308 vs 314 stainless steel

[EngineerDave]

Metals Handbook defines very similar properties for both 308 and 314 stainless steel.

Is there any reasonable justification for the use of 308 vs 314?

 

[mcguire]

These are grades only used for welding rods. They have slightly higher alloy content than the base metals with which they are intended to welded. This is because welds are not homogeneous because of their as-solidified structure which can leave some regions under-alloyed.

 

[unclesyd]

I'll have to give "mcguire" half credit.
Both alloys are produced in all forms though wire being the
biggest use.
314 S/S is widely used in used the fabrication of mesh belts for ovens of all kinds. Due to its' composition it has the highest heat resisting properties of the straight Cr-Ni grades. I don't have the data and the link is dead, but as I remember it, the continuous use temperature was around 1050°C.

308 S/S is also used in mesh belts but is primarily used as welding wire for 304 S/S. The continuous use temperature is 980°C

 

[EngineerDave]

Unclesyd, this is just the application I am interested in. I need to compare the meshbelt temperature properties of 308 and 314 and possibly others to see if one is better.

You stated the continuous use data link is dead. Are there any other good references for this. ASM volumes and Metals Handboooks seem to be lacking.

Interesting ASM Specialty handbook on Stainless reveals that the maximum service temperatures for 308 are the following: Intermittent service 925 degrees C (1700F) or 980 degrees C (1795F)for continuous service.

No data is included for 314, I'll have to go with what you say.

Real dumb question here though. Why would the intermittent service be lower than the temperature listed for continuous service?

 

[Metalguy]

"Why would the intermittent service be lower than the temperature listed for continuous service?"

Cracks in the thin protective oxide layer from thermal cycling.

 

[unclesyd]

Here are some websites that have 314 S/S wire mesh belts. I don’t see any with 308 S/S. Go with what’s available if possible.

http://www.wire-mesh.com/index.html

http://www.meshbelt.com/index.html

http://www.davieswovenwire.co.uk

http://www.cambridge-inc.com/index.html#