Elevated Temperature Yield Strength AISI 1340 1

[redpicker]

Does anyone know what the yield strength of 1340 steel would be at 1500 deg F?
How about 4140 at the same temperature?

The best info I can find tells me it should be around 10,000 PSI for either material. Anyone have any better data?

Thanks

rp

 

[InTheField]

just saw your posting - I'll check tomorrow, I don't have the source with me right now.

 

[InTheField]

okay - nothing on 1340 - sorry - if it helps ASTM A 829 is equivalent to 1340.

For steels with over 0.3% carbon I do have some info on the modulus - it drops well below 15x10^6 psi above 1200-F I don't know about its suitablility for use over 1200 F

Sorry - nothing on 4140 - guess I wasn't much help

 

[RPstress]

Some limited data on 4140: 1500 F is in 4140's annealing range. Extrapolating wildly, the yield strength could be reduced to 3-6% of it's RT value. (This is from MIL-HDBK-5, and may not really be appropriate for annealed properties, never mind the extrapolation. The temperature knockdown graph goes up to 1200 F, where yield is 22% of RT.)

According to ASMH, the RT annealed strength of 4140 is 60 ksi. The strength at temperature data in ASMH only goes up to 1000 F max. However, ASMH gives creep for annealed material at 1200 F. At 1200 F and 10 ksi you'd be greeping at 1% strain an hour, and the creep rates are shooting up. It looks from that as if 4140 at 1500 F isn't really good for much in the way of load. (Kind of unsurprising. NB: max use temperature is about 1025 F for softer tempers.)

 

[redpicker]

Thanks for the help.

I have a shaft made from either 1340 or 4140 (will get an analysis soon) that failed in tension. Reports are that the mateial may have exceeded 1500 deg F during service and I am trying to determine what the load was at failure.

rp

 

[CoryPad]

Table 2 in ASM Handbook Volume 14 Forming and Forging, section Precision Forging -> Selection of Process Temperature shows the Yield Stress of 4140 at 1500 [°]F to be 11 ksi.


Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.