Root penetration problem on MAG welding

Date 11-21-2001 09:28

I had a fillet weld test with PF (upwards) position by using MAG. Although I tried with different parameters, I couldn't get a proper penetration at root. The weld performed one by one by weaving and straight, however after the fracture test no sufficient penetration was observed. Could anyone have an advice on this? Thanking you in advance.

By - Date 11-21-2001 17:21

To perform a MIG/MAG weld out of position with a standard power source, requires that you use a dip transfer mode. This transfer mode is a naturally low penetration method and very often leads to incomplete penetration and lack of fusion.

Try keeping the arc on the leading edge of the puddle. Best would be if you could get a power source that allows you to perform pulsed spray transfer.

Regards
Niekie Jooste

By George-kh (**)

Date 11-21-2001 19:21

As Niekie 2 said, pulse mig is best choice.
If you use a standard machine and a weave motion, the weave width MUST be short; otherwise weld metal doesn’t penetrate at root. However, a short weave motion prone to make a picky weld (like a hump of a camel). So, you MUST pass width of weld very fast and PUASE at sides to prevent undercut.
But, I prefer to use a triangle motion. In this case, first you MUST lead your arc at root to make penetration and PAUSE at sides to make weld profile. However, triangle motion makes welds with a little more weld length.
Best Regards

By dong won oh (*)

Date 11-22-2001 05:16

1) CO2 100% may increase penetration at the root
2) If you can reduce the thickness of the test coupon, you may have better root penetration.
3) Keep the stick-out as short as possible.
Use smaller nozzle diameter.

dong won oh
Seoul, Korea