When to normalize?

weo

weo

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Sep 21, 2014
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Hello all. I think I understand the basics of normalizing, and this question is related specifically to my current forging practice.
I focus mostly on damascus blades and don't have any power forging equipment in my current set-up. So what I do is: forge weld up a billets in my shop, then within a few days, I can get to a friend's shop and use his power hammer to draw out them out. Go back to my shop to grind, cut, re-stack and weld, then back to his shop to draw them out, etc. Once I have the number of layers I want, i forge, normalize, heat treat and finish the blades at my place.

My question is: should I normalize my steel after each forging session, or am I OK just normalizing once after the final forging?

Thanks.
 
but for future reference, what are the steels that should be normalized after each session?
 
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Normalize between steps when using steels that are prone to air hardening even though they are oil hardening. O1 in this case. O1,O2, L6, and cru-v are some to watch out for. 1080/84, 1095, 15n20 etc. shouldn’t create too much stress between cycles. Always finish forge at the lowest possible temperature.

Hoss
 
Your post indicates you are using simple carbon steels, like 15n20, 1080, 1095, O1.

After forging, as long as you practiced good forging techniques, there is only the need to “normalize” once. After the “normalizing” cycle has been done, the advice is to “thermal cycle”. This is done close to the steels “critical” temperature, and roughly 3 times. The terms are often used interchangeably (normalizing vs thermal cycling), but there are differences between the two. Normalizing is about stress relief from the forging process and carbide refinement (in the steels we are discussing). Thermal cycling is about overall grain refinement, shrinking the grain structure by fitting more within a given volume.

For the steels you mentioned, after forging, normalize at 1650f, soak, air cool. Then “thermal cycle” around 1500f 3x, air cool. You are now ready to harden (austentize and quench).

Bottom line....after all forging is done.....normalize once....thermal cycle 3x.....austenitize/quench. That’s a rough guide.
 
Sorry to hijack thread weo but after forging o1 I done a 2 hour 1200f thermal cycle then normalised 1650 to cool
1550 to cool.1450 etc then 1350 etc and 1250 to cool
Is that acceptable or have I been doing it wrong
 
With most all carbon steels it's good advice to dial down the heat as the cross section of the blade diminishes. If you cut out, profile a blade from your 15n20 mix, lower the working temperature as you forge close to finished geometry. I forge with well head gas , in a blown forge, as the blade thins, the temp goes down. Forge at 2000 or a little higher and finish out at 1650; in this way you will be refining grain as well as lowering the stress in the forged blade. Make it part of your process. There is a good deal of things to learn in this craft.

Regards, Fred
 
Thanks Fred, and great advice. I hope I can remember that when I get to that stage with my current billets
 
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