Killed carbon steel- for desgin temp of 485 deg c 1

[PV design Engr]

My Licensor had specified killed carbon steel for a column for design temperature of 485 deg C. Since SA516GR70 falls under creep for this temperature, can I ask Licensor to propose P11 or P12 for this case. Is it advisable to use SA516GR70 for this design temperature.

 

[weldstan]

SA516 no. SA515-70 maybe since you have not provided any service details othe than design temp. Can you ask for Grage 11 or 12? Of course.

 

[MJCronin]

Your Licensor has no background in metallurgy and no understanding of the effects of creep on carbon steel. Having a killed or non killed steel has no effect on high temperature performance.

There may be an opportunity to save money by going with a thinner walled, but higher alloy material

https://www.tiogapipe.com/newsletter/issue2_p_grades.aspx

At a design temperature of 485C (~905F), you are well within the region where carbon steel will degrade under long term service.

As a background review, I suggest that you review the material and temperature limitations for carbon steel piping contained within ASME B31.1 and B31.3. Both put a design temperature maximum of ~775 - 800F for simple carbon steel. Above that limit Chrome-molly steel (e.g. ASME A387 P11 or P22) materials should be considered)

You should note that P11 materials have a very narrow high temperature range where they can be used ..

Many organizations have a policy where they do not use P11 materials and simply use the (slightly) more expensive P22 or higher grade materials.

There have been many threads on eng-tips discussing this topic

https://www.eng-tips.com/viewthread.cfm?qid=415661

MJCronin
Sr. Process Engineer