Should I descale/sand after Normalizing, before heat treat (1095)

[JimDiGritz]

I've normalized my blades and was wondering if I should descale/sand them before I HT?

I've always done this in the past, however I've had a backlog of blades since I replaced my blowtorch forge and wondered if I could HT the cold, normalized steel?

https://flic.kr/p/2mN9bY2

You can see that the 1095 is dark and scaled - will it matter if I HT as is??

Cheers

Jim

 

[weo]

I'll be curious to see what others say, but IMO, if you use an anti scaling agent (ie,ATP-641) for HT, then yes, remove the decarb. If not then I think you'll just be repeating this step after HT.
But to be completely honest, this question is part of the reason why I'm now in the habit of doing my normalizing/thermal cycling at the end of my final forging for each blade (forge --> normalize/refine grain --> grind --> HT with ATP-641).

 

[JimDiGritz]

I'll be curious to see what others say, but IMO, if you use an anti scaling agent (ie,ATP-641) for HT, then yes, remove the decarb. If not then I think you'll just be repeating this step after HT.
But to be completely honest, this question is part of the reason why I'm now in the habit of doing my normalizing/thermal cycling at the end of my final forging for each blade (forge --> normalize/refine grain --> grind --> HT with ATP-641).

Thanks, I'm following this process and not using any anti-scale agent

Stock removal > Grind to 90% leaving .75mm @ edge > Normalize > Sand off scaling > HT > Light scale removal with sandpaper > Temper > Final Grind & finish knife

Feels like a duplication to remove the scaling after each of the 3 heating stages... but just wondered if the crud on the blade might affect final HT

 

[Natlek]

I've normalized my blades and was wondering if I should descale/sand them before I HT?

I've always done this in the past, however I've had a backlog of blades since I replaced my blowtorch forge and wondered if I could HT the cold, normalized steel?

https://flic.kr/p/2mN9bY2

You can see that the 1095 is dark and scaled - will it matter if I HT as is??

Cheers

Jim

I do normalizing of steel before I cut/shape knife from that piece of steel.That way I have small pieces which I can HT , then break it and see where I m with grain size ....and that way I need to sand/grind only very thin layer decarburization after I HT blade
On your picture with knife inside oven , i would turn tip of blade when you HT towards Thermocuple .When TC is already placed in the position where the knife is, keep the tip closer to TC .
I would like to see more pictures of that oven if you don't mind ? It looks pretty good to me .

 

[weo]

but just wondered if the crud on the blade might affect final HT

it shouldn't. Maybe a bit more decarb to sand through because there's a build up from each of the cycles, but you'll still have good steel once it's gone.

 

[JimDiGritz]

I do normalizing of steel before I cut/shape knife from that piece of steel.That way I have small pieces which I can HT , then break it and see where I m with grain size ....and that way I need to sand/grind only very thin layer decarburization after I HT blade
On your picture with knife inside oven , i would turn tip of blade when you HT towards Thermocuple .When TC is already placed in the position where the knife is, keep the tip closer to TC .
I would like to see more pictures of that oven if you don't mind ? It looks pretty good to me .

Thanks again for the feedback - you can see a bit more on the oven in my other post here

FYI that was a stage pic just to illustrate another question I had - I've actually made a simple blade rest from an old fire brick. Good shout on keeping the TC nearer the tip

My question to you is - I believed that Normalizing is to re-establish the grain after the metal has been worked on (in my case, bandsawed and bevel grinding) Since I can't ensure that I've 100% worked both sides exactly the same I also (hope) that the normalizing will reduce the potential of blade warping/waving when I quench.....

Jim

 

[DevinT]

Scale can slow the quench speed, a very small amount of oxides on the surface can actually help the speed of the quench. 1095 is sensitive to quench speed.

Hoss

 

[Alex Topfer]

D DevinT does that mean you should just brush off any built up scale but not worry beyond that?

My question to you is - I believed that Normalizing is to re-establish the grain after the metal has been worked on (in my case, bandsawed and bevel grinding)

my understanding is that cutting and grinding won't affect the grain. to cause grain growth you need to forge it, and maybe cold forging could introduce some stress? but i've never heard that it's necessary after grinding or cutting