induction hardening how does it work

Induction Heating Handbook (McGraw Hill, ISDN 07 084515 8) goes into a lot of detail on how induction heaters work and how to tweak them for specific applications.

I've been plunking away at one as a "back burner" project for over a year now. I just blew up some mosfets yesterday, in fact. It's not as easy as a charcoal forge, but I believe it is do-able.

An induction heater is a transformer. The workpiece is the transformer secondary. It's a shorted secondary. Lots of current flows and the workpiece gets hot fast.

Frequency needs to be inversely proportional to the square root of thickness. For knives, you need a minimum of 1 to 3 MHz. Not easy, but do-able. You also need a good "power density." That means you need lots of kilowatts per unit area. You can reliably get about 1.5 or 2 kilowatts out of an American wall outlet, so treating small areas of the blade at a time is more feasable than trying to zap the whole blade at once.

I'll try to keep folk posted on how things go once I've replaced my mosfets.

Some good websites on the subject:

HWG Inductoheat

LectroTherm

and

I've made steel with induction heating

Click to expand...

Hey Mete... a littel birdie told me you melted the HEATER before you melted the STEEL!

Davies and Simpson's(McGraw Hill, ISDN 07 084515 8) goes into a lot of detail on how induction heaters work and how to tweak them for specific applications.I've been plunking away at one as a "back burner" project for over a year now. I just blew up some mosfets yesterday, in fact. It's not as easy as a charcoal forge, but I believe itdo-able.An induction heater is a transformer. The workpiece is the transformer secondary. It's a shorted secondary. Lots of current flows and the workpiece gets hot fast.Frequency needs to be inversely proportional to the square root of thickness. For knives, you need a minimum of 1 to 3 MHz. Not easy, but do-able. You also need a good "power density." That means you need lots of kilowatts per unit area. You can reliably get about 1.5 or 2 kilowatts out of an American wall outlet, so treating small areas of the blade at a time is more feasable than trying to zap the whole blade at once.I'll try to keep folk posted on how things go once I've replaced my mosfets.Some good websites on the subject:and ASTM Hey Mete... a littel birdie told me you melted the HEATER before you melted the STEEL!