| 420 / | HD | ALLOYS OR METALLIC COMPOSITIONS |
| 8 | DF | FERROUS (I.E., IRON BASE) {24} |
| 99 | DF | .~ One percent or more carbon containing, but less than 1.7 percent {1} |
| 100 | DF | .~.~ Chromium containing {1} |
| 101 | | .~.~.~ Molybdenum containing {1} |
| 102 | DF | .~.~.~.~> Cobalt containing |