Greetings, let me begin by saying how informative and well put together I found your site to be.
I have enjoyed it since stumbling across it in a google search.
I noticed you have answered some of your readers questions and on that note I have a few if you have some time.
I will be taking an x ray weld test coming up and was curious to know if you had any tips to use while filling and capping?
First the details: 2 3/4" schedule 80 carbon steel pipe, 6g fixed position. 6010 root with a second pass of 6010, followed by fill passes and stringer cap with 7018.
I have been told it is good to grind my start and stops on my fill passes and will be running very hot in an attempt to burn out any slag I may have missed with the wire wheel.
I am keeping a tight puddle with a slight 10 degree rod angle and have been having seemingly satisfactory results, however porosity is a concern given the testing procedure and I need to minimize it as much as possible.
Any other advice you can give so far as passing the x ray would be greatly appreciated. Thank you in advance and keep up the great site work. Regards, Joe
Joe, If the test supervisor will let you, yes you should grind stops and starts...especially on the bottom where you might see porosity when you grind. Grind just enough to let you make a smooth tie in and to get rid of the porosity. And make sure you understand what the test super might consider excess grinding.
To prevent porosity, strike your arc about an inch directly ahead of the place you want to start. For about a second hold kind of a long arc while you pull the arc to your starting point and gradually tighten up the arc as you zero in on the start. All this should be in a direct path of the bead so that you will weld over top of any arc strikes or porosity left by the long arc.
It helps a lot to make sure the amperage is hot enough so that when you tighten the arc length, you dont stick or sputter. File the tip of any 7018 that reuse so that you dont break off half the flux without knowing while you are tapping the tip of the rod to restart.
Other than that , stagger your restarts on the sides of the 6g joint so that stops and starts are not all lumped in one area.
I will repeat ...make all arc strikes so that you will weld over them. Test supervisors do not like to see any arc strikes on the finished weld..period.
Its good to run hot, but there is a limit before you get out of scope and start having undercut or a high crowned bead. ...and be careful on that hot pass after the root.
I busted my first test from blowing a hole on the hot pass. so it always sticks in my mind.
hope this helps,
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