classifications for acceptance of defects in forging

[duk748]

hello - please excuse the way this question is asked so bear with me - we currently have a forging made from a694 f52 it is a very large round forging (60" in diameter)
while machining the part imperfections started showing up & the machining was stopped - after uting this part & others we may have to scrap the majority of these large parts -
is there any info as to what classifications for acceptance are allowed (depth, length, type of defect, etc.) that an inspector would use to say yes or no to the acceptance of a forging this large - the a694-f52 material spec refers to a961/a961m as the inspection criteria but does not give any classes of imperfection & under what circumstances or details this part is rejected or passed (this spec seems to refer to pipe & pipe falnges - not large forgings) - is a 1/16 deep by 1/8 long defect ok or not?? - if there is anything else i can add please let me know - thank you in advance

 

[KENAT]

As memory serves, there are standards you can reference which help control defects or inclusions etc. Can't recall if it was an SAE or ASTM or other spec I used, it was about 8-9 years ago sorry. I've also seen notes added to drawings to address this type of thing.

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[MintJulep]

Have a look at:

A370 Test Methods and Definitions for Mechanical Testing of Steel Products
A388/A388M Practice for Ultrasonic Examination of Steel Forgings
A788/A788M Specification for Steel Forgings, General Requirements

 

[KENAT]

ASME Y14.8M, Castings & Forgings, may even give some hints.

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[dhengr]

I don’t have those SAE, ASTM or ASME specs. and stds. in hand, but.....

You may want to spec. how the original piece is cast, rolled or made; and the areas which tend to collect impurities which become inclusions, piping, and the like, be removed prior to forging so these impurities are not formed into the final piece. Your original processors should help you with this, and modify their methods.

The size and orientation of various defects really has more to do with how they relate to the stress fields in your designed piece, than to a specific std. A small inclusion which lays parallel to a surface, and shows up during machining, but can be ground and smoothed out, and is not too deep, particularly when the lines of stress run parallel to that surface; may not be the worst thing in the world, on the finished piece. That same inclusion size laying perpendicular to that surface, shows up as an apparent crack across the stress lines, and would be a killer. That same crack parallel to the stress lines, might be ground out and welded full, and not be too detrimental. One size, one std. does not fit all. This may be more a designers and engineers problem, than an inspectors problem, if you can’t clean up the making of the original piece and then the later processing methods.

 

[metengr]

is there any info as to what classifications for acceptance are allowed (depth, length, type of defect, etc.) that an inspector would use to say yes or no to the acceptance of a forging this large - the a694-f52 material spec refers to a961/a961m as the inspection criteria but does not give any classes of imperfection & under what circumstances or details this part is rejected or passed (this spec seems to refer to pipe & pipe flanges - not large forgings) - is a 1/16 deep by 1/8 long defect ok or not??

Not to be funny, it all depends on end use of the product. Boiler and Pressure vessel codes and standards have acceptance criteria, aerospace, other industries. You need to determine end use and either follow the stated construction code or standard. If none of the above applies, you need to either establish your own set of acceptance standards or beg, borrow or steal from an established standard as close as applicable to your end use.

If this is for flanges, you can use ASME B16.5 or B16.47, both of which have reference to acceptance criteria for forgings and castings in ASME B16.34.


C2.2 Forgings and Rolled or Wrought
Material
Maximum acceptable indications are as follows:
(a) Linear Indications:
(i) 0.2 in long for materiais up to 0.5 in. or
(2) 0.4 in long for materials over 0.5 in. to 1
(3) 0.6 in. long for materials over 1 in. thick.
For linear indications, the indications must be separated
by a distance greater than the length of an
acceptable indication. A linear indication is one with
length in excess of 3 times the width.
less thick;
in. thick;
(b) Rounded Indications
(I) 0.2 in. diameter for materials up to 0.5 in. thick;
(2) 0.3 in, diameter for materials over 0.5 in. thick.
Four or more rounded indications in a line separated
by a 0.06 in. or less edge to edge are unacceptable.
Rounded indications are those which are not defined
as linear indications.

 

[duk748]

hello again & thank you for all your help - this forum is amazing along w/ the talented people who contribute - it just so happens that our company has a standard that no one knew of until this afternoon - it references astm a603 & 609 which is exactly what we needed - i am going to keep this page as a reference for myself in case this pops up again - on a side note so much for our "outsourcing" our critical parts - sigh a sign of the times - thank you again

 

[KENAT]

In fairness, if you didn't explicitly tell them defects of this type weren't permissible, then it's debatable how much justification you have in being upset by their presence.

Does the drawing say anything about no defects of certain type or size, or reference a relevant spec, I gathered not from your OP.

If you care about it, it should be on the drawing, be it directly or indirectly via reference to a relevant spec (industry or company specific).

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[MintJulep]

A603 is for wire rope and A609 is for castings.

Neither seem particularly applicable to forgings.

 

[eyec]

have a search @ EverySpec
there may be something that applies to you

 

[duk748]

hello again - sorry about the mistake on the spec number - the specs were 609 & 903 which deal w/ castings - we had another spec bs-en 10228 which was for forgings but the levels seem to be reversed from spec 609 for ultrasonic testing & defects - the higher the level on the bs spec i believe means less defects as i read it yet on spec 609 the lower the level the less defects - my brain is mush afetr all these specs so please bear w/ me - if kenat could possibly post that drawing example he might have that would be greatly appreciated - once again i thank you

 

[KENAT]

Sorry, the drawings were at a previous employer on a different continent, I can't recall their phrasing.

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[SnTMan]

duk748, one way to do it is with a drawing note: "UT 100% (or other extent) per (specification) with acceptance per (specification).

100% UT per SA-388 with accceptance per SA-578 Level B

Regards,

Mike