Use of materials for pressure vessels
Thread Content
Generally, Q345R (16MnR, 16Mng) or Q245R (20R, 20g) are the most widely used materials. Materials such as Q370R (15MnNbR), 18MnMoNbR, and 13MnNiMoR (13MnNiMoNbR) seem to be less commonly used. In what situations are these materials employed? Those who have experience with them please share their insights. Additionally, the new standards for steel plates used in pressure vessels no longer include the grades Q235-A, B, and C. Does this mean that Q235 material can no longer be used in pressure vessels?
In the standards for steel plates used in pressure vessels, there is no such thing as Q235 steel plates (neither in the former standard 6654 nor in the current standard 713); it is a carbon structural steel plate. In standard 150, it is recommended that Q235 steel plates can be used under certain conditions. The selection of container steel plates should take into account the pressure, temperature, medium involved, as well as the welding properties of the container, with choices being made in order of increasing price of the steel plates
In terms of the design approach, the choice of material is primarily determined by the medium, pressure, and temperature; while ensuring safety, steel materials are selected in sequence, from lower to higher grades； For Q235 series steel, the domestic steel available in China is now sufficient for use in domestic containers; therefore, the Q235 series has been removed from the newly revised GB713-2008 standard. To improve the safety level of containers, the use of Q235 series steel is not recommended.
The Q235 series can be selected in accordance with the provisions of GB150, and it should work fine； Q370R(15MnNbR), 18MnMoNbR, and 13MnNiMoR(13MnNiMoNbR) have high strength levels and are used in applications with high operating parameters such as pressure and temperature ； Q245R and Q345R are the most commonly used and are well-established.
For high-strength steels such as Q370R (15MnNbR), 18MnMoNbR, and 13MnNiMoR (13MnNiMoNbR), they are generally used in applications with high pressures, and are often employed in spherical tanks. Among the Q235-A, B, and C grades, Q235-A has been removed in Amendment 1 to GB150-1998 ； Q235B and C steels are not originally designed for use in pressure vessels; they are carbon structural steel plates. Their use in the vessel industry is subject to certain restrictions. However, due to their lower cost, they are still governed by GB150-1998.
Replying to the person above: The key point is that among the grades Q235-A, B, and C, Q235-A has been discontinued in Amendment 1 to GB150-1998； Q235B and C steels are not intended for use in pressure vessels; they are carbon structural steel plates that are only allowed to be used in the vessel industry under certain restrictions”