Had a flange weld crack on a boiler in Toledo last Thursday

We were doing the final hydro test on a 500 psi boiler and heard that pop. Found a hairline crack running about 4 inches along the flange weld. Had to drain the whole thing, grind it out, and re-weld with a 7018 rod. Took us an extra six hours and the foreman was not happy. What's your go-to method for checking welds before a hydro to avoid this mess?

4 comments

4 Comments

joel_jones29d agoMost Upvoted

Used to skip the soap test thinking it was extra work for nothing. After a cracked seam on a pressure vessel cost us a full day of rework, I'm a total convert. Now we hit every weld with soapy water at about 50 psi air pressure. Caught a tiny leak just last month that looked perfect to the eye. It takes five minutes and saves those awful surprises during the real hydro.

luna_wright29d ago

Man that sucks, extra six hours is brutal. You ever try a simple soap bubble test on the welds before you even fill it? I mix up some dish soap and water in a spray bottle and hit all the seams while we slowly bring the pressure up with air. Any leak shows up as bubbles immediately, way before you get to full test pressure. Found a few pin holes that way that would have blown later.

the_linda1d ago

Yeah, soap and air is the only way. We pressurize the whole system to about 30 psi with air, then spray every single weld joint with a heavy mix of dish soap and water. Even the tiniest pin hole will blow a bubble you can see from across the room. It takes ten minutes tops and finds the problems before you waste all that time filling with water. Skipping it is just asking for a nasty surprise during hydro.

evanc5929d ago

Feel your pain on that one. A good dye penetrant test before hydro saves me a lot of headaches.