Saving Sanding Belts Annealing and Normalizing

bobbywett

bobbywett

Joined
Jul 23, 2006
Messages
1,231
Hi Everyone,

Sometimes after forging, I do a full anneal on my blades to soften them before grinding. I do this to save wear and tear on expensive sanding belts.

My question is this. Should I normalize after annealing and before grinding? Or should I normalize after grinding, right before the quench?

I have a tendency to hand sand to 600 grit or so before quenching as well. Most of my blade edges are taken down to about .035 - .040 before quenching. That's when I usually do my normalizing. I'm concerned about the decarb that this creates on my hand sanded flats and bevels.

If I normalize after annealing will I lose that "softness" from the anneal? I'd like to start normalizing my blades before I put that hand sanding into them and prevent decarb as much as possible. In addition, I'd like to save as much life as possible on my sanding belts.

Thanks for any recipes,

Bobby
 
Generally, you normalize ( return the steel grain and structure to "normal") and then anneal. A full annealing is best metallurgically, where you program a HT oven to hold at specific temps for six to ten hours. However, for our purposes, heating to 1250F and holding for a few minutes to half an hour followed by air cooling to black and then water quenching will make it quite soft. This is called a sub-critical anneal. If you can hold it to 1250F for 30-60 minutes, you get a spheroidal anneal, which is the very best for filing and grinding. In a spheroidal anneal, all the carbides are balled up in spheres and the matrix is mostly iron.

So:
Heat to 1500F hold for 5 minutes, quench in oil, cool for a minute.
Heat to 1400F, hold for 5 minutes and air cool to black, quench in water
Heat to 1350F, hold, and cool as above.
Heat to 1250F and hold as evenly as practical, cool to black and water quench ( if using a HT oven hold for 30 minutes to an hour. If using a forge, just do your best to stay below 1300F and hold for a few minutes.)
 
Thanks for the information Stacey.

I have a Paragon oven and anneal my 1084 steel as follows:

Ramp to 1500 ... 10 min Hold

Cool to 1450 ... 10 min hold

Cool to 1400 ... 10 min hold

Cool to 1350 ... 10 min hold

Cool to 1300 ... 10 min hold

Cool to 1250 ... 10 min hold

Cool to 1200 ... 10 min hold

Let cool in to room temp over night in oven

Each ramp down in temperature is accomplished over 60 min.

I've never normalized right after forging is complete. I believe I will start to do so though and possibly save myself from cleaning up undo decarb. Most of my blades are edge quenched and decarb should be limited to the lower third of the blade by only bringing the "edge" up to critical. I'll be grinding that area no mater what.

I always normalized right before I get ready to quench. I'm also going to try out your recipe for annealing on my 10xx series blades.

Thanks Again Stacey for your dedication to us here on BF

Bobby
 
Decarb isn't related to hardening. If the blade gets hot enough to glow red, it will create decarb. The higher the temp and the longer the time...the more the decarb.\

Your 8 hour descending anneal with an 8 hour cool down could easily be replaced with six hours at 1250-1300F and a water cool once cooled to black.

Just for info, some metallurgists suggest that slow cooling after reaching 900F ( during anneal) may make a structure that does not machine quite as easily as when quick cooled from 900F.
 
I'm sorry Stacey, I should have phrased my comment differently. I want to normalize directly after forging and before annealing so the decarb will be removed during the initial grinding.

Then I won't be normalizing and creating decarb on a closer to finished blade.

Next blade I'm going to implement your normalizing and annealing sequence.
 
After doing a sheroidal anneal and finish grinding. Is it ready straight for heat treat or should it be normalized again?

Thanks
 
It should be fine unless you got it hotter than 900F in grinding, but most folks just give it one trip to 1500F and air cool to black before the austenitization to eliminate any possible issues.

In an oven HT, once it is at the target temp, just pull it out and let air cool for ten/fifteen seconds and stick it back in. Once the temp rebounds to the target, start the clock.

With a forge HT, just run a heat/cool cycle and then austenitize.
 
Kieran,

That's what scares me ... I'm just so used to normalizing right before the final heat and quench. But, as I'm learning, a lot of makers don't normalize right before quenching.

They do it right after forging. When I first started forging blades I had a few crack during the quench. Then I learned about normalizing to refine the grain and make things "nice" again. Unfortunatley, I think by normalizing right before the quench, I was creating a lot of unnecessary rework. You know, cleaning up the decarb throughout the entire width of the blade.

I just purchased som Brownells Anti Scale (liquid state). I've only used it once thus far. I was impressed with the lack of decarb, however, I had one heck of a time getting the anti scale off after the quench. I believe that you can mix it with a bit a water, to thin it down a bit. I may have applied it while it was too hot, not sure.

I think I need to play with it a bit more to come up with the right way to use it.
 
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