Solution Anneal vs Heat treatment U-Bends (UCS-56)

[OscarAb]

In regards to post-forming heat treatment of SA-179 U-bends for a thickness of <= 0.134" via

Soak time (15min) at temperature (1150°F)(ASME Section VIII, Division 1 UCS-56)
vs
Brought to temperature via electric resistance (no soak time) to temperature (1150°F)

1. Has anyone studied the effects of hardness and grain structure analyzing the differences between the two?
2. Can anyone point me to an article describing the differences?


Thank-you.

 

[EdStainless]

Isn't the temp in the spec 1200F min?
For these low C grades the hold time is not needed.
You are just aiming for strain relief, there is no phase change or diffusion involved.
And likely you only need it for the inner 5 or 6 rows, beyond those the strain levels are very low.
Some mills need to HT ubends in order to control dimension.

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