Some steel makers use the word “temper” to indicate the amount of carbon, expecting the user of the steel to be familiar with the amounts of carbon each different temper represents. For instance, a razor-temper steel represents one that contains 1.50 per cent carbon and a tool-temper steel represents one containing about 1.25 per cent. The word “temper” as used in this connection should not be confused with the word as it is used in the art of tempering, where it indicates the operation of reducing the hardness of the metal in order to make it less brittle and more suitable for some particular use.
86. Uses of Different Grades of Steel.—As the percentage of carbon, and consequently the quality of steel, will vary somewhat with different makes, it is rather difficult to give a rule that will apply generally, but the following list of different grades of carbon will give a general idea of how steel should be selected, forged, and hardened.
Steel of 0.7 to 0.8 per cent carbon should be used for snaps, rivet sets, cupping tools, etc. This grade of steel should be forged at a light red heat. It can be welded easily and will harden at a light red heat.
Steel from 0.8 to 0.9 per cent carbon should be used for drop-forging dies, hammers, cold sets, track chisels, blacksmith’s tools, well drills, etc. It should be forged at a light red heat; it welds easily and hardens at a light red heat.
Steel from 0.9 to 1 per cent carbon should be used for large hand chisels, large punches, shear blades, dies, etc. Forging should be done at a light red heat. It welds readily and hardens at a bright red heat.
Steel from 1 to 1.1 per cent carbon should be used for hand chisels, punches, punch dies, small shear blades, etc. Forging should be done at a light red heat. It welds readily and hardens at a bright red heat.
Steel from 1.1 to 1.2 per cent carbon should be used for screw-cutting dies, large cutting and trimming dies, small punches, small hand chisels, large milling cutters, cups, cones, etc. Forging should be done at a light red heat. It welds readily when care is taken in heating, and hardens at a bright red heat.
Steel from 1.2 to 1.3 per cent carbon should be used for drills, taps, reamers, milling cutters, circular cutters, cutting and trimming dies, mill picks, engraving tools, twist drills, etc. Forging should be done at a bright red heat. Welding can be done when precaution is taken against overheating and burning. It hardens at a dull red heat.
Steel from 1.3 to 1.4 per cent carbon should be used for small drills, taps, cutters, boring tools, etc. Forging should be done at a bright red heat; welding can be done with care against overheating. It hardens at a dull red heat. This steel should be handled carefully.