What material is the saw blade made of? What is the hardness? What are the requirements for saw blades during installation?

Hand saw blades are mostly carbon tools, while machine saw blades are mostly "wind steel" (W 18Cr4V, etc. ). Carbon steel saw blade is cheap, its hardness and strength are lower than that of wind steel, and it is not as durable as wind steel.

Saw blades are universal in most cases, so there is no need to choose them. However, for materials with higher hardness, it is more suitable to choose wind steel saw blade.

T7 and T7A sub-steel precipitation. It has good plasticity, toughness and strength, and a certain hardness, and can bear vibration and impact loads, but its cutting ability is poor. It is used to manufacture tools that bear small impact load and require appropriate hardness, wear resistance and good toughness, such as forging dies, chisels, hammers, punches, metal scissors, reamers, steel seals, woodworking tools, pneumatic tools, machine tool bits, locksmith tools, drilling tools and blunt medical instruments.

T8, T8A *** Steel Analysis. It is easy to overheat when quenching and heating, with large deformation, low plasticity and strength, and is not suitable for manufacturing tools that bear large impact, but it has high hardness and good wear resistance after heat treatment. Used to make tools whose cutting edges are not heated when working, such as woodworking tools, pneumatic tools, benchwork tools, simple molds, rivet molds, central hole chisels and molds, tools for cutting steel, bearings, cutters, aluminum-tin alloy die-casting plates and cores, and various springs.

Analysis of T8Mn and T8MnA *** steel. It has high hardenability and hardness, but low plasticity and strength. Used for manufacturing woodworking, hand saws, carving tools, rivet dies, clockwork, band saws, circular saws, chisels for coal mines, chisels for masonry, etc.

T9 and T9A undergo steel precipitation. It has high hardness, but low plasticity and strength. It is used to manufacture various vise tools with high hardness and certain toughness, such as engraving tools, rivet dies, pressing dies, punches, carpenters, cutting parts of household machines, drilling tools, die split nails, etc.

T 10 and T 10A are subjected to * * * steel precipitation. The grains are fine, and will not overheat when quenching and heating (the temperature reaches 800℃), and the fine grain structure can still be maintained; There are excessive undissolved carbides in quenched steel, so its wear resistance is higher than that of T8 and T8A steel, but its toughness is lower.

Tools that do not become hot when working, tools with sharp and slightly tough cutting edges that do not bear impact load, such as wood processing tools, cross saws, joinery tools, joinery tools, twist drills, wire drawing dies, stamping dies, cold heading dies, screwdrivers, reaming tools, thread washers, turning tools, planers, milling cutters, currency dies, etc.

T 1 1, T 1 1A for steel analysis. It has good comprehensive mechanical properties (such as hardness, wear resistance and toughness). ), the grain is finer, and it is less sensitive to the formation of carbide network when heated.

Tools used to make cutting edges that do not get hot when working, such as saws, chisels, taps, files, scrapers, clockwork, gauges, reamers, dies, tobacco cutting tools, small-sized cold stamping dies with no sharp change in cross section, woodworking tools, etc.

T 12 and T 12A were precipitated by steel. Because of the high carbon content, there are still more residual carbides after quenching, so the hardness and wear resistance are high, but the toughness is low and the quenching deformation is large. It is not suitable for manufacturing tools with high cutting speed and large impact load. Used to manufacture tools with no impact load, low cutting speed and no heating of cutting edge, such as turning tools, milling cutters, drill bits, reamers, taps, dies, scrapers, gauges, blades, small punches, steel files, saws, clockwork, tobacco cutting tools, cold trimming dies, small cross-section punching dies, etc.

T 13 and T 13A undergo * * * steel precipitation. Due to the high carbon content, there are more residual carbides after quenching, so the hardness is high and the toughness is poor; Moreover, due to the increase of carbide quantity, uneven distribution and poor mechanical properties. Not suitable for manufacturing impact load and high-speed cutting tools.

It is used to manufacture metal cutting tools that are not subject to impact load but require extremely high hardness, such as razors, scrapers, wire drawing tools, files, carving tools, drill bits, hard rock processing tools, carving tools, etc.

high-speed steel

1. Overview

High-speed steel, also known as wind steel or front steel, means that it can be hardened even if it is cooled in air during quenching, and it is very sharp. It is a kind of alloy steel with complex composition, which contains carbide forming elements such as tungsten, molybdenum, chromium and vanadium. The total amount of alloying elements is about 10 ~ 25%. High hardness can still be maintained under the high heat condition (about 500℃) caused by high-speed cutting, and HRC can reach above 60. This is the main feature of high-speed steel-red hardness. Although carbon tool steel has a high hardness at room temperature after low-temperature quenching and tempering, when the temperature is higher than 200℃, the hardness drops sharply, and when it reaches 500℃, the hardness is similar to the annealed state, and the ability to cut metal is completely lost, which limits the use of carbon tool steel for making tools. High-speed steel can make up for the fatal shortcomings of carbon tool steel because of its good red hardness, and can be used to manufacture tools.

The heat treatment process of high-speed steel is complex, and it has to go through a series of processes such as annealing, quenching and tempering. The purpose of annealing is to eliminate stress, reduce hardness, make the structure uniform and facilitate quenching. The annealing temperature is generally 860 ~ 880℃. Due to poor thermal conductivity, quenching is usually carried out in two stages. Preheat at 800 ~ 850℃ (to avoid causing large thermal stress), then quickly heat to the quenching temperature of 1220 ~ 1250℃, and then oil cool. All factories use salt stoves for heating. After quenching, some (about 30%) retained austenite did not transform into martensite due to internal structure, which affected the properties of high speed steel. In order to transform retained austenite and further improve hardness and wear resistance, it is generally necessary to temper for 2 ~ 3 times at 560℃ for 65438 0 hours each time.

(1) manufacturing method: electric furnace is usually used for production. Recently, high-speed steel was produced by powder metallurgy, which made carbides evenly distributed in the matrix with extremely fine particles and improved the service life.

(2) Application: It is used to manufacture various cutting tools. Such as turning tools, cobalt heads, hobs, machine saw blades and demanding molds.

2. Main production plants

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

3. Major importing and producing countries

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