DIN 2635.C PN40 Pressure Temperature ratings

[CSGWB]

I am currently looking at a piece of pressure equipment fitted with Flanges nominated as "PN40 NFE29225/DIN2635.c C22.8 VD TUV 350".

I understand that these are essentially a 40Bar Flange from Carbon Steel, however I am not sure what the pressure rating at the design temperature (50C)would be for this material. Can someone assist?

Is it as simple as 40bar up to 200C (for example)and after that the pressure rating tapers off as temperature increases?

Regards

CSGWB