Most of the manual saw blades are made of carbon tool steel. Most of the mechanical saw blades are made of “wind steel” (W18Cr4V, etc.). The carbon steel saw blades are inexpensive, and their hardness and strength are lower than those of wind steel. There is no wind steel. Durable.

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Saw blades are common in most cases and there is no need to choose. However, for materials with higher hardness, wind steel saw blades are suitable.

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T7, T7A subeutectoid steel. Has good plasticity, toughness and strength, and a certain hardness, can withstand vibration and shock load, but poor cutting ability. It is used to manufacture tools with low impact load, suitable hardness and wear resistance, and good toughness, such as forging dies, chisels, hammers, punches, metal shears, reamers, stamps, carpentry tools , pneumatic tools, machine tools, fitter tools, drilling tools, blunt medical supplies and other medical equipment.

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T8, T8A Eutectoid steel. Quenching and heating are easy to overheat, deformation is also large, plasticity and strength is relatively low, it is not appropriate to manufacture tools to withstand greater impact, but after heat treatment has a higher hardness and wear resistance. Used to manufacture work tools that do not change heat during cutting, such as woodworking tools, pneumatic tools, fitter tools, simple dies, rivet dies, center holes and dies, tools for cutting steel, bearings, tools, aluminum tin Alloy die-casting plates and cores, as well as various types of springs.

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T8Mn, T8MnA eutectoid steel. Has higher hardenability and hardness, but lower plasticity and strength. It is used to manufacture woodworkers with large sections, hand saw blades, marking tools, rivet dies, winders, band saw blades, circular saw blades, coal mining chisels, and masonry chisels.

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T9, T9A hypereutectoid steel. Has higher hardness but lower plasticity and strength. Used for the manufacture of various nails requiring high hardness and certain toughness, such as imprinting, rivet die, press die, punch, woodworker, home machine cutting part, rock driller and mold Wait.

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T10, T10A hypereutectoid steel. Fine grain, can not be overheated during quenching and heating (temperature up to 800°C), can still maintain fine grain structure; there is undissolved excess carbide in steel after quenching, so it has higher wear resistance than T8 and T8A steel. But less resilient.

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Tools for making cutting edges that do not change during operation. Tools that do not receive impact loads and have sharp edges and little toughness. Tools such as wood processing, hand saws, hand wood tools, machine tools Wood Tools, Machine Wood Tools, Twist Drills, Wire Drawing Dies, Dies, Cold Heading Dies, Screw Tapers, Reaming Tools, Reeling Dies, Turning Tools, Planing Knives, Milling Cutters, Currency Stampers, Small Cold Cross Sections Cutting edges and punching dies, low-precision and easy-to-shape card holders, fitter squeegees, hard rock drills, rivets and nail tools, screwdrivers, trowels, chisels for cutting, paper cutting, and cutting tools for tobacco leaves.

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T11, T11A hypereutectoid steel. With good comprehensive mechanical properties (such as hardness, wear resistance and toughness, etc.), the crystal grains are finer, and the sensitivity to formation of a carbide network of grain growth upon heating is small.

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Used to make tools that do not change the cutting edge during operation, such as saws, trowels, taps, trowels, squeegees, clockwork, gauges, reamers, dies, cutters for cutting tobacco, small size, and no sharp cross-sections. Change of cold die and woodworking tools

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T12, T12A hypereutectoid steel. Due to the high carbon content, there are still more excess carbides after quenching, so the hardness and wear resistance are high, but the toughness is low, and the quenching deformation is large. Not suitable for making tools with high cutting speeds and impact loads. Used for manufacturing tools that are not subjected to impact load, low cutting speed, and that the cutting edge is not heated, such as turning tools, milling cutters, drills, reamers, reamers, taps, dies, scrapers, gauges, blades, small Tools for punches, steel boring, saws, clockwork, cutting tobacco, and cold cutting edges and punching dies with small cross-sectional dimensions.

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T13, T13A hypereutectoid steel. As the carbon content is high, there are more excess carbides after quenching, so the hardness is higher and the toughness is worse; and because the number of carbides increases and the distribution is not uniform, the mechanical properties are poor. Not suitable for manufacturing cutting tools that are subject to shock loads and high speeds.

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It is used to make metal cutting tools that are not subject to shock loads, but require extremely high hardness, such as razors, scrapers, wire drawing tools, files, engraving tools, drills, hard rock processing tools, and engraving tools.

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High speed steel

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1 Overview

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High-speed steel, also known as wind steel or front steel, means that when quenched it can harden even when cooled in air, and it is sharp. It is a complex composition of alloy steel, containing tungsten, molybdenum, chromium, vanadium and other carbide forming elements. The total amount of alloying elements is about 10-25%. It can maintain high hardness even when high-speed cutting generates high heat (about 500°C), and HRC can be above 60. This is the most important characteristic of high-speed steel - red hardness. The carbon tool steel after quenching and low temperature tempering, although at room temperature, although there is a high hardness, but when the temperature is higher than 200 °C, the hardness will drop sharply, at 500 °C hardness has dropped to the same degree as the annealing state The ability to cut metal is completely lost, which limits the use of carbon tool steel for cutting tools. High-speed steel, due to its red hardness, makes up for the fatal flaw of carbon tool steel and can be used to make cutting tools.

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High-speed steel heat treatment process is more complex and must be subjected to a series of processes such as annealing, quenching, and tempering. The purpose of annealing is to eliminate stress, reduce hardness, make the microstructure uniform, and facilitate quenching. The annealing temperature is generally 860-880°C. Quenching due to its poor thermal conductivity is generally carried out in two stages. It is preheated at 800-850°C (so as not to cause large thermal stress), then quickly heated to the quenching temperature of 1220°C to 1250°C, and then oil cooled. The factory uses salt furnace heating. After quenching, part of the retained austenite (about 30%) remains unchanged from martensite due to internal microstructure, affecting the performance of high-speed steel. In order to change the retained austenite and further improve the hardness and wear resistance, it is usually carried out 2 to 3 times tempering, and the tempering temperature is 560° C. Each time the temperature is kept for 1 hour.

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(1) Manufacturing method: Usually produced by electric furnace. Recently, powder metallurgy was used to produce high-speed steel so that carbides were distributed on the substrate evenly and finely, which improved the service life.

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(2) Uses: Used for manufacturing various cutting tools. Such as turning tools, cobalt heads, hobs, machine saw blades and high-demand molds.

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2. The main production plant

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China's Dalian Steel Works, Chongqing Steel Works, and Shanghai Steel Works are the main producers of high-speed steel.

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3. Major import producing countries

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China mainly imports from Japan, Russia, Germany, Brazil and other countries