2 replies to this topic

[sameercnn]

Dear elites,

 

How to calculate furnace heater tube failure due to continuous exposing temperature above the max tube metal temperature. is there any thumb rule to know this like material deformation or is there any calculation to know this.

 

for example if we use or expose temperature to tube continuously for more than max tube metal temperature when the  tube will start failing or deforming?

 

please advise me on this.

 

thank you,

 

regards,

Sameer

[Saml]

Furnace tubes are usually designed for a certain number of hours (ie: 100 000) until strength is limited by creep. 

Time to failure vs temperature is usually described following a Larson Miller parameter that is dependent of the tube material.

 

But (taken from Wikipedia, and quite valid for a case I have calculated)

"Typically a 5% increase in absolute temperature will increase the rate of creep by a factor of ten"

[sameercnn]

Thank you sir.