Good Evening,
I am sitting in an empty house with the wife and kids gone camping leaving me with a bunch of free evenings that will be spent working on knives. I spent a few hours today forging out two large 5160 camp choppers. I am working on getting the full picture for heat treating 5160 since it is a new steel for me.
The steps I believe I need to take after forging to shape are...
1. Triple normalize, once from 1550 to below 800 - How long do I hold it at this temp?
then 1500 to 800 - Time at temp?
then 1450 to 800 - This triple cycle should fix all the stresses in the steel and shrink the grains
2. Spherizoid anneal,to allow easy drilling of pin holes, draw filing bevels, etc....
- Right after third normalization process is completed bring the steel up to 1400 - time at temp?
- slow cool in vermiculite overnight
3. Hand finish bevels, flats, edges of blade to 400 grit.
I am looking for maximum toughness with good edge holding properties with the 4 camp choppers I have in the works. They all have 12 inch or longer blades, one is a clip point, two are drop points, and the fourth which will ride on my hip this hunting season is a Persian / Kukri cross. I have a two burner propane forge without a thermocouple. I use a pipe in my forge to help control temps for the steel. I have a five gallon bucket full of Canola oil, which I was happy to read is a good if not great oil for 5160. I don't believe that I can soak the steel for 3 to 5 minutes and hold a totally consistant heat. This leave me planning to triple quench the blades to get all the carbon where I want it.
4 - Quenching the blades
A. Heat to 1550 and hold for 30 seconds to 1 minute
B. full depth quench in 125 degree canola oil for 10 seconds
C Roll blade back so most of the spine is out of the oil and let cool to 400
D. Repeat two more times
5. Temper blades for 2 hours @ 375- Three times.
6. Clean up finish and hand sand to 600 grit hand rubbed finish.
I think I am close on this process. I would love everyones input on anything I missed or can improve on. Am I close?
Clay Walker
Ragnarok Forge
I have to assume that I am all right to provide the input you requested, so please know that I trying to do that and not pick or preach, I hope I can help
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It may be better to avoid using the term “shrink†in grain refinement as it perpetuates some very detrimental myths. One can only shrink matter in bad Disney movies with Rick Moranis, or better yet 60’s sci-fi movies starring Raquel Welch <img src=' http://www.americanbladesmith.com/ipboard/public/style_emoticons//biggrin.gi f' class='bbc_emoticon' alt=':D' />. Metallurgy could be a lot easier to study if we could find ways of including Raquel in her prime <img src=' http://www.americanbladesmith.com/ipboard/public/style_emoticons//wink.gi f' class='bbc_emoticon' alt=';)' /> . What the cycles do is simply make newer and finer grains. In fact there is so much misunderstanding about grains and recrystallization it would make a good discussion for a thread unto itself, perhaps I will do that when I get a second.
What you describe is a little more like a lamellar anneal instead of a spheroidizing treatment. Without an oven with a ramping function the best way to get spheroidal carbide, and mind you, you won’t get much with 5160, is to cycle around 1300F to 1375F several times being careful not to approach non-magnetic. You can do this right off from the last normalizing heat and since spheroidal carbides precipitate from martensite most evenly you could even do a quench to refine grain and carbide immediately before starting the spheroidizing.
Due to the lack of carbon in 5160 you could also do a lamellar anneal without many difficulties in later operations. Heat above nonmagnetic (or if you can measure it, between 1500F and 1525F) and bury in vermiculite. If you can measure and hold 1525F is a little better for 5160 and since you are repeating you could even play it safer with lower heats.
"One test is worth 1000 'expert' opinions" Riehle Testing Machines Co.
Kevin,
I really enjoy reading your posts and learn a lot from every one of them.
A lamellar anneal it is. I really need to buy a good knife kiln!
I also need to buy some books that cover the most common knife steels and their heat treatment.
Thanks for your input on this. I will fire up the forge and anneal the first two blades and forge out the next two choppers tonight.
