How to deal with cracks in pressure vessels
How to deal with cracks in pressure vessels
Cracks on base material of pressure vessel
(1) Cracks on the surface and near the surface. Eliminate it with arc-transition grinding method, and then use magnetic particle inspection and re-inspection.
(2) Internal cracks. First use ultrasonic testing to find out the location of the crack, and then use radiographic testing to find out the physical pattern of the crack, and then use truncation or excavation to deal with the crack.
Truncation method processing. Suitable for single linear cracks. The treatment process is as follows: clean and polish the surface of the cracked part until the crack is exposed, then use magnetic powder or coloring or radiographic inspection or magnifying glass to determine the direction of the crack, and swap out the two tips of the crack, extending straight from the tip along the crack About 40~50mm, drill a "cut-off hole" each, when the wall thickness of the vessel is less than or equal to 16mm, the hole diameter is 6~8mm, when the wall thickness of the vessel is more than 16mm, drill the hole of 6~8mm first, then expand and repair welding .
Digging method processing. It is often used in the treatment of star cracks and branch cracks. The treatment process is as follows: first find the area where the crack is located, and then dig out the crack with gas cutting. The cut area is 40-50mm larger than the original crack area on each side, and then a new plate is added, or the cracked plate is replaced as a whole.
Cracks in heat affected zone of pressure vessel
Eliminate it by general grinding method, and use magnetic powder or coloring flaw detection to confirm that there are no cracks.
Cracks in weld zone of pressure vessel
Use radiographic or ultrasonic inspection to find the tip of the crack, and then use the cut-off method to drill cut-off holes at both ends of the crack. The depth of the hole is slightly greater than the depth of the crack. Then remove the entire crack and grind it into a suitable groove. Use radiographic inspection to verify that the crack has been After digging completely, repair welding.
