Weld penetration problem with fillet weld on 20mm square bar steel

[bod1]

I'm welding fillet welds on the end of 10mm square bar onto the side of 20mm square bar using an r-tech mig251 using 1mm wire and easy set for 8mm work thickness. Mostly working 2F or 3F and assumed that 4 welds one per face would give a strong weld with good penetration. Unfortunately I had one weld fail on the 20mm surface when testing with a 2lb hammer....
So do I need to weave / multi pass this (a weld on one face builds up pretty fast - one second or two) and should I angle the torch head more towards the 20mm (was doing 45 degree angle).
Thanks for any help on this

 

[chip]

I have no experience with the welder, Id try taking it out of easy set mode and crank it up to full and dial in voltage etc manually you may get a bit more juice out of it.
or get some 7018,s on it.

 

[Rrobson]

As above, even at full beans your welder won’t achieve a full pen weld because it doesn’t have the power for that thickness. 300a might just about do it in one pass.

Your best bet would be a good pre heat (at least 150 degrees c) and full power from your welder, or stick weld it.
I doubt multiple passes with the mig will help much at all either.
And make sure your surface is clean, no mill scale, dirt, grease etc.

 

[addjunkie]

Stick weld it!

 

[bod1]

I have no experience with the welder, Id try taking it out of easy set mode and crank it up to full and dial in voltage etc manually you may get a bit more juice out of it.
or get some 7018,s on it.

I have 23.5 volts with a line speed of 10 metres/min which is the easy set setting for 1mm wire, 8mm work thickness. I can manually select a maximum of 24.5 volts. Any suggestions for manual mode? Thanks

 

[Hitch]

Have you hit the mill scale off first....?

 

[Erie Fred]

What flavor of shielding gas are you using ?

 

[chip]

I have 23.5 volts with a line speed of 10 metres/min which is the easy set setting for 1mm wire, 8mm work thickness. I can manually select a maximum of 24.5 volts. Any suggestions for manual mode? Thanks

Hi pal, I only suggest it because synergic settings (on my machine at least) just throw you in the vicinity of where you want to be.
For example I run a cheap 230 amp machine(actual amps closer to 250) in synergic mode and opt for its max setting which is 10.2mm, while the settings seem on point on thinner stuff, on the thicker stuff, I prefer manual settings, Having up to 15 metres a minute and 28.5 volts to play with.
Like said i'm not familiar with your machine But a setting for 8mm welding 10 to 20mm bar is an ask, id get the rods on it

 

[Richiew]

Can you bevel the edges some?

 

[bod1]

What flavor of shielding gas are you using ?

Argon 12% CO2

 

[bod1]

Can you bevel the edges some?

the 20mm is 2m long, 10mm butts onto side of 20mm so assume bevel wouldn't help penetration into 20mm

 

[Erie Fred]

Argon 12% CO2

Are you in spray mode ?

 

[bod1]

Have you hit the mill scale off first....?

Can't say I have - Using A15 wire - isn't that ok for mild mill scale?

 

[bod1]

Are you in spray mode ?

I don't think so...

 

[Hitch]

Can't say I have - Using A15 wire - isn't that ok for mild mill scale?

Yes and no...
If you're struggling on penetration due to welder limitations, I'd be looking at grinding the majority of the scale off. It will help quite a bit.

 

[Jack Ryan]

If you were welding 10mm plate to 20mm plate I'd think about arc welding, but you are welding bar.

I would have thought that, with the correct preparation, and concentrating on the 20 mm bar, you could weld that OK.

You said one weld failed. Can you post high resolution closeup pictures of the failure?

You only have a 10 mm long fillet - does your machine have something to help with cold starts

the 20mm is 2m long, 10mm butts onto side of 20mm so assume bevel wouldn't help penetration into 20mm

Bevel the 10 mm bar. You only need penetration into the joint, not into the 20 mm bar.

Jack

 

[Jack Ryan]

I forgot to ask, is this holding the the guns of Navarone or a brood of chickens?

 

[denlow60]

Can't say I have - Using A15 wire - isn't that ok for mild mill scale?

If you take a picture of the sticker with data it would help to see what you can weld with it.

And you indicate how much wire/ampere and volt your machine can handle.

Or whether you can also weld the welding machine on manual control
or only on automatic.
or on both

 

[bod1]

If you take a picture of the sticker with data it would help to see what you can weld with it.

And you indicate how much wire/ampere and volt your machine can handle.

Or whether you can also weld the welding machine on manual control
or only on automatic.
or on both

Just opened up the welder: It is SifMig SG2 Copper coated mild steel MIG wire for welding mild and medium tensile steels, for impact toughness EN ISO 14341-A G 42 3 M21 3Si1
The welder spec sheet says
Amperage Range MIG 30 - 250A
Input voltage/amps 240v 32A
Duty cycle MIG 250A @35% - 200A @60%
Max Thickness Steel 9MM Single Pass
Max Thickness Steel 22MM Multiple Passes
You can turn off auto mode and dial in settings for wire feed and voltage, max voltage is 24.5V

 

[bod1]

I forgot to ask, is this holding the the guns of Navarone or a brood of chickens?

Garden structure - so not very structural but none of the joints should fail!