Titanium

[Shox Dr]

Hotrodder, I was thinking the same I've seen an awful lot of Trick and expensive parts made for Cars and Bikes both Track and Road that have the colours within the weld area.

Now I'm reading this is a poor quality weld I'm confused

[B2N3 Welder]

The shop i weld in doesnt allow any color darker than a light straw if its dark or discolored Your in for a chewing,and some grinding also. The jobs we do all have back purge with aluminum foil or Titanium discs that are aluminum taped on and heavily back purged. Ive seen it done differently but Ive also seen what happens when its done wrong. I have repaired alot of chemical tanks where the only problem is the weld,the chemicals attack the weld seams and i get to go and grind them out and reweld them with tipladium,its a nasty job.If you would like i can show you pics of how to set a good purge system. I just have to remember a camera.

[Propulsion]

Nice machining (& welding)!
I worked for Aeroquip, Aerospace for a number of years and programmed/machined a %&^$load of those type's of fittings!

Thanks mtncrawler, I use a lot of Aeroquip fittings on my race engine and dynamometer, I really like there quality.


Regards,

[Propulsion]

They look good. I have not fusion welded titanium. However I believe because of its tenacity it would lend itself to fusion welding.

I have machined titanium, and some of the manganese titanium was so tuff you cannot band saw it. It was so tuff that surface grind marks that were pushed against steel shoes, did not rub or wear down. Just the little ridges left by the grind stood up against the steel. Amazing.



Sincerely,


William McCormick

Thanks,

[Supe]

Hotrodder, I was thinking the same I've seen an awful lot of Trick and expensive parts made for Cars and Bikes both Track and Road that have the colours within the weld area.

Now I'm reading this is a poor quality weld I'm confused

You'd be amazed if you saw how poorly some "professional" products were welded.

Like B2N3, anything other than shiny silver or a golden straw color was an automatic reject for us.

[William McCormick Jr]

Pure titanium?

There are 13 grades of titanium. the first 3 are commercial grades. Kind of brittle.
The 6AL4v6 is the middle grade and prefered for bicycles because it is not so prone to cracking. It is more ductile. But the 3 maunufacturers do not make some tubing sizes in this grade due to insuffcient demand.

A titanium weld should look like chrome,glass smooth. if it is discolored it was exposed to oxygen. It is simular to welding stainless but smoother surface.
When welding titanium tubing where there is no drafts the shielding gas will flow right around the round tube.

Welding filler wire selection is covered by ANSI/AWS A5.16-90
If you need any info, I have that booklet. just post or leave private email.

I believe it is called commercially wrought titanium. Or was.

Sincerely,


William McCormick

[Donald Branscom]

this should provoke some interesting comments

http://www.arcfabrication.com/images/DSC0002610.JPG

It is a motorcycle swing arm.
Looks like they sure could use some pro tube bending.
Nice workmanship and machining.

[Donald Branscom]

I believe it is called commercially wrought titanium. Or was.

Sincerely,


William McCormick

Thanks William for the info.

[Donald Branscom]

You'd be amazed if you saw how poorly some "professional" products were welded.

Like B2N3, anything other than shiny silver or a golden straw color was an automatic reject for us.

The color of the weld does not mean the quality is poor.
The oxide colors are produced at around 975º when there is any reduction going on.
Like different colors from differing amounts of reduction. Could be from
machining or cutting oils, not necessarily in the weld zone but within a couple inches of the weld getting hot and reducing the area.

If you are welding stainless for example stainless melts at around 2500º
so as it is cooling hot metal a couple inches away could get up to 975º and the smoke (reduction material) could drift over the weld area after it is welded and produce those rainbow colors. You will notice that the smaller the weldment the more likely the weld will look silver or gold and have no reds or blues.
That is because there is no material producing any reducing (burning) material in the area. This can go on for several minutes after welding. It could even be something on the table you sit the weldment on. Anything that could burn.

If you take a small stainless tooth brush and brush the weld after has cooled
it will look silver. The colors are just oxides on the surface. the same as with
Raku ceramics. There can be beautiful reduction colors on copper,steel etc.,.
Now those oxides are being used in the electronics industry.

[G3farms]

if that had a spear in the middle of it i would use it to move round hay bales lol

what is it hotrodder?
G3

[hotrodder]

it's a motorbike swingarm, as suggested a couple of posts ago. 'nice' is not the term i'd expected though.

if the last part of the address is deleted the link will take you to the website

[Supe]

The color of the weld does not mean the quality is poor.
The oxide colors are produced at around 975º when there is any reduction going on.
Like different colors from differing amounts of reduction. Could be from
machining or cutting oils, not necessarily in the weld zone but within a couple inches of the weld getting hot and reducing the area.

If you are welding stainless for example stainless melts at around 2500º
so as it is cooling hot metal a couple inches away could get up to 975º and the smoke (reduction material) could drift over the weld area after it is welded and produce those rainbow colors. You will notice that the smaller the weldment the more likely the weld will look silver or gold and have no reds or blues.
That is because there is no material producing any reducing (burning) material in the area. This can go on for several minutes after welding. It could even be something on the table you sit the weldment on. Anything that could burn.

If you take a small stainless tooth brush and brush the weld after has cooled
it will look silver. The colors are just oxides on the surface. the same as with
Raku ceramics. There can be beautiful reduction colors on copper,steel etc.,.
Now those oxides are being used in the electronics industry.

Stainless and Ti are two different beasts. If you have ANY cutting oil, cross contamination, you name it, and have discoloration as the result of it, you've got issues. Cleanliness is the number one priority when working with Ti, and in virtually every environment I've been exposed to it, anything other than a golden straw color or bright silver without any post-weld cosmetic touchup is an automatic failure.

[B2N3 Welder]

Supe if i were to classify any materials with Ti .I would have to say zirconium and tantalum are the 2 closest. Clean for Ti is scotch brite first 2inches from the weld area or seam. then cleaned with acetone which isnt the greatest i would rather use mek. It doesnt weld the same as stainless to me,i weld ti totally different. We use #12 cups with large gas lenses and the gas regulated between 15 and 30 cfh and trailing shields 30-50cfh. How do you prep Ti Supe? Do you make up your own trailing shields?

[Propulsion]

Stainless and Ti are two different beasts. If you have ANY cutting oil, cross contamination, you name it, and have discoloration as the result of it, you've got issues. Cleanliness is the number one priority when working with Ti, and in virtually every environment I've been exposed to it, anything other than a golden straw color or bright silver without any post-weld cosmetic touchup is an automatic failure.

Donald,
You are misinformed on the attributes and proper welding procedures for Titanium. Removing the surface oxidation with a brush does not change the fact that the material as absorb nitrogen causing embrittlement. Supe is right, every Titanium welding specification that I have ever worked with has a picture chart criteria for visual inspection and acceptance or rejection. I have also seen Titanium parts on motorcycles that were discolored I don't know why that is other than the engineers must have decided that the embrittlement condition in the material on those applications will not cause a fit or function problem. I can confirm this conditon is not acceptable in the Aircraft and Aerospace industries.

[Rojodiablo]

Donald,
You are misinformed on the attributes and proper welding procedures for Titanium. Removing the surface oxidation with a brush does not change the fact that the material as absorb nitrogen causing embrittlement. Supe is right, every Titanium welding specification that I have ever worked with has a picture chart criteria for visual inspection and acceptance or rejection. I have also seen Titanium parts on motorcycles that were discolored I don't know why that is other than the engineers must have decided that the embrittlement condition in the material on those applications will not cause a fit or function problem. I can confirm this conditon is not acceptable in the Aircraft and Aerospace industries.

When I raced bikes, we had several 'works' exhausts that were Ti. and they all had some bluing on them. I talked then to our in house welder about the wild colors, and he said the color was not an issue.( I had NO CLUE about welding at the time.) So I think you are right; it would depend on how critical the part was to determine if 100% backpurge was necessary. All we needed the Ti exhaust for was weight reduction, not strength or heat/ corrosion resistance. Never had a weld crack or fail onthe exhausts, but they broke rather easily when I crashed the bikes for some reason.....

[Supe]

Supe if i were to classify any materials with Ti .I would have to say zirconium and tantalum are the 2 closest. Clean for Ti is scotch brite first 2inches from the weld area or seam. then cleaned with acetone which isnt the greatest i would rather use mek. It doesnt weld the same as stainless to me,i weld ti totally different. We use #12 cups with large gas lenses and the gas regulated between 15 and 30 cfh and trailing shields 30-50cfh. How do you prep Ti Supe? Do you make up your own trailing shields?

I agree completely with you here.

Most of what I've done has been small diameter parts in T joint configurations. Copper backing/diffuser blocks behind the joint, large gas lens on the torch. CFH typically between 15-20cfh. Ditto on the cleaning as well. Scotch brite and acetone. Shop safety laws where I was prohibited using much else. All material was handled with a set of clean cotton gloves as well, to keep hand oils off the surface.

[hotrodder]

just as a point of interest the reason Ti is so expensive is not because it's a rare element (9th most abundant on earth?), but because it's so easily contaminated it's extremely awkward (read expensive) to refine. the kroll process is briefly explained in the link below, note the sacrifice of magnesium (expensive in itself) during refinement

how many of us use a pencil to do layout work? do that with Ti and you leave a potential source of carbon for the formation of TiC

here's hoping that something fruitfull comes of this (then maybe i'll be able to afford/justify using the stuff)... http://www.techreview.com/Biztech/16963/



B2N3, Supe, Propulsion or anyone working with Ti regularly. any chance of some numbers to quantify 'embrittlement' for different levels of discolouration?

the only data i've found compared CP Ti welded within a chamber to welded with just torch shielding- the (relatively) poorly shielded weld exhibited 25% the strength of the parent plate. as said the strength reduction wouldn't be an issue for a select few applications but, as i understand it, with Ti embrittlement comes EXTREME notch sensitivity

[B2N3 Welder]

Hotrodder I dont have any numbers for embrittlement,or discoloration clarification either.They have been in the Ti fab business since the early 60's they could probably tell me but ive never asked.Im sure they had issues in the beginning,but there policy is no color,clean 2 inches around surfaces being welded and the backing plates we use are TI also.We also use diffusers in our backing plates .I will see what our engineers have to say on the subject.

[WANNAWELD]

I have Ti headers for a cbr 929 laying around in the garage for the last 7yrs I wonder what i should do with them???

[Rojodiablo]

I have Ti headers for a cbr 929 laying around in the garage for the last 7yrs I wonder what i should do with them???

Sell them. You can't change them into headers for something else; too many different angles. And, that is some very expensive scrap to use for practice. If you go to some supply shops, they will have srap and rems of Ti. It is not cheap, but much less expensive than hacking up good headers. If you want headers/ exhaust for practice, go to your local club races for roadracing. I see Ti exhausts go down the road sideways all the time. Hey- so long as it wasn't my fault the exhaust got crashed, I don't mind. It's all scrap to me.

[hotrodder]

Hotrodder I dont have any numbers for embrittlement,or discoloration clarification either.They have been in the Ti fab business since the early 60's they could probably tell me but ive never asked.Im sure they had issues in the beginning,but there policy is no color,clean 2 inches around surfaces being welded and the backing plates we use are TI also.We also use diffusers in our backing plates .I will see what our engineers have to say on the subject.

cheers pal,

i can understand the 'no more than straw/no colour at all' policy in aerospace (or when Ti is used for increased service life over cunifer with regards to corrosion resistance) but it'd be nice to be able to quantify the damage to mechanical/corrosion properties of, say, a blued weld/HAZ.

[Brainfarth]

Where are you at, welder155? I currently work for an outfit that makes heat exchangers. We have a few exchangers on the floor that have some titanium parts.

not sur what you guys are welding ti but for all titanium tantalum hastelloy zirconium etc. you need a trailing cup. ive welded lots of heat exchangers made out of titanium. to be up to code and a pure weld it needs to be basically a chrome color.