Brazing Qualification Procedure per sec IX question

By Kix

Date 03-26-2012 18:38

I just want to know if I am interpreting QB-200.4 correctly. We recently qualified a BPS with a piece of .049" wall x 5/8" dia copper tube to a 4"dia .122" wall copper pipe. When populating the BPS with the thickness range qualified I believe it could be written in a couple different ways. Which is correct, 1, 2 or 3?

1. Base material thickness- Thinnest member- .024 to .098
   Thickest member- .061" to .244"
   Collectively qualified- .024" to .244"

2. Base material thickness- Thinnest member- .024" to .098"
   Thickest member-.061" to .244"

3. Base material thickness- .024" to .244"

Another question would be could we braze two pieces of the same thickness together under this PQR within the thickness range qualified? Say, .049" to .049" or can we only write dissimilar thickness BPS's off of this BPQR?

Lastly, for the brazer that brazed this procedure coupon under QB-302.3 well, I'll be honest and say that I'm lost in how to interpret this clause. It sounds like my man that brazed this procedure coupon would be qualified for the ranges listed above and could braze 2 pieces the same thickness together, but for Joe shmoe that qualified on .035" copper to .035" copper with the same filler a year ago, he can only braze two pieces of material together that are the same thickness within his qualification range and not dissimilar thicknesses. Correct?
   I apologize ahead of time if I have totally confused everyone. I hope someone can make sense out of what I'm asking. If not, please ask away and I will try to clear things up a bit.

Thanks,
Kix

By MBSims

Date 03-27-2012 02:29

I believe #2 is correct. The range qualified for each thickness would apply.

For brazing materials of the same thickness, the range would be 0.061" to 0.098".

For a brazer qualified on 0.035" to 0.035", the qualified range should be 0.018" to 0.070". The brazer would be qualified to braze any combination that falls in this range, such as 0.018" base metal brazed to 0.070" base metal. The key to QB-302.3 is in the last sentence: "The range of thickness of each of the base metals shall be determined individually per QB-452."

By Kix

Date 03-27-2012 15:08

"I believe #2 is correct. The range qualified for each thickness would apply. ----- Ok,good deal. Thanks!

For brazing materials of the same thickness, the range would be 0.061" to 0.098".------- Ahhh, so it's the overlapping range where you can do same thickness to same thickness. Thanks for clearing that up!

For a brazer qualified on 0.035" to 0.035", the qualified range should be 0.018" to 0.070". The brazer would be qualified to braze any combination that falls in this range, such as 0.018" base metal brazed to 0.070" base metal. The key to QB-302.3 is in the last sentence: "The range of thickness of each of the base metals shall be determined individually per QB-452."------ Ok, QB-302.3 was tripping me up where it says- When joints are brazed between metals of different thicknesses, a performance qualification shall be made for the applicable combination of thicknesses, even though qualification tests have been made for each of the individual metals brazed to itself. I thought it was reading like a man that qualified on .035 to .035 would still have to take a test for a production brazement of .027 to .060 because it said comma even though qualification tests have been made for each of the individual metals brazed to themselves. Question, Is a man that qualified on dissimilar thickness only qualified for same thickness to same thickness in his overlapping range like the procedure qualification or does he actually get the collective range?

By Kix

Date 11-30-2012 15:50

Anyone want to take a stab at my last question? This subject has come up again and I just want to be knowledgable on the subject.

Thanks,
Kix