O1 Tool Steel

[ddickey]

Made a nice little punch for a guy at work made out of some left over O1 TS.
I heated it up to ~1425°F adn quench in oil. Let it cool a bit, actually probably to much adn tempered @~400°F for 30 minutes and air cooled.
2 questions. It is magnetized. I thought it would loose its magnetizism after heat treatment?
Any tricks to clean off this scale? I worked on it quit awhile and still parts are quite dirty, although I think it looks sort of neat.

 

[Dave Paine]

The steel loses its magnetism as it heats. At high temperatures the crystal structure changes causing the loss of magnetism. After quenching the crystal structure returns and so should the magnetism.

I have cleaned off the black film/scale with wet-dry abrasive and water. Did not take long. Perhaps a wire brush may also work.

 

[EmilioG]

I've read that covering the part with a paste mix of DN alcohol and Boric acid powder then wrapping in HT wire keeps most of the scale off.
See:

 

[mikey]

Made a nice little punch for a guy at work made out of some left over O1 TS.
I heated it up to ~1425°F adn quench in oil. Let it cool a bit, actually probably to much adn tempered @~400°F for 30 minutes and air cooled.
2 questions. It is magnetized. I thought it would loose its magnetizism after heat treatment?
Any tricks to clean off this scale? I worked on it quit awhile and still parts are quite dirty, although I think it looks sort of neat.

A few comments:

• Can't tell what tempering to ~400 degrees will do to the tool. Typically, we want the tip of a punch to temper to an amber color or even softer, and the rest of the tool to be softer still so it doesn't shatter with hammer blows.
  
• The scale is hard to clean off. You might try soaking it in some Muriatic Acid to see if that helps.
• It is easier to prevent the scale from forming. As Emilio mentioned, mix a small amount of denatured alcohol into some Boric Acid powder to form a slurry. Wrap the part with some wire (rebar tying wire works well) to suspend it and coat the part, wire and all, with the slurry. Then heat treat as usual.
  
• In my experience, completely covering the part in wire does nothing at all. I've tried wrapping so you can barely see the part for all the wire, tried loose wraps, tight wraps and now I use almost no wraps - just enough to securely hold the part.

Using the Boric Acid will leave a gray coating but it comes off easily with Scotchbrite.

And yes, it will be magnetic after quenching.

 

[Silverbullet]

Found a place selling lots of tool steel , oil quench lots of sizes $5.00 per lb I think water quench too. It's north of me so I'm out no one to get any for me it's in Quakertown pa , near Allentown ,daul st. , lots of stuff

 

[Dave Paine]

I live northwest of Allentown. Quakertown is an easy drive. What is the name of the place?

 

[Silverbullet]

I live northwest of Allentown. Quakertown is an easy drive. What is the name of the place?

Star maintenance 2715 Dahl st , pick me up 5 lbs of it. Hes got a bin of taper drills more YA buy cheaper they are start at $12.00 .there's a few pages of adds.
Large shelf with wooden boxes look like starrett or other tools no mention of if there empty or full. Surface plate with chip on corner , says arbor presses parts cabinets vinmar lots of things
Sale starts Sat 8:00 am says use 2631 Dahl rd for gps

 

[Dave Paine]

I have found the ads. I saw one a few days ago for a horizontal bandsaw. He is asking more than I feel it is worth. I did not see the tool steel.

I will have to give him a call tomorrow (Friday). Send me a PM with phone number. If I go,I will call you from the place to advise details before I get anything.

 

[mikey]

Duane, I don't know why I didn't think of it but you just got a heat treating oven, right? If you used that then clearly Boric Acid is not the thing for you. I believe stainless foil will do the same thing in that oven. For punches, I don't think you can differentially temper stuff so you might need to temper with a torch - softer for the body and harder for the nose.

 

[ddickey]

You mean less temper for the nose. That would just be less time or less temperature. I tempered the whole thing in the oven. From what I read it said to immediately temper after quenching to 125 degrees. It takes hours for my heat treat oven to cool down.
On a side note a guy at work found that oven in a dumpster somewhere. I put a new controller, and thermocouple on it. I thought he was giving it to me but informed me he wants it back. He said I could use it anytime. He lives 35 minutes away so that probably won't happen.