Hi,

According to the me, thermal bowing will only occur when the top of pipe and bottom of pipe will have a different temp. So if you are using operating temp as -180 deg C with thermal bowing temp as 50 deg C, Then it is correct (according to me). kindly make sure you are using the hold down guides at regular interval (not the conventional guides support).

We also had faced lots of issues because of this, it will be better if you can share the pic where it is failed, so it gets more clear.

One more thing, if the bowing is casued by end reactions on the piping system, then increased flexibility plus spring loaded support can solve your problem. Hope this helps.

Regards,
R.K.