微合金化在正火態(tài)管線用無縫鋼管中的應用

Application of Micro-alloying to Manufacture of As-normalized Seamless Steel Linepipes

摘要: 研究了微合金元素Nb、V、Ti在正火態(tài)管線用無縫鋼管成分體系中的不同作用及其機理，并分析了C、N等元素對微合金化效果的影響。結(jié)果表明：Nb、V、Ti在正火態(tài)管線用無縫鋼管成分體系中，可有效細化晶粒，并產(chǎn)生析出強化效果，從而提高鋼的強韌性；提高氮元素含量可有效提高V的析出強化和細晶強化效果；降低碳含量可有效提高沖擊韌性，但在碳當量同等的情況下，會降低強度。

Abstract: Studied here in the essay are the different roles and mechanisms of the micro-alloy elements （i.e.，Nb，V and Ti） in the chemical composition system of the as-normalized seamless steel linepipe. Also analyzed is how chemical elements like C and N，etc. affect the micro-alloying result. Accordingly，the facts as following are revealed. In the chemical composition system of the said linepipe，elements Nb，V and Ti can get the grains well refined，and bring about the segregation strengthening effect so as to enhance strength and toughness of the steel.Increasing N content can remarkably enhance the segregation-strengthening and grain refining-strengthening effects by Element V. And reducing C content can obviously enhance impact toughness of the steel，whereas with the same carbon equivalent，the strength might be decreased.