classifications for acceptance of defects in forging
classifications for acceptance of defects in forging
(OP)
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
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





RE: classifications for acceptance of defects in forging
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: classifications for acceptance of defects in forging
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
RE: classifications for acceptance of defects in forging
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: classifications for acceptance of defects in forging
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.
RE: classifications for acceptance of defects in forging
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.
RE: classifications for acceptance of defects in forging
RE: classifications for acceptance of defects in forging
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).
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: classifications for acceptance of defects in forging
Neither seem particularly applicable to forgings.
RE: classifications for acceptance of defects in forging
there may be something that applies to you
RE: classifications for acceptance of defects in forging
RE: classifications for acceptance of defects in forging
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: classifications for acceptance of defects in forging
100% UT per SA-388 with accceptance per SA-578 Level B
Regards,
Mike