Scarfing Powder

Date 03-18-2013 19:59

Going to qualify a procedure using Oxweld 200 Cutting scarfing powder using the SAW Process (5/16 square groove with backing). Classification F7A2-EM12K. The only nomenclature found in D1.1 (2010) is Table 4.5, Filler Metal, Note 7, In regards to a "supplemental filler", I find nothing else pertaining the use of, even in commentary. I find in 4.12.3 Consumable Verification Test, Test shall be ran on 1" test plate, Is this a problem when all I need to qualify is a 5/16", square groove test plate?

Also in my view the need for a all weld-metal tension specimen should be performed during mechanical testing, what is your view? Am I correct in regard to performing a all weld metal tension specimen is when a non pre-qualified base metal or filler metal is not recognized?
Thanks
Roger

By 803056

Date 03-18-2013 22:11

Maybe have it all wrong, but I thought scarfing powders were used for cutting stainless and cast iron with an oxy-fuel torch. I thought they were typically injected into the cutting oxygen stream to prevent oxidation from arresting the cutting action.

Please explain what you are doing.

Best regards - Al

By rshanks (**)

Date 03-18-2013 23:19

Al,
I worked for a prominent railcar manufacture for 21 years, Weld engineers qualified M12K iron/scarfing powder to add as a filler consumable to the Center Sills with large root opening between the sections of CZ material manufactured in Germany ( the only manufacture in the world). I'm having root opening issues from time to time at my new employer. Yes, I'm trying to make the supplier step up their quality of supplied material, but a battle I seem to be loosing. I'm wanting to qualify the use of Iron Powder at the max root opening the shop has been running into. When I read D1.1, Table 4.5 @ note 7, I assume this is what AWS is regarding as "supplemental powdered or granular filler metal?

I will set parameters based from depth of fill in the weld joint regarding amount of iron powder used, pull in-house NDE and destructive testing if good results will weld up a test plate send to 3rd party test lab. Would you advise a all weld metal tension test? I'm not a weld engineer just a CWI and I realize their is a difference between being certified and qualified in writing procedures, not so sure if I fit the bill in the qualified department on this one.

By 803056

Date 03-19-2013 01:58

I looked up scarfing powder on ESAB's web site. It appears to 100% iron powder.

If I understand what you've said correctly, you want to use the iron powder in the root of grooves with excessive root openings. You haven't stated what welding process is being used, if you did, I must have missed it. Base on the fact that you reference AWS D1.1, table 4.5, it appears that the welding process is SAW since it is the only welding process that lists supplemental powder as an essential variable.

I have concerns that the final diluted weld chemistry will match the target chemistry on a consistent basis. The chemistry will vary as a function of the root opening, the amount of powdered iron that dilutes/mixes with the electrode and base metal that is melted and mixed in the common weld pool. That being the case, how do you control the deposited chemistry of the weld and the resulting mechanical properties? A root opening that is 3/8 inch wide will result in a deposited weld chemistry that differs considerably from a root opening measuring 1/8 inch. As the chemistry changes, so does the mechanical properties. Ultimately, how do you possibly match the mechanical properties of the base metal on a consistent basis?

You have your work cut out for you. Going back to table 4.5; the reasons why items 8 and 9 are listed as essential variables relate specifically to the issues I have noted in the preceding paragraph.

Good luck.

Best regards - Al