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

[bod1]

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



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

Jack

Here is the failed joint- obviously been outside for months after welding

 

[bod1]

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



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

Jack

Here is the failed joint and one that hasn't failed. Was welded months ago, has been outside so the rust is expected

 

[BrokenBiker]

Given your welder is under powered for a single pass weld, set it manually to give all its got, prep the welds properly, clean the scale off and if you really need a strong weld you are going to need to bevel it enough to get a few passes in to make up for the lack of penetration...

Either that or stick weld it nice and hot

 

[Dave-sparks]

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

I'm an amateur at best when it comes to welding but one thing I have learned is that no matter how tolerant of unclean steel a rod or wire is supposed to be you will always have the best chance of making a good weld if you get the steel as clean as possible.

 

[8ob]

That’s a typical cold lap weld where the weld pool is trained on one part and the weld is pushed/ramped up on the other.

Bob

 

[chip]

If you don't want to stick it you could try welder on max and run a continuous weld up from 6 to 12 But personally like others have said i'd be done with it swap leads over for stick. you won't need anything close to max amps, it won't be going anywhere.

 

[Richiew]

Bevel the 10mm and stick the wire right in there.

 

[Dcal]

That looks like 4 individual tack welds.
If you can, set it up so you can start the weld and continue so you are back at the start.
Cleaning and a bit of a bevel will help as will some preheat, keep at the front of the weld pool to improve penetration.

Having said all that I'd stick weld it with 7018s.

Is your welder the multi process MTS255s?

 

[aesmith]

Here is the failed joint and one that hasn't failed. Was welded months ago, has been outside so the rust is expected

That looks more like decades of rust, or was it really old before you welded it?

 

[Barking Mat]

Photos please !

 

[Dcal]

Post 22

 

[Erie Fred]

The cross piece should be penciled down on a bench grinder or belt sander to a cone.

 

[Jack Ryan]

Here is the failed joint- obviously been outside for months after welding

Pretty hard to tell what's happening there, it looks like it broke many months (years) ago.

I can't see much evidence of fusion on the 20 mm bar, even though the 20 mm break is not shown. If that is the best your machine can do, you'll need to arc weld it. A bevel on the 10 mm part won't help if you can't melt the 20mm part.

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

Why are you choosing an 8 mm work thickness? Is that as far as it goes? If so, try manual and flat out.

As a matter of interest, does your machine tell you what current it is supplying?

Jack

 

[BrokenBiker]

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

Crank the voltage up as high as it will go, crank the wire right up, try on a bit of scrap...tweak the wire speed down until it's not trying g to push the tkrch away from the weld and that will be as hot as it goes for that wire diameter.

There generally isn't a set it and go type of deal with welding unless you have a welding g procedure with ideal technique, perfect prep and a controlled environment...for this, flat out and deep bevel prep is really the only way forward for anything even remotely structural to take place...oh, and shiny steel...clean it til you think it's good enough, then hit it with a brush again.

Personally I would still stick weld it with a 3.2mm or 4mm rod, slightly hot for the rod and bevel it to get atleaset 3 passes in, alot easier to set the welder for stick if settings are a concern

 

[Popcorn]

As well as all the above, that's probably Wrought Iron which is basicaly iron with assorts of other impurities in it,

 

[denlow60]

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

good to get all the information, then it saves you from searching.

we start with your wire EN ISO 14341-A G 42 3 M21 3Si1.

Welding consumables - Wire electrodes and weld deposits
for gas shielded metal arc welding of non alloy and fine
grain steels - Classification (ISO 14341:2020)

G=The symbol for a weld deposit produced by gas shielded metal arc welding shall be the letter G placed at
the beginning of the designation.

42 is in this table and you can weld your material with your wire because if it is correct you use steel S235 or S355

3= is your impact value and it is -30 degrees

M21 is your gas ratio Argon with 15 < CO2 u 25 carbon dioxide

3Si1 is the chemical composition

I assume you have an air cooled welding machine. 250A/24,5V

my conclusion is that you can just weld this with your welder.

200-220 amp and 24V you are in the globiare/open arc area.

1 disadvantage is that your gun will get hot.

 

[Ace Paul]

Not my forte, can’t find video in question.

This. Guy. https://m.youtube.com/@ICWeld


Likes to simply butt weld whatever together by tacking, Then grinding a lump out, (like cutting down a tree), fill with weld and repeat.

Presumably when it failed it was still fresh shiny metal?

 

[bod1]

That looks more like decades of rust, or was it really old before you welded it?

Nope - welded 2 months ago on clean new metal. Painted with equal volumes of salt, vinegar and hydrogen peroxide a few times over a few weeks to really kick off the rusting finish

 

[bod1]

Thanks for all the replies.
I moved from stick to mig to avoid all the chipping so would prefer to stay on mig. So I'll try:
a) increase voltage to max and set wire speed to suit
b) grind off mill scale
c) angle torch more onto 20mm

I'll then bandsaw a joint in half to check fusion
If no good I'll try preheat, ?bevel and multiple passes.
I'll report back in a week or so
Thanks