Yield strength of P11 material above 525°C 1

[Dutch-EGR]

Hello,

I'm in surge for Yield strength of A335 P11 materials at temperatures above 525°C.
Allowable stresses go upon 650°C in ASME II. Yield stops in ASME II at 525°C.
I found tables in PV Elite but to me they are not really trustworthy at these temperatures.

Those somebody know an solution or literature about this?

Thanks!

 

[MJCronin]

... and by "surge" I assume you mean "search"

ASTM/ASME P335 P11 is a low alloy product configured as piping (1.25 Cr - 1.0 Mo) intended for use in moderately high temperature applications
________________________________________________________________________________________________________________________________________

About ASTM A335 P11 Pipe From: -----

https://www.usmetals.com/alloy-pipe-seamless-p11.html#:~:text=P11 Pipe Applications,Spacecraft

Trade Name: 1 ¼ Chrome
Grade: P11
UNS #: K11597
Pipe: A335/SA335
Forged/Bored Pipe: A369/SA369

Chromium and molybdenum are important elements of P11. Chromium, or chrome, improves high-temperature strength, increases oxidation resistance and raises the tensile, yield and hardness at room temperatures. Molybdenum increases the strength, elastic limit, resistance to wear, impact qualities and hardenability. It increases the resistance to softening, restrains grain growth and makes chromium steel less susceptible to embrittlement. Moly is also the most effective additive for increasing high temperature creep strength, or creep resistance. It also enhances the corrosion resistance of steel and inhibits pitting.

___________________________________________________________________________________________________________________________________________
Regarding its use at elevated temperatures:

"The material P11 is especially suited for steam boiler, boiler parts, boiler drum, pressure vessel for the apparatus engineering and similar purposes. It can be used in permanent operation with wall temperatures up to about 590 °C '1094 °F+."

It has been my experience that,over the decades industry has moved away from P11 in favor of it's big brother, A335-P22 ...

The move to the slightly more expensive P22 is because of occasional temperature spikes possible in long-term operation. P11 is considerably more susceptable to creep failure where there are spikes above 590C than P22

There is a long sorry history in thermal power plant operation where P11 Main Steam and Reheat Steam piping has catastropically failed (creep failure) after many years of usage. There were deaths ..... It was most often replaced by P22 (or better) piping materials.

https://www.eng-tips.com/viewthread.cfm?qid=246903

https://www.eng-tips.com/viewthread.cfm?qid=114837

Can you tell us more about your project ???

MJCronin
Sr. Process Engineer

 

[Dutch-EGR]

Hello MJCronin, I’m indeed in search of information. Sorry English is not my native language.

This has to do with a fitness for service assessment.
We have in a running plant a special problem with P11 that’s is under corrosion attack.
This only happened after the previous P11 part was renewed after 30years of service without problems.
The phenomenon Carbonisation and Metaldusting appears in a wedge looking pattern.
We have some hypotheses why this is happening.
To solve it we will use another type of material that is less or not susceptible for this type of problem.

Until we have new material we are monitoring the thickness reduction, unfortunately with everything happening in the world right now delivery times are very difficult.

The problem is that I need some extra info on the yield and tensile strength of the material for a proper FFS. Problem, ASME II does not give me these only upon 525°C.
What is strange to me is that ASME gives allowable upon 649°C.

In my PV elite program values are given, they do not really look trust wordy.
For example; Allowable stress @649°C is 8.2 MPa, the given yield @ this temperature is 9.1 MPa.

Thanks for helpful information.

 

[Christine74]

There are a few materials for which the Section II Part D allowable stress values have a higher maximum temperature than the yield strength values shown in Table Y-1. So far I haven't found a source for high-temperature yield strength values, and I don't recommend attempting to extrapolate the published values. Sorry I know that's not much help.


-Christine

 

[GD2]

Dutch-EGR,

What is the temperature for the FFS Evaluation? You can use an analytical method to compute the YS as a function of temperature given in API STD 530. A335 P11 can be used upto max temperature of 621 degree C per API STD 530.
API 579 allows this computation to be used in FFS evaluation.

GDD
Canada

 

[EdStainless]

What is the code allowed stress at those temperatures?
You might be able to work it out that way.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[Dutch-EGR]

@ Ed stainless, Code allowable at 649°C is 8.2MPa.

@ GD2, The working temperature is 560 to 580°, design 649°C.
Thanks for the idea, in API 530 usable tables are given.
I think I can work this out further.

Thanks for all your idea's.

 

[GD2]

Dutch-EGR,
Perhaps A335 P11 was the material at that time when the equipment was constructed but surely it has been applied above its normal application range of 427 - 552 deg C. Present day will use P91/P92 in this temperature range.
An integrity management system must be in place to monitor the P11 tubes.

GDD
Canada