Drilling in Welding Line

You can drill a hole anywhere, whether it is a good idea or not depends on the application.

As stated, it can be done.

Is it allowed per ASME code?

ASME: Engineering Standards News and Resources for ...

Yes. Only anticipated problems are if the weld is rounded above the metals or shallow between them you may have some problems getting the bit started without crawling due to the curvature of the weld. This is solved by using a narrow center punch to locate the drill where you want the hole. Follow up with a wide center punch to give the bit more of an indent to locate itself in for drilling.

Also, if necessary, use a small drill bit to make a pilot hole and then the larger drill bit (or several incremental bits if necessary) to drill the full size hole. As always, use copious quantities of drilling fluid to lube and cool the drill bit.

Good Luck, Old Salt

Might give you some good insight if the welding was done properly!

Is not a good practice, but if you don't have another solution, like a new lay-out. Yes, it is acceptable. If the vessel seam welds are 100% radiographed, then no problem you can open the hole. If the vessel is spot radiography, you should RT at least 6 inches on either side of the hole (Opening) before welding the component, fitting or nozzle. (You do not say for what you need to drill de seam weld.

Check the following points in your ASME VIII div1 code:

UW-41

UG-36

Appendix L

Appendix K

WP

Thanks alot for your help

With Best Regards

I could not get your link to work, I suppose I have not the correct software.