Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

At what temperature is steel at its strongest?

  1. Jun 29, 2008 #1

  2. jcsd
  3. Jun 29, 2008 #2
    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.
  4. Jun 29, 2008 #3
    well for starters i dont 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
  5. Jun 29, 2008 #4


    User Avatar
    Gold Member

    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.
  6. Jun 29, 2008 #5
    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?
  7. Jun 29, 2008 #6


    User Avatar
    Gold Member

    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.
  8. Jun 30, 2008 #7


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    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.
  9. Jun 30, 2008 #8
    Hm, got ya. Good response.
  10. Jun 30, 2008 #9


    User Avatar
    Science Advisor

    Just to throw something in to further mess up the original notion...one can have different heat treatments of the same alloy that will perform differently.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook