Nb is the element that must be insist in 2.25Cr-1Mo-0.25V steel submerged arc welding weld metal which is demanded in ASME CODE CASE.是什么意思_Nb is the element that must be insist in 2.25Cr-1Mo-0.25V steel submerged arc welding weld metal which is demanded in ASME CODE CASE.在线翻译_英语_读音_用法_例句