A bad weld on a 3/4 inch steam line in a Philly plant...

We were doing a shutdown job about eight years back, replacing a section of old steam line. I was prepping a joint for a new valve, and my partner laid down what looked like a solid root pass. Pressure test came up fine, but when we fired the boiler back up, we got a steady hiss from the flange. The weld had a cold lap you couldn't even see. We had to shut it down again, cut out a six inch section, and redo the whole thing under the plant manager's watch. Lost a full day of production time for them. Ever had a weld pass a test but fail under real heat?

2 comments

2 Comments

haydenburns2d ago

Pressure tests lie when the metal expands.

victor3892d ago

Okay but if the metal expands, the pressure reading goes up. That's the whole point, it shows the real stress on the system.