镍基耐蚀合金N10276开坯开裂原因分析和工艺改进

Analysis of Cogging Cracking and Process Improvement of Ni-Base Corrosion Resistant Alloy N10276

采用3 t VIM真空冶炼+3 t电渣重熔双联工艺生产的镍基耐蚀合金N10276在开坯过程中极易出现开裂缺陷。采用微观组织表征、能谱检测以及透射电镜标定等方式对缺陷进行了分析,并用热力学计算与差式扫描量热法确定析出相重新固溶条件,并通过热压缩模拟对改进措施进行了验证。结果表明,合金中析出的μ相是造成锻造开坯过程中开裂的直接原因;合金在1110℃以上长时间退火,可使析出相重新回溶;将均匀化处理工艺由1150℃24 h改进为1190℃36 h后,合金中析出相充分回溶,热压缩试验模拟开坯生产表明工艺改进后合金热加工性能明显提升,可避免开坯开裂发生。

The cracking defects of the Ni-base corrosion-resistant alloy N10276 produced by duplex process of 3 t vacuum induction melting furnace+3 t electroslag remelting ingot are greatly easy to appear in the process of cogging.The defects are analyzed by means of microstructure characterization,energy spectrum detection and transmission electron microscope calibration.The re-dissolved conditions of precipitates are determined by thermodynamic calculation and differential scanning calorimetry.The improvement measures are verified by thermal compression simulation.The results show that theμphase precipitated in the alloy is the direct reason for cracking in the process of forging cogging.When the alloy is annealed above 1110℃for a long time,the precipitates can be redissolved.After the homogenization process is improved from 1150℃for 24 h to 1190℃for 36 h,the precipitates in the alloy are fully dissolved.The simulation of the hot compression test exhibits that the hot workability of the alloy is improved obviously after process improvement,and the cogging cracking can be avoided.