At what temperature is steel at its strongest?

[Qaiphyx]

^^^

asdf

 

[Qaiphyx]

What?

Like, steel at 240 degrees is weaker than at room temp, cause the heat energy weakens the bonds in the metal, or like when you hit it with liquid nitrogen and hit it, it will shatter, cause the bonds become weaker at those temps than at room temp.

 

[phlegmy]

well for starters i don't know for sure. but:
yes generally stell weakens as it gets hotter, and becomes softer.
when its cooler it becomes stronger, but more brittle

also something can be quite strong and yet very brittle, i know it sounds strange but glass for example is actually quite strong, but as most ppl know, quite brittle.

also a quick google threw up
http://cr4.globalspec.com/thread/5058

 

[turbo]

There are MANY different alloys of steel, and they all have their qualities, weaknesses, and strengths. Your question is too vague and too broadly posed to get a reasonable answer. For instance, there are some steels that (properly tempered) can be used to make tools for use in machining operations that have to either dissipate a lot of heat, be moderately cooled, or be bathed in coolant during operation to maintain their edge. This is a high art. Tool-makers who can select alloys, shape the tools, temper them, establish proper cooling during machining and set cutter feed-rates that can optimize finish quality and tool longevity are wizards. They can make or break a machine shop.

 

[Qaiphyx]

well for starters i don't know for sure. but:
yes generally stell weakens as it gets hotter, and becomes softer.
when its cooler it becomes stronger, but more brittle

also something can be quite strong and yet very brittle, i know it sounds strange but glass for example is actually quite strong, but as most ppl know, quite brittle.

also a quick google threw up
http://cr4.globalspec.com/thread/5058

Right so there should be an average point of temperature that a certain material is most structurally sound right? Where its less likely to break when induced to kinetic energy. How much could different steels differ?

 

[DaveC426913]

Right so there should be an average point of temperature that a certain material is most structurally sound right? Where its less likely to break when induced to kinetic energy. How much could different steels differ?

Consdiering they use different materials in different temperatures for that very reason, they differ quite a bit.

For example, titanium is used where high temperatures ar common, such as supersonic airplanes.

 

[Mapes]

Qaiphyx, you're overly simplifying the question of maximum strength. There's no one number that reaches a maximum, then decreases. The tensile strength decreases with increasing temperature, while the fracture toughness increases with increasing temperature. The optimum temperature will vary depending on load, load rate, geometry, even surface finish.

Like, steel at 240 degrees is weaker than at room temp, cause the heat energy weakens the bonds in the metal, or like when you hit it with liquid nitrogen and hit it, it will shatter, cause the bonds become weaker at those temps than at room temp.

The bonds are not weaker at low temperature. Rather, the bonds are stronger and less ductile, and it becomes favorable for a crack to propagate right through the material instead of terminating in a plastically deformed area.

How much could different steels differ?

Certainly a huge amount! Take a look at any metallurgy textbook, I think you'll find it very useful in clearing up your questions.

 

[Qaiphyx]

Qaiphyx, you're overly simplifying the question of maximum strength. There's no one number that reaches a maximum, then decreases. The tensile strength decreases with increasing temperature, while the fracture toughness increases with increasing temperature. The optimum temperature will vary depending on load, load rate, geometry, even surface finish.



The bonds are not weaker at low temperature. Rather, the bonds are stronger and less ductile, and it becomes favorable for a crack to propagate right through the material instead of terminating in a plastically deformed area.



Certainly a huge amount! Take a look at any metallurgy textbook, I think you'll find it very useful in clearing up your questions.

Hm, got ya. Good response.

 

[FredGarvin]

Just to throw something into further mess up the original notion...one can have different heat treatments of the same alloy that will perform differently.