Classification and Development of Abrasives

Release time:

2023/08/24

Among them, the abrasive products are mainly divided into two categories: corundum abrasive and silicon carbide abrasive. Specifically, there are basically the following: 1. Brown corundum abrasive, the main component is Al2O3, with medium hardness, high toughness, sharp particles, relatively low price, suitable for processing metals with high tensile strength. Microcrystalline corundum abrasive and black corundum abrasive are derived varieties.

Among them, the abrasive products are mainly divided into two categories: corundum abrasive and silicon carbide abrasive. Specifically, there are basically the following:

1, brown corundum abrasive, the main component is Al2O3, with medium hardness, toughness, sharp particles, the price is relatively low, suitable for processing high tensile strength metal. Microcrystalline corundum abrasive and black corundum abrasive are derived varieties.

2, white corundum abrasive, its hardness is slightly higher than brown corundum, but the toughness is poor, easy to cut into the workpiece when grinding, good self-sharpening, heat is small, grinding ability is strong, high efficiency. Chromium corundum abrasive is its derived varieties.

3, single crystal corundum abrasive, the particles are composed of a single crystal, and has a good multi edge cutting edge, high hardness and toughness, grinding ability, grinding heat less, the disadvantage is higher production costs, lower output, so the price is relatively high. Zirconium corundum abrasive is also a crystal compound, the hardness is slightly lower, the crystal size is fine, and the wear resistance is good.

4. Black silicon carbide abrasive, green silicon carbide abrasive, cubic silicon carbide abrasive, cerium silicon carbide abrasive, etc., belong to silicon carbide abrasive, the main component is silicon carbide SiC, high hardness, brittleness, sharp abrasive particles, good thermal conductivity, strong wear resistance, more suitable for processing hard and brittle metal and non-metal products.

AbrasivesIt is a tool for grinding, grinding and polishing. Most of the abrasive tools [1] are usedAbrasiveMan-made with bonding agentAbrasivesIt is also useful for natural mineral rock directly processed into natural abrasive tools. Abrasives are widely used in machinery manufacturing and other metal processing industries, but also for food processing, paper industry and ceramics, glass, stone, plastic, rubber, wood and other non-metallic materials processing.

During the use of the abrasive tool, when the abrasive particles are blunt, due to the partial fragmentation of the abrasive particles themselves or the fracture of the bonding agent, the abrasive particles partially or completely fall off from the abrasive tool, and the abrasive tool on the working surface continues to appear new cutting edges, or constantly expose new sharp abrasive particles, so that the abrasive tool can maintain cutting performance within a certain period of time. This self-sharpening of the abrasive tool is the outstanding feature of the abrasive tool compared with the general tool.

As early as the Neolithic Age, human beings have begun to use natural grinding stones to process stone knives, stone axes, bone tools, angle tools, dental tools and other tools. In 1872, ceramic grinding wheels fired with natural abrasives and clay appeared in the United States. Around 1900, artificial abrasives came out, and various abrasive tools made of artificial abrasives were produced one after another, creating conditions for the rapid development of grinding and grinding machines. Since then, the proportion of natural abrasives in abrasives has gradually decreased.

Grinding according to its source of raw materials, there are two types of natural abrasives and artificial abrasives. The only natural abrasive tools commonly used in the mechanical industry are oilstones. According to the basic shape and structural characteristics, artificial abrasives are divided into five categories: grinding wheel, grinding head, oilstone, sand tile (collectively referred to as consolidated abrasives) and coated abrasives. In addition, it is customary to classify abrasives as a class of abrasives.

Fixed abrasives according to the different abrasives used, can be divided into ordinary abrasive fixed abrasives and super hard abrasive fixed abrasives. The former is made of ordinary abrasives such as corundum and silicon carbide, and the latter is made of superhard abrasives such as diamond and cubic boron nitride. In addition, there are some special varieties, such as sintered corundum abrasives.

Ordinary abrasive bonded grinding tool is a kind of grinding tool which is consolidated into a certain shape and has a certain strength by bonding agent. Generally composed of abrasive, bonding agent and pores, these three parts are often referred to as the three elements of fixed abrasive tools.

The abrasive plays a cutting role in the abrasive tool. Bonding agent is the loose abrasive bonded into abrasive materials, there are two types of inorganic and organic. Inorganic binders include ceramics, rhombilite and sodium silicate; organic ones include resin, rubber and shellac. Among the more commonly used are ceramic, resin and rubber binders.

The air hole plays the role of chip holding and chip removal on the grinding debris during grinding, and can accommodate the coolant, which helps to dissipate the grinding heat. In order to meet some special processing requirements, the pores can also be impregnated with certain fillers, such as sulfur and paraffin, to improve the performance of abrasive tools. This filler is also called the fourth element of the abrasive tool.

The items that represent the characteristics of ordinary abrasive bonded abrasives are: shape, size abrasive, particle size, hardness, organization, back velvet, back glue and bonding agent. Abrasive hardness refers to the abrasive grain under the action of external force, from the abrasive surface fall off the degree of difficulty, it reflects the bond holding abrasive strength.

The hardness of the abrasive mainly depends on the amount of binder added and the density of the abrasive tool. The abrasive grains that are easy to fall off indicate that the hardness of the abrasive tool is low; on the contrary, it indicates that the hardness is high. The hardness level is generally divided into super soft, soft, soft, medium, medium hard, hard and super hard seven levels, from these levels can be subdivided into a number of small levels. The method of determining the hardness of abrasive tools is more commonly used, such as hand cone method, mechanical cone method, Rockwell hardness tester method and sandblasting hardness tester method.

The hardness of the abrasive has a corresponding relationship with its dynamic elastic modulus, which is conducive to the determination of the dynamic elastic modulus of the abrasive by the audio method to represent the hardness of the abrasive. In the grinding process, if the material hardness of the grinding workpiece is high, the abrasive tool with low hardness is generally selected; on the contrary, the abrasive tool with high hardness is selected.

The abrasive tissue is roughly divided into three categories: tight, medium and loose. Each category can be subdivided into fractions and so on, which are distinguished by organization numbers. The larger the abrasive tissue number, the smaller the volume percentage of the abrasive in the abrasive, and the wider the gap between the abrasive grains, the looser the tissue. Conversely, a smaller organization number indicates a tighter organization. The looser tissue of the abrasive tool is not easy to be passivated when used, and the heat is less in the grinding process, which can reduce the heat deformation and burn of the workpiece. The abrasive grains of the abrasive tool with tighter organization are not easy to fall off, which is beneficial to maintain the geometric shape of the abrasive tool. The organization of the abrasive tool is only controlled according to the formulation of the abrasive tool at the time of manufacture, and is generally not measured.

Keywords: Abrasive classification and development history

Saluting Our Great Motherland: Shenli Company Employees Watch the Military Parade

Simple introduction of abrasives

Saluting Our Great Motherland: Shenli Company Employees Watch the Military Parade

Simple introduction of abrasives