[anthony-wohali]

Mt on bevels is an examination that you will do thousands of times and not find anything but once in a while you may find a lamination os segregation that will prevent welding being carried out. This is the main reason for the bevel examination.
MT shoud be carried out after all mechanical work has been completed and some argue that if you use white contrast paint the welders will then grind the paint off so that is a further mechanical work….. etc. Some manufacturers of MT chemicals also supply paint remover in a spray can. The fluorescent method is an alternative but requires darkness. Most norms don’t say that you must use a contrast paint but only if the background doesn’t give sufficient contrast.
Yes PT is a good alternative, the main disadvantage is cost (time). A proper PT examination, even on one bevel, will take you at least 30 minutes (depending on the norm) whereas MT is usually completed in a few minutes.