My stainless experience

[Georgie]

So some of you have seen my thread on my learning process of doing aluminum. Well this thread is about the same machine, just doing stainless 316 pipe instead.

Diameters vary from 1 to 6 inch, and wall thicknesses of 1/16 to a 1/4.
These pipes belong to a high temperature dying machine. You can check their web site, Gaston County.

So we got this machine and moved it from a much larger company to our much smaller one. We are in the process of cutting and modifying most of the piping to make it fit around all the other machines we have.

The machine runs fabric threw a keer, with water,salt,and chemicals. The "Vessel" is heated with steam and keept under pressure to be able to reach a higher temperature than the boiling point without boiling, thus changing the atmosphere inside the "vessel". This is what alows us to dye polyesters and syntetic fabrics.We usualy run at 160 celcius.

So it reaches a maximum of 53 psi and the pipes have heated water and chemicals going threw them.

My welds are done with 1/16 thoriated with traditional cup(6) and 50 amps controlled via pedal.
Filler is 316 stainless, I am cleaning all the joints with a flap wheel then acetone inside and outside the mating pipes.

Ive tried all different argon flows...from as low as 4 to 15 lph. My post flow time is at 12 seconds and Ive got it set to DCSP.

all my welds are blackish, but clean up nice with a brush... on with the pics!

ok heres a joint setup for welding. I did this one vertically...not easy to stay straight.. i ddint clean this joint up




here it is welded




here is another joint

befor cleaning



After cleaning




One of the plumbers at work is telling me its looking black like this because the stainless is "old"....i think ima get some "new" stainless pipe and try to weld a small piece if i dont get any answers as why my welds are turning black..

Thanks

 

[Shox Dr]

Do you not require welding certs/codes to work on Pressurised systems in Canada?

 

[pedrobedro]

Lack of cleaning and too much heat/slow travel ?

 

[Georgie]

dude im cleaning it like crazy.... someone else also told me too much heat.

but according to the book that came wigh the machine, it says i should be doing these weldes at 130-160 amos!!!! and im only running 50!

 

[Paul.]

If your amps are too low, then you will need to move slower and pump more heat into the joint, turn up the set and move quicker.. I would weld round that at around 100 amps, probably with a 1/16 filler rod, your no 6 cup is a little small, a no 8 or better still a gas lens setup will improve the gas coverage, as the angle of attack changes as you work round the pipe the gas is lost very quickly, try to keep the torch slope angle high, almost pointing the tungsten at a point in the centre of the pipe, keep the arc tight and the electrode stickout as short as possible.
Much of the contamination may be being pulled in from the inside of the pipe and floating to the top of the weld pool, purging the joint will eliminate this and is good practice on pressure pipework

 

[Georgie]

how would i go about purging the pipe myself?

 

[Shox Dr]

Do you not require welding certs/codes to work on Pressurised systems in Canada?

I guess not

 

[Georgie]

why would you need a certifide for tgese types of welds? 52 psi isnt crazy pressure...?

what is a stainless 316 tigged supposed to look like?

thanks

 

[Georgie]

ok here is a chart for stainless that came with the machine. is this accurate?




ok here is a bracket i had to cut off the main cat walk and weld to another location in order to modify the orientation of the hand rail.







this is what it looks like after i welded and brushed it




here is another shot, you can see my weld VS the original (right)





so what do you guys think? Any advice? Not some pussy **** like (get a certificate...) gimme some good tips please as to why my welds are turning black, and if you dont know, your useless comments wont help anyone that in the same position as me...


thanks

 

[wheresmejumper]

i wouldnt use the settings on that chart.they look too hot.
they have a 1/16th lap weld hotter than a fillet?
130 to 150 for a 1/8 fillet is too hot
and the tungsten size is a bit different to what id use also

 

[Shox Dr]

Any advice? Not some pussy **** like (get a certificate...) gimme some good tips please as to why my welds are turning black, and if you dont know, your useless comments wont help anyone that in the same position as me...


thanks

Put the handbag down will you. You'll learn nothing acting as you are.

Regardless of what you think is acceptable, 160c of Steam at 53psi is going to cause one hell of a problem to anyone in the area if one of your welds let go.

53psi is 3.6 times atmospheric pressure, if thats not a pressurised, I don't know what is.

While you may be able to weld pressurised systems at that pressure, without a cert (why I asked) you don't know if you can or can't. That speak volumes in itself.

But I'm sure the little man with the clipboard and Government Badge will understand, when it all goes tits up

 

[BrokenBiker]

to be honest, getting a certificate is probably the best advice anyone can give, as you will have to go through a carefully planned out course of learning each and every weld type for that certificate under the supervision of a qualified TIG welder...

also, 53psi is a hell of a lot when it blows a hole in one of your welds and covers whoever is walking past in steam, probably causing quite nasty burns.

even if its not a pressure related regulation, it should be a health and safety issue

 

[Lawnmowerboy]

Any pressure is too much pressure when you're dealing with water hotter than boiling point! I have not long finished the first year of my welding and fabrication apprenticeship and still not qualified to weld pipework yet. People go through years of stringent training to be able to weld pipework. I wouldn't be happy with those welds on a non load bearing item. Let alone something that could make someone's day go badly wrong. How much of it are you going to x ray for faults?

 

[hotrodder]

why would you need a certifide for tgese types of welds? 52 psi isnt crazy pressure...?

Car tyre lets go and kills woman... http://news.bbc.co.uk/1/hi/scotland/edinburgh_and_east/8600833.stm that's less than 52psi of air at ambient temps, no steam or chemicals

Pressure aside volume plays a BIG role... pounds per square inch remember. This is why lorry tyres are a LOT more dangerous than a car tyre and bicycle tyres a lot less. This is also why pressure regulations talk about bar.litres not just pressure and to be excempt from regulations in the case of say a boiler the number would be less than 3 bar litres http://www.tsmee.co.uk/page4.php

Dangerous, irresponsible and aside from that a waste of time as you're not listening to the advice you're asking for in this or the other thread

 

[Rrunnach]

HR, that tragic tyre incident happened just up the road from me, in fact, my mate owns the garage the couple pulled into.

Playing with pressure, can kill!!

 

[Georgie]

Ok I get what you guys are saying. But consider this, we have modified 5 of these machines in the past 5 years and all the work was done by someone with less experience than myself, and also was done with arc welding. Let me just tell you all those welds look porrous and nasty compared to mine. Secondly, the working area on these machines have no pipes passing close by. All the pipe work is in the back of the machine. If i have to pay a certified welder to weld all these pipes, i might as well go out of business...

Thats why I need tips from you guys to make these welds as safe as possible. So whats involved in purging?

 

[Lawnmowerboy]

filling the airspace behind the weld with an inert gas, usuallly argon the same as you are using. It is easier to get faults within the weld with tig than MMA. Its people's lives at risk. What if it did go wrong?

 

[BrokenBiker]

Ok I get what you guys are saying. But consider this, we have modified 5 of these machines in the past 5 years and all the work was done by someone with less experience than myself

that is all well and good, but have you heard the expression "there is a first time for everything"?

do you really want the first time a weld blows for it to cause potentially life threatening injuries to an employee, and then find out it is your weld that has been defective?

before welding up anything that holds any sort of pressure I would be making sure that a governing body had considered me safe to be doing the work, especially if this is your business that could potentially be ruined by 1 faulty weld due to inexperience.

also, a point that no one else has mentioned yet (I don't think), if you do have to be certified in order to weld those pipes up, and you aren't, if one blows and causes damage or injury, your insurance wont even think about covering you to re-gain costs

 

[Shox Dr]

Ok I get what you guys are saying. But consider this, we have modified 5 of these machines in the past 5 years and all the work was done by someone with less experience than myself, and also was done with arc welding. Let me just tell you all those welds look porrous and nasty compared to mine. Secondly, the working area on these machines have no pipes passing close by. All the pipe work is in the back of the machine. If i have to pay a certified welder to weld all these pipes, i might as well go out of business...

Thats why I need tips from you guys to make these welds as safe as possible. So whats involved in purging?

I'll just quote you on that statement it might just be used on the day everyone has to wear a suit

 

[Georgie]

Wow you guys spend too much time behind your screens, and obviously dont work in an environment full of textile machinery. Do yall actually believe one if these welds would give way to heated pressurized water? If so, I think we have different values of common sense.

Our boiler pushes out 120 psi of steem. All the piping is black pipe and done with threads, unions, teflon tape, welded joints etc... None have ever blown in the last 20 years and when they leak(also the welded areas) they only dripp... Worst case sceneario you get a little pussy burn...