Do high-pressure metal manual valves need to undergo penetrant testing before leaving the factory?
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I would like to ask the experts: Is penetrant testing required for high-pressure manual metal valves before they leave the factory? Recently, several valves made of SAF2507 purchased were found to have cracks during use on site. The welders said that these valves already had cracks before leaving the factory; such cracks are usually not visible to the naked eye and require penetrant testing. Our quality control department reported that the valves passed pressure tests and leakage tests before leaving the factory, so the cracks might be caused by welding stresses. I’m not sure which explanation is reliable
You can ask the factory to perform a spectrum analysis. Then, take a valve with you and go to the quality supervision agency to have a spectrum analysis done there.
As the old saying goes, all merchants are deceitful; return products if the quality is unsatisfactory.
1. Biphasic stainless steel can develop cracks during actual welding due to improper operations (selection of welding materials, post-weld heat treatment)； 2. Since you have not specified the type and specifications of the valve, as well as the welding method for the connection ports (SW/BW/PE/BE), I am unable to determine the likelihood of cracks occurring ； 3. Valves with welded connections should undergo non-destructive testing upon leaving the factory; the NDT methods used vary depending on the specifications and material type. PT (penetration) is the least advanced method in NDT, as it can only detect surface defects. Additionally, it is also necessary to be able to use UT/RT (MT can also be used for carbon steel) to inspect different areas inside ； 4. The cost of a PT test is very low; this amount is not sufficient to motivate legitimate valve manufacturers to cut corners ； 5. Since there are problems now, I suggest that you conduct an NDT inspection on both the installed and uninstalled valves; specifically, you can ask the manufacturer to bring the equipment to your site to carry out the work directly. After all, since a contract was signed, it is believed that there is a certain level of trust between the two parties. More communication should take place in the future, and it would be better to have witnesses present for some important inspections.