Does this sound right for a 1084 heat treat?

[dukesilver]

Hey guys,

I'm in the middle of making my first knife and I'm going to attempt to heat treat it this weekend. The knife is made for 1/8" 1084 from Aldo. I have done some searching on this forum and others for the proper heat treating regimen and have encountered some varying opinions. I have tried to parse all of these together into a plan:

Normalize: heat to 1500F and air cool to ambient temperature
Austenitize: heat to 1500F and then quench to with 120F canola oil
Temper: 2x 2 hour cycles at 400F

Does this sound like a good plan. I am open to any suggestions or hints. I will be using a crude firebrick forge. To judge temp I will be using a magnet and color (heat treating at night). Tonight I practiced getting a nice even heat on an old file. It worked ok but too longer than expected to get to non-magnetic. Also, the blade looked orange to me rather than cherry red when it became magnetic so I can see why using color to judge temp is not a good system. Thanks for all of your help guys. I have learned a ton from reading on this forum.

 

[NC Biker]

Here is what I picked up from Stacy and I get really good results following this recipe:

Here is a basic HT regimen for 1084:
1084 HT:
refine grain and normalize -
heat to 1500F and air cool to black, then quench to cool
heat to 1350F ( just non-magnetic) and air cool to black, then quench to cool
heat to 1200F ( still magnetic) and air cool to black, quench to cool
Straighten any warp or twist

Austenitize-
heat to 1500F and hold long enough to allow the blade to be evenly heated
quench in a fast quenchant (or as fast as you have, canola will work for all but big blades)
Check for warp after holding in the quench oil for 5-8 seconds. Straighten immediately. Stop after about 20-30 seconds, as the blade will be too cool and may break.

Temper immediately at 450F for two hours, twice. Quench in water to cool between temper cycles.
( If there is any warp after the blade cools, it can usually be straightened while at tempering temperature. Let it heat for 30 minutes before any straightening.)

 

[jdm61]

1500/400 will give you a hardness in the 60-61Rc according to Mr, Cashen and others assuming you got everything right. I have found no need to go any softer than that.

 

[Rancho5]

I didn't think you had to normalize Aldo's 1084 because it comes normalized already. I thought you Austenitize and then temper and then you're done. Am I wrong?

 

[i4Marc]

Rancho5,

I think you might be confusing annealed and normalized.

 

[Stacy E. Apelt - Bladesmith]

That sounds good.

Normalizing is to remove any stress from forging and get the alloys distributed. If you ground it from bar stock, it really isn't needed,, but I do what you listed most times just to get a dry run at judging the austenitization temp.

It will take a little while to heat the steel up to non-magnetic and then to 1500F,...... and that is good. Doing it too fast with too much heat is an easy way to go far past the target temperature.

 

[Rancho5]

Rancho5,

I think you might be confusing annealed and normalized.

Thank you. I'm new at this and there are lots of terms to remember. It looks like even after all my reading I may have missed a step?

So if doing stock removal I THOUGHT you heated past non-magnetic, then quenched in oil, then baked in your oven twice. But from the OP I see I need to do a step before this and heat to 1500 and let air dry. Is this correct?

If so I'm wondering how I missed that first step in all my reading. Glad I read that post.

And from reading Stacy's post, the first step isn't critical but it's helpful for practice on getting the temp right.

Does normalizing help the quality of the blade?

 

[dukesilver]

Thanks for all of the responses guys. I feel much more confident going into this now that my plan has been approved by the pros.

Thank you. I'm new at this and there are lots of terms to remember. It looks like even after all my reading I may have missed a step?

So if doing stock removal I THOUGHT you heated past non-magnetic, then quenched in oil, then baked in your oven twice. But from the OP I see I need to do a step before this and heat to 1500 and let air dry. Is this correct?

If so I'm wondering how I missed that first step in all my reading. Glad I read that post.

And from reading Stacy's post, the first step isn't critical but it's helpful for practice on getting the temp right.

Does normalizing help the quality of the blade?

Rancho5, obviously I'm new to this but this is my understanding of normalizing. Normalizing helps to refine and reduce the grain size of the steel. The smaller the grain sized the finer edge you can put on the knife so normalizing can increase the quality of the blade. I'm sure others who know more than I do will chime in.