Opinions on test welds

[stef1]

Good evening all,

Can I ask for your opinions on a couple of test welds I have just done?

3x25mm mild steel flat bar
10lpm argon/c02 80/20%
wire feed 7.4m/minute

The first two pictures were set as above using 18.5v and have virtually no penetration?

and the other 2 pictures were set as above using 19.0v

I got the settings from the millers calculator. First time I have done any fillet welding with the R-tech MTS210.
I have got a bit of mig/stick experience from when I used to work for a place doing gates, railings and decorative stuff.

Just trying to see where I can improve and try to sort things out early before I continue practising bad habbits.

thanks

 

[Tigman]

you would be better off cutting through the weld and polish it out and check for fusion you dont need penetration to show out the back of the angle ! etch it and look for fusion right to the root of the fillet .

 

[stef1]

you would be better off cutting through the weld and polish it out and check for fusion you dont need penetration to show out the back of the angle ! etch it and look for fusion right to the root of the fillet .

Thanks,

I will cut them in half tomorow and have a look at the penetration if I can

I will post up the pics again if im not sure

 

[Tigman]

Sorry Stef , does that make sense to you ? your welds look fine !

Google Macro etch and look at the images you will see whats required !

 

[stef1]

Sorry Stef , does that make sense to you ? your welds look fine !

Google Macro etch and look at the images you will see whats required !

yeah I think so, reading the guide on here about using nitric acid?

As for the look of my welds, they would probably have been better but i was struggling to keep a steady hand, a better position would have helped me.
To be perfectly honest, its the first time I think I have produced a weld that is relatively flat and not just a big lump in the middle with nothing touching the metal on the sides lol.
I was trying to use a method I picked up on from here and youtube, making C shape movement and hanging at the top to let the weld pool form n all that..
at the moment I'm just messing around getting myself used to it all again. I will be looking to make some gates and railings shortly and when I feel I am ready I need to modify my trailer slightly.

thanks

 

[Tigman]

If you have lack of fusion you will see it without Nitric Acid , as you say lump in the middle and nothing touching the sides , good luck with it !

 

[Ed.]

I would up the voltage more if possible and grind off the mill scale before you weld, get the metal shiny and it will weld better.

Cheers

Ed.

 

[stef1]

I would up the voltage more if possible and grind off the mill scale before you weld, get the metal shiny and it will weld better.

Cheers

Ed.

Cheers Ed,

I was thinking there 'I did grind the metal to make it shiny' but I then realised that was the pieces that I used for making butt joints.

I would normally clean any metal up for welding, I was probably just being lazy this time around.

By how much would you up the voltage? and what affect would it have on the wire speed setting?

cheers

 

[Ed.]

Cheers Ed,



By how much would you up the voltage? and what affect would it have on the wire speed setting?

cheers

Hi, That would depend on the welder type as different welders have different characteristics, If you up the voltage too much then you will probably get burn back at the tip or at the least it will undercut the walls as there will be too much heat and not enough wire filler to fill up the weld pool. If you then turn up the wire feed a little bit more you may get too big a weld bead, up the wire too much and the current increase may burn through or else go to short circuit welding.

So it's a fine line, however looking at your last weld pictures just keep increasing the voltage slightly till you get a more even bead, once you are happy with the result, ie; smooth, no undercut or burn through, good penetration, then write down those setting in a book along with the metal thickness and positions and that way you can refer to those setting for future welds.

Not sure of what your welder is capable of in the way of settings but from the looks of those last pics it wouldn't imagine it would take more than 1 volt or so increase to get a better bead, with my welder I can increase in 0.1V but most home welders use either set increments so as I said it depends on the welder.

After a while you get to know rough ball park settings for your unit and after a small test on scrap and a small tweak you will get a satisfactory result.

Using an 80/20 mix like you do may also mean that may be almost as good as you are going to get to, as in one of the pics (3rd) it looks like there may be some slight under cutting at the end of the left side of the bead, but can't tell for sure from the pics. It is all trial and error.

It would also help if you use two hands to hold the torch and let the left hand (or non trigger holding hand) slide along on the table to even out the shakes.

The image below is one of a bearing holder I recently made for a table wood saw I am making which shows you what I mean. It is 10mm plate and I used 1.2mm wire. At my age my hands shake a lot more than when I was younger so have to try much harder to steady my hands by any means available. Hope this helps.

Cheers

Ed.

 

[stef1]

Nice welding Ed!

Thank you very much for your advice, much appreciated.

The welder I have is the R-tech MTS210 inverter so voltage increments can be in 0.1v.

I will certainly take your advice of saving settings in a book, thats a great idea, a small notepad will easily fit in the bottom of the wire side of the unit.

Do you think I should also get a bottle of 95/5 for the thinner metal? For what I have in mind, I could be welding anything from 1mm to 6mm really.

I am going to try have a play around this afternoon and will try adjusting the settings like you say to see what happen and I will report back with some pics.

cheers

 

[Ed.]

Hi, Regarding the gas, it all depends if you can justify the cost of hiring or buying another bottle. Over where I am in Oz, it costs about $180 for just a years hire for each bottle and you can't buy the bottles, so as I am retired now and don't do much welding I have settled on a Tri-Mix gas, 93%Ar, 5%CO2 and 2%O2 for my only gas. I generally weld anything between 2mm to 20mm with it with the majority being in the 3-12mm plate, but at the thicker end I ideally should use a much higher CO2% mix. However it does give very fluid welds. Since I am not doing anything structural as such, so it is my mix of choice.

So if you can afford it go for it but before you do go changing the gas, see if you can fine tune your welding a bit more using that gas first, I don't weld down to 1mm so can't give you any advice on the 95/5% mix though but I suspect it would be better suited for real thin metal better than my mix, I should try my mix and weld a sample of 1mm (assuming that I can find some 1mm scrap) to see what would happen although my welder is probably way too big to go down that low and will probably blow through it like a plasma cutter.

Cheers

Ed.

 

[stef1]

Cheers Ed,

I go for the rent free bottles, £55 deposit and £30 or £40? to refill. I cant remember the exact prices but I am due to change my bottle soon as its just about done.

I might actually just get a 95/5 bottle next and see what its like.

 

[stef1]

Well I cut through the welds for a look, to be honest I cant see anything. I cut them using a hacksaw so the heat wouldn't make it harder to see and cleaned the surface up with emery cloth.

 

[Tigman]

if you cant see any lines cracks holes or dark areas , the welds must have fused and penetration must be good !

 

[stef1]

if you cant see any lines cracks holes or dark areas , the welds must have fused and penetration must be good !

Well that's good news, definitely no holes or dark areas.

Next thing will be to get myself some steel for my welding trolley. Going to using 25x3mm equal angle as I can plenty of it cheap enough.