Ceramic Corundum Abrasive
Abstract: Ceramic corundum abrasive (also known as SG abrasive) is a kind of new type of abrasive with excellent performance. It shows good application effect and development prospects in many fields such as automobile, bearing, tool and mold. This article describes the manufacturing technology, application and development prospects of this type of abrasive.
Key words: Ceramic corundum (SG abrasive), Manufacturing technology, Performance
Ceramic corundum abrasive is a new type of corundum abrasive developed successfully in the world more than ten years ago. Since its chemical composition is Al203, it is also called a new ceramic alumina abrasive. At home and abroad, it is also called SG abrasive according to the characteristics of its preparation process. After years of development and application, this kind of abrasive shows excellent grinding performance, which is regarded as the epoch-making abrasive in the world. The production and application of such abrasives is considered to be a major technological achievement in the field of grinding in the world. This article will explain the manufacturing technology and abrasive properties of this type of abrasive.
2 Manufacturing technology of ceramic corundum abrasive
Ceramic corundum abrasive is a high-purity corundum abrasive with a fine crystal structure synthesized by a unique ceramic technology. There are two typical manufacturing processes, one of which is synthesized by a sol-gel process (ie, a sol-gel process) and sintered. The specific method is as follows: firstly, the raw material is made into a hydrosol, and then gelatinized, and then dried, pre-crushed, granulated, sieved to form a certain particle shape and size, and finally calcined and sintered to make it high. Abrasives of toughness and hardness. The raw material may be made of soft boehmite or other aluminum medium, and nucleating materials such as Fe2O3 and Al2O3 may be added during the manufacturing process. To promote nucleation and lower the crystal transition temperature. At the same time, crystal growth inhibitors (such as TiO2, MgO, ZrO2, etc.) can be added to reduce grain growth to achieve a fine grain structure. The obtained gel body can be made into a dense solid by pressing or pressing, thereby ensuring the uniformity of the sintered abrasive. This type of process is currently used in the world to prepare the abrasive. The other type is directly obtained by grinding, extruding, granulating, drying and sintering a-Al2O3.
3 Characteristics of ceramic corundum abrasive
Ceramic corundum abrasives are produced differently from ordinary corundum abrasives, so they are not identical in structure and performance. Specifically in the following aspects:
(1) Microstructural aspects
Ordinary fused corundum abrasives contain only a very small amount of single crystals (sometimes only a single crystal) per crystal grain, and the crystal size is about 50 μm or more. The new ceramic corundum abrasive grains are composed of thousands of submicron or micron fine crystals. The crystal size of the abrasive grains is 1/15 to 1/200 of the crystal size of ordinary corundum abrasive grains. These large amounts of tiny abrasive particles give the abrasive particles a number of sharp cutting edges.
Due to its different microstructure, it differs in the abrasive fracture behavior. The new ceramic corundum abrasive exhibits fracture along the grain boundary, while the conventional fused corundum abrasive grains mostly exhibit transgranular fracture damage. Therefore, the new ceramic corundum abrasive has higher toughness than ordinary fused corundum abrasives, and is generally about 1 times higher.
(3) Wear mechanism and self-sharpness
The conventional fused corundum abrasive grains are flattened and passivated after being ground away at the working point. Under the action of grinding force, these blunt abrasive grains are not detached from the abrasive tool, or are ruptured along the crystal plane, and are macroscopically broken, and the abrasive grains are lost more. When the abrasive grains of the new ceramic corundum abrasive are broken after wear, they break along the grain boundary and are microscopically broken, and rarely cause macroscopic fracture, so the abrasive grain loss is less, the wear is less, and the service life is longer. The entire wear process of the new ceramic corundum abrasive particles is also a self-sharpening process of the abrasive particles themselves, during the effective service life. The surface of the abrasive grain layer is bluntly detached from the abrasive grain by the grinding force, and the new micro-cutting edge is continuously exposed, so that the abrasive grain is always in a sharp state, thereby ensuring The self-sharp function and the grinding performance of the grinding tool are stable. Therefore, the new ceramic corundum abrasive has good self-sharp performance and wear resistance compared with ordinary fused alumina abrasive.
Since the new ceramic corundum abrasive has excellent properties in terms of structure, toughness, wear characteristics and self-sharpness, it has the following advantages in terms of grinding performance:
(a) Sharp grain, strong cutting ability and high grinding efficiency. Large depth of cut, large feed, heavy load and efficient grinding. According to the relevant test, the single-stroke feed rate can reach O.25mm, and the metal removal rate can be more than 50% higher than the ordinary corundum grinding wheel.
(b) Self-sharpness, less grinding heat, low grinding temperature, no burns on the workpiece.
(c) Good toughness, low wear, good shape retention of the grinding wheel, for precision grinding and profile grinding, easy to obtain high dimensional accuracy and dimensional consistency.
(d) The grinding wheel has high durability and long service life (up to 2 to 10 times that of ordinary corundum grinding wheel), and the frequency of replacement is small. Reduced auxiliary machining time and downtime, facilitating the use of CNC automatic machine tools and automated production.
(e) The grinding wheel has good white sharpness and no clogging, which can maintain stable grinding performance, thus reducing the amount of dressing (1/2 to 1/3 of the general corundum grinding wheel), which can reduce the number of dressings (can be reduced by 80%) , to extend the trimming interval, reduce downtime and auxiliary processing time, and improve production efficiency.
(f) The performance is far superior to ordinary fused corundum abrasive, the price is far lower than CBN and diamond abrasive, and its hardness is similar to ordinary corundum abrasive. Therefore, special grinding equipment and dressing devices are not required, there are no special requirements for CBN and diamond grinding equipment and difficulties in dressing. There is no special requirement for grinding fluids for CBN grinding wheels. Therefore, it is easy to promote the application.