双晶直探头在模具钢厚板探伤中的应用法

Application Method of Dual-Crystal Straight Probe for Ultrasonic Flaw Detection of Die Steel Plate

我公司扁平材厂生产的模具钢规格较多,超声波检测要求较严。若采用单晶直探头势必要制作大量对比试块,且操作繁琐,对现场探伤来说很不方便。双晶直探头有着灵敏度高、盲区小和近场区小的优点,本文从理论近似计算和实际性能测定确定了探伤模具钢厚板所采用双晶直探头的型号。由于内控要求模具钢板点状缺陷不得大于Φ3mm,所以采用距离—波幅曲线来调整检测灵敏度最为合理。

Specifications for the die steel manufactured in the flat products plant are various, so strict ultrasonic flaw testing is required in our company. Adopting the single-crystal straight probe could lead to a large number of the test samples and tedious operation, it is inconvenient for on-site testing. The dual-crystal straight probe has advantages of high sensitivity, the small blind and near-field zone. The specification of dual-crystal straight probe type used in the ultrasonic test on die steel plate was determined from two aspects of theory approximate calculation and actual performance determination in this paper. Because internal control requirement for the diameter of point defect on the die steel plate shall not he greater than 3mm, adjusting detection sensitivity by use of distance-volatility curve is the most reasonable.