The DTⅡ(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 2.5MHz and diameter of 14mm can meet the requirement for detection sensitivity.Under this condition

the butt weld defect that was lack of penetration which occupied above 15.6% of the weld thickness can be detected.