微合金化及铸坯加热温度对新型高氮螺纹钢组织及性能的影响  

Influence of microalloying and billet heating temperature on microstructure and properties of new type of high-nitrogen rebar steel

作　　者：邓必荣[1] 徐光 DENG Birong;XU Guang(Technology Center,Hunan Valin Lianyuan Iron and Steel Co.,Ltd.,Loudi 417000,China)

机构地区：[1]湖南华菱涟源钢铁有限公司技术中心,娄底417000

出　　处：《江西冶金》2024年第6期465-471,共7页Jiangxi Metallurgy

摘　　要：利用Thermo-Calc热力学软件对氮、钒和铌对螺纹钢中析出相的影响规律进行了研究,并对新型高氮螺纹钢成分进行了设计。基于转炉→钢包精炼炉→连铸工艺对新型高氮螺纹钢进行了试生产,研究了氮、钒和铌含量和铸坯加热温度(1050、1100、1150℃)对螺纹钢微观组织及力学性能的影响。结果表明,随着钢中氮的质量分数增加,析出相的析出温度升高,析出量增加,增加氮含量可有效提高析出强化能力并降低生产成本;随着铌含量增加,Nb(C,N)开始析出温度升高且析出量增加,V(C,N)析出受到抑制。钢中适宜的氮、钒和铌质量分数分别为0.020%、0.020%和0.0050%。随着铸坯加热温度升高,试验钢晶粒尺寸增大,珠光体比例呈现先减小后增大的趋势。当铸坯加热温度低于析出相开始析出温度时,析出相无法充分回熔。新型高氮螺纹钢铸坯最佳加热温度为1100℃。Thermo-Calc thermodynamic software was employed to investigate the effects of nitrogen,vanadium,and niobium on the precipitation phases in rebar steel,leading to the design of a high-nitrogen rebar composition.A trial production of the new high-nitrogen rebar steel was conducted using the BOF→LF→CC process,and the effects of billet heating temperature(1050,1100 and 1150℃)on the microstructure and mechanical properties of the rebar steel were studied.Results indicated with the increase of nitrogen mass fraction in steel,the temperature at which the precipitated phase begins to precipitate and the number of precipitations increase.Enhanced nitrogen content effectively improves precipitation strengthening while reducing production costs.As niobium content increased,the temperature at which Nb(C,N)begins to precipitate rose along with the precipitate volume,concurrently the precipitation of V(C,N)is inhibited.The optimal mass fraction for nitrogen,vanadium,and niobium in the steel were determined to be 0.020%,0.020%,and 0.0050%,respectively.With higher billet heating temperatures,the grain size of the steel enlarged,and the proportion of pearlite initially decreased before increasing.When the billet heating temperature was lower than the precipitation temperature of the precipitated phase,the precipitates could not be fully redissolved.The optimal billet heating temperature for the new high-nitrogen threaded steel was determined to be 1100℃.

关 键 词：微合金化 氮 螺纹钢 铸坯加热温度 力学性能 

分 类 号：TF769.4[冶金工程—钢铁冶金] TG142.1[一般工业技术—材料科学与工程]