GH4169合金叶片楔横轧预制坯成形质量研究

Study on the Forming Quality of GH4169 Alloy Blade Preformed by Cross Wedge Rolling

以航空发动机GH4169合金叶片预制坯为对象,通过热压缩试验分析GH4169合金高温变形行为,构建GH4169合金楔横轧预成形数值模拟模型。开展了楔横轧试验,并将试验件和仿真件进行了对比,对叶片预制坯的成形质量进行了研究。结果表明,若工艺参数选择不当,预制坯的表面会出现拉细缩颈甚至拉断缺陷。初始成形温度会影响表面成形质量,轧件在高温条件加工更容易出现缩颈现象。同时,初始成形温度会显著影响预制坯心部成形质量,在较高的初始成形温度下,预制坯心部易形成尺寸较大、数量较多的微孔洞,尺寸多集中在20~30μm范围内,主要在NbC碳化物的脱落处形核,形成微孔洞。为获得无成形缺陷的GH4169合金叶片预制坯轧制,轧制时初始成形温度应不高于1 020℃,断面收缩率和轧辊转速应不高于55%和10 r/min。

Taking GH4169 alloy blade preform as the object,the deformation behavior of GH4169 alloy at high temperature was analyzed through the hot compression experiment,and the numerical simulation model of the cross wedge rolling preforming of GH4169 alloy blade was established.Meanwhile,a cross-wedge rolling experiment was carried out,and the experimental parts and simulated parts were compared to study the forming quality of the blade preform.The results show that,if the process parameters are not selected properly,the preform will be stretched and necked or even broken.The initial forming temperature will affect the surface forming quality.Rolled parts are more prone to necking when processed under high temperature conditions.At the same time,the initial forming temperature can significantly affect the forming quality in the core of the preform.At a higher initial forming temperature,larger and more microholes are easily formed in the core of the preform.The size of the microholes is mainly concentrated in the range of 20-30μm,and the microholes are mainly nucleated where the NbC carbide falls off.Therefore,in order to obtain the GH4169 alloy blade preform without forming defect,the initial forming temperature should not be higher than 1020℃,and the area reduction and the roll speed should not be higher than 55%and 10 r/min respectively.