12Cr1MoVG alloy steel pipe is the details of boiler steel pipe

1. Introduction to alloy steel pipe
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 the steel, except for individual micro-alloying elements, are generally expressed in percentages. When the average alloy content is <1.5%, the steel number generally only indicates the element symbol without indicating the content, but in special cases that are easy to confuse, 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%, and the latter has a chromium content of 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.
③ Alloy elements such as vanadium V, titanium Ti, aluminum AL, boron B, and rare earth RE in steel are all micro-alloying. Although the content is very low, they should still be marked in the steel number. For example, in 20MnVB steel, vanadium is 0.07-0.12% and boron is 0.001-0.005%.
④ High-quality steel should add "A" at the end of the steel number to distinguish it from general high-quality steel.
⑤ For alloy structural steel for special purposes, the steel number is prefixed (or suffixed) with a symbol representing the purpose of the steel. Alloy steel pipes and seamless steel pipes are both related and different, and cannot be confused.

2. Material of alloy steel pipe
16-50Mn, 27SiMn, 40Cr, Cr5Mo, 12Cr1MoV, 12Cr1MovG, 15CrMo, 15CrMoG, 15CrMoV, 13CrMo44, T91, 27SiMn, 25CrMo, 30CrMo, 35CrMo, 35CrMoV, 40CrMo, 45CrMo, Cr9Mo, 10CrMo910, 15Mo3, A335P11, P22, P91, T91, Gangyan 102, ST45.8-111, A106B.

3. Quenched and tempered hardness of alloy steel pipe
When the hardening conditions of 12Cr1MoVG high-pressure alloy steel pipe are the same, the hardness after quenching and tempering can reflect the yield strength and tensile strength of 12Cr1MoVG high-pressure alloy steel pipe. Therefore, the drawings and technical conditions of 12Cr1MoVG high-pressure alloy steel pipe generally only specify the hardness value. Only very important parts are specified for other mechanical properties.
The determination of the hardness of the quenched and tempered 12Cr1MoVG high-pressure alloy steel pipe must take into account the requirements of the manufacturing process and the load conditions during use. From the perspective of the manufacturing process, it is hoped that the parts will be quenched and tempered in the blank state and then cut and assembled. In this way, the deformation and decarburization caused by the heat treatment of the 12Cr1MoVG high-pressure alloy steel pipe will be eliminated in the subsequent cutting process. However, the hardness of the parts using this manufacturing procedure cannot be too high, generally not exceeding 300HB, and some not exceeding 350HB, otherwise, it will be unfavorable for cutting. Parts that require higher hardness (such as some automobile axles that require a hardness of 341 to 415HB) can only be cut first and then quenched and tempered. At this time, the 12Cr1MoVG high-pressure alloy steel pipe should be heated to prevent decarburization and deformation, and sometimes a straightening process should be added after heat treatment. For parts produced in small batches or single pieces, the hardness allowed by cutting can be appropriately increased.
When determining the hardness of quenched and tempered 12Cr1MoVG high-pressure alloy steel pipes, the characteristics of production must also be taken into account. For products produced in small batches, different 12Cr1MoVG high-pressure alloy steel pipes can be selected with different hardnesses. For factories producing in large quantities, it is hoped that the hardness range of most 12Cr1MoVG high-pressure alloy steel pipes is consistent or fixed within several hardness ranges, which is very convenient for organizing heat treatment production.
From the perspective of the use of 12Cr1MoVG high-pressure alloy steel pipes, when determining the hardness of quenched and tempered parts, attention should be paid to the working conditions and shape of the 12Cr1MoVG high-pressure alloy steel pipes. Generally speaking, the higher the hardness value, the higher the tensile strength, yield strength, and fatigue strength of smooth samples, but the plasticity index decreases, the brittle failure tendency and the sensitivity to stress concentration increase. Therefore, when there is a notch (spline, groove, or large cross-section change) on the 12Cr1MoVG high-pressure alloy steel pipe that acts as a stress concentration, to make the stress distribution uniform and reduce the stress concentration phenomenon, the lower hardness can obtain higher fatigue performance.

4. Development of alloy steel pipes
12cr1movg alloy steel pipes have a very wide range of uses. To make 12cr1movg alloy steel pipes develop well, a good high-end market trend is "Noah's Ark" in the eyes of many 12cr1movg alloy steel pipe companies. In the tide of the high-end market, the product value of many 12cr1movg alloy steel pipes deviates from market demand, but the development potential of 12cr1movg alloy steel cannot be ignored.
GB3087 —— China National Standard
GB5310 —— China National Standard
ASME SA210 —— American Boiler and Pressure Vessel Code
ASME SA213 —— American Boiler and Pressure Vessel Code
DIN17175 —— Federal German Industrial Standard
API —— American Petroleum Institute

5. Calculation of the weight of alloy steel pipes
[(outer diameter-wall thickness)*wall thickness]*0.02466=kg/m (weight per meter)