Note: vt- visual inspection, mt- magnetic particle inspection, pt- penetrant inspection, ut- ultrasonic inspection and rt- ray inspection?
*1:NDT of Class I welds is only applicable to tensile butt welds of special components (such as butt welds of lower flange plate of bridge crane main beam, upper and lower flanges of portal crane boom system, web splicing and other tensile butt welds with definite loads) or non-pipeline connection butt welds under periodic loads. Generally, when the thickness of the steel to be inspected is ≥ 12mm, ultrasonic flaw detection can be used; X-ray inspection can be used when the thickness is less than 8 mm; In addition to ultrasonic flaw detection of 8mm or 10mm manual arc welding seam, when necessary, RT can also be used to spot check 5% of the cumulative firewood and take photos ≥ 1. ?
* 1: NDT of Class II welds is generally applicable to pressure butt welds (such as flat-seam of flange plate on main girder of bridge crane and other pressure flat-seam with certain load, etc.). ) or static load non-pipe connection weld. ?
*3: When obvious defects are found in welds through visual inspection, and it is necessary to further understand the actual situation of weld defects, magnetic particle flaw detection or penetrant flaw detection can be used as an auxiliary means to evaluate the appearance quality level of multiple welds. ?
For fillet welds?
(1) The longitudinal fillet weld of the box generally does not need flaw detection; ?
(2) For fillet welds close to boom, luffing bracket, lifting lug and important drawings that need flaw detection, super welding shall be adopted.
Acoustic flaw detection.