3 ms·
What do you mean by Handle? Steel won't melt at 300-400 Celsius but "handling" those temperatures for 10 minutes will change the properties of the material, po
by fluffything 7y ago
What do you mean by Handle?
Steel won't melt at 300-400 Celsius but "handling" those temperatures for 10 minutes will change the properties of the material, possibly by a lot, so you don't need "melting" for structural collapse (Twin Towers style).
As the GP says, if you put cold rolled steel, which has an elastic yield strength of >1500 MPa, at 300-400 Celsius, then it is only a matter of time (30-120 min) till the elastic yield strength sinks to 500 MPa or less.
So either this is a single use device, or the steel isn't reaching temperatures over 250 Celsius, or the steel isn't cold rolled but is a low strength steel instead (although that would have other problems).
- ricardobeat 7y agoRe-entry will take something on the order of 10m or less. Even the space shuttle only took 30 minutes while flying like a plane. There will be no circumstances where the ship is going to be subjected to that amount of heat for 30-120 minutes. > or the steel isn't reaching temperatures over 250 Celsius That might be the case. The space shuttle had an aluminum structure that would fail at 175C, and now we have 40 years of technology advancements for the heat shield.
- strainer 7y agoAlso I notice Cr-Steel's elastic yield strength at 400C is about 87% of its strength at room temp and I don't think it does alter significantly over these timescales at that temperature. It will be interesting to see how high it can be routinely cycled without losing its temper, but it seems to certainly provide much more overhead for safety margins as well as routine operation. [1] https://www.engineeringtoolbox.com/young-modulus-d_773.html https://www.engineeringtoolbox.com/young-modulus-d_773.html
- deleted 7y ago[deleted]