creep range 1

[mech212]

I have a heat exchanger of material SA516-70 , I need to know the creep range of this material and other material , where can I find such a data whether in a code or website ?

 

[EdStainless]

Look in the allowed stress tables, below the dark line is creep limited.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[metengr]

The time dependent (creep) allowable stress values are in ASME Section II, part D in italicized font.

 

[mech212]

Merengr , I have ASME Section 2 part D ,, but can't find th exact page , I found wording about time dependant only but I can't find the table

 

[metengr]

Ok, the table in the 2015 Edition of ASME B&PV Code is 1A. Page 20, the time dependent values start at 750 deg F for SA 516 Gr 70.

 

[TGS4]

For the first time that I can recall, I am actually going to disagree with metengr . The italics that he refers to are when the allowable stress becomes governed by time-dependent behaviour.

However, that is NOT when creep starts. For that, you will need to refer to API 579-1/ASME FFS-1, Table 4.1, titled "Temperature Limit Used To Define The Creep Range". Here, you will find that the creep range actually starts at a lower temperature than would be inferred by the italics method in Section II, Part D. SA-516 Gr. 70, being a carbon steel with a UTS > 60 ksi would start the creep range at 700°F (371°C).

 

[metengr]

TGS4 you are technically correct, if you only accept FFS-1 versus ECCC versus NIS creep-rupture data and definitions. I could disagree on the temperature when creep-rupture begins as defined by FFS-1 versus the approach by Section II, part D. I am going on memory here but the European Creep Collaborative Committee (ECCC) publishes an even lower threshold creep temperature than what is published in FFS-1 or even the time dependent value in Part D.

 

[DSB123]

TGS4, Metengr,
Agree with you on the lower temperature at which creep starts but it is hard to convince people of this.

 

DSB123,
If it can happen it will happen, somewhere, sometime. Materials are perverse that way.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[pradipgoswami]

Hi Mech212,
In addition to the guidance provided by metengr, you may find additional resources at this link

http://www.ommi.co.uk/etd/eccc/advancedcreep/DSheets05ax.pdf.

The steel specifications mentioned in these data sheets conforms to European Specifications. However nearest ASME/ASTM equivalence could always be found by proper searches.
Hope this would help you.
Thanks.


Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist
Ontario,Canada.
ca.linkedin.com/pub/pradip-goswami/5/985/299

 

[DSB123]

ironic metallurgist,
Eh????