Friday, 8 January 2010

WELDER PERFORMANCE QUALIFICATION - PART 4


ROOT PASS  UPHILL 3G 

Starting the root weld did not require a preheat as the temperature was about 70 degrees outside. To start the root I got comfortable and started to weld. The technique I used was a side to side weave. I hold the sides of the bevel where the bevels edge feathers into the backing bar until I could see the arc of the electrode start to roll to that side. Once the arc is rolled and the flux is burned off on that side of the electrode, I weave onto the other side, and keep repeating that process. By allowing the arc to roll on the electrode it penetrates the bevel and gives the electrode a chance to ride up on the bevel for a moment. This helps to avoid slag inclusions. I used three welding electrodes and had two restarts. Here is the root weld cleaned with a wire wheel and as the procedure states it was inspected.

“The root of the weld shall be inspected, and there shall be no evidence of cracks, incomplete fusion, or inadequate joint penetration.





FINISHED AND CLEANED

FILL PASS


For the hot pass or fill pass I used the same technique as the root weld. That is holding the sides and rolling the arc until the weld rides up onto the side of the bevel. I used four electrodes and had three restarts.
Again I waited for the plate to cool and lightly grinded it down. I did not have to grind it, but why risk getting a slag inclusion. As you can see the first restart was a little rough.


Cover Pass and Cap.

The cap was done using a weave technique holding the corner of the bevel until it was filled and the moving onto the other side. If you do not wash weld properly into the corner of the bevel you run the chance of not penetrating the test coupon properly. On the cap of the weld I used four electrodes. Here is the picture of the cap weld.



“The face of the weld shall be flush with the surface of the base metal, and the weld shall merge smoothly with the base metal. Undercut shall not exceed 1/32 in. (1 mm). Weld reinforcement shall not exceed 1/8 in. (3 mm)”