Part two
420 modified stainless, has been successfully used by some commercial knife producers, but availability is not practical for the hobby knife maker since darn few of us order steel in mill rolls.
VASCO WEAR is rather expensive but very, very good in edge holding. Resists grinding very well too! You'll swear your belts have all gone dull when you try it. Do everything you have to before heat treating, cause you sure aren't going to be able to do much afterward. Priced like lobster tails, when you can find it. Try Vasco-Pacific in the Los Angeles area. Vasco - Pacific uses their own series of names for their alloys.
DAMASCUS steel is such a widely made product that it is impossible to make too many general statements about it, other than it seems to catch collectors better than any other type. Each smith does his in a slightly different way, ranging from the fellow who toughs it out, starting with three layers, to the guy who welds a 300 layer sandwich of shim stock into a billet with one hit in a 40 ton press. They're all pretty. Reese Weiland suggests that the last etch of a Damascus blade be done with phosphoric acid, which will sort of, parkerize the metal and help protect it. He said that you have to play around with the concentration of the acid and immersion times a bit, depending on the steel you're using. This will also work on most carbon steel blades. If a Damascus blade has been hardened with a softer section at the spine or guard, you will get a much better looking etch if you use muriatic acid first, to get the depth you want, and then ferric chloride for adding color.
STELLITE 6-K fits into the same category as Vasco Wear in the wear resistance area, but doesn't need heat treating since there is no iron in it at all. The trick is exceptionally hard particles embedded in a rather soft alloy. Very flexible and easy to bend. Virtually cannot be brought to a mirror finish. Stellite blades are very much in demand by some collectors. The alloy best suited for knives now must be ordered from Canada and costs about a hundred bucks a pound. Part of Stellites toughness comes from the rolling process used to form the bars. Cast Stellite is not nearly as tough.
TITANIUM is only a marginally acceptable metal for a knife blade. It cannot be hardened much past the mid 40's of the Rockwell C scale, and that's spring, or throwing knife territory. Aside from that, I'm sure that there will soon be collectable titanium knives on many custom makers tables, designed to catch collectors, and not for cutting.
Powdered, cast and fused stainless and tool steel alloys, (Alphabet Alloys ) have popped up all over during the past few years, and they are some of the darndest steels ever encountered. The advantage is that elements can just be stirred in to create desirable properties. ( A vastly simplified description.) Virtually all of them are terribly tough to grind, but hold a cutting edge beyond all reasonable expectation. The names of these alloys change weekly, and they're too numerous to list, but they work in a lot of applications that send normal knife steels running for cover. The one possible drawback is unusual brittleness.
Many steel mills hang their own labels on regular alloys. This confuses things no end. Then, cutlery manufactures jump in with trick names for the alloys they use and fuzz it up even worse. A blade marked 440 is hardly ever 440-C, the best of the three 440 alloys. If it was, they would have marked it with the C. Trick names, like Tungsten 6 or Vanadium 3 are usually an effort to capitalize on a trace of desirable alloying element in a generally poor quality steel. If the steel is any good, a knife manufacturer will not hesitate to tell you what the alloy is, using the proper standard name.
Hack sawing any bar stock into knife sized chunks can be a real chore, and will use up a lot of saw blades. Abrasive wheel cutoff saws are now very competitively priced and a labor saving gadget when it comes to chopping steel. Bargain wheels run around $4 for a 14 inch disc. Get the externally re-enforced type. They last about three times as long as the internally re-enforced versions. Keep an old jacket or long sleeved shirt in the shop to shield your arms from the fiberglass that the wheel sheds while it's working. The darn stuff itches like crazy.
If anyone knows of a small rolling mill that would take 500 lb lots of, say, 52100 round rod, and roll it into rectangular bar stock, please let us know. In fact let everybody in knife making know. There are dozens of great alloys out there that distributors refuse to stock in useful sizes, and a custom rolling mill would help all of us.
HARDENING SIMPLE STEELS
All of the really low alloy steels have one feature which make them virtually foolproof when it comes to cooking them for hardening. When one of the low alloy steels reaches the critical temperature where it can be hardened by quenching, it turns non - magnetic. As the steel heats, check it with a magnet. At a certain point, the magnet won't stick. That's usually at a temperature ( color ) far lower than you would think. Once the magnet won't stick to the blade, give it a moment more in the fire and then into the quench it goes. ( An extra 50 degrees over the critical temperature insures better hardening and won't hurt the steel.)
The simple aloys can also be selectively hardened, not with a fancy temper line, but with a softer back that will make the spine and tang less susceptible to breakage. All you have to do is take the blade up to heat very quickly, getting the thin parts along the edge hot before the thicker spine. You could also just dip the cutting edge into the oil, allowing the spine to cool more slowly, not hardening it.
Should you err and get the spine too hot and inadvertently harden it, you can use a torch to partially anneal the critical areas. I recommend that all stick tang blades have a softer section where the tang joins the blade.
When the hot blade hits the oil, you will almost always get some fire. Don't leave the tang half out of the oil. It is near red hot, sticking out of the oil and acting like the wick of a candle to start a fire in the tank. NEVER use a small tank of oil to quench a lot of blades. Sooner or later, you'll find the flash point of the oil. That's where it starts burning all by itself, and you won't like that one little bit.
Forged blades will always have stress than needs to be worked out before hardening. They should be annealed, preferably several times before hardening. Some knife makers have had wonderful results by annealing their blade steel three times before hardening. It reduces grain size significantly, making a much tougher blade.
SERIOUS HEAT TREATING
1040 to 1050 steel Water quench from 1525 to 1550 F. Hardens to approx. RC 58. Very easy to get cracks with water quenching. Draw at 350 F. for spring temper, best for daggers, etc. Shallow hardening and can be done with beautiful, Japanese style temper lines.
1050 to 1095 steel Brine quench from 1475 to 1500 F. hardens to RC 60 to 65. Draw immediately. Oil quench at the same temperatures for slightly lower hardness. Shallow hardening and can be done in the Japanese style with a decorative temper line.
4150, 5150, 6150 steel Oil quench from 1525 to 1600 F.
5160 steel Oil quench from 1525 to 1600 F.
52100 steel Oil quench from 1525 to 1600 F. Harden, cool and let the blade settle for a day (24 hours). Re-harden twice more at the same interval. Cutting edge toughness is fantastic. Draw at about 350 F, three times, and the spine may be torch drawn to spring temper. Ed Fowler gets incredible cutting and flexibility with this method.
O-1, O-2, O-6, O-7 steel Preheat slowly to 1200 F. Oil quench from 1450 to 1500 F. Draw at about 350 F. O-6 reaches RC 65.
W-1, W-2, W-3 steel Preheat slowly to 1050 F. Water (brine) quench from 1400 to 1500 F. Draw immediately. May also be oil hardened if cross sections are radical, or simply for less chance of cracking. Shallow hardening and will work with Japanese temper lines.
L-6, L-7 steel Quench from 1450 to 1550 F in water or brine. Doesn't really need to be drawn. L-7 will give slightly more hardness.
D-2, D-7 steel Preheat at 1500 F. Harden from 1850 to 1875 F. Draw immediately.
A-2 steel Preheat at 1450. Air harden from 1700 to 1800 F. Draw at 350 F.
S-1, S-2, S-5, S-7 steel Preheat at 1200 to 1300 F. Harden from 1650 to 1750 F for S-1, 1550 to 1650 F for S-2, 1600 to 1700 F for S-5 and 1700 to 1750 F for S-7. Draw at 350 to 400 F.
M-2 steel Preheat at 1400. Oil or air quench from 2175 to 2250 F. Draw at 1000 F.
440-C steel Air harden from 1850 to 1950 F. Draw at 325 F. Freezing to dry ice temperature for several hours before the draw will enhance toughness and hardness remarkably. Don't bother with 440-A or 440-B.
154 CM, ATS 34 steel Air harden from 1975 F. Straighten before they cool below 250. Freeze at -220 F for 6 to 8 hours. Double draw at 950 F, two hours each cycle. (Paul Bos method) Gives RC 59 - 60 and marvelous durability.
Damascus Harden to specifications of the highest carbon content component. Damascus may be treated a bit rougher than homogenous alloys. San-mai Damascus sometimes has severe shrinking problems which will pull apart the center layer.
Water hardening is a mis-used term. In virtually all cases where a steel is referred to as water hardening, they're actually talking about quenching in brine, heated to a temperature of 170 degrees, (F) or above. Brine is made by dissolving non-iodized salt in water until a egg will float in it. Jim Hrisoulas uses bluing salts to make his brine. The whole idea is to raise the boiling temperature of the liquid and make it transfer heat better. Brine will eat right through an ordinary steel barrel in a very short time. Jim Ferguson just mixes in borax and detergent to reduce the surface tension.
Drawing is normally done for 30 minutes when one has the equipment to properly maintain the temperature. Flash drawing, that is, heating to show a certain oxide color on the metal surface and then letting it cool, is fine for softening a spine, but not best for the cutting edge.
Any steel which has a low draw temperature may be drawn to a softer temper along the spine to give it better shock resistance. If this is done, the blade will almost always curve a bit towards the softer part of the blade. This works better on shallow hardening steel than on others but can be done on 5160, 52100, A-2, 440-C and others.
Many of the low alloy steels, like 0-1 and 5160, will show a temper line if the blade is selectively hardened, but the line is rather plain, merely a division between hard and soft. A proper, decorative line, needs either the 10 series, or W series of steel. Oil quenching will produce a temper line in those steels, but water quenching is necessary if one desires the more intricate details of the Japanese style line.
). My point to Tyrkon is to first use a single, complete, tested method, before inventing your own.