RE: Flanges near creep range

From: <SARE>
Date: Thu Aug 23 2001 - 04:43:00 EDT

If the flange used are within the rated pressure per B16.5 and still leaks, calc the equivalent pressure and add to actual pressure. Compare the sum with the pressure rating. If low, replace the flange with higher class.

The use of stud bolts ensures that the creep will be distributed over the entire lenght of the bolts. You wont get the same results with machine bolts since the head is not free to rotate. USe austenitic bolts for alloy flanges since ferritic bolts will strecht a lot of time during the cycle. Normally we used A193 grade 8.

Tightened nuts to achieve a romm-temp stress of 30 kis. The elongation athis point will be around 1 thou per inch lenght of thje stud.

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-----Original Message-----
From: hirap_napinoy@yahoo.com [mailto:hirap_napinoy@yahoo.com] Sent: 22 August, 2001 6:40 PM
To: PipingDesign@yahoogroups.com
Subject: [PipingDesign] Flanges near creep range

How does one evaluate the adequacy of flange near the creep range. Bolts will strecth over time resulting in flange leak.

Why is the stud bolts the preferred bolting material for the flange. What's wrong with a machine bolts?

What is the normal practice to tightened flange bolt near the creep range?

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Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ Received on Thu Aug 23 04:43:00 2001