在我厂生产的彩色显象管中,有相当一部分零件是由进口的复杂模具加工的。在一次修复进口的大型铸造荫罩模凹模时,由于操作上的失误,数控铣掉刀,啃掉一大块,造成有65×50×50mm的大缺口,如报废,将造成价值外汇十几万元以上的经济损失。经分析,考虑焊接修复的可行性。但由于模具材质是灰口铸铁,铸铁焊接容易产生较大应力而出现裂纹,一般采用热焊法较多,而荫罩模的凹模形状为非球面曲线图形,上面 In my factory production of color picture tube, a considerable part of the parts are imported from the processing of complex molds. In a repair of imports of large cast mask die, due to operational errors, CNC milling knife, chew a large piece, resulting in a large gap of 65 × 50 × 50mm, such as scrapping, will result in the value of foreign exchange ten Tens of thousands of yuan of economic losses. After analysis, consider the feasibility of welding repair. However, due to the mold material is gray cast iron, cast iron welding prone to greater stress and cracks, the general use of hot welding more, while the shadow mask die shape aspherical curve, the top