大型离心压缩机叶片热成形回弹研究

Research on hot forming springback of large centrifugal compressor blade

研究了大型离心压缩机叶片热成形工艺参数对回弹的影响。对叶片材料沉淀硬化不锈钢FV520B进行了高温力学性能实验,并建立了该材料高温下本构方程。利用所建立本构方程,对叶片热成形工艺进行了有限元建模仿真,探究了叶片加热温度、摩擦系数和保压时间对回弹的影响。发现叶片加热温度对回弹影响较大,在800~900℃温度区间回弹下降趋势明显,900~950℃区间下降趋势变缓,同时叶片厚度减薄加剧,说明900℃是合适的叶片加热温度;摩擦系数对回弹影响较小,较低和较高的摩擦系数都会减小回弹,但较大的摩擦系数会导致叶片减薄,影响表面质量,应尽可能将摩擦系数控制在0. 25以下;保压时间控制在100~150 s区间内较为合适。同时确定了回弹前后比对基准区域,并对回弹较明显区域进行了标识划分。最后将优化后的工艺参数应用于生产验证,结果表明除掉少数边缘区域外,叶片大部分区域回弹都控制在±1 mm内,模拟结果与试验结果在回弹发生区域基本符合。

The effect of hot forming process parameters on springback of the large centrifugal compressor blade was studied. The high temperature mechanical properties of the blade material precipitation hardening stainless steel FV520 B were tested and the constitutive equation at high temperature was established. Based on the constitutive equation,the finite element simulation of the blade hot forming process was carried out,and the effects of blade heating temperature,friction coefficient and holding time on springback were investigated. It is found that the heating temperature has great impact on the springback,in the temperature range of 800-900 ℃,the springback has a decreasing trend,in the range of 900-950 ℃,the trend becomes slower while the thickness thinning of the blade is increased,indicating that 900 ℃ is a suitable heating temperature for blade. The friction coefficient has less impact on the springback,both the low and high friction coefficient reduce the springback,however,the higher friction coefficient leads to the thinning of the blade and affects the surface quality,the friction coefficient should be controlled to 0. 25 or less as much as possible. It is more suitable to control the holding time in the 100-150 s interval. At the same time,the comparison reference area before and after springback was determined,and the springback area was marked and divided. Finally the optimized parameters were applied to the production. The results show that except of small end area of the blade,the springback value is controlled within ± 1 mm. The simulation results are basically consistent with the experimental results in the area of the springback.