带阻尼台叶片精锻过程卸载冷却对形状偏差的影响

Influence of Unloading and Cooling on the Deviation of Blade Geometry in Precision Forging of Blade with Damper

叶片精锻卸载—冷却阶段,因为弹性回复及冷却不均匀的影响,叶片实际尺寸与理论尺寸之间将出现偏差,严重影响叶片形状精度。为此,根据叶片形状偏差的特点及类型,建立了叶身形状偏差评判准则的数学表达式,并基于DEFORM-3D,建立了叶片成形—卸载—冷却过程的三维热力耦合弹塑性有限元模型,研究得到了带阻尼台叶片精锻过程卸载—冷却对叶片形状偏差的影响规律:卸载对阻尼台附近偏差影响较大,而冷却对叶尖部位偏差影响较大;精锻结束后叶身实际厚度小于理论厚度;阻尼台部位偏差主要出现在顶端及排气边附近。

In the process of unloading and cooling, deviation between the actual and nominal blade geometry occurs mainly due to elastic recovery and non-uniform cooling, which greatly affect the blade geometry. Therefore, equations for quantifying the deviation of blade geometry in precision forging are established according to features and types of the deviation. Then a three dimensional coupled thermo-mechanical and elastic-plastic finite-element model for the process of forming-unloading-cooling is built on the basis of DEFORM-3D. The influence of unloading and cooling on the different types of deviation is obtained. The results show that ： unloading and cooling have great influence on the deviation of bow and twist in the region of damper platform and blade tip, respectively; the value of actual thickness of blade body is less than that of theoretical thickness; the deviation of damper platform occurs mainly at the top region and outlet edge.