Ordinary grinding wheel material, granularity, hardness, grinding wheel mark, code

1. Material of grinding wheel:
1. Material types: A, WA, SA, PA, GC, C, 38A, DA, 19A6 S3 W j” G, _4 [2 G$ g
2. Material selection: 4 d l” `5 A1 h# g0 H
A ——Brown corundum abrasive with brown color, high hardness and high toughness. Suitable for grinding metals with high tensile strength, such as carbon steel, alloy steel, malleable cast iron, hard bronze, etc. $ d, c( Y) j3 O: r/ S
WA-white corundum abrasive, with white color and higher hardness than brown corundum, abrasive grains are easily broken, sharp edges and corners, good cutting performance, and small grinding heat. Suitable for grinding hardened steel, alloy steel, high speed steel, high carbon steel, thin-walled parts, etc.
SA——Single crystal corundum abrasive with light yellow color. Compared with A and WA abrasives, it has high hardness and high toughness. It is single-particle spherical crystal and has strong crush resistance. It is suitable for grinding materials with high toughness and high hardness such as impermeable steel and high vanadium high speed steel and workpieces that are easily deformed and burned.
PA-chrome corundum abrasive with rose or fuchsia color, sharp cutting edge, good edge retention and high durability. It is suitable for grinding workpieces with low surface roughness values ​​such as knives, measuring tools, instruments, threads, etc. % `: B” a* s, ?# F5 m
GC——Green silicon carbide abrasive with green color, high hardness, brittleness, sharp abrasive and certain thermal conductivity. Suitable for grinding cast iron, brass, lead, zinc and rubber, leather, plastic, wood, ore, etc. ‘\/ T+ i: s1 G% L# [7 Q s2 s, [
C——Black silicon carbide abrasive with gray-black color, high hardness, high brittleness, sharp abrasive grains and good thermal conductivity. It is suitable for grinding hard and brittle materials such as cemented carbide, optical glass and ceramics. . }. @ a’A4 p8 O
2. Grinding wheel granularity: ←Coarse…20#, 24#, 30#,…180#, 220#, 240#,… Fine →’M$ Z: L) L6 `4 b G
3. Hardness of grinding wheel: ←Soft E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T Hard →
4. Marking of the grinding wheel: For example, the marking of the grinding wheel is: WA46L5V351A350×40×127, where the letter codes and data represent the meanings as follows: WA→Abrasive material used for the grinding wheel 35→The linear speed of the grinding wheel is 35M/S 46→Grinding wheel size 1A→ Grinding wheel shape L → Grinding wheel hardness 350 → Grinding wheel diameter size 5 → Grinding wheel organization number 40 → Grinding wheel thickness dimension V → Grinding wheel is ceramic grinding wheel 127 → Grinding wheel inner hole size
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1) Single crystal corundum abrasive
Single crystal corundum abrasive is Al203 precipitated from the melt in the form of single crystal of physical corundum, and most of the abrasive grains obtained by chemical treatment are single crystal abrasives. It has high toughness and hardness, and strong cutting ability. It is used to process tool steel, stainless steel, high vanadium steel and other tough and wear-resistant materials with high hardness, which is superior to other materials.
Main technical performance index:. E” B9 l( V$ U0 W# T
–Technical parameters of smelting equipment: 1100KVA electric arc furnace, electrode garden: D=900MM;
–Average grain size: 0.5MM “W6 h$ C0 I! s1 C( c# o
– Yield: greater than 92%;! C9 E5 Y* i! x# V, k: C
–Chemical composition: TiO2 (0.27%), SiO2 (0.1%), Fe2O3 (0.16%), Al2O3≥94%.
(2) High-grade brown corundum calcined abrasive% T5 n ]0 w6 ~3 ^. m7 O
The product has the characteristics of high chemical composition, good particle size and shape, high cleanliness and high bulk density. Widely used in industries such as airplanes, automobiles, ships and machinery manufacturing. The main technical performance indicators are in a leading position in the country.
(3) Diamond grinding wheel for CRT! }/ c3 ?; F9 K( [+ m” j
This product was successfully developed under the guidance of a well-known domestic superhard material expert. Compared with traditional products, it has strong adhesion, high grinding rate, and long life (150000 hours/piece); compared with imported products However, it is mainly used in the grinding and polishing of kinescopes, and has been put into mass production.
(4) Metal nanomaterials
The product has passed the test of the Test Center of the Iron and Steel Research Institute of the Ministry of Metallurgy. It can be widely used in the fields of electronic information technology, mechatronics technology, bioengineering technology, energy, new materials and national defense science and technology. The technical level is in a leading position in the country and has reached the advanced technical level of similar foreign products. Its main technical performance indicators are:
– Particle size: The average particle size of metal nanopowders converted by BET specific surface area measurement method is ≤100nm;% m$ k/ m7 e. O” q” D- i
–Purity: The element content is basically the same as the raw material 99.99% (except oxygen);; n# S% k( T8 C7 v1?
–Rated arc power: single-stage 10kw, double-stage 20kw, three-stage 30kw;
–Operation mode: continuous operation ≥8 hours; 5 _: W H$ n S
– Yield: Ni, Cu ≥ 100 g/h; “z; g” r7 `’r$ J6 q
–Suitable for the extraction of various metal nanomaterials.
(5) Black corundum abrasive
Black corundum is a kind of physical corundum, which has the characteristics of improving crystallization rate, yield rate, grade and so on. It is widely used in the field of special metal processing polishing and grinding. Skill
The main technical performance indicators are as follows: ‘\1 c1 }6 o- w
–Technical parameters of smelting equipment: arc power: 1100KVA, electrode circle D=900MM-G’q) q2 r( t4 M9 o” z: r
–Process parameters: V=102, I=9000A, smelting time H=12 hours
–Average grain size: 0.5MM; N! M) Y; {T* s
–Chemical composition: TiO2(2-3%), SiO2(4-8%), CaO+MgO(<4%)) |5 b8 y2 h- o( M. V+ o+ e
(6) Semi-crisp corundum
The hardness of semi-brittle corundum is higher than that of brown corundum, and the toughness is between brown corundum and white corundum. The processed sand grains are protruding, sharp, and self-sharpening. It is mainly used for titanium alloy, stainless steel and other alloys with obvious work hardening. Processing efficiency and processing quality are far superior to other ordinary abrasives. The technical indicators are as follows:
–Color: light red 2 I# t8 [‘E+ p2 g3 O% O; \?
–Crystal size: ≥1mm The crystal is pure, without obvious carbide impurities. $ y, F- o) z1 \3 ~5 s
–Chemical composition: Al2O3 %: ≥97.3 TiO2%: =1.6±0.2: X1 ^+ m; S3 ?3 @ C
SiO2 %: ≤0.45 Fe2O3%: ≤0
Abrasive tools are tools for grinding, grinding and polishing. Most abrasive tools are artificial abrasive tools made of abrasives and binders, and natural abrasive tools directly processed from natural mineral rocks. In addition to being widely used in machinery manufacturing and other metal processing industries, abrasive tools are also used in food processing, paper industry, and processing of non-metallic materials such as ceramics, glass, stone, plastic, rubber, and wood. During the use of the abrasive tool, when the abrasive particles are blunt, the abrasive particles are partially broken or the bond is broken, the abrasive particles are partially or completely detached from the abrasive tool, and the abrasive on the working surface of the abrasive tool is constantly cutting The cutting edge, or new sharp abrasive particles are constantly exposed, so that the abrasive tool can maintain the cutting performance within a certain time. The self-sharpening of the grinding tool is a prominent feature of the grinding tool compared with the general tool. As early as the Neolithic era, humans have begun to use natural grinding stones to process tools such as stone knives, stone axes, bone tools, prongs, and dental tools; in 1872, a combination of natural abrasives and clay appeared in the United States. Ceramic grinding wheels; around 1900, artificial abrasives came out, and various abrasive tools made of artificial abrasives were produced one after another, which created conditions for the rapid development of grinding and grinding machines. Since then, the proportion of natural abrasives in abrasives has gradually decreased.

Abrasives are divided into natural abrasives and artificial abrasives according to their raw material sources. The only natural abrasive used in the machinery industry is oilstone. Man-made abrasive tools are classified according to their basic shape and structural characteristics. There are five types of grinding wheels, grinding heads, oil stones, sand tiles (collectively referred to as consolidated abrasive tools) and coated abrasive tools. In addition, it is customary to classify abrasives as a class of abrasives. According to the different abrasives used, consolidated abrasives can be divided into ordinary abrasive consolidated abrasives and super-hard abrasive consolidated abrasives. The former is made of ordinary abrasives such as corundum and silicon carbide, and the latter is made of super-hard abrasives such as diamond and cubic boron nitride. In addition, there are some special varieties, such as sintered corundum abrasive tools. Ordinary abrasive consolidating abrasive is a kind of abrasive that has a certain strength and is consolidated by a binder. Generally composed of abrasives, bonding agents and pores, these three parts are often referred to as the three elements of consolidated abrasives. The abrasive plays a cutting role in the abrasive tool. Binders are materials that consolidate loose abrasives into abrasive tools. There are two types, inorganic and organic. Inorganic binders include ceramics, lodestone and sodium silicate; organic ones include resin, rubber and shellac. The most commonly used are ceramic, resin and rubber binders. The air holes play a role in chip removal and chip removal during grinding, and can contain cooling liquid, which helps dissipation of grinding heat. In order to meet some special processing requirements, the pores can also be impregnated with certain fillers, such as sulfur and paraffin, etc., to improve the performance of abrasive tools. This filler is also called the fourth element of the abrasive. The items representing the characteristics of ordinary abrasive consolidated abrasives are: shape, size abrasive, particle size, hardness, structure and bonding agent. Grinding tool hardness refers to the difficulty of the abrasive particles falling off the surface of the abrasive tool under the action of external force, which reflects the strength of the binder to hold the abrasive particles. The hardness of the grinding tool mainly depends on the amount of binder added and the density of the grinding tool. The abrasive particles easily fall off indicating that the hardness of the grinding tool is low; otherwise, the hardness is high. The hardness level is generally divided into seven major levels: super soft, soft, medium soft, medium, medium hard, hard and super hard. From these levels, several small levels can be further subdivided. The methods for measuring the hardness of abrasive tools are more commonly used: hand cone method, mechanical cone method, Rockwell hardness tester and sandblast hardness tester.

The hardness of the grinding tool has a corresponding relationship with its dynamic elastic modulus, which is beneficial for measuring the dynamic elastic modulus of the grinding tool by the audio method to represent the hardness of the grinding tool. In the grinding process, if the hardness of the workpiece to be ground is high, generally use low hardness abrasive tools; otherwise, use high hardness abrasive tools. Abrasive tools are roughly divided into three categories: tight, medium and loose. Each category can be further subdivided, etc., to distinguish by organization number. The larger the abrasive tissue number, the smaller the volume percentage of abrasive in the abrasive, and the wider the gap between abrasive grains, the looser the tissue. Conversely, the smaller the organization number, the tighter the organization. Abrasive tools with looser structure are not easy to passivate when used, and generate less heat during grinding, which can reduce the heat deformation and burns of the workpiece. Abrasive particles of tightly organized abrasives are not easy to fall off, which is helpful to maintain the geometric shape of the abrasive. The organization of the abrasive tool is only controlled according to the abrasive formula during manufacturing, and generally not determined. Super-hard abrasive consolidating abrasives are mainly abrasives consolidated with diamond, cubic boron nitride and other bonding agents. Due to the high price of diamond and cubic boron nitride, and good wear resistance, the fixed abrasives made of them are different from ordinary abrasive fixed abrasives. In addition to the super-hard abrasive layer, there is also a transition layer and a matrix. The super-hard abrasive layer is the part that plays the role of cutting and is composed of super-hard abrasive and bonding agent. The base body plays a supporting role in grinding, and is composed of materials such as metal, bakelite, or ceramics. The transition layer is used to connect the substrate and the super-hard abrasive layer, and is composed of a bonding agent, which can sometimes be omitted. Commonly used binders are resins, metals, electroplated metals and ceramics.

The manufacturing processes of consolidated abrasives include: distribution materials, mixing materials, molding, heat treatment, processing and inspection. Depending on the binder, the manufacturing process is different. The ceramic bond abrasive mainly adopts the pressing method. After weighing the abrasive and the bond according to the weight ratio of the formula, it is placed in the mixer and mixed evenly, put into the metal mold, and the abrasive blank is formed on the press. The blank is dried and then loaded into the kiln for roasting. The firing temperature is generally around 1300℃. When a low melting point bonding agent is used, the firing temperature is lower than 1000°C. Then accurately processed according to the specified size and shape, and finally check the product. Resin bond abrasives are generally formed on a press under room temperature conditions, and there are also hot pressing processes that apply pressure while heating under heating conditions. After molding, it is hardened in a hardening furnace. When phenolic resin is used as the binder, the curing temperature is 180-200°C. Rubber bond abrasives are mainly mixed by a pair of roller machines, rolled into sheets, and then punched and formed by punching; some are also made of loose materials, put into a metal mold and formed on a press. After molding, it is vulcanized in a vulcanization tank at a temperature of 165-180℃. There are two kinds of manufacturing methods for metal bond abrasives: powder metallurgy and electroplating, which are mainly used for super-hard abrasive consolidating abrasives. The powder metallurgy method uses bronze as a binding agent. After mixing, it is formed by hot pressing or pressure molding at room temperature, and then sintered. In the electroplating method, nickel or nickel-cobalt alloy is used as the electroplating metal, and the abrasive is fixed on the substrate according to the electroplating process to form an abrasive tool. Special varieties of mills have sintered corundum abrasives and fiber abrasives. The sintered corundum abrasive is made by mixing and shaping alumina fine powder and appropriate amount of chromium oxide, and sintering it at about 1800℃. This abrasive tool has a compact structure and high strength, and is mainly used for processing clocks, meters and other parts. Fiber abrasives are made of fiber filaments (such as nylon filaments) containing or adhering abrasives. It has good elasticity and is mainly used for polishing metal materials and their products.