[TheForge] Normalize vs Annealing prior to hardening

[James Binnion]

Yes there is a difference in grain structure and mechanical properties between annealed and normalized. Normalizing will if done right remove strain on the crystal matrix and provide a more uniform grain structure. Annealing is normally done to make the steel as soft as possible and may lead to grain growth.

On Jun 4, 2013, at 4:09 AM, Paul wrote:

> Thanks James,
> Do you know if the normalizing differ substantially from the annealing (at least as I've described it) ? My guess is that if I get the piece up past critical, assuming a uniform temperature throughout, and stuff it into a drum of vermiculite, that it will stay hot enough for the grains to stabilize (essentially soaking for an extended, although uncontrolled period of time).
> 
> Without a controlled furnace and atmosphere (to prevent excessive scaling and decarborization) the "slow cooling" method seems like a reasonable compromise. What I hope to learn is what trade-offs I'm making by my choice in process.
> 
> Thanks,
> **Paul
> 
> On 6/4/2013 2:06 AM, James Binnion wrote:
>> 
>> To normalize one needs to hold the steel 100F above the austenizing temperature for an extended period of time (15 min-1 hr) then air cool. This extended time is needed to allow all the steel to convert to an austenite grain structure. This will result in a uniform, fine pearlite grain structure upon cooling. Whether you should do it will depend on the steel you are working. If the steel air hardens then normalizing is not a good idea because it can lead to cracking in the steel. So W-1, 1095, O-1 etc will benefit from normalizing but high alloy tool steels (A2, D2, H13, S7 etc.) are typically not considered good candidates for normalizing.
>> 
>> James Binnion
>> jbin at well.com
>> 
>> 
>> 
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James Binnion
jbin at well.com