Jerrod Miller

You're going to want to include a LOT more information. Do you make them to order? Do you just happen to have a couple for sale? Let's see some pictures and specs. Maybe some general pricing.

Remember that non-ferrous metals generally need to be quenched to avoid a stressed state. Also, steel that is tempered above 900F is often required to be quenched to below 500F to avoid temper embrittlement.

A quench is a "fast" cooling. So yes, going from 500F to room temp via a dunk in water is a quench. Going from 1600 to room temp via fans is an air quench. Without the fans it would be a "still air cooling". A sub-critical anneal is just a very high temp tempering cycle. The speed of cooling after the soak at temp is pretty irrelevant. I generally shoot for 1250-1300 for a subcritical anneal, just to ensure your don't go over critical. Soaking for at least an hour is great, but even a couple minutes is extremely helpful. A bucket of ashes or vermiculite has ab

Your "refractory" is not really much of a refractory. You would be money ahead to stop now and get rid of it and line your forge with 2" of ceramic wool. you will get may better fuel efficiency that will pay for itself fast, plus your forge will get hotter, and do so faster. There is a reason every propane forge build discussion on this forum says to use the ceramic wool, and it isn't because "Big Ceramic Wool" is paying us (but that would be pretty cool, so if the folks at Kaowool, Inswool, etc. see this hit me up, I'll take your money!). And you will definitely want to be getting hotter

I should note that my information is just my interpretation of the data in the ASM Heat Treater's Guide, not experience with this alloy. The book also says nothing about a need to soak at temp.

At 400F 6150 should be near 54 HRC, 450 should be closer to 52 HRC. That is some pretty heavily tempered martensite. I wouldn't worry too much about differential hardening with that, especially considering how tough 6150 is anyway. You have about 3 seconds to beat the nose of the curve, but if you go a little slower you will get a little retained austenite, ferrite, and carbide. The carbide isn't too bad of a thing, and your tempering will probably take care of the retained austenite (and more carbide formation), so you will likely end up with very little performance loss. This may come i

You should have tempered before any grinding. Always temper immediately after hardening. Not only does it make grinding easier, but more importantly there can be stresses in the blade that cause failure in the blade while it just sits there.

You have your volts and amps reversed. That is a 30V/5A supply. More amps means a faster etch. Since it can be done with a 9V battery or car battery, you definitely don't need high voltage, but depending on how aggressive you want your etching process to be you may want higher amps (like 50A as mentioned in the link below). BTW, I assume you have seen this thread, but in case you haven't, here it is:

You don't want to do the typical anneal, that requires controls you don't have. What you want to do is a "process anneal" or "sub-critical anneal". Basically a really hot temper. Heat to about 1250-1300 for as long as you feel you can accurately hold it. Several minutes should help a lot, but if you had a controlled oven I would recommend an hour. The key is to not heat it so much that you get phase transformation. Good luck!

I have tried several "top of the line" units to replace our S types and they were not at all adequate. If you know of one that can give accurate readings through the smoke and slag in an induction furnace and/or ladle for reading molten steel and irons I would love to know of one. The last one I played with required emissivity adjustments based on alloy group (stainless and low alloy were different, for example) and the slag was an issue at all times. We were able to find adequate angles to keep the unit away from the heat, but it did get pretty awkward due to the distance-to-spot ratio. I

In my experience with IR, you get what you pay for. I've used units that worked fairly well on liquid steel, but get rather finicky when slag got in the way due to extremely different emissivity constants. It is also very important to be aware of how they work, especially in regards to the emissivity constants and the cone for measurement area (30:1 in the one linked above). You will want to figure out the emissivity constant for your refractory and always point at that, not your steel as the reading area will be bigger than your steel at most distances. I definitely prefer K-type thermoco

What Brian and Jaron said (minus Jaron's puns ). I've never even heard of a high carbon bolt. Even the highest strength bolts are generally no more than about 0.40 %C, but they can have a few other things in them, too. The big thing is that they are properly heat treated for their use. I'd recommend staying away from anything that was overly abused for things that are going to be hardened or roughly used (e.g. Hardie tooling). But if it looks pretty decent then you are probably going to be OK. If you are going to make something for sale then it is generally best practice to use new mater

Those don't appear to me to be stress fractures at all. They look like heat checks from the surface grinding. Basically they took a little too aggressive of a pass. They will likely clean up just fine with a flap wheel. That mentality (you are not even remotely close to being alone in having it) is something that adds a couple hundred dollars to the price of new anvils. Yes, it can be done, but it comes at the price of either extreme re-work or scrapping of parts. If more people expected and accepted that completely unimportant defects would be present then production cos

I'm surprised nobody has mentioned this yet: It doesn't matter all that much if you are using good epoxy. Look at any example of a good epoxy being used and you have to absolutely destroy the handle to get it off the tang. As long as you get the cavity pretty well filled, say 80%, then the 20% air bubbles will not be an issue. Having your tang properly prepped is more important than getting bubbles out.

What Brian said. I completely disregard anything someone says if they insist on magnetic north playing a role in quenching.