EricJergensen

As Thomas said, to do h13 to spec will require a heat treating oven / furnace. Some people get results acceptable to them from skipping the anneal and doing the quench and temper by eye. Do also note that high alloy steels like this often have to be significantly above magnetic to harden. h13 is about 1900°F, i.e. several hundred degrees above magnetic. Do not forge below 1650°F. Actually, consider some other steel.

No. You really only lose spring when you push something past the yield point. You're not pushing the spring very far. And, if you're welding a die piece on the end of that, the weld is likely the first thing to go. Edit: not because of the steel used for the spring, but just because of the heat affected zone of the weld, etc. Preheat and normalize to reduce that.

Check out my article in the February, 2016 newsletter for a review of an induction heater. There is also a youtube video to go with it.

Turning a prototype into a product is often an order of magnitude more expensive even when you have an industrial infrastructure. Sadly, the odds have always been against Josh's project. Even getting a prototype into a DIY kit is much more work than the prototype itself.

arkie: they are 3M Protective Eyewear Infrared Welding Flip-Up Lens 40427-00000-10 Shade 3. I bought mine on amazon.

The 3M flip up welding shade #3 clip-ons that I use specifically cover IR and mention uses like furnace viewing. I think most welding shades DO cover IR. But as arkie says, check the specs on the product. Do NOT weld with them if they do not. All forms of welding produce tons of IR.

If you have a way to cut off a slice to try hardening, that's probably your best approach.

Clinker material generally congeals into more-or-less a single lump. So, like jumbojak, I let my fire idle (no blower) for a couple of minutes so that it solidifies and then dig it out with my rake. It generally stays together or breaks into just two or three pieces. You'll need to do this once an hour or so. How often depends on your coal and usage. If I wait too long, I end up pulling out a piece that is virtually a casting of the bottom of my firepot.

Just to make things clear: hurting lungs is not a symptom of carbon monoxide (CO) poisoning (headache is one of the first symptoms). Carbon dioxide (CO2) asphyxiation is possible, sort of, but in the very unlikely case you managed to accumulate that much, your forge would be producing truly lethal levels of CO due to the low O2 levels. I've used mine for longer with less ventilation (tho always with my CO detector). Your symptoms sound much more like asthma than anything else (i.e. the allergy thing others have noted). Asphyxiation symptoms clear up very fast. I'm not even an armchair doctor.

gote: I like it. I'm going to copy it using a used furnace draft inducer blower.

It depends very much on the alloy. Last week, I folded a bit of leaf spring back on itself and got a weld with borax for flux using my induction heater. It could be 5160, but it was "junkyard steel" so I don't really know what it was. I've never tried welding known 5160 to 5160, but others report it is tricky and blame the chromium. Makes me suspect my leaf spring is not 5160.

arkie: I agree with you (and Charles). Sucker rods are made of various good steels with fairly tight specs. What I mean by "junkyard steel" is that it's an unknown steel (when salvaged without specs). Same with spring steels. I think most people in our hobby / trade use the "junkyard steel" label to mean "unknown" not "poor quality". I certainly do.

Yes. The chrome is a problem. Burning it off will produce some hexavalent chromium, which is a cancer risk if inhaled. It may also have nickel and copper under the chrome it as well.

Sucker rod tends to be pretty good for tongs. Most of the tongs I've made are sucker rod. It's generally not above 40 points of carbon. That said, it's still a "junkyard steel" and my sucker rod may be a rather different alloy from yours.

Or weld on the reins with an electric welding process if you have that (stick, MIG, TIG). Most of the fun is in the jaws anyway.

You've probably only found 15kVA in single phase. You really need to look at wattage instead. The commonly available LH-15A is 15kVA but 7.5kW. 7.5kW is over 30A @ 240v. 15kW would be over 60A!

As you suspect and Charles points out, "everyday" steels work with these rules of thumb. The full answer is: to properly work your steel, read the datasheet and follow the instructions. For high-alloy steels, cooling in still air might harden and cooling in vermiculite might not even result in normalization.

It's kW in the International System of Units, but people get sloppy on the capitalization.

Axle should work well for a hardie.

Gergely: a stringer is a narrow arc welding bead resulting from straight (that is without deliberate side-to-side movement) rod motion. It's not particularly relevant to Arkie's point that it be that kind of welding pattern. Any practice piece with a lot of welding build up is equivalent...

Owen has a real point. I went back to the first post just to refresh my memory. Andrew asked a couple of fairly reasonable questions, acknowledged that he wasn't going to jump right into a sword and generally showed that he'd done some reading. It sounds to me like he's trying integrate some chaotic info. He really got more of a public humiliation than an answer. So, here's what I think we should've said: Andrew, I'm glad to see you know to start with a smaller project and work up! That's exactly what you should be doing. As far as an alloy goes, 6150 is often used for swords. It's a tough spring steel. It's sometimes used for larger knives for that reason as well, but often knives have higher carbon to improve edge retention with a potential reduction of the toughness and springy-ness. The "sabering" of a katana is caused by a differential quench where part of the blade is insulated by a clay coating. A good, even quench in an appropriate medium (probably oil, depends on alloy) has minimal distortion. You could manage to pre-compensate like you mention but that would be phenomenally tricky. Hopefully that helps you make sense of what you've been reading. Show us your work as you go - we love pictures. The experts here give great feedback!

Iron-Iron Carbide Phase Diagram Note that the eutectic point is at 4.3% carbon. That's where steel (well, we'd call it cast-iron with this much carbon) melts at 2066 °F. The significantly lower melting point makes casting with iron/carbon alloys much less expensive. (I'd also bet it avoids burning the iron in air.) OTOH, the eutectoid point is .83% carbon. That is not the lowest melting point alloy, but it *is* the alloy with the lowest temperature of a full austenite conversion. So, it is a lowest transition point but one that happens entirely in the solid phase. So, it's LIKE (as Frosty points out) a eutectic point but it isn't exactly one because it's not a melting transition rather a transition between lattice arrangements in solid phase. I use alloy here in the general sense: iron/carbon mixture is an alloy, but in blacksmithing we more often use that term to talk about iron/carbon + other metals such as manganese and chromium. Note that a previous post by someone else listed the eutectoid point as .77% carbon. That was a typo or mis-remembering. If you want to see a pretty cool eutectic alloy, look up Field's Metal.

Frosty: note the approximate times on our posts. We cross posted. Yours didn't show (for me) until after mine posted. I find those temps useful, because they point out that it won't be much of an issue until the metal glows visibly and even then you've gotta get to cherry red or so. Probably should've completed the thought and given colors.

Right. The porta-band can do metal.

I second the porta-band option. I drilled a couple holes in angle iron so I can replaced the handle on mine with it. For small pieces, esp, it's nice to put the saw in the vice (i.e. clamp the angle iron) and use it like a bench-top unit. Note that all of Harbor Freights cheap bench top units are for wood *not* metal. They run way too fast.