why wont my stainless welding shine???

[Matt Kenyon]

Hi. Ive landed a job where theyre gratefully gonna give me time on my sharp TIG welding curve. Im at the serious novice stage but the only way is forward. Im puzzled why my tig runs look so dull and cloudy?

 

[eSCHEn]

That's usually because you got it too hot and washed the chromium out. Trust me I've just been learning that very lesson lol.

What's your setup and stock?

Edit: congrats on the job as well

 

[slim_boy_fat]

Are you using pure argon? Also, what size ceramic nozzle are you using [to maintain gas coverage]?

 

[Matt Kenyon]

Yeah using pure argon. Not sure about size of ceramic. Im wondering if im moving to slowly. Does this sound like a possibility?

 

[eSCHEn]

Definitely. Too slow and you build up too much heat.

What amps, gas flow, post flow, tungsten and stock size are you using? Are you cleaning up the stock first?

 

[Richard.]

Eschen has it nailed.
In order for stainless to be stainless it needs a minimum of around 12% Cr. If you start welding it at too high current or too slowly you risk cooking the Cr out of the weld and the bead has that dull grey appearance .
Gas flow also plays a part in the surface finish on stainless, you need a nice coverage and a decent post flow to succeed in stainless tig.
Now for the helpful part. Try 20-25 amps per 1mm thick material.
I like a number 8 cup for SS
I run 6-7 LPM through a gas lens

 

[Matt Kenyon]

Struggling to keep up with the lingo a bit but appreciate the help. 2mm stainless 60-65 amps set about 15 post flow. not sure what size tungsten. Heres a few pics which will hopefully solve the problem

 

[eSCHEn]

Nice prep but looks very hot. Your amps seem high, try dropping down to say 40A. 15s is maybe a bit OTT but won't hurt. You could halve that without any issues I think. What flow rate are you on?

 

[Richard.]

Struggling to keep up with the lingo a bit but appreciate the help. 2mm stainless 60-65 amps set about 15 post flow. not sure what size tungsten. Heres a few pics which will hopefully solve the problem

Too hot. At 65 amps I'd be welding 3mm. A purge on the inside is also needed there if that is to be a fab. You'll be going right through especially at that current and if it's coking on the back side it's likely to crack/corrode. I hate to say it but those joints are no good anymore.

 

[Tinbasherdan]

Deffo too hot, 45 amps max, 7lpm flow, a decent gas lense and large ceramic. 1.6 mm tungsten, 1-1.2mm filler

 

[Richard.]

Deffo too hot, 45 amps max, 7lpm flow, a decent gas lense and large ceramic. 1.6 mm tungsten, 1-1.2mm filler

I definitely agree with 90% of that but the large ceramic part I'm not a fan. No 8 is the biggest I use

 

[Tinbasherdan]

Sorry I should've been clearer, was making some tea as well as posting, I just meant a larger ceramic , rather than the monster ones that seem so popular for all the "weld porn" welders

 

[Richard.]

Titanium also I believe as surface oxides on that is a big no no. I've not had the pleasure of having a go on ti yet but should the chance arise I'll have to buy a bigger lens.

 

[Tinbasherdan]

With the price of ti rods, unless the customer supplies them I won't be playing with it! Watched the ti welders in the yard though, amazing guys

 

[hotrodder]

Assuming that the weld is gonna be ground down and regrained then a 'burnt' grey weld isn't a big deal and even a bit of coking/sugaring isn't necessarily gonna ruin the corrosion resistance, it all depends on what it is and what it's service environment is gonna be like. Yeah, some of the chromium has been burnt out but most, if not all, of the chrome depleted zone is gonna be ground off when blending welds out and regraining
http://www.bssa.org.uk/topics.php?article=2 explains how even 'good colours' lower the corrosion resistance in some environments and how a chromium rich surface is usually restored with pickling pastes etc

FWIW Ti is slightly different in that it'll react with most things including oxygen & nitrogen at high temps which can result in alpha case embrittlement which is why it's usual to go to what ever lengths are necessary to prevent heat tints beyond straws & browns... above 400 ish °C it starts turning violet/purple and by 440 ish it's dark blue. With OCD attention to cleanliness & shielding it's looooovely stuff to weld and once used to it's 'sticky' nature* pretty easy too.

* the filler wire has a tendancy to stick to the weldpool, especially if you catch it's edges. Kinda like what happens if trying to use wire that's too big in dia for the size of the weldpool when welding steels but just how Ti is

 

[Richard.]

Assuming that the weld is gonna be ground down and regrained then a 'burnt' grey weld isn't a big deal and even a bit of coking/sugaring isn't necessarily gonna ruin the corrosion resistance, it all depends on what it is and what it's service environment is gonna be like. Yeah, some of the chromium has been burnt out but most, if not all, of the chrome depleted zone is gonna be ground off when blending welds out and regraining
http://www.bssa.org.uk/topics.php?article=2 explains how even 'good colours' lower the corrosion resistance in some environments and how a chromium rich surface is usually restored with pickling pastes etc

FWIW Ti is slightly different in that it'll react with most things including oxygen & nitrogen at high temps which can result in alpha case embrittlement which is why it's usual to go to what ever lengths are necessary to prevent heat tints beyond straws & browns... above 400 ish °C it starts turning violet/purple and by 440 ish it's dark blue. With OCD attention to cleanliness & shielding it's looooovely stuff to weld and once used to it's 'sticky' nature* pretty easy too.

* the filler wire has a tendancy to stick to the weldpool, especially if you catch it's edges. Kinda like what happens if trying to use wire that's too big in dia for the size of the weldpool when welding steels but just how Ti is

Does the nipping of the rod in the pool happen due to freezing rate or something along those lines.

 

[eSCHEn]

the price of ti rods

Had a look on eBay and jings you're nae kidding' pal!

@Matt Kenyon - you had a shot on a lower heat yet mate?

 

[Richard.]

Assuming that the weld is gonna be ground down and regrained then a 'burnt' grey weld isn't a big deal and even a bit of coking/sugaring isn't necessarily gonna ruin the corrosion resistance, it all depends on what it is and what it's service environment is gonna be like. Yeah, some of the chromium has been burnt out but most, if not all, of the chrome depleted zone is gonna be ground off when blending welds out and regraining
http://www.bssa.org.uk/topics.php?article=2 explains how even 'good colours' lower the corrosion resistance in some environments and how a chromium rich surface is usually restored with pickling pastes etc

FWIW Ti is slightly different in that it'll react with most things including oxygen & nitrogen at high temps which can result in alpha case embrittlement which is why it's usual to go to what ever lengths are necessary to prevent heat tints beyond straws & browns... above 400 ish °C it starts turning violet/purple and by 440 ish it's dark blue. With OCD attention to cleanliness & shielding it's looooovely stuff to weld and once used to it's 'sticky' nature* pretty easy too.

* the filler wire has a tendancy to stick to the weldpool, especially if you catch it's edges. Kinda like what happens if trying to use wire that's too big in dia for the size of the weldpool when welding steels but just how Ti is

Sorry another Q.
Surly we select ss for it's corrosion resistance and we remove oxides and heat tint etc to aid with those characteristics. I cannot think of a case scenario where sugaring/coking is ok. Yeah I suppose a dull weld can soon be brightened back up but the underside is knackered surely if you create coking.

 

[Matt Kenyon]

Thanks for all your replies, im actually looking forward to going to work for the 1st time ever to get stuck in. Its a partition in a horsebox so its not as though strength is to big of an issue its more a case of me wanting to learn how to TIG for so long without ever getting the chance so now I've been given the chance I don't wanna mess it up. Im a bit stuck with the lens issue as im using a supplied solar helmet which does seem very dark but apart from that im gonna take all your help onboard and see what happens.

Thanks to you all. Mondays pics will follow.

 

[eSCHEn]

Hey nice one Matt, sounds very exciting mate

If you're wanting any explanations on terms just shout. The TIG tutorial at the top of this site is very good as well, got some videos of it in action which are real useful.

How do you mean you're stuck on the lens issue? I can't see how it applies to your helmet either but it's likely I've just not understood (story of my life lol). Even though they're 'solar' they do need a battery to work. Usually it's a rechargeable of some sort and the helmet needs light to charge it. If it's not working as it should try cleaning it up and putting it in full sun next to the windae for a day. That sorts mine out when it's misbehaving from lack of love and use.

Does your mask have shade adjustment? For 40A I'd be on shade 9 which is the lowest mine does.

Looking forwards to seeing tomorrow's runs. Good luck and have fun