First welds, pics, questions and advice please.

[Jgguinness]

Hi all

Having purchased a GYS Smartmig 162 I have set about getting some practice in before starting on my Land Rover.

Wire is 0.8mm, gas used is Argoshield Light. Power settings are on the lowest (I am pretty certain, certainly for the thinnest material), gas flow is around 18-20lpm

The first pics are on some steel slightly under 2mm thick. Just trying to lay some beads. One on its own, and two side by side.


Then I tried welding some slightly thinner steel to the 2mm stuff





I then tried on some thinner material. This is just under 1mm thick. I've tried butt welding two pieces together and laying some beads on this material.

The two welds North, East and West are butt joints, some holes blown through and tried to fill them up. Slight attempt at grinding (but was 10:30, kids asleep and in an attached garage I didn't want to make too much noise). The weld running South was just trying to put a bead down. All done with pulses of weld.



Underside pic



The one issue that's causing me some headache is where you come to the end of the sheet edge, I find very regularly I'm ending ultra with some material melting away and not having a flush edge.

Any advice/comments/ribbing greatly appreciated.

Kind regards

 

[mike 109444]

You will find it difficult to weld right up to the edge on sheet. You could try if there is access having a backing piece of copper or ally and effectively run of the edge and just onto the copper/ally or if no access then tack the edge first. then weld up to that tack. Reason it burns the edge is that the heat is building up as you weld and when in the middle of the sheet it can go out to the sides as well as in front and to rear but at the edge you lose one of these directions. If you look at your 4th pic the "south" going weld shows the HAZ (heat affected zone) to the sides of the weld. You can see the build up of heat as you have traveled down. It starts cold then heat is building in middle (you may have slowed down) then towards the end looks like you speed up as there is reduced HAZ .
And welcome BTW

 

[Jgguinness]

Hi Mike

Thanks for the reply. Also thanks for the pointers re the edge of a sheet. I'll give that a go, thanks. Regarding the South weld in the pic, I started at the bottom of the pic and made my way towards the East/West weld that I had done prior. The HAZ you mention, is it narrower at the start of the weld because I just started there and the metal was cold, or is it due to me not giving it enough time on the initial few pulses?

Apart from that, any other advice? What about the little dimple holes in the pools?

Kind regards
Jonny

 

[AndersK]

Try 0,6mm wire on thin material, makes it easier.

A tip to weld up to the edge, take a small piece and place at the end. Tack where it meets your other sheet (like a T intersection). Now you csn start at that tack or weld up to it without melting that edge. When done, break it off and grind flush.

 

[Richard.]

This is not the answer to your problem/question but your wasting a lot of gas at that flow rate and Ar mix isn't that cheap. Try 10-12 LPM. Also I see quite a bit of talk about the HAZ. The areas you see are heat tinted areas where the steel around the weld will show various colours depending on the temp they have got to. It's not the heat effected zone. The HAZ cannot be seen from the face side of a weld the part needs to be cut and etched in order to see it.

 

[Jgguinness]

This is not the answer to your problem/question but your wasting a lot of gas at that flow rate and Ar mix isn't that cheap. Try 10-12 LPM. Also I see quite a bit of talk about the HAZ. The areas you see are heat tinted areas where the steel around the weld will show various colours depending on the temp they have got to. It's not the heat effected zone. The HAZ cannot be seen from the face side of a weld the part needs to be cut and etched in order to see it.

Hi Richard

Thanks for the reply. I will turn the gas flow down a bit and see how I get on.
A question regarding gas flow rate if you dont mind...If the flow rate is too high, or higher than it should be, is it simply wasting gas or does it effect the temperature of the weld? I have read somewhere about welding outside, and having a higher flow to reduce the effect wind may have on welding.

Kind regards
Jonny

 

[Richard.]

The main problem with having a really high flow rate is turbulent in the flow. Rather than having a nice "blanket" of shielding gas protecting your weld pool you could get outside air been drawn in contaminating your pool from the harsh flow rate. Regards to the temp been effected well you could be cooling it quicker with a higher rate. But in general the biggest issue is its just a waste of money. Yes your outside but my way of thinking would be put in the relevant measures like wind breaks etc then on a scrap bit start off with around 8lpm and weld. Keep adjusting it up till things are clean and stable then stop there. No point in giving it away.

 

[Jgguinness]

Great thanks Richard. Ill do some more practicing tonight when I get in. I need to call into BOC and get some more wire too.

Is it worth trying some 0.6mm wire or just persevere with 0.8mm?
I also bought some anti spatter spray and tried that. Seemed to make a difference.

 

[Kent]

Stick with 0.8 unless you just doing thin cat panels a lot. Turn the gas down as Richard suggests. I don't hardly ever bother with anti spatter other than on Jigs or fixtures, the trick is minimum or no spatter not spaying stuff to help you get it off after the fact.
I have met a few welders who were obsessed by the stuff but they were all that way for a reason

 

[mike 109444]

Think the other guys have cover what you asked
Ref the dimples, could be your welder has burn back control. I think this kicks in as you release the trigger and controls that last split second as the arc stops, to stop the wire sticking in the weld pool. I am not 100% on this though as I don't have it on my migs.
One thing you might want to practice is plug welds (think that might be what you are referring to as "spot welds". You may need to do these when replacing parts that were originally factory spot welded (once you have drilled out original spot welds) You have to drill a 6,8 or 10mm hole(s) in top plate. Then fit to car then weld into (fill) the hole by welding the plate underneath, circling around till you fill and fuse with top plate (think that makes sense!)
Search forum for plug welds or there might be a guide in the mig tutorials on the home page.

 

[Jgguinness]

Thanks for all the replies guys, very friendly forum. Haven't made it into the garage this evening other than to put in a compressor that I've bought (there will be a question on that in the relevant section) due to sampling Guinness.

The pulse welding I mentioned was the technique used on thin metal, so not a continuous bead of weld, but rather weld, rest to cool slightly, move a touch, weld again, rest...repeat. Maybe I've used the wring phrase to describe it.

 

[mike 109444]

TMT aka Thin Metal Technique. Some welder do have a pulse facility but that is totally different thing (think it's where a high frequency voltage is superimposed over the normal welding voltage, but I could be wrong )

 

[Richard.]

Hi Mike

Thanks for the reply. Also thanks for the pointers re the edge of a sheet. I'll give that a go, thanks. Regarding the South weld in the pic, I started at the bottom of the pic and made my way towards the East/West weld that I had done prior. The HAZ you mention, is it narrower at the start of the weld because I just started there and the metal was cold, or is it due to me not giving it enough time on the initial few pulses?

Apart from that, any other advice? What about the little dimple holes in the pools?

Kind regards
Jonny

The little divet on top of your spots is what's known as a small crator. It's really common but on critical application can be a stress riser and can crack. It's caused by contraction of the pool as it cools. A bit of torch manipulation just before you come off the trigger will help to reduce. On a longer run I tend to before letting off the trigger back track over the end of the run only 10-15mm to fill it before it develops.