I need a drink....and help with 52100!

I started using 52100 for the first time after hearing so many good things about it. I ground out 5 of my best grind jobs to date. The other day I followed the directions of others for refining grain(as Follows)

1650-10 minute soak, cool to black
1550-10 minute soak, cool to black
1450-10 minute soak, cool to black

I then ground off the decarb.
Today I went to harden. Blades in the oven, ramp to 1475- 10 minute soak. Quench in warm (120) Canola. When I opened the oven, I thought the blades looked cool, but I've been doing stainless lately so I just chalked it up to be the higher temps of stainless. I ground the tangs clean with 120 grit belt, and did an Rc. Rc ranged from low 30's to mid 40's. The smaller blades had the higher Rc's. I checked the Rockwell with test blocks and came up fine. I screwed up something.

I talked with a friend, he recommended bumping up to 1525. I did another HT. 1525-10 Minute Soak quench in the same Canola. Same clean-up after quench. This time Rc of mid 40's to low 50's. Again the smaller ones were higher.

I figure third times the charm. The blades go back in the oven, this time 1475-10 minute soak, then 1550-15 minute soak. Quenched (should mention time out of oven into oil is 1-2 seconds), and cleaned up. This time I just grabbed a file and checked the blades, the file bit into tang with out an issue.

What am I doing wrong, or what is wrong? At first I was thinking my Rockwell was off, but the file test ruined that theory. My next thought is that the oven is off. It's less than 1 year old, and have had no HT issues in the past.

Am I missing some major step! Did I accidentally get 1018 instead of 52100? I'm just lost!

Any help is appreciated, or you can just buy me a drink too.

Jess, have you got a scrap of that 52100 you could test quench in water and see what happens?

Yeah, I could cut a small piece, it won't be off the same bar, but from the same batch I got from Aldo. I really don't think it's the wrong steel, but I don't know what else to think.

I have used a fair amount of it. Forged blades mainly. Grain refining seems a little long on the soak to me. That aside. Should have hardened. I austenize at 1525 myself. Quench in Medium speed oil from McMaster Carr. Parks 50 is my usual quench oil except for 52100 and O-1 tool steel. I think your oven may be off. I promise it's actually 52100 if you got it from Aldo. He wouldn't make that mistake. He assured me that he marks his steel. He does this for a living. He can't afford to screw that up. Do you have a forge or torch handy? Try heating it up like that and see if it will harden. I suspect your not getting hot enough. Try quenching in actual medium speed quench oil if possible. It should have hardened in canola, just not ideal. Hope this helps

You might want to go over to hypefreeblades and search that site. It wasn't too long ago that there was a discussion there about this same problem with the same steel from the same source. I think that the solution found there was to take the austinizing temperature up to about 1475°. With that first heat cycle of 1650° you should be getting the carbides into solution so I doubt that it's the problem.

Doug

I had the same problem. I would use the same H/T procedure with different bars of steel from the same batch and some would harden and some would not. I completely solved the problem by switching to O1 & A2 tool steels. 52100 is great when it comes out right but I don't have the time or $$$ to waste on a steel that is so fickle, no matter what the cause is.

Aldo isn't perfect. While he is a rock star in my book, I was sent 15n20 instead of 1095 last year. But he made it right and then some. I see these threads every now and again about 52100, and I must say after Kevin's explanation of coarse spheroidized structure and how to deal with it, every 52100 blade I quench comes out just screaming hard, including yesterday's two Wharncliffe's I am working on.

Mr Hoffman, it may indeed come down to wrong steel in your case. If you have verified your kiln temps (sounds like a clue here....you mentioned they looked cooler than you were thinking), and you are indeed getting thru any decarb that might be present, the HT you typed up should give around 66HRC...as you probably know. Sounds like you aren't dilly dallying around between heat and quench either, which some do. 100°F-130°F canola is what I use for 52100 as well, and I think it is a pretty darn good quench for this steel.

1475°F should give max RC out of quench, if your oven temps are right. Bumping up temps should not make it harder, unless the temps are off.

Yesterday I did a slight variation of what I normally do (exactly what you typed up). I don't have access to Rockwell tester, but I know I am getting a good bit harder than a file, and my coupons break with a velvety grain structure.
1650°F for 20 minutes, air cool
1475°F for 15 minutes, air cool
1475°F for 10 minutes, air cool
1430°F for 10 minutes, air cool
1475°F for 10 minutes, quench in 130°F canola oil

File would not even begin to touch the steel, even with decent pressure, I was afraid I was going to ruin my file teeth. ATP anti scale was used on all cycles. Basically ZERO decarb present.

We may have to meet up, all of us, and have a few drinks to solve the issue!!!!

samuraistuart said:

.....
We may have to meet up, all of us, and have a few drinks to solve the issue!!!!

Click to expand...

Now that sounds like more fun than the BLADE show. :35:

Jess what oven do you have? sugar creek? I had the same problem with some 1095 not long ago.
It turned out my oven is a manual dial and takes a 9 volt battery for the digital read out (that was going dead) and was reading the wrong temp, put new battery in and all my woes went away. (found it by accident seen it was reading 195 when shop was 70 degrees)

Speriodized 52100 steel will not go into complete solution under 1830 F. and minimum of 20 minutes according to Dr Verhoveven.

I do a 20 to 30 minute soak at 1830F, then several normalization at 1500 and finally the 1500 degree quench before a 425F temper.

I have a special pump driven quench tank to ensure a fast quench and I treat this steel as though it was 1095 for speed of getting into the quench.

Works well and I get super edges that cut well.

Most probably, if the steel is actually 52100, the temp readings are off.
If they were right, your treatment should have unlocked enough carbon to give you way higher readings...assuming the rc tester is dialed on.