GH4169合金精锻叶片腐蚀条带组织的成因分析及预防措施

Causative Analysis and Preventive Measures of Etched Band Microstructure on GH4169 Alloy Precision Forging Blade

目的分析精锻工艺成形的GH4169合金压气机转子叶片出现腐蚀条带组织的原因,以制定相应的预防措施。方法对精锻叶片用GH4169合金开展锻造热过程模拟试验,采用电镜观察其显微组织,以判断叶片锻件异常组织与原材料组织的关联。采用数值模拟方法对锻造工艺参数,尤其是锻造变形量进行分析与验证,找出锻造工艺方案的不足之处。结果当原材料存在δ相偏聚时,容易导致叶身及榫头部位出现纵向腐蚀条带组织;当叶片锻造变形设计不合理,盆弧侧、背弧侧的预锻件与终锻件的变形体积比超出1.1~1.4时,会导致榫头部位出现金属流动异常的现象,进而产生应变剪切带、导致叶片榫头部位出现异常组织。结论在叶片精密锻造生产前要确保原材料组织均匀,不能出现δ相偏聚,同时采用数值模拟方法来合理控制锻造各阶段的变形量与应变场,确保叶片预锻件与终锻件的变形体积比合理、金属变形均匀,这样才能保证叶片叶身和榫头部位不出现腐蚀条带组织。

The work aims to investigate and analyze the causes of etched bands on the compressor rotor blades of GH4169 alloy formed by precision forging process,so as to formulate corresponding preventive measures.The simulation test was carried out on the forging thermal process of GH4169 alloy for precision forging blade,and the microstructure of blade was observed by electron microscope to determine the relationship between the abnormal microstructure of the blade forging and the microstructure of raw material.In addition,the numerical simulation method was used to analyze and verify the forging process parameters,especially the forging deformation,and find out the deficiencies of the forging process scheme.Whenδphase segregation existed in raw material,longitudinal etched bright band microstructure was easy to appear in blade body and tenon part.When the blade forging deformation design was unreasonable,the deformation volume ratio between the pre-forgings and the final forgings at the basin arc side and back arc side exceeded the range of 1.1-1.4,which led to abnormal metal flow in the tenon part,resulting in strain shear bands and abnormal microstructure in the tenon part of the blade.Before precision forging production of blade,it is necessary to ensure the uniform microstructure of raw material and avoidδphase segregation.At the same time,numerical simulation method can be used to reasonably control the deformation and strain field at each stage of forging,so as to ensure that the deformation volume ratio of the pre-forgings and final forgings is reasonable and the metal deformation is uniform,thus ensuring that the blade body and tenon part do not have etched band microstructure.