GH4169合金冷轧板材的成形工艺性能

Forming property of cold rolled GH4169 alloy sheet

对厚度为1.0 mm的固溶态GH4169合金冷轧板材进行了室温拉深、杯突等成形工艺性能实验,并对测试后试样不同位置的组织和显微硬度进行了研究。结果表明,GH4169合金冷轧板材经固溶处理后,组织均匀,晶粒为等轴晶,平均晶粒度直径为7.8μm。板材的极限拉深比LDR为2.15,杯突值IE为12.87 mm。拉深试样局部变形较大,最大塑性变形量达到48%时发生开裂。杯突试样的塑性变形相对均匀,最大塑性变形量达到62%时发生开裂。成形工艺实验过程中试样发生塑性变形并产生加工硬化,获得了硬度与塑性变形量间的幂函数关系式。试样开裂位置的晶粒被拉长,晶粒内部取向梯度增大,形成大量滑移线,大块碳化物发生破碎和脱落,裂纹易于在碳化物周围及位错塞积严重位置萌生及扩展,最终连通而发生开裂。

The deep drawing and cupping properties of cold rolled and solution treated GH4169 alloy with a thickness of 1.O mm were tested at room temperature,and the microstructure and microhardness of different positions of the tested samples were studied.The results show that the GH4169 alloy cold rolled sheet,after solid solution treatment,has a uniform structure,equiaxed grains,and an average grain size diameter of 7.8μm.The limited drawing ratio(LDR)and the cupping test value(IE)of sheet are 2.15 and 12.87 mm,respectively.The local deformation of the deep drawing sample is observed,and the fracture occurs when the maximum deformation percentage reaches 48%.However,the deformation of the cupping sample is relatively uniform,and the fracture occurs when the maximum deformation percentage reaches 62%.During the forming process experiment,the sample undergoes plastic deformation and undergoes work hardening,obtaining a power function relationship between hardness and plastic deformation.The grains at the fracture location are elongated.It is found that a large number of slip lines are formed and carbides break and fall off near the fracture.The crack is prone to initiate and propagate around the carbide and the location with serious dislocation congestion,ultimately leading to connectivityand cracking.