Saturday, May 6, 2017

Flange - tolerance on bolt hole of a ASME B16.5 flange

Hugo Julien

As you know, bold hole diameter in a certified ASME B16.5 flange shall be 1/8'' bigger than the stud's one. But what happen if it's 3/16'' bigger because of corrosion issue? No tolerance for bolt hole exists in ASME B16.5-2013 (par. 7.8). Any advise for me?

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Hugo Julien I'm proposing the following tolerances maximum if washers certified per ASTM F436 or ASME PCC-1 appendix M are used:

Bolt nominal diameter + 1/8'' (ASME B16.5 requirement) + 1/16'' = maximum bolt hole diameter without Fitness-For-Service (FFS) engineering assessment.

Feeling?

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Trevor Seipp, P.Eng. That seems quite reasonable. Make sure that the washers are through-hardened as per PCC-1 Appendix M.

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Warren Brown Hugo Julien, there are consequences that need to be considered in addition to strength (FFS), such as the ability of the bolts to locate the gasket and prevent gasket blow-out (for example with spiral wound gaskets). Those consequences are likely to be of more importance with this question. We have just completed the second round of a JIP into bolted joint corrosion which defines the limits for bolted joint component corrosion. We will be presenting a paper on the findings of the first round at this years ASME PVP conference in Hawaii. The JIP reports may be purchased from us if anyone has corroded joint components.

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Hugo Julien Thank! What is the link to find out your document Warren Brown?

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Warren Brown Hugo Julien, no link yet. It will be published after the conference in July

 

 

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