DTⅡ(A)型带式输送机滚轮对接焊缝的超声波检测  

Ultrasonic inspection on butt weld of DTⅡ(A) type belt conveyor rolling wheel in a 660MW unit

作　　者：敬尚前[1] 牛晓光[1] 郝晓军[1] 王强 刘长福[1] 董国振[1] 孙澎[1] 代真 薛永波 

机构地区：[1]河北省电力公司电力科学研究院,河北石家庄050021 [2]国电科学技术研究院,江苏南京210031 [3]国华沧东发电有限责任公司,河北沧州061103

出　　处：《热力发电》2014年第1期74-79,95,共7页Thermal Power Generation

摘　　要：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。The DT Ⅱ （A） belt conveyor rolling wheel was welded by plain low-carbon steel and cast-steel. Due to the special structure,ultrasonic test was performed on cast-steel side of the butt weld. There are biggish difference of acoustic property between low-carbon steel and cast-steel, which causes indetermination of the ultrasonic test. The ultrasonic test sensitivity was determined on the basis of theoretical calculation. Combining with the actual detection data and the dissection validation, comparison between each process standard and quality standard was conducted, and the defect judgement sensitivity and the defect evaluation grade were identified. Moreover, the static and dynamic echo characteristics of butt weld that was lack of penetration and with fatigue crack was analyzed. The results showed that, using longitudinal wave normal probe with frequency of 2.5 MHz and diameter of 14mm can meet the requirement for detection sensitivity. Under thiscondition,the butt weld defect that was lack of penetration which occupied above 15.6%of the weld thickness can be detected.

关 键 词：滚轮 铸钢 对接焊缝 超声波检测 回波特性 

分 类 号：TG115.285[金属学及工艺—物理冶金]