I'm on the subcommittee for ASTM A370 and written the standard for tensile testing of round tubing, currently under ballot consideration. This draft standard has received commentary, some affirmative, other negatives, from all over the industrial world because ASTM standards are widely used. The CVN specimen for square or rectangular tubing is generally taken with its long axis in the same direction of the long axis of the tubing, never at welds or corners. However, for round tubing, which could be pressurized, it makes sense to take the CVN specimens in both transverse and longitudinal axes of the tubing. Hoop stresses in highly pressurized tubing can result in pressure bursts, especially if the interior is pitted or its fracture toughness is minimal. Moreover, since tubing may exhibit "fibering" where there is grain elongation and magnification of the length of grain boundaries, a transverse CVN test specimen should be sampled. ASTM is conservative about mandating specimen orientation, so most of the time this is left to the "purchaser" to require testing locations in the Ordering Information.
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Christopher Hahin
Engineer of Structural Materials & Bridge Investigations
Illinois Department of Transportation
Springfield IL
(217) 522-4023
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Original Message:
Sent: 07-30-2020 10:06
From: Joel Russo
Subject: Longitudinal Charpy V Notch Position
Greetings all. I recently attended a joint ASTM/API meeting designed to develop acceptable recheck tolerances for mechanical properties. There was a lively debate as to whether the L-C or the L-R position should be specified for longitudinal testing of bar product, assuming the product code was silent. Does anyone have an opinion as to which position would be more appropriate? For the most part, the product would be in tension with possibly some bending.
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Joel Russo
Chief Materials Engineer 1
TechnipFMC
Houston, TX
(281) 591-4247
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