中厚钢板超声波探伤不合格原因分析

Cause Analysis on Disqulification of the Ultrasonic Flaw Detection in the Heavy and Medium Plate

针对中厚钢板超声波探伤出现的两类典型缺陷,通过低倍检验和金相检验等手段,并结合实际探伤过程中缺陷的分布位置对探伤不合格的原因进行了分析。结果表明:点状密集型缺陷主要与连铸坯的中心偏析有关,侧边条型缺陷则主要来源于连铸坯的三角区裂纹或靠近三角区的中心裂纹,钢板体部的条型缺陷则是由连铸坯的中间裂纹造成的。

Two typical flaws were found in both heavy and medium plate by means of ultrasonic flaw detection. Utilizing macroscopic examination and metallograpbic examination combining with the distribution of these flaws in the plate, the forming reason of the flaws was investigated. The results show that the cluster flaws were related to the center segregation in the continuous casting billet. Stripy flaws on the narrow side of the plate derived from the cracks within the triangular zone or central cracks close to the triangular zone. Furthermore, stripy flaws inside the steel plate mainly resulted from the intermediate cracks.