I seem to recall that the onset of creep in plain carbon steels occurs at around 430C (800F). Pressure vessel design codes would be the best source of accurate information.
Don’t forget that yield stress and modulus of elasticity are also temperature dependent.
Further to the above, Australian Standard AS1210-1997 “Pressure vessels” seems to infer that the upper temperature limit on plain carbon steel plate (equivalent to ASTM A283-D) is 350C (660F).
Some carbon-manganese and low-alloy steels have temperature limits up to 650C (1200F), albeit with very low design tensile strength.
Thanks dbuzz. The steel is typically grade 43 and grade 50 steel, which relates to a UTS of 430, etc., I believe.
Does operating at these high temperatures have an effect on the material properties of the steel over time, besides the effect of strain accumulation from creep?
I’m not familiar with your Grades 43 and 50. FYI, the steel I’ve mentioned above has a tensile strength of 410MPa and its composition is 0.22%C and 1.7%Mn with up to 0.3%Cr, 0,1%Mo, 0.5%Ni and 0.5%Cu.
According to the Australian standard AS4100-1998 “Steel structures”, at 350C the yield stress ratio is 0.80 and the modulus of elasticity ratio is 0.85. However, according to AS1210-1997 “Pressure vessels” the design tensile strength at 350C is just 79MPa.
Is your application for a pressure vessel or is it for structural steel in a high temperature environment.
Thanks Stephen, I haven't got BS 5950 but I'll try and get a copy.
For dbuzz, the answer to both questions is yes.
Is there information on the effect of age on steel and the possible degradation of material properties, regardless of whether or not it's operating condition was at high temperature?
