I watch a YouTube channel by Alec Steele where a lot of metal forging is done. From this I know that varying the carbon content in steel drastically alters the physical properties of the metal, as does different heating cycles (time for cooling and temperature of the forge). I am interested what is happening at the atomic structure during the forging process.

Here are some of my ideas on what is occurring. I think cooling time must affect the grain size of the steel microstructure. I have a vague idea that grain size affects material strength but I don't really know why. I also assume that the crystal structure varies with temperature. At a higher temperature, higher energy polymorphs are probably observed. I know adding carbon to the iron increases the strength of the material but again I don't know why. I assume there is some pi - d bonding occurring which may act akin to semiconductor doping, adding energy states for Fe electrons to populate, increasing metallic bonding?

This does not answer my question: What chemical characteristics give types of steel their properties? I am looking for an answer more focused on bonding and energy level population.

  • $\begingroup$ To know how steel works you need to know about all this stuff like pearlite, ferrite etc. - it's their structure, and transformations, not some energy states. For example graphite can be dissolved in Fe or not. There can be even stuff like nanotubes found in some steels. It's generally quite complex and seems not exactly as you imagine. $\endgroup$
    – Mithoron
    Dec 16, 2019 at 22:46
  • $\begingroup$ @Mithoron the question is legitimate so either answer it or don't. Posting 'oh you're so thoughtless' isn't what this forum is for. $\endgroup$
    – Bertram
    Dec 17, 2019 at 1:37
  • $\begingroup$ @Joe, there is a difference between physical and chemical change, and both effects occur in steel making. Chemically, carbides and intermetallic compounds form, and physically, there are differing allotropes, separation of phases, sizes and shapes of crystals, usw. $\endgroup$ Dec 17, 2019 at 1:53
  • $\begingroup$ @Bertram I agree with your core message. I would still like to point out that this is not a forum. Comments (should) aim to improve and clarify a question. Some of the aspects mentioned here are indeed addressed in the other question, albeit not in that clear words. || Joe, this question needs a bit more focus, there are currently a few close votes on it. $\endgroup$ Dec 17, 2019 at 13:53


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