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I Forge Iron

the importance of temperature control and normalizing


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That's a very nice demo! Good photos too! I have to confess that I rarely normalize anything... but I am careful not to overheat and I do work my metal fast and hard while it is hot. I also try to minimize heating areas that are not being worked. In future I will be more alert though and normalize whenever I am not real confident of my ongoing grain control.

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Some steels are so high in alloys that it's difficult to grow the grain. That's true. (S1 has quite a bit of chromium and a bunch of tungsten, for example, both of which inhibit grain growth.) But in line with what you're saying, Thomas, those tend to be steels that most of us lack the capacity to HT properly, anyway. (E.g., the recommended hardening procedure for S1 is, "Heat slowly. Preheat at 650 C (1200 F). Austenitize at 900 to 955 C (1650 to 1750 F), hold for 15 to 45 min, then quench in oil.)

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Matt thanks so much for posting this. It is a procedure I have shown to several folks in my shop for along time. And In fact the pics are so much easier for folks to view rather than trying to see in their mind. I wrote the procedure up in almost every step not long ago in this chat room for a newcomer to try in his shop. I did take it one step farther if anyone would like to give it a go: I over heated the steel another time and then normalized three times before breaking. It may surprise you with the results.

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Interesting demonstration but slightly less than scientific. Were the pieces heated to exactly the same temperature and were they held at temperature for exactly the same time. Every published document that I have been able to find says that normalizing is a function of time at temperature. That is the metal is heated to the correct temperature for the alloy, and the temperature varies considerable from one alloy to the next, and then the steel is soaked at that temperature for a given period of time. Then the steel is allowed to air cool. On page 69 of Metallurgy of Steel for Bladesmiths & Others who Heat Treat and Forge Steel John D. Verhoeven Emeritus Professor Iowa State University it shows how heating the steel to 1450 degrees F holding for 4 minutes and then quenched in rapidly stired oil 3 times reduced grain size in 1045, 1086 and 5150

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I'd say it was very scientific. They were clear that they were using a single steel and varied heats to observe the result. It demonstrated their intention very well.

If I wanted to know the same about 1045 or 5160 I would repeat the same experiment on each of them. Who knows... you might find something different.

I'm grateful to folks that will go to that much trouble and then freely share their findings.

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