high heat effects

[JTPE]

Can someone give me an idea or reference for infomation on the effects of high heat on A36 steel properties. What happens to Fy and E at temperatures around 1500 deg C (2730 deg F)

THANKS

 

[Goahead]

Iron melting point is reported as 1536.5 C (2798 F).
No mechanical properties to speak of.

http://www.welding-advisers.com/

 

[Metalguy]

I imagine you meant 1500 F. Even that temp is way beyond what A36 should be used at.

 

[JTPE]

Thanks.

The steel in question is part of a burner lance in a cement kiln...1500 deg C. The lance is encased in a refractery, but I was curious what effects temperature has on the steel alone. I suppose it is not a valid question, the refractery must be there or the steel will melt.

Forgeting the high temperature of the kiln, is there a rule of what happens to yield stress and modulus at high temeratures?

 

[NickE]

the rule is they both go down. Modulus varies linearly as temperature. and If I remember correctly Yield remains relatively stable until the strengthening mechanism for the material is exceeded. Then it falls off rapidly.

I think its MIL-HDBK-5J that has the graphs of modulus vs temp.

 

[Metalguy]

YS can actually drop so fast you wouldn't believe it. I've measured something like a 30% drop at 500 deg F. in both A36 and some low alloy steels. It varies greatly even with diff. heats-never could figure out why.

You'd expect this w/alum. alloys but it happens with steel too.

 

[stanweld]

Metalguy,
When I was in the steel making business, A-36 was next to the bottom of the barrel; only steel "lower" being continuous butt welded "Fence Post". A-36 was a dumping ground for high strength materials that didn't meet chemical requirements. The permitted chemistry variations and melting practices of A-36 gaurantee substantive changes in mechanical properties with temperature from heat to heat.