by one in addition to ensuring chemical composition and mechanical properties. Steel pipes are delivered in heat-treated condition.

In addition, there are certain requirements for the microstructure, grain size and decarburization layer of the finished steel pipe.

Specifications and appearance quality of high-pressure boiler tubes: GB5310-95 "Seamless Steel Tubes for High-Pressure Boilers" has an outer diameter of 22-530mm and a wall thickness ranging from 20-70mm. The outer diameter of the cold drawn (cold rolled) tube is 10-108mm, and the wall thickness is 2.0-13.0mm.

The principle of purifying hydrogen by 15CrMo boiler tube is that when the hydrogen to be purified is passed into one side of the 15CrMo boiler tube at 300-500 ℃, the hydrogen is adsorbed on the wall of the 15CrMo boiler tube, because the 4d electron layer of palladium lacks two Electrons, which can form unstable chemical bonds with hydrogen (this 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°C), so protons can be combined with electrons through the 15CrMo boiler tube under the action of palladium to form hydrogen molecules again, and escape from the other side of the 15CrMo boiler tube. On the surface of the 15CrMo boiler tube, the undissociated gas is impermeable, so the 15CrMo boiler tube can be used to obtain high-purity hydrogen.

15CrMo boiler tube representation method:

① The two digits at the beginning of the steel number indicate the carbon content of the steel, expressed in ten thousandths of the average carbon content, such as 40Cr.
② The main alloying elements in steel, except for individual microalloying elements, are generally expressed in percent. When the average alloy content is less than 1.5%, only the element symbol is generally indicated in the steel number, but the content is not indicated. However, in special cases, if it is easy to cause confusion, the number "1" can also be marked after the element symbol, such as the steel number. "12CrMoV" and "12Cr1MoV", the former has a chromium content of 0.4-0.6%, the latter is 0.9-1.2%, and the rest of the components are all the same. When the average content of alloying elements is ≥1.5%, ≥2.5%, ≥3.5%..., the content should be indicated after the element symbol, which can be expressed as 2, 3, 4...etc. For example 18Cr2Ni4WA.
③Alloying elements such as vanadium V, titanium Ti, aluminum AL, boron B, and rare earth RE in steel are all microalloying elements. Although the content is very low, they should still be marked in the steel grade. For example, in 20MnVB steel. Vanadium is 0.07-0.12% and boron is 0.001-0.005%.
④High-quality high-quality steel should add "A" at the end of the steel number to distinguish it from general high-quality steel.
⑤ For special purpose alloy structural steel, the steel number is crowned (or suffixed) with a symbol representing the purpose of the steel. For example, the special 30CrMnSi steel for riveting screws, the steel number is expressed as ML30CrMnSi.

Alloy pipes and seamless pipes have both relationships and differences, and should not be confused.
Alloy pipe is defined by the steel pipe according to the production materials (that is, the material), as the name suggests, it is a pipe made of alloy; while the seamless pipe is defined by the steel pipe according to the production process (seamless), which is different from the seamless pipe. Seamed pipes, including straight seam welded pipes and spiral pipes.

15CrMo boiler tube weight calculation formula:

[(outer diameter-wall thickness)*wall thickness]*0.02466=kg/meter (weight per meter)