still pick up a thermocouple and display. will give you a better idea of what is going on. sending it out is ok, just be sure the company knows the blade is forged and what heat treatment you have given the blade.
It will, but the thing you have to keep in mind with austenizing in a forge; you're actually "shooting" for a higher temp than you would in an HT kiln, because you can't hold the soak times. Remember, it's time, and temperature. That doesn't mean, you need X temp and X time period, it means the two are linked intrinsically, you can increase time and lower temperature, to some degree, or increase temperature, and lower time, to achieve your results (within specific limits).
There's a lot of differeing views on whether this is better or worse, but some steels respond really well to austenizing at a higher temp without any soak, as evidenced by their performance and higher as quenched RC, and there's plenty of historical data that supports the idea that the faster austenization with low alloy/simple carbon steels can give better performance (i.e., austenizing as fast as possible, which mitigates grain growth, etc).
I'm saying all this, not to start a debate on that subject, just to be clear that, if he does use a thermocouple to determine temp, he's gonna see worse performance most likely in that kind of forge, if he tries to hold at the "by the book" hardening temps, which will inevitably be uneven no matter how much he's moving the work piece in and out of the burner "sweet spot" at that temp.
He's better off doing it by eye, in dark lighting, watching for uniform above critical temp, watching for the last shadow to move out, and quenching immediately. That is, with the current equipment. Countless exceptionally performing knives have been made this way. In fairness, this is more in the "art" vs "science" area of skill, takes lots of practice, and helps if you've been shown how to judge this properly by someone with proven results, as opposed to "internet self education".
Now, to be clear, I'm not saying this is the "best" way to do your HT, and 90% of my stuff is done with a digitially controlled kiln and a pretty specific process. However, I've made stuff under the correct circumstances that performed just as well, or better using the above methodologies. The old W2 is a great example, typically it'll show better grain, less decarb, and 1-2 points higher as quenched hardness when heat treated in a forge, vs soaking at the "on paper" temps in a kiln.
