[wolverine_arc]

hello mates!

Any tips, tricks, video links and advice on how to do flat (not to convex nor concave)
weld beads in GMAW.

i run weld beads w/ its five essentials of welding followed and still getting convex results on my test plate.

what seem to be the problem and how to fix it?

stuff used:

straight CO2, 0.35" mig wire.

thank you.

[noddybrian]

It would help to know what your welding / thickness / position / machine parameters to give an informed opinion - but unless things are different the other side of the pond I'd say the gas is an issue - in the UK if you only use Mig for hobby use on non critical very thin material ( car body panels mainly ) mostly with .6mm wire then CO2 is OK on a budget but leaves a fairly rough looking weld with some dark discoloration - for anything else you need argon mix - I doubt you will achieve good results no matter what else you try until you change gas.
Good luck with whatever the project is.

[Otto Nobedder]

You said "test plate", so I assume it's for an employer?

All you really need to do is slow down just slightly without other changes. Remember, when you see the puddle come flush and move, all that molten steel is going to shrink when it cools and leave you concave. If you slow just a bit, and build the puddle convex by the same amount your finished weld is currently concave, you'll be much closer to flat when the metal cools.

Brian's right, 75/25 Ar/CO2 is a better gas for control, but I'm thinking that's not an option for you...

I've had to do this weld overhead (with 75/25), where underfill was not accepted, but convexity must be ground flush. I hate grinding, especially overhead, so I got pretty good at "barely enough"...

Steve S

[wolverine_arc]

You said "test plate", so I assume it's for an employer?

All you really need to do is slow down just slightly without other changes. Remember, when you see the puddle come flush and move, all that molten steel is going to shrink when it cools and leave you concave. If you slow just a bit, and build the puddle convex by the same amount your finished weld is currently concave, you'll be much closer to flat when the metal cools.

Brian's right, 75/25 Ar/CO2 is a better gas for control, but I'm thinking that's not an option for you...

I've had to do this weld overhead (with 75/25), where underfill was not accepted, but convexity must be ground flush. I hate grinding, especially overhead, so I got pretty good at "barely enough"...

Steve S

thanks Otto for your advice i'll take it.

@test plate:
i'm on a welding training programs. (MIG/TIG) particularly.

[wolverine_arc]

It would help to know what your welding / thickness / position / machine parameters to give an informed opinion - but unless things are different the other side of the pond I'd say the gas is an issue - in the UK if you only use Mig for hobby use on non critical very thin material ( car body panels mainly ) mostly with .6mm wire then CO2 is OK on a budget but leaves a fairly rough looking weld with some dark discoloration - for anything else you need argon mix - I doubt you will achieve good results no matter what else you try until you change gas.
Good luck with whatever the project is.

for welding positions:

i'm done trying, flat, horizontal and vertical up for straight CO2 gas and still my weld comes out convex.

i'll take your advice on changing gas mate

[weldin mike 27]

hey,

A slight increase in voltage can help the bead "wet' in better and become flatter.

Mick

[Alexa]

(...) Any tips, tricks, video links and advice on how to do flat (not to convex nor concave) weld beads in GMAW. (...)

=====

Wolverine.

What type of joints are you welding (wall thickness, bevels)?

Often a flat cover pass with depend upon the planning of your passes, in particular the second to the last layer.
The degree of overlapping your side-by-side stringer passes will also make a difference on flatness.
Instead, if you are weaving, you will need to fill the sides, and adjust your speed across the middle to make it flat.

Needless perhaps to say, if we are simply welding a pass on a flat surfaced piece of metal, then of course, it will never be flat, in that all the deposited metal is excessive. But it is a good practice to see how the torch angle affects flatness. Start dragging, then gradually change the angle of the torch until it is perpendicular to the surface, and then gradually descend to pushing. You should see a different in pass appearance.

Alexa

[wolverine_arc]

hey,

A slight increase in voltage can help the bead "wet' in better and become flatter.

Mick

thanks for the tips Mick.

[wolverine_arc]

(...) Any tips, tricks, video links and advice on how to do flat (not to convex nor concave) weld beads in GMAW. (...)

=====

Wolverine.

What type of joints are you welding (wall thickness, bevels)?

Often a flat cover pass with depend upon the planning of your passes, in particular the second to the last layer.
The degree of overlapping your side-by-side stringer passes will also make a difference on flatness.
Instead, if you are weaving, you will need to fill the sides, and adjust your speed across the middle to make it flat.

Needless perhaps to say, if we are simply welding a pass on a flat surfaced piece of metal, then of course, it will never be flat, in that all the deposited metal is excessive. But it is a good practice to see how the torch angle affects flatness. Start dragging, then gradually change the angle of the torch until it is perpendicular to the surface, and then gradually descend to pushing. You should see a different in pass appearance.

Alexa

metal thickness: 6 to 7mm mild steel plate, no bevels.


i'll try your tips. Thanks



-wolverine