>How can we diffrentiate from a Microstructure whether it is >forged or Rolled and Machined Flange ? When macro-etched, there will be material flow lines in a forged material, following the contours. In a rolled and cut product, similar flow lines will be missing.

Arvind, Macro etch testing - ASTM Method E 381 is the standard applied for forged samples. This simple test will differentiate the heterogenity in steel or alloy steel samples - to know variations in grain size, dendrites and columnar structure. variations in segregations, coring and banding can also be seen at low magnification by simple acid test. Choosing etching agent depends on the alloy specified in P.O. If P.O. has specified the tolerances in grain size, the expected percentage of discontinuity like segregations, banding, columnar or exquiaxed grains,coring, flake conditions etc then you can go for detailed micro examiantion of the samples. Trust this answers your question. C.V.Srinivasan Nishi Engineers Pvt Lttd Chennai India May 14 E-mail:nishi@vsnl.com >Arvin, > >Respectfully,....why are you concerned ?? > >If the flange is manufacted to a DIN or ASME/ANSI standard, >isn't it pressure/temperature rated ? (all piping/equipment >flanges in my experience have been clearly marked an >certified by the manufacturer) > >Is this concern part of some type of legal verification of >the manufacturing process ? > >MJC