B31.1 Temperature Ratings

I know they had some problems with fatigue cracking on the Comet airliner and low-temperature embrittlement on the Titanic, though you won't see -425F very often on this planet.

If I recall my old metallurgy classes, low carbon steels will start to lose tensile strength around -45F. You will want to carefully research the low temperature strength characteristics and determine how much you might want to derate the material used based on the internal and external temperatures that might occur.

Operating below -20F carbon steels (A106, A53, A36)are susceptable to brittle failure.

Special Nickel bearing carbon steels have been developed for operating in that temperature range.

Austenitic stainless steels (304, 316) are not susceptable to brittle failure in this temperature range

www.shipstructure.org/pdf/65pdf

http://www.nationalboard.org/index.aspx?pageID=164&ID=192

Thanks everyone for replies. Abdel, good job as usual, -50F would cover it. Matrix99, this is the specific answer I was looking for. So far it does look like they're chemically similar, are you aware if they are heat treated in a different manner to reduce brittleness at low temps? I bought A333 to review specs, I'll do the same with A106 and A53 and see what there is to see.