精铸型壳高温弯曲破碎强度测定仪的研制

Instrument for Bending Strength at High Temperature of Investment Casting Shell

介绍了一种新型精铸型壳高温弯曲强度测定仪的结构、工作原理和操作方法。在试验用加热炉内近似地模拟了型壳浇铸后的高温应力状态,在加热炉侧壁上开出测量孔,测定仪位于加热炉外,测量杆穿过测量孔,对准加热炉内高温胎具里的圆形试样中心进行加载,将载荷信号通过测力传感器和A/D转换装置输入计算机进行处理,计算机输出相应的载荷曲线和实验温度值。高温胎具由G2高纯石墨材料制成,以胎具上的环形槽将试样精确定位,可以保证胎具在高温下的强度和硬度,减小测量误差。在测量杆和传感器之间采取隔热措施,消除了温度对测量精度的影响。本测定仪可以测量室温至1350℃范围内型壳试样的抗弯强度,相对误差不大于1‰

The significance of measurements for high temperature strength of investment casting shell materials was expounded. The structure, measuring principle and operation of a new measuring tester for bending strength at a high temperature are introduced. The measuring tester can obtain high accuracy-position and reduce synchronous-temperature testing time between mould and sample by holding sample in a high temperature model, approximately exhibiting stress state of poured shell mold. Based on above principle, computer can visualize the loading curves and experimental temperature through treating measuring symbol from loading device-measuring-force-sensor-A/D converter. The results show that the measuring error of the measuring tester is below 0.1%, showing high accuracy. Meanwhile, measuring results indicated as loading curves and temperature is accurately visualized, which is helpful to finding out abnormal data and to treating experimental data, meeting the requirements of research institution and enterprises.