Summary for astm b700 class j vs class n Discussion
ASTM B700 class j vs class n is the core question here: a customer spec still calls out Class J in ASTM B700, Type II, Grade D for silver plating over a copper flash, but the poster was told Class N is the current revision. McHenry, Illinois reports that the current 2020 B700 includes supplementary surface treatment classes N, S, and T, while the 1997 and 2008 editions had only N and S. He says Class J may have existed in an older version not readily available from ASTM, so the practical next step is to ask the customer for the original standard or have them approve a current-class substitute. No direct technical difference between J and N is identified in the thread.
Q. We have an old customer spec. that calls out Class “J” in ASTM B700, Type II, Grade D. We have been told that Class “N” is the current revision. What is the difference between Class “J” and Class “N”? It is a silver plating over a copper flash.
Dann-O
QC Supervisor – Tyrone Pennsylvania
October 31, 2024
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A. Dann-o,
From what I can find, the current (2020) copy of B700 contains “Supplementary Surface Treatments” Classes N, S, and T. The 1997 and 2008 versions had only N and S. Presumably some version, even older still, might have the Class J.
ASTM’s site doesn’t seem to have copies older than the 1997. Presumably your customer had one at some point and may be able to supply you with it, or ask if they would designate a Class in the current revision as a substitute.
Ray Kremer
Stellar Solutions, Inc.
McHenry, Illinois
