Dear Piping Experts

Could you please advise me if CAESARII material database has MONDI ductile iron, used in sulphuric acid plants, (http://www.acidpiping.com/mondi/mondi.htm#mondi) built in and if not, how to add this material and what properties have to be known in order to address all Code requirements.
Any guidance on what should be taking into consideration doing stress analysis of sulphuric acid plants piping will be also truly appreciated
Thanks

Vikoll

The material is not an ASTM (or AWWA) specification and it is not listed in B31.3 so you have to go to paragraph 323.1.2 and comply with that. If (big "if") you can develop all the required properties in accordance with that paragraph (and its references) you could add them to the database. Then you might start thinking of other limitations (e.g., supporting). I think the word "ductile iron" is a relative term so see also Appendix F and paragraph F323.4(a).

John

Thank you Sir John

I had a look on these references. but it's not quite clear for me how to proceed. Any other sugestions that can shine a light on how to perfom stress analysis in this case?

Many thanks for all you input
Vikoll

Vikoll,

The MONDI material is a controlled chemistry composition of ductile iron with pipe barrels made to general requirements of ASTM A 395 Tp 60-42-10 with the pipe spools fabricated to AWWA A 21.51 , while the fittings are to AWWA C 110 of ASTM A 536 grade 70-50-05 with wall thickness equal to C.I. CL250. The acid piping industry uses only a small fraction of the volume of ductile iron of the water works industry, and so it uses the same patterns and molds for the D.I. pipe and fittings castings.

D.I. pipe has different O.D. from steel pipe. The centrifugal pipe casting process allows thicker wall thicknesses to be made for the corrosion requirements of the acid piping industry. The pipe barrels have wall thickness such that pipe I.D. matches fittings I.D. The MONDI piping and fittings have I.D. such that nominal size Nps inches = I.D. inches, for example Nps-12 MONDI has 11.98 inch I.D. (for thick wall corrosion allowance)

The pipe spools and fittings are flanged, so there will be weights at the joints and branch connections. The flanged fitting dimensions are different than steel weld fittings, and the elbows have different radius from steel weld elbows.

The acidpiping.com website used to have more information on the MONDI material properties.

modulus of elasticity 23. x10E6 lb/in2 (1.617 x10E6 Kgf/cm2)
poisson ratio 0.29 - 0.32
specific weight 0.26 lb/in3
Yield strength 42,000 lb/in2 (2953 Kgf/cm2) pipe
50,000 lb/in2 (3515 Kgf/cm2) fittings -Flange
Tensile strength 60,000 lb/in2 (4218 Kgf/cm2) Pipe
70,000 lb/in2 (4921 Kgf/cm2) fittings -Flange
Elongation 10% pipe
5% fittings
Thermal expansion 7.0 x10E-6 inch/inch deg F (32-212 deg F)

Reminder that the strong sulfuric acid has 1.8 specific gravity.

Thank you very much Sir Richard for your valuable input.

As far as I understand I have to add this material to CAESARII material database. I have found allowable stress only for temp. 21 and 149 deg.C and yield stress appears to be the same for both temperatures. Is this information sufficient for performing stress analysis or I need to dig deeper into properties if my temperature range for stress check is beyond mentioned above (lower than 21 deg.C)?
And where I can find fittings weight-dimension information for modeling and SIFs for branch connection?

Please kindly advise and thank you in advance

Vikoll

Vikoll,

The allowable stress information for 149 deg C would be valid, and there would not be MONDI applications above that temperature.

The supplier of MONDI has weight-dimension information. Any information should be confirmed with your supplier. Design dimensions probably need to be used for creating CAD database, as well as for stress analysis. Catalog data of manufacturers like ACIPCO, Clow, Tyler, and USPipe could provide additional data and design guidance.

There is previous thread 'ductile iron piping stress analysis' from Aug02 2005 that could be located by search of the forum.

Just a thought............

http://www.ductile.org/didata/Section12/12intro.htm

This one comes from Paul Bowers' excellent Pipingdesign.com

Regards, John