I have never heard of this happening. If your investigations reveal the root of the problem, then please let me know. It sounds like an interesting problem.
Regards
Niekie
I wonder if there was a mixup in packaging or marking and you got some type other than 2% Thoriated?
Marty
I've been in the welding business for 27 years and it amazes me that there is always something new and sometimes these new things we learn are so unbelievable.
I have received electrodes labeled 2% thoriated but found them to be pure, and therefore lost the sharp point inexpectedly when in straight polarity and couldn't handle much amperage in AC. Not really defective, only mislabeled. Still anything man can make, he can screw up, so I do not doubt your story..
I don't have an answer back from the supplier. The red paint on the end is an i.d. marking. These should not have been in a weld shop as far as I'm concerned. The electrical characteristics are so strange. It seemed to be worse after the initial try. (initial heating) This leads me to believe we got some low grade tungsten with unknown impurities. We'll see. I kept (1) piece in case our local metallurgist is interested in the specimen.
Currently, I'm looking at phasing out the 2% Thoriated Tungsten electrodes. Maybe Ceriated or Lanthiated from a more reliable manufacturing source. Any recomendations?
Be carful we use 2% thoriated and if you use Lanthiated you must turn in new test cupons for those electrodes.
Just curious...what code requires requalification of the WPS if you change the tungsten electrode? Charles Hall
I think it has more to do with my employer than the code.
they certify you per AMS-STD 1595. Then you must qualify for each type of metal (7) and process (14). And by process I mean TIG, MIG, STICK...ETC. or if you are GTAW and change the gas in any way, say 50% hel 50% argon to my employer that is a different process than 100% argon. They also feel this way about thoriated and lanthiated electrodes. Being that the lanthiated will drive the voltage up during the weld I guess they just want to see if it a problem for you. And they just want a new set of cupons for every process you are qualified on (every 12 months) just to cover them.
I like thier thinking, but that's alot of testing when you have alot of welders. I too like to see if a welder can adapt to changes.
John Wright
We use 2% Th almost exclusively and I have never come accross this problem. I therefore do not think that changing the type of electrode is necessarily the answer. I think changing the supplier is a better bet.
Regards
Niekie
I'm with Niekie here,
Tungsten electrodes are produced by the Powder Metallurgy method and different manufactures have slightly different techniques they employ to meet the requirements of AWS or other specifications. It sounds like you just got a bad batch, but; If your vendor is not providing you with what you want to know than out them right here! Being dogged out on this website may give them just the motivation they require to be more responsive to your needs and the needs of others in the future.
Since different manufactures of electrodes provide slightly different characteristics (especially lanthanum) We poll the welders (both manual and automated) on not only measurable data like arc starting/transfer quality but also, we judge how the electrodes fracture and cut when we need special sizes.
My personal preferences are as follows:
"Anchor Brand" for Thorium *red*and Zirconium *brown* electrodes
"Sylvania" for Ceriated *orange* electrodes
"International Tungsten" (Formerly Bavarian Alloys) for Lanthanum *black*.
We've been using "Anchor Brand", "Red" as long as I can remember. This last lot was mfg. in China. I'm supposing their ISO program is failing or the bad Tungsten would not have made it into the packages. The reason I'm thinking of switching to Lanthaniated or Ceriatedis to eliminate the chance of any workers comp claims by someone claiming negligence on our part. Yes welders are trained to use respirators. The problem is that they don't all follow the safety rules. Or other rules as far as that goes. The issue with qualification is true. Kind of ironic when you can get such a poor quality electrode that you can't hold an arc and your qualified to weld with it. Such is the life when we need so many rules.
Thanks Guys,
My vendor hasn't caalled with more details on this.
I'll post again as a new posting when I finally find out.
maybe the defective electrodes were mixed in the package. if the arc can not be ignited, it seems the composites of electrode include some other materials.
By -
Date 07-16-2002 01:38
IAM WITH LARENCE HERE,
DEAR SIR,
WE ARE INDIAN BASED COMPANY INTO WELDING BUSINESS. WE WISH TO HAVE SOME TUNGSTEN ELECTRODE MANUFACTURERS SHALL GET THE MANUFACTURERS DEATISL WITH ADDRESS AND EMAIL OR WEBSITE. PLEASE GIVE METHE DETAILS.
ONE MORE QUESTION TUNGOWELD BRAND STILL IS THERE IN THE MARKET?
YOU MAY MAIL ME TO gopalrajan@rediffmail.com
regards
reddy,
india
I ran into this a few years back as well. At the time I was a finish weldor on stainless. The company switched brands to save a few pennies, and the tungsten was the shoddiest stuff I have ever used. If you were lucky you could use 1 whole stick out of a pack, but not without major frustrations. It would leave a tanninsh residue, the same as if you were running out of argon. It was extremely brittle, and sometimes broke while you were welding. And it would often split, yes split! After a constant stream of complaints, the company finally switched back to Anchor. I don't recall the name of the other brand, but I am sure I would remember it if I heard it!
Nothing new on this subject. We have not had a recurrence and are still using Anchor brand, made in china. I gave the shop a chance at switching to ceriated or lanthanated and even got some to test. They weren't impressed so we continue with 2% Thoriated. I agree with the problem of having to requalify/rewrite our procedures and believe this is a somewhat isolated case of bad product. I would like to see what Anchor has to say about it. Does anyone know how to contact them?
Thanks all,
Brad_J
Hi Brad;
We got rid of the Thoriated tungsten a long time ago because of an exposure to radiation concern, a small amount, but none the less it's gone.
We went with the Lanthinated (2%) because it has basicaly the same welding characteristics as the Thoriated. Give it a try, and let me know what you think about the choice.
