镦制温度对GH4169合金紧固件组织的影响

Effect of heading temperature on microstructure of GH4169 alloy fasteners

采用试验研究和有限元模拟相结合的方式研究了热镦过程中温度对GH4169合金紧固件组织的影响。结果表明:GH4169合金紧固件的组织对镦制温度极为敏感,镦制温度过低时头部会存在充型不满的风险,头杆转接圆角部位晶粒尺寸会存在较大的级差;镦制温度过高时紧固件头部的中心部位会存在组织失稳的可能,飞边部位会存在严重的混晶现象。因此,在GH4169合金紧固件热镦过程中需严格控制温度在950~1000℃为宜。DEFORM-3D有限元模拟分析结果表明,GH4169合金紧固件在热镦过程中会存在明显的温度梯度。飞边部位温升极为明显,局部温度可高于δ相的回溶温度,飞边部位易出现混晶现象。因此,在GH4169合金紧固件热镦过程中应合理选择温度,并综合考虑温度不均匀性对组织的影响。

Effect of temperature on microstructure of GH4169 alloy fasteners during hot heading process was investigated by combining experimental studies and finite element simulations.The results show that the microstructure of the GH4169 alloy fasteners is very sensitive to heading temperature.When the hot heading temperature is too low,the head of the fasteners will be have the risk of mould cavity nonsaturate,and the grain size in transition area between rod and head will have a significant difference.When the hot heading temperature is too high,there is the possibility of microstructure instability in the central part of the fastener head,and there will be serious mixed crystal phenomenon in the flash area.Therefore,it is appropriate to strictly control the heading temperature at 950-1000℃in the hot heading process of the GH4169 alloy fasteners.DEFORM-3D finite element analysis results show that the GH4169 alloy fasteners will have a significant temperature gradient in the hot heading process.The temperature rise of the flash area is very obvious,the local temperature can be higher than that of the solution temperature of theδphase,and the phenomenon of mixed crystal is easy to appear in the flash area.Therefore,the temperature should be reasonably selected during the hot heading process of the the GH4169 alloy fasteners,and the effect of temperature in-homogeneity on the microstructure should be considered synthetically.