铌钒微合金化对风电法兰用Q345E钢析出相的影响

Effect of Nb and V Micro-alloying on the Precipitation Phases in Q345E for Wind-electron Flange

中文关键词: Q345E Thermo-Calc 铌钒微合金化 析出相

英文关键词: Q345E, Thermo-Calc, micro-alloying of Nb and V, precipitation phase

中文摘要:

      采用Thermo-Calc热力学计算软件，对铌钒微合金化风电法兰用Q345E钢在400~1600 ℃存在的平衡析出相以及铌、钒在奥氏体相中的固溶规律进行了计算，并探讨了碳、氮、铌、钒元素含量变化对析出相的影响。结果表明：风电法兰用Q345E钢在400~1600 ℃存在的主要平衡析出相为MnS、AlN、MX#1（富含铌）、MX#2（富含钒）和M7C3相；MX#1相的主要组成元素为铌、碳、氮和少量的钒、铬，MX#2相的主要组成元素为钒、碳、铌、氮和少量的铬；MX#1相析出量和析出温度主要受钢中铌含量的影响，而受碳、氮、钒含量的影响不大。TEM分析表明，风电法兰用Q345E钢轧后析出相尺寸变化范围为几纳米到100纳米，大颗粒析出相为近似于立方形的富铌MX#1相，小颗粒析出相是球形或椭圆形的富钒MX#2相，这同热力学计算所得的MX#1相和MX#2相成分与析出温度基本吻合。

英文摘要:

      Equilibrium precipitation phases of Nb-V micro-alloying Q345E steel for wind-electron flange in the temperature range of 400-1600 ℃ and Nb-V dissolved in austenite were calculated by thermodynamic software Thermo-Calc. Effects of C-N-Nb-V alloying elements on these equilibrium precipitation phases were also discussed. Results showed that main equilibrium precipitation phases in Q345E steel for wind-electron flange at the temperature of 400-1600 ℃ were MnS, AlN, MX#1 (Nb-rich), MX#2(V-rich) and M7C3. Main composition elements of the MX#1 phase were Nb-C-N and a few V-Cr. V-C-Nb-N and a few Cr were composed of main composition elements for MX#2 phase. Precipitation amount and temperature of MX#1 phase were mainly effected by the content of Nb and had little effect of the C-N-V content. TEM analysis showed that the size of precipitation phases in the rolled wind-electron flange Q345E steel was in the range of several nanometers to more than 100 nm．Large precipitation particles were Nb-rich MX#1 phase with the cubic shape, small precipitation particles were V-rich MX#2 phase with spherical or elliptical, these were basically tallied with the thermodynamic calculation results about phase composition and precipitation temperature of MX#1 and MX#2.