Forged W2 Heat treat recommendations

flatblackcapo

flatblackcapo

Well-Known Member
Hi there folks. I am going to be using some W2 that was forged down from round stock for a project. I am making a modified Kwaiken design with a hamon for a customer that is well aware of my lack of experience with W2 and hamons but he is a brave soul and is willing to give me a shot. If any of you would be generous enough to share your time and knowledge with me to aid me in making the best cutting tool I can it would be greatly appreciated.Here is what I am working with.
Steel - forged W2 .250
HT method - Evenheat oven with Rampmaster control
Quenchant - I need some recommendations here. I would like to use oil. A quench oil that I could get from Maxim would be ideal for me.Also, a quenchant temp recommendation would be great.
For achieving the hamon I will use furnace cement.
The hamon is secondary to a good cutting tool. If I get a good hamon , that would be great but getting the best cutting tool that I can make is way more important to me.
A little about the knife . It will be a full tang design with a chisel grind , convex tip and zero edge.The thickness at quench time will be close to 3/16"
Mr. Cashen , any input from you would be very much appreciated. I did go to your page on W2. I still had questions. Is there any soak time recommend ? what would you for recommended oil quenchant. What is a good quenchant temp? What would be a good starting temp for temper? When walking the hardness down are 25* F steps OK or would smaller steps be recommended?
 
flatblackcapo, there a few things that you can use as red flags as to whether heat treating advice is reliable or suspect, two of which are exact HRC numbers for tempering temperatures and exact soak times for any situation. Neither of these should be given as more than very broad and general recommendations as precise numbers are only applicable to the specific circumstances. This is why you often see very general recommendations for soak such as 1 hour/ inch of thickness, this is not industrial specs being unreliable it is them being as accurate as possible for any number of circumstances. Your situation is one that takes things well beyond normal industrial recommendations- hamons; industry would just scratch their head and wonder what you were talking about and why anybody would want to do that. The idea behind the soak is to evenly distribute a homogenous austenite solution throughout the steel, the exact opposite of what you want in the end product with a hamon. It is because of this that I have seen more vibrant hamons from forges than from ovens. The idea here is to use a simple shallow hardening steel, get it up to temperature and cool only the part required to form martensite as soon as possible; soaking will increase depth of hardening and will help your steel ignore the ashi lines that you want it to follow. So, as you can see, standard recommended soak times are a problem with a clayed blade, your best bet it to simply level out the temperature to know the blade has assumed the target heat and quench.

Along with this, if you want to use an oil and are already looking at Maxim, Park Metallurgical/Heat Bath Corp. #50 quench oil is the only oil I have encountered that will consistently get you close to the old fashioned water quenching effects. Look around the internet at the guys who are really known for their wild hamons, i.e. at the top of their game, on a variety of knives, and those guys prefer the #50, as do I when I need to do the occasional hamon demonstration. If you go with Parks #50 keep it between 80F and 100F.

Tempering is another general thing that I would only steer you wrong if I tried to give you a specific result for a specific temp without accounting for all of the variables in your unique circumstances. Remember that the body and spine of the blade probably won't even need tempering, that is what hamon was originally all about, and over-tempering could detract from the vibrant contrast of the hamon. If you are going to walk it in I would start at 350F and then bump it up by 20F to 25F but would probably not go above 400F for a blade like a kwaiken.
 
You must log in or register to reply here.
Back
Top