Graphite powder using graphite electrodes does have many advantages, but how to use the advantages of this material to truly improve efficiency, reduce costs, improve market competitiveness. These issues are only considered by graphite manufacturers, but also for graphite. The user should be careful about the problem. So what problems should be solved first when applying graphite materials?
Dust removal: Because graphite has a fine particle structure, a large amount of dust will be generated during machining, which has a greater impact on the factory environment; in addition, the impact of dust on equipment is mainly reflected in the impact on the power supply of the equipment, due to the conductivity of graphite Very good, after entering the power box, it is easy to cause power short-circuit other faults; therefore, it is recommended to equip a graphite processing machine for processing. However, due to the high investment cost of special graphite processing equipment, many companies are more cautious in this regard. In this case, the following solutions can be adopted:
Graphite electrode outsourcing: With the increasing application of graphite in the mold industry, more more mold foundry (OEM) companies have also introduced graphite electrode foundry business.
Processing after immersion in oil: After purchasing graphite, soak it in spark oil for a period of time (according to the volume of graphite), then put it in the machining center for processing. In this way, graphite dust will fly randomly, but Down. This will minimize the impact on equipment the environment.
Modification of the machining center: The so-called modification is mainly to install a vacuum cleaner on an ordinary machining center.
Discharge gap during electrical discharge graphite machining: Different copper, because the graphite electrode discharges faster more slag is corroded per unit time, how to effectively discharge the slag becomes a problem; therefore, the discharge gap is required to be larger than copper some. Generally speaking, when setting the discharge gap, the discharge gap of graphite is 10-30% larger than that of copper.
Correctly understand its shortcomings: In addition to dust, graphite also has some shortcomings. For example, when processing mirror molds, compared with copper electrodes, graphite electrodes are more difficult to achieve the desired effect. To achieve better surface effects, you need to choose the finest particle graphite, the cost of this kind of graphite is often more than ordinary Graphite is 4 to 6 times higher. In addition, the reusability of graphite is low. Due to the production process, only a small part of graphite can be used for reproduction utilization. The waste graphite after EDM cannot be reused temporarily, so it brings a certain test to the company's environmental management. In this regard, the waste graphite can be recycled for customers free of charge, so as to avoid troubles for customers' environmental certification.
Corner chipping in machining: Since graphite is more brittle than copper, if you use the method of processing copper electrodes to process graphite, it is easy to cause electrode chipping, especially when processing thin-ribbed electrodes. In this regard, we can provide free technical support for mold manufacturers. It is mainly achieved through tool selection, the way of cutting, the reasonable configuration of processing parameters. Natural flake graphite was cold-pressed without binder to form natural flake graphite samples, the effects of the changes in molding pressure holding time on the density, porosity flexural strength of the samples were studied. The relationship between the microstructure flexural strength of natural flake graphite samples is qualitatively analyzed. Two systems of boric acid-urea tetraethyl silicate-acetone-hydrochloric acid were selected to study discuss the antioxidant properties mechanisms of natural graphite powder natural graphite electrode samples before after the antioxidant treatment. The main research contents results are as follows: The molding properties of natural flake graphite the influence of molding conditions on the microstructure properties are studied. The results show that the greater the molding pressure of the natural flake graphite sample, the greater the density flexural strength of the sample, the smaller the porosity of the sample; the holding time has little effect on the density of the sample, the sample is formed after 5 minutes The performance is better; the flexural strength shows obvious anisotropy, the average flexural strength in different directions is 5.95MPa, 9.68MPa, 12.70MPa. The anisotropy of flexural strength is closely related to the microstructure of graphite.
The oxidation resistance before after the preparation of boron nitrogen system silica sol coating natural flake graphite powder by solution method sol method was studied. The results show that as the number of immersion increases, the amount of silica sol boron nitrogen system coated on the surface of the graphite powder is more, the oxidation resistance is better; the oxidation starting temperature of natural flake graphite is 883K, the oxidation at 923K The weight loss rate is 407.6mg/g/h; the boric acid-urea system the ethyl silicate-ethanol-hydrochloric acid system are used for 9 times of immersion, the graphite powder is heat-treated under 1273K, N2 atmosphere for 1 hour. 923K was 47.9 mg/g/h 206.1 mg/g/h, respectively; after heat treatment in 1973K 1723K N2 atmosphere for 1 hour, the oxidation weight loss rate of natural flake graphite was 3.0 mg/g/h 42.0 mg/h at 923K, respectively. g/h; Both systems can reduce the oxidation weight loss rate of natural flake graphite, but the antioxidant effect of the boric acid-urea system is better than that of the ethyl silicate-ethanol-hydrochloric acid system.
Graphite electrodes are mainly used in large-scale industries such as electric furnace steelmaking, ore furnace phosphorus production, fused magnesia, electric fusion preparation of refractory materials, electrolytic aluminum, industrial production of phosphorus, silicon, calcium carbide. Graphite electrodes are divided into two types: natural graphite electrodes artificial graphite electrodes. Compared with artificial graphite electrodes, natural graphite electrodes do require the graphitization process, the production cycle of natural graphite electrodes is greatly reduced, energy consumption pollution are also greatly reduced, the cost is significantly reduced, it has obvious price advantages economic benefits. It is one of the main reasons for the development of natural graphite electrodes.
In addition, natural graphite electrode is a high value-added natural graphite deep-processing product, which has great development application value. However, the forming performance, oxidation resistance mechanical properties of natural graphite electrode are currently inferior to artificial graphite electrode, which is the main obstacle to its development. Therefore, overcoming these obstacles is the key to developing the application of natural graphite electrodes.
The oxidation resistance before after the preparation of boron nitrogen system silica sol coating natural flake graphite block by solution method sol method was studied. The results show that the silica sol-coated natural graphite block has worse oxidation resistance with the increase of the number of dipping; the boron nitrogen system coated natural graphite block has the better oxygen resistance with the increase of the number of dipping; natural graphite block The oxidation weight loss rates at 923K 1273K were 122.432mg/g/h 191.214mg/g/h, respectively; boric acid-urea system ethyl silicate-ethanol-hydrochloric acid system were used for 9 impregnations, at 1273K, N2 atmosphere After 1 hour of heat treatment, the oxidation weight loss rates of natural graphite blocks were 20.477mg/g/h 28.753mg/h at 923K; 37.064mg/g/h 54.398mg/g/h at 1273K; After treatments at 1973K 1723K, the weight loss rates of natural graphite blocks were 8.182 mg/g/h 31.347 mg/g/h at 923K; 126.729 mg/g/h 169.978 mg/g/h at 1273K. ; Both systems can greatly reduce the oxidation weight loss rate of natural graphite blocks. Similarly, the antioxidant effect of the boric acid-urea system is better than that of the ethyl silicate-ethanol-hydrochloric acid system.