How to distinguish between the advantages and disadvantages of Expandable Graphite?
1. The flexural strength of the data
The flexural strength of the data is an indirect representation of the intensity of the data, showing the rigorous level of the external structure of the data. High strength of the data, the discharge loss of the function is absolutely better, on the high precision electrode, try to choose a better strength of the information. For example: TTK-4 can meet the requirements of ordinary electronic connector mold, but some special precision requirements of the electronic connector mold, you can use the same particle size, but the strength of slightly higher data TTK-5 information.
2. Data of Shore hardness
In view of the submerged view of Expandable Graphite, Expandable Graphite is generally thought to be a relatively soft data. But the actual test data and the use of the situation shows that the hardness of Expandable Graphite than the metal data. In the special Expandable Graphite industry, the general hardness test specification is the Shore hardness measurement method, the test principle and the metal test principle is different. Due to the layered structure of the Expandable Graphite, it has a very superior cutting function in the cutting process. The cutting force is only about 1/3 of the copper material, and the appearance after machining is easy to handle.
But because of its high hardness, in the cutting, the tool on the loss will be slightly larger than the cutting metal tool. At the same time, the hardness of the data in the discharge loss control is better. In our EDM data system, the use of more information on the same size of the two materials are available to choose from, a slightly higher hardness, a slightly lower hardness to meet the different requirements of the customer's demand. Such as: uniform particle size of 5μm information, ISO-63 and TTK-50; uniform particle size of 4μm information, TTK-4 and TTK-5; uniform particle size of 2μm information, TTK-8 and TTK -9. The second is to think about the variety of customers on the discharge and the direction of the processing of the machine.
3. The average particle diameter of the data
The uniform particle diameter of the data indirectly affects the discharge of the data. The smaller the uniformity of the data, the more average the discharge of the data, the more resolute the discharge, the better the appearance quality.
In the metallurgical industry, the natural scale scalable graphite due to better oxidation resistance can be used for consumption of magnesium carbon brick and aluminum carbon brick and other refractory materials. Natural Expandable Graphite can be used as a steel-making electrode, and naturally extrudable graphite electrode is difficult to use for more demanding steel-making electric furnace.
In the machine industry, Expandable Graphite data is usually used for wear and smooth data. Natural scales Expandable Graphite smoothness is good, commonly used as a smooth oil additives. Conveying corrosive media equipment, commonly used in natural Expandable Graphite made of piston rings, seals and bearings, the obligation without the need to participate in smooth oil. Natural Expandable Graphite and polymer resin composite materials can also be used in the above range, but the wear resistance as natural expansive graphite.
In the chemical industry, the natural expansive graphite with corrosion resistance, good thermal conductivity, permeability and other characteristics of the first. In the chemical industry is generally used in the manufacture of heat exchangers, reaction tanks, absorption towers, filters and other equipment. Natural Expandable Graphite and polymer resin composite materials can also be used in the above range, but the thermal conductivity, corrosion resistance as natural expansive graphite.
Pyrolytic carbon and pyrolytic Expandable Graphite have good high temperature resistance and corrosion resistance, so in the expansion of graphite material surface by chemical vapor deposition method to deposit a certain amount of pyrolytic carbon or pyrolytic expansive graphite, can increase the expansion Graphite material oxidation resistance, however, the most serious shortcomings of pure pyrolytic carbon coating is anisotropic, easy to peeling in practice.