mig v butt root run

[liamreid123]

im at college currently on the v butt mig weld, i have 6mm metal 150mm long with a 45 degree bevel then grind the metal, when i do my root run instead of getting penetration i burn the edges of the V. my setting are as low as the machine can go so dont think thats the problem any tips on what im doing wrong?

 

[Lawnmowerboy]

It would help if you could describe it in something other than Chinglish! Pic would help to

 

[Wozzaaah]

What part of that post don't you understand then LMB?
It makes perfect sense to me!

Liam, what machine are you using, how much 'land' are you leaving on the bevelled edge and what gap?

 

[the snooper]

It makes perfect sense to me!

+1

do we take it you mean you burn to top edges of the v and that you are not blowing through the bottom edges

 

[pedrobedro]

It sounds like too much penetration if you are burning the metal away If the edge of the V is feathered you will burn it, as above it needs a land squaring off to leave some thickness so it doesn't hole.

 

[backpurge]

You need to set a really nice crisp dip transfer arc, about the same settings you would use for welding sheet metal work, play around with the inductance settings, you will probably find it runs better with a lower inductance but this can vary from machine to machine

Reduce the bevell to 30 degrees, put a 2mm root face on each edge, set a gap around 2mm, run the wire right up the middle of the gap keeping your wire right on the front edge of the weld pool, if the weldpool starts getting in front of you, speed up, if you are burning the edges away, slow down.

Don't fall into the trap of over filling the joint with your root run. For your hot fill and cap passes get the machine up into spray transfer and dont weave, use stringer beads