Thread: O1 heat treating problem

Originally Posted by gregg71

Mike,

thank you for thet details. I will ask for more things soon.

Bad news: retempered, regrinded, repolished, rehoned and reshaved but it does not work. The edge is too sensitive, wear out during the shaving.

Attachment 219327

Sounds to me like the steel is too soft. Either over tempered, pulled from quench too soon, or overheated during buff.

Have you measured the bevel angle?

Sure looks good, hate it that it just has no soul. I've done it quite a few times my friend. Last batch of knives I made I warped one, tried to straighten...snapped it. Best I did anyways, it was grainy.

Lovely looking razor. Pity about the issues you are having.

Originally Posted by bluesman7

Sounds to me like the steel is too soft. Either over tempered, pulled from quench too soon, or overheated during buff.

I think they were right. I suspect to the thinly grind edge (0.8 mm) before the HT. Because the situation has improved, that took off the edge but not enough.

Originally Posted by bluesman7

Have you measured the bevel angle?

Yest. It is perfect, 16° with one layer of tape.

Just do not practice the heat treatment. It has made by other master.

Originally Posted by shooter74743

Sure looks good, hate it that it just has no soul. I've done it quite a few times my friend. Last batch of knives I made I warped one, tried to straighten...snapped it. Best I did anyways, it was grainy.

I am sorry about it.

If it were mine, i would do a couple of things. I would take it to a coarse stone (not grinder) and take 2-3mm off the edge by honing at about 45 degrees. Then re-hone and shave.

If it is still a bad HT, you can still learn from it. Make a pattern off it. Then, if it were mine I would put it in a vice straight up and down and break it in the vice to see what the grain is doing. That way not all is lost and you can "see" what is wrong.

Originally Posted by shooter74743

... I would take it to a coarse stone (not grinder) and take 2-3mm off the edge by honing at about 45 degrees. Then re-hone and shave.
...

I will do this and I will see.

In addition I will make a simple razor fort test.

My plan for the HT:

I leave at least 1 mm (3/8") thikness of the edge.
soaking: 805C / 1480F, 8-10 min.
quenching oil: 50-60C / 130F, 30-60 sec
tempering: after cooling to room temperature, 205C / 400F, 2x1h (between cooling to room temperature) or 1x2h

What do you think? This should work, isn't it?

Tim Zowada wrote about this:

"
First, the blade must be properly normalized and spherodize annealed. Then,

If using a gas forge, for O-1:

1. Heat to 1500F - All "shadows" are gone. No soak at temperature. It is too easy to overheat in a forge. This is why I would prefer 1084 or 1095 over O-1 in a forge.
2. Immediatly quench in warm (160F/70C) oil (Park AAA) - rapid agitation of blade.
3. Interrupt quench when blade reaches about 400F/204C (pseudo martemper)
4. Air Cool to room temperature.
5. Temper at 380F two times.
"

My question is the 3. point. How importance to interrupt at this temperature? What is the significance of this?

Originally Posted by gregg71

3. Interrupt quench when blade reaches about 400F/204C (pseudo martemper)


My question is the 3. point. How importance to interrupt at this temperature? What is the significance of this?

Interesting. I just read a bit about martempering in Verhoeven's book. It helps prevent quench cracks. I will have to give this a try. Might be a bit tricky to interrupt at the right time though

An other guy's recipe. Sorry but I dont rememeber hes name, I copied from SRP.

"Heat to 1450 F and hold for 15 minutes. This is called soaking, and it allows the carbon to dissolve back into the iron.

Quench in Parks AAA quench oil, preheated to 130 F. This is a slow cooling oil. You could also use vegitable oil or any number of other oils, but this stuff was designed specifically for heat treatment. For about $10 a gallon, I'd rather just use the best.

After a minute, take the steel out and allow it to air cool. When it's cool enough to touch, put it in the oven to temper it. I temper at 425 F for two hours. Allowing the steel to cool down in one hour cycles isn't necessary."

One minute or less? Cool enough to touch: this is the room temperature or higher?