Properties and uses 
 T7, T7A sub-eutectoid steel. Has good plastic, toughness and strength, and a certain hardness to withstand vibration and shock loads, but poor cutting ability. Withstand shock loading is not used in the manufacture and requires a proper hardness and wear resistance, toughness and good tools, such as forging dies, chisels, hammers, punches, metal shearing knives, reamers, stamp, wood tools, pneumatic tools, machine top, locksmith tools, drilling tools, the more blunt surgical appliances. 
 T8, T8A eutectoid steel. Can overheat when the quenching, large deformation, plasticity, and relatively low intensity, not to bear a greater impact on making the tools, but after heat treatment have a higher hardness and wear resistance. For the manufacture of cutting edge work in the same hot tools, carpentry tools, pneumatic tools, locksmith tools, simple mold, rivet die, the center hole gun and die, steel cutting tools, bearings, cutting tools, aluminum-tin alloy Die plate and core, and a variety of spring. 
 T8Mn, T8MnA eutectoid steel. Has a high hardenability and hardness, but ductility and lower strength. Used in the manufacture of woodworking tools for a large cross-section, hand saw blades, engraving tools, rivet die, spring, band saw blades, circular saw blades, mine with the hammer and masonry chisel to use and so on. 
 T9, T9A eutectoid steel. High hardness, but ductility and lower strength. For the manufacture of higher hardness and toughness of certain tools, such as engraving tools, rivet die, press die, punch, woodworking tools, agricultural cutting parts, drilling tools and molds diversion nails and so on. 
 T10, T10A eutectoid steel. Fine grain, when the quenching (temperature up to 800 ℃) without overheating, the organization can maintain fine grain products; after quenching of steel in excess of undissolved carbides, and therefore have more than T8, T8A higher wear resistance of steel , but the toughness is low. 
 For the manufacture of cutting edge work in the same heat tool, not to shock loading and has a sharp edge and a little toughness of the tool, such as processed wood tools, hand crosscut saw, wood with a fine hand tools, machine with a fine wood tools, twist drills, drawing dies, dies, cold heading die, corkscrew, reaming tools, thread rolling plate, turning, planing, milling, currency dies, small cross-section and uniform cold punching die trimming , low-precision shape simple card board, bench scraper, hard rock drills, rivet and nail manufacturing tool, screwdriver, file, tap with a chisel, cutting with knives and tobacco. 
 T11, T11A eutectoid steel. Has good mechanical properties (such as hardness, wear resistance and toughness, etc.), finer grain, grain growth in heating and the formation of carbides on the sensitivity of a small network. For the manufacture of cutting edge work in the same heat tools such as saws, chisel, tap, file, scraper, spring, ritual, reamers, die, cut tobacco with a knife, small size and cross-section without sharp changes in the Die and woodworking cutting tools. 
 T12, T12A eutectoid steel. As a high carbon content. After quenching the excess carbon is still more so the high hardness and wear resistance, but the toughness is low, and the quenching deformation. Not suitable for manufacturing high cutting speed and by the shock loading tool. Used in the manufacture from the impact load, cutting speed is not high, constant heat cutting edge tools, such as turning, milling, drills, reamers, reamer, tap, die, blade, gauge, blades, small red head, steel file, saw, winding, cut tobacco with a knife, and a small section size trimming die of cold and blurted molds. 
 T13, T13A eutectoid steel. As the high carbon content, after quenching the excess carbide more, so higher hardness, toughness is even worse; and because of the uneven distribution of carbides and the increase in the number, so poor mechanical properties. Not used in the manufacture shock loading and high speed cutting tools. 
 Used in the manufacture from the impact load, but requires very high hardness of the metal cutting tools, such as razors, scrapers, drawing tools, file, tap Tools, drills, and hard rock processing tools and carving tools. 
 Alloy tool steel 
 Alloy tool steel hardened, hardenability, wear resistance and toughness than high-carbon tool steel, the end-use can be divided into cutting tools, dies and measuring three types of steel. Including high carbon content steel (carbon mass fraction is greater than 0080%) more than for the manufacture of cutting tools, measuring and cold-working die, this type of steel after quenching hardness HRC60 or more, and have sufficient resistance to abrasion; medium carbon steel (carbon mass fraction of 0.35% to 0.70%) than for the manufacture of hot die, the hardness of steel after quenching such lower for HRC50 ~ 55, but the toughness is good.