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RE: Pipe Analysis

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I would agree with what Harold has said here and add the following:
A mechanical engineer would not use a carbon steel in an area where prolonged tempeatures exceed 750 F.  This is due to the carbide phase of the carbon steel will convert to graphite.  The graphite will make the steel brittle which will severely change its design mechanical properties.  Usually you will need a Cr-Mo steel at these temperatures.  The ASME Boiler and Pressure Vessel Code (B&PVC) will govern the design.  For 1500 F you will probably need to use SA-213 steel and the grade will be determined by the temperature.  I do not have a current copy of the ASME B&PVC so I cannot specify the grade.  I am not familiar with ANSI R211.
 
Albert Ford
-----Original Message-----
From: Sprague, Harold O. [mailto:spragueho(--nospam--at)bv.com]
Sent: Friday, October 10, 2003 10:36 AM
To: 'seaint(--nospam--at)seaint.org'
Subject: RE: Pipe Analysis

Steel is definitely considered molten at 2900F. Ingots are rolled when steel is between 2150F and 2450F.  Shapes are rolled from blooms at 2250F. 

 

A36 steel is generally not used for stacks where the temperature is above 750F because of creep.  You also have to adjust the allowable stresses and modulus of elasticity.  (Mechanicals are not yet using limit state.)  Look at STS 1, Appendix B for the adjustment to the steel properties at various temperatures.  Technically, you can use A36 all the way to 1300F, but the yield stress of A36 steel drops to 7.7 ksi.  And again, creep has to be a concern.  For 1500F service, I would suggest ASTM A242 or A 588 carbon steels. 

 

I would suggest that you get the following:

ASME STS 1-2000 Steel Stacks.

Catalogues from Piping Technology & Products, Inc.

Manufacturers Standardization Society MSS SP-58 Pipe Hangers and Supports - Materials, Design and Manufacture

MSS SP 69

MSS SP-77

MSS SP-89

MSS SP-90

Piping and Pipe Support Systems, Design and Engineering, Smith, Van Laan

Grinnell catalogues

 

ANSI does not develop standards.  Standards such as B31.1 are developed by ASME using ANSI accreditation standards.  They put the ANSI tag on the standard just to say that people voted on the standard. 

 

I have IHS service, and did a search on R211.  There is nothing relating to piping in the various R211's that popped up.  This was the closest:

ISO   R211   01/01/1961  Essential Oils - Labeling and Marking Containers - First Edition

Regards,
Harold O. Sprague

-----Original Message-----
From: MBREngineering(--nospam--at)aol.com [mailto:MBREngineering(--nospam--at)aol.com]
Sent:
Thursday, October 09, 2003 5:56 PM
To:
seaint(--nospam--at)seaint.org
Subject: Pipe Analysis

 

This might be a little off subject but it deals with stress analysis on pipes, maybe I should go into the ME email group, but let me try anyways.

 

I am currently working on a pipe that requires a thermal expansion analysis.  The pipe is an exhuast pipe for  a generator.  The material of the pipe consist of low carbon steel.

 

First Question:

Specs call for a differential temperature of 50F to 1500F.  My comment was that the pipe will melt at 1500F.  Typically I am use to seeing a max temp of 1100F for carbon steel.  I have notified the spec writers and informed them of the concern I have.  Any comments on the max temp of carbon steel?

 

2nd Question:

We have typically designed pipes under the ANSI B31.1 code but the specs call for ANSI R211.  Is anyone familiar with this R211 code.  I can't seem to find it anywhere.

 

Thanks for any help that you guys might be willing to give.