Study On The Submerged Arc Welding Consumables For 2.25Cr-1Mo-0.25V Steel And Its Microstructure And Mechanical Properties Of The Deposited Metal

Hot wall hydroprocessing reactor is the key equipment in oil refinery and coal liquefied. Through many years development, the hot wall hydroprocessing reactor fabrication technique in China has grown up. Shell material already domestically produced, but the welding consumables still need to import from foreign countries. 2.25Cr-1Mo-0.25V steel is regarded as the most prospective steel in hydroprocessing reactor fabrication. This paper develops Submerged Arc Welding (SAW) materials for 2.25Cr-1Mo-0.25V steel and investigates the microstructure and mechanical properties of its deposited metal.This paper successfully developed the hot wall hydroprocessing reactor butt welding SAW materials (solid wire and flux) for 2.25Cr-1Mo-0.25V steel. The composition and mechanical properties and purity of deposited metal achieved the requirements of ASME code and hot wall hydroprocessing reactor main welds' specification.The effect of Nb on microstructure and mechanical properties were investigated. The experimental results showed that: As one of the elements must exist in 2.25Cr-1Mo-0.25V steel weld metal, when the composition of Nb at the lower limit in ASME code, the deposited metal could obtain good mechanical properties.The effect of Nitrogen on the mechanical properties of deposited metal was discussed. The experimental results showed that: Low Nitrogen composition for deposited metal could obtain good low temperature toughness.The weldability, deposited metal's mechanical properties and purity of the new developed shell butt welding SAW material as the same level compared with Kobe Steel US-521HD/PF-500D.