Thermal Shock of Pipe - How big of a temp differential is needed?

[ad911001]

Hello - We are looking at pressure testing some pipe. It will be a heated test with the fluid heated to ~80C. It will then be introduced to the system of heavy walled, #1500 carbon steel pipe that may have cold spots on exterior sections as low as -25C. I feel like the temperature differential and the heat transfer will be low enough to be safe. Does anyone think any ill effects may come of this?

 

[BigInch]

Using 0F as the no thermal stress point, stress on the hot side of the wall has the potential to reach +34320 psi while the cold side could reach -2535, the net being 34320 --2535 = 36855 psi. If each was applied to opposite sides of a pipe wall, then the 36855 psi would be the effective shear stress in the pipe wall. More than enough to fail mild carbon steel.


Independent events are seldomly independent.