论文部分内容阅读
分别在9.2,10.4,12.2,21.0kJ·cm-1焊接热输入下对12MnNiCrMoV钢薄板进行对接焊,研究了焊接热输入对焊接接头粗晶热影响区显微组织、晶粒尺寸、硬度和冲击性能的影响;为了确定不同热输入下接头粗晶热影响区的焊接热循环曲线,对焊接过程的温度场进行了有限元模拟。结果表明:随着焊接热输入增大,粗晶热影响区的组织变化并不明显,均为粒状贝氏体和块状铁素体,但晶粒尺寸逐渐变大,-20℃冲击韧性和维氏硬度均逐渐降低;晶粒粗化是粗晶热影响区产生脆化与软化的最主要原因;通过有限元模拟可知,随着热输入增大,粗晶热影响区相同位置处的峰值温度逐渐升高,并且在高温停留的时间延长。
The butt welding of 12MnNiCrMoV steel sheets was carried out under the welding heat input of 9.2, 10.4, 12.2 and 21.0 kJ · cm-1 respectively. The effects of welding heat input on the microstructure, grain size, hardness and impact In order to determine the thermal cycle of welding under the influence of different heat input, the temperature field in the welding process was simulated by finite element method. The results show that with the increase of welding heat input, the microstructure changes in the coarse heat affected zone are not obvious, which are granular bainite and massive ferrite, but the grain size becomes larger and the impact toughness at -20 ℃ Vickers hardness decreases gradually. The grain coarsening is the main reason for the embrittlement and softening of the coarse heat affected zone. Finite element simulation shows that as the heat input increases, the peak at the same position of the coarse heat affected zone The temperature rises gradually, and the stay time at high temperature prolongs.