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Up Topic Welding Industry / Technical Discussions / Code Tolerances - Bends, tensiles and such
- - By hawkeye (*) Date 07-13-2015 12:19
So, I was asked a while back and I didn't have a good answer for it at the time.  For an example, D1.1:2010, figure 4.10, 4.11, 4.12, 4.13, etc. when you cut specimens out for tests, what is the tolernace of these requirements?  On some of the details there is "min." for like a length becuase someone's machine may be able to handle something longer but what about a width on a bend?  It shows 1.5 for face or 3/8" for a side but what's the tolerance?  Is it plus/minus 0.030" or 0.060" or 0.125" or is it suppose to be dead-nuts?
Parent - - By Mwccwi (***) Date 07-13-2015 17:58
I have ask that same question and was never able to get a response so in looking for the answer myself took me to AWS B4.0M:2000 (R2010).Figure A4 – Bend Test Nomograph on page 8
note 2 Required accuracy of measurements is as follows:
(1)  Specimen thickness: + 0.5mm
(2)  Elongation: + 1percent
(3)  Bend radius: + 1.6mm
I don't know how applicable this may be for your situation since B4.0 isn't referenced in D1.1:2010. this is what I have been using since 2001 and no one has ever challenged or corrected me on it.
Parent - By hawkeye (*) Date 07-14-2015 11:14
Ok, I have AWS B4.0 not 4.0M.  Do you know what figure it would be in 4.0?
Parent - - By welderbrent (*****) Date 07-15-2015 01:48
You will notice that some cuts are indicated to be made 1/8" oversized and then machined, ground, sanded down to the required dimension. 

When it comes to thickness, at one point you are sent to a section of Clause 5 (5.24.3.1) that indicates that base material thickness cannot be removed over 1/32".  So when grinding, sanding, or machining down the face and root you best not take off too much material. 

My personal two tin pennies opinion, when the codes give you a dimension you should be within 1/32" and preferably on the positive side.  Undersized welds, unacceptable.  Material too thin, unacceptable.  Standard practice if a size indicated by engineer is not available, next size LARGER (get it approved of course).  Machinists are generally within single digit thousandths of an inch, not 30 thou.  Taking more material out suggests trying to get rid of the discontinuity.  It is a welding test, not a grinding test. 

Now, end of personal opinion, what does the code say beyond 5.24.3.1?  Look at note 3 on Figure 4.9.  Look at note 3 on Figure 4.10.  And 4.11.  Maybe it's just me, but I would think that "all dimensions are minimum." (emphasis mine)

He Is In Control, Have a Great Day,  Brent
Parent - By 803056 (*****) Date 07-15-2015 15:37
That's how I handle it. However, I don't remove anything but a trace of the bend specimen thickness when preparing them. The undercut stays as well as any incomplete fusion in the root where the backing isn't tied in as good as it should be. If they break, they break.

Al
Parent - - By pipewelder_1999 (****) Date 07-15-2015 15:51
Page xvi in AWS D1.1-2010 refer to AWS B4.0 by stating ... "AWS B4.0, Standard Methods for Mechanical Testing of Welds, provides additional details of test specimen preparation and details of test fixture construction.

Have a great day.

Gerald Austin
Parent - By Mwccwi (***) Date 07-17-2015 19:33
Thank you Gerald, I can't believe that I missed that being that it is in bold type in my code book.
Up Topic Welding Industry / Technical Discussions / Code Tolerances - Bends, tensiles and such

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