Teller
Canyon
Forge
Teller
Canyon
Forge
The American Iron and Steel Institute (AISI) and the The Society of Automotive Engineers (SAE) have compatible numbering systems used to classify steels by their elemental content. There are other standards and designations relevant to tool steels and many non-US standards but we're only interested in the AISI/SAE standard here. The chart below summarizes it; all occurrences of XX in the chart are the part of the number which designates the nominal carbon content, in points, where 1 point is .1% (the entries relevant to the steels we ordinarily use for knives are highlighted like this):
| Carbon steels | 10XX | Plain carbon, Mn 1.00% max |
| 11XX | Resulfurized free machining | |
| 12XX | Resulfurized/rephosphorized free machining | |
| 15XX | Plain carbon, Mn 1.00-1.65% | |
| Manganese steel | 13XX | Mn 1.75% |
| Nickel steels | 23XX | Ni 3.50% |
| 25XX | Ni 5.00% | |
| Nickel-chromium steels | 31XX | Ni 1.25%, Cr .65-.80% |
| 32XX | Ni 1.75%, Cr 1.07% | |
| 33XX | Ni 3.50%, Cr 1.50-1.57% | |
| 34XX | Ni 3.00%, Cr .77% | |
| Molybdenum steels | 40XX | Mo .20-.25% |
| 44XX | Mo .40-.52% | |
| Chromium-molybdenum steels | 41XX | Cr .50-.95%, Mo .12-.30% |
| Nickel-chromium-molybdenum steels | 43XX | Ni 1.82%, Cr .50-.80%, Mo .25% |
| 47XX | Ni 1.05%, Cr .45%, Mo .20-.35% | |
| Nickel-molybdenum steels | 46XX | Ni .85-1.82%, Mo .20-.25% |
| 48XX | Ni 3.50%, Mo .25% | |
| Chromium steels | 50XX | Cr .27-.65% |
| 51XX | Cr .80-1.05% | |
| 50XXX | Cr .50%, C 1.00% min | |
| 51XXX | Cr 1.02%, C 1.00% min | |
| 52XXX | Cr 1.45%, C 1.00% min | |
| Chromium-vanadium steels | 61XX | Cr .60-.95%, V .10-.15% |
| Tungsten-chromium steels | 72XX | W 1.75%, Cr .75% |
| Nickel-chromium-molybdenum steels | 81XX | Ni .30%, Cr .40%, Mo .12% |
| 86XX | Ni .55%, Cr .50%, Mo .20% | |
| 87XX | Ni .55%, Cr .50%, Mo .25% | |
| 88XX | Ni .55%, Cr .50%, Mo .35% | |
| Silicon-manganese steels | 92XX | Si 1.40-2.00%, Mn .65-.85%, Cr 0-.65% |
| Nickel-chromium-molybdenum steels | 93XX | Ni 3.25%, Cr 1.20%, Mo .12% |
| 94XX | Ni .45%, Cr .40%, Mo .12% | |
| 97XX | Ni .55%, Cr .20%, Mo .20% | |
| 98XX | Ni 1.00%, Cr .80%, Mo .25% |
In the real world, nominal is just that and the analysis of any given heat-lot of any of these steels reveals that they vary over a range of .08% or thereabouts
If a given heat-lot is near the upper or lower limit of the carbon content range it might be just as validly sold as the steel just above or below it; most of what the suppliers are calling 1080 nowadays appears to be at the low end of the carbon-content and was probably really intended by the mill to be 1075. The real issue is whether there is enough carbon in the steel to make it suitable for a blade. The amount of carbon needed is dependent on how you forge it and whether or not you intend to do any forge-welding of it. The multiple high heats needed to forge-weld (e.g. for "damascus") inevitably cause some decarburization of the steel and you typically need more carbon in the steel to start with so that there's still enough when you're done. When welding heats aren't needed and the steel is heated in a good reducing fire it is not nearly so important to start out with a really high carbon content. Generally, for non-damascus blades, a starting carbon content above .5% is adequate to make a good blade providing that overheating is avoided and a good reducing fire is used
page last modified Sun, 12 Oct 2003 09:59:23 -0700 (MST);
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