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[MW:2571] RE: 2567] Help Needed in Brazing

By Materials & Welding

Hi!

I could not open the file but For lap joint  when two strips are to be joined some time vacuum brazing are carried with thin sheath is used as a filler ,  and this passes peel test

Regards

 

Hegde

 

From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Sachin Joshi
Sent: Monday, June 29, 2009 10:16 AM
To: materials-welding@googlegroups.com
Subject: [MW:2567] Help Needed in Brazing

 

Dear Sir,

We are having some difficulty in coming to common grounds with our customer on interpretation of ASME Section 9 qualification requirements for Copper to Copper lap joint with filler metal. I will try to explain you the entire case for your perusal and advice.
We are in the business of large motors for cement plants, generators and similar applications. The customer asks for qualification of operators in welding and brazing as per ASME section 9. The entire details of the joint are as attached in the document.
As per our interpretation of code the code asks for Tension test, Peel test and Section test. We get the tests done in approved authorised laboratories.
In all the tests the trend is such that the brazing coupons are passing in tensile tests and sectioning tests.
But the Peel test coupons does not have consistency in qualifying as per norms. As per the qualification criteria the test are basically visual inspection and have some inbuilt subjectivity hence the dispute keeps on recurring about the consistency of qualification.
In the clause QB-141.4 its is suggested that if the filler metal used has a greater strength than the base metal strength ( in out case UTS of base metal is 205 N/sq.mm, and filler metal UST is 250 N/sq mm) then the Peel test can be replaced with sectioning test. The customer is not agreeable as he feels that we are finding escape route by pointing to this clause.

Can you please throw some light on this issue with technical details of this substitution of peel test with sectioning test.

Kindly revert.

Regards,
Sachin Joshi

 


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