How to differentiate between 316 and 316L based on material composition.

[CSunny]

I am having some confusion if the material I have is 316 or 316l. This is a SA-249 Stainless steel tube. Based on the material composition and strength requirements, the material fall into both.

If I consider the tube as 316, I could use the HA2 chart for external pressure and the required thickness for the tube will be less than the HA4 chart for 316L. So, how should i approach it?



C Mn P S Si Ni Cr Mo Ti
Actual Tube 0.029 1.43 0.026 0.018 0.41 10.18 16.25 2.1 -

 

[EdStainless]

If it qualifies as 316L then you must design as 316L.
You don't get to do one part of the design calling it 316, and another part calling it 316L.

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

 

[dig1]

What does the MTR say? If it is 304 regardless of the carbon content being less than 0.08 then use the appropriate properties. If the MTR calls it 304L even though the mechanicals are higher then use those.

 

[CSunny]

@EDStainless. The carbon content of the material as per the MTR is 0.029%. Do this mean the material is both 316 and 316L? The mechanical properties also meet the requirements for both 316 and 316L. So, i am wondering what grade this material belong to?

 

[SnTMan]

What does the MTR say?

What does the MTR say? It'll say it is one or the other or dual certified.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[CSunny]

@SnTMan If the material is dual certified, is it ok to use the stress values and charts for 316, which is higher?

 

[XL83NL]

Yes. Refer to one of the appendices in ASME IID for more details on the use of dual certified markings.

Huub
- You never get what you expect, you only get what you inspect.

 

[Christine74]

If your client requires 316 and the material is dual-certified 316/316L, you can use the higher strength 316 as the basis for your calculations if you list 316 with an asterisk as the on the Manufacturer's Data Report. Then in the Remarks section you can state that the tube material also meets the metallurgical requirements of grade 316L.


-Christine

 

[SnTMan]

CSunny, yes you can, but you have to completely treat it as 316. No mixing properties between the two.

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[Krausen]

The best way to avoid this headache is to ensure you are getting dual cert SA249-316/L material & use the higher stress values for 316