Manufacture of Advanced 2.25Cr-1Mo-V Pressure Vessel Steel for High Pressure and High Temperature Hydrogen Service

At this moment, the materials which are applied for high pressure and high temperature services are selected from conventional 2.25Cr-1Mo, 3Cr-1Mo-V and 2.25Cr-1Mo-V steels. Especially, the application of 2.25Cr-1Mo-V steel is increased extremely rather than the other steels in order to take the advantage of higher strength and better resistance to hydrogen damages such as hydrogen attack, hydrogen assisted crack growth and also hydrogen induced disbonding. In order to achieve these properties, the vanadium element is added intentionally into base material and welding consumables. Due to the addition of vanadium, the engineer have recognized that there is some possibility of cracking in the weldment due to the higher hardness and insufficient manufacturing practices caused by lack of knowledge for preheating, intermediate/final postweld heat treatment and other factors. The manufacturers have to establish the proper technologies to avoid this problem during fabrication stage while the pressure vessels are to be fabricated in their shop and/or fields. In this paper, the manufacturing technologies of 2.25Cr-1Mo-V steel pressure vessel through actual fabrication is presented herewith.