Possible the steel air quenched in the thinner sections faster than the thicker, giving a LITTLE bit of internal stress. Definitely not a full oil quench (fastest and produces the best overall hardness in MOST cases, aside from your AX tool steels).
5160 is probably the best all around choice in hardenable steels, and is readily available (truck leaf springs), but requires forging / milling down after an annealing cycle or 5 to bring it back to an unstressed state.
I use a LOT of chromoly alloy steels (4140, 4340, etc) in my work designing downhole tools that can get very close to 200ksi yield strength, but theyâre quite brittle and not impact resilient (charpy testing) at that state. Sometimes you want it to âsnapâ instead of âstretchâ though (mechanical fuse), as fishing and retrieving can be easier.
Yâall should google up MIL-H-6875H. Should be readily available on the intarwebs and a good resource if you can chew through the jargon.
I like this mention because I certainly donât know what types of metal are used routinely for parts you might find in a junk yard.
You lost me there. I would need someone like you or Hank or Richard right there with me to read it. It looks like it was written by a lawyer. MIL-H-6875H.PDF (1.4 MB)
Lots of legalese that basically narrowly (or broadly) defines some terms and then process expectations to ensure uniformity across a boatload of suppliers.
No thinking outside of the box if you want to conform to standards, just a matter of applying the process.
*and ensuring the outcome with rigorous testing and validation
I spend so much time yelling @ suppliers trying to cut corners and attempting to pass off their negligence in ensuring our mat standards for our parts, itâs insane.
Whew! Okay Iâm really stepping in it here. Please keep in mind my background is woodworking. Now that Iâve dove into the plasma cutting world itâs opening up a whole new world. I drew and cut some knives because they were easy to draw and cut. The material I use is scrap from a steel fabricator that we rent our office from. I cut them out of 305 SS. I was looking for some specs on heat treating the blades before I put handles on them and UGH I saw this thread. I didnât know how much I didnât know. I see I need to study up on different types of metal. Any advice on heat treating 305 SS? Is this a bad choice? Thanks
Any kind of stainless youâre going to want in some kind of controlled atmosphere, either argon purged or wrap the part in stainless foil to limit oxygen and decarb.
400 series stainlesses are (typically) better as far as edge retention and toughness go.
I made my first knives out of non hardenable steel as well. I think most people do. haha As far as I know you donât gain anything positive from heat treating 305ss. 305 is an Austenitic ss. If you want to harden ss it needs to be a Martensitic grade.
If you want corrosion resistance and the ability to harden it I would suggest AEB-L stainless steel as a starting point for SS. To be honest wouldnât start with SS. There are way more things that can go wrong in a knife build with SS vs 1095 or 1084.
Yeah I saw a guy heat treat his blade on TV and he had it wrapped in something. I didnât know what it was. Thanks for the advice. I miss my Dad, he knew a lot of this stuff after working for Pratt & Whitney for 35 years.
