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采用超声波于铸钢侧对DTⅡ(A)型带式输送机滚轮普通碳素钢筒皮与铸钢接盘对接焊缝的内部缺陷进行了检测。通过理论计算确定检测灵敏度,结合实际检测数据和现场解剖,在对比各工艺和质量标准的基础上,确定了缺陷判定灵敏度和缺陷评定级别,并对此类焊缝根部未焊透并伴有疲劳裂纹缺陷的静、动态回波特性进行了分析。分析表明,采用2.5MHz、Φ14mm纵波直探头,以Φ6mm平底孔作为检测灵敏度可以满足检测要求,在此条件下可以检测出未焊透缺陷占焊缝厚度15.6%以上的缺陷。以GB/T 12469-90《焊接质量保证钢熔化焊接头的要求和质量分级》Ⅲ级为判废标准,≥-22.9dB的缺陷回波均判定为Ⅲ级及以上。
Ultrasonic was used to test the internal defects of butt-welded joints of ordinary carbon steel shell and cast steel disk of DTⅡ (A) type belt conveyor rollers on the cast steel side. The sensitivities were determined by theoretical calculation. Based on the actual test data and on-site anatomy, the sensitivity and defect evaluation level of defects were determined on the basis of comparing the technology and quality standards. The weld root joints were not welded with fatigue Crack defects of the static and dynamic echo characteristics were analyzed. The analysis shows that using 2.5MHz, Φ14mm longitudinal wave straight probe, Φ6mm flat bottom hole as the detection sensitivity to meet the testing requirements, under this condition can detect imperfections accounted for more than 15.6% of the weld thickness defects. To GB / T 12469-90 “welding quality assurance of welded steel welded joint requirements and quality grading,” the third grade for the sentence criteria, ≥-22.9dB defect echoes were judged to be Ⅲ and above.