hp 250 graphite electrode

Pubdate: 08-02 2021

Hp 250 graphite electrode production and processing application characteristics

hp 250 graphite electrode mainly uses petroleum coke and needle coke as raw materials, coal tar pitch as a binder, and is made by calcination, batching, kneading, pressing, roasting, graphitization, and machining. It is made in the form of electric arc in an electric arc furnace. The conductors that release electric energy to heat and melt the furnace charge can be classified into ordinary power hp 250 graphite electrode, high power hp 250 graphite electrode and ultra-high power hp 250 graphite electrode according to their quality indicators.

hp 250 graphite electrodehp 250 graphite electrode

The main raw material for the production of hp 250 graphite electrode is petroleum coke. For ordinary power hp 250 graphite electrode, a small amount of pitch coke can be added, and the sulfur content of petroleum coke and pitch coke cannot exceed 0.5%. Needle coke is also needed when producing high-power or ultra-high-power hp 250 graphite electrode. The main raw material for aluminum anode production is petroleum coke, and the sulfur content is controlled not to exceed 1.5% to 2%. The petroleum coke and pitch coke should meet the relevant national quality standards.

Advantages of hp 250 graphite electrode

(1) The increasing complexity of mold geometry and the diversification of product applications have led to higher and higher requirements for the discharge accuracy of the spark machine. The advantages of the hp 250 graphite electrode are that it is easier to process, the removal rate of electrical discharge machining is high, and the graphite loss is small. Therefore, some group-based spark machine customers abandon the copper electrode and switch to the hp 250 graphite electrode. In addition, some special-shaped electrodes cannot be made of copper, but graphite is easier to form, and copper electrodes are heavier and not suitable for processing large electrodes. These factors have caused some group-based spark machine customers to apply hp 250 graphite electrode.

(2) The hp 250 graphite electrode is easier to process, and the processing speed is significantly faster than that of the copper electrode. For example, the use of milling technology to process graphite, the processing speed is 2 to 3 times faster than other metal processing and does not require additional manual processing, while the copper electrode requires manual frustration. Similarly, if a high-speed graphite machining center is used to manufacture electrodes, the speed will be faster and the efficiency will be higher, and there will be no dust problems. In these processes, choosing tools with appropriate hardness and graphite can reduce tool wear and copper electrode damage. If you specifically compare the milling time of the hp 250 graphite electrode and the copper electrode, the hp 250 graphite electrode is 67% faster than the copper electrode. In general electrical discharge machining, the machining with the hp 250 graphite electrode is 58% faster than the copper electrode. In this way, the processing time is greatly reduced, and the manufacturing cost is also reduced.

(3) The design of the hp 250 graphite electrode is different from that of the traditional copper electrode. Many mold factories usually have different reservations for roughing and finishing of copper electrodes, while the hp 250 graphite electrode uses almost the same reservations, which reduces the number of CAD/CAM and machine processing. The reason is enough to improve the accuracy of the mold cavity to a large extent.

hp 250 graphite electrode machining

(1) Processing form of graphite material

There are three main types of processing for hp 250 graphite electrode: pressurized vibration method, numerical control automatic forming method and mechanical processing method.

(1) Pressurized vibration method: The pressurized vibration method requires a special machine tool, and the electrode master mold has the opposite shape to the electrode. The graphite material and the forming tool are placed relative to each other during processing, leaving a certain gap. The machining fluid, which is a mixture of water and abrasives, is injected into it. While passing the machining fluid, the graphite and the forming tool are ultrasonically vibrated. Under the action of the abrasive impact force, the graphite is slightly exfoliated into the required shape. The abrasive is SiC, B4C or diamond. The coarser the abrasive, the faster the processing speed. When the machine is working, it adopts the sealed type and water curtain type for processing. It is suitable for EDM forming in mass production.

(2) Numerical control automatic forming method: The numerical control automatic forming method requires a special hp 250 graphite electrode forming machine, which adopts the numerical control method, has an automatic tool exchange device, and can accommodate multiple tools. In order to improve the processing environment, the processing hp 250 graphite electrode is surrounded by a water curtain to prevent graphite dust from dispersing everywhere. In addition, the wet machining method can also be used to prevent tool wear and graphite dust from scattering by water-soluble cutting fluid. The machine tool has a high-performance filter device, which can separate the cutting fluid and graphite chips, and can ensure long-term continuous processing. It is an ideal special equipment for hp 250 graphite electrode processing, and is suitable for electrode processing for molds. However, its price is relatively high, and its application in China is not yet widespread.

(3) Mechanical processing method: The mechanical processing method is the main method adopted by general domestic mold production units.

Graphite materials can be processed by turning, milling, drilling and grinding methods. In addition, graphite materials are prone to fly ash during mechanical processing, which will adversely affect processing equipment and operators.

(2) Processing procedures for graphite materials

1) Graphite immersion oil. Graphite materials should be immersed in engine oil for dozens of hours before machining, so that the oil can penetrate into the graphite material so that the ash will not fly up during machining and a smoother surface can be obtained.

2) Paint and mark. After the electrode is rough-processed on the contour surface, a thin layer of white paint is sprayed on the scribed surface and then scribed, so that the lines are clear and easy for mechanical processing.

3) Perform mechanical processing.

Production characteristics of hp 250 graphite electrode

(1) Long production cycle. The production cycle of the ordinary power hp 250 graphite electrode is about 45 days, the production cycle of the ultra-high power hp 250 graphite electrode is more than 70 days, and the production cycle of the hp 250 graphite electrode joint that requires multiple dipping is longer.

(2) Higher energy consumption. The production of 1t ordinary power hp 250 graphite electrode requires about 6000kW·h of electricity, thousands of cubic meters of gas or natural gas, and about 1t of metallurgical coke particles and metallurgical coke powder.

(3) There are many production processes. The production process includes raw material calcination, crushing and grinding, batching, kneading, molding, roasting, impregnation, graphitization and mechanical processing. Its production requires a lot of special mechanical equipment and kilns with special structures, and the construction investment is relatively large, and the investment recovery period is relatively long.

(4) A certain amount of dust and harmful gases are generated during the production process, and it is necessary to adopt perfect ventilation and dust reduction and environmental protection measures to eliminate harmful gases.

(5) Petroleum coke and coal tar pitch are by-products of the production and processing of carbonaceous raw materials required by oil refineries and coal chemical companies. The quality and stability of the raw materials are difficult to be fully guaranteed, especially high-power and ultra-high-power hp 250 graphite Needle coke for electrode production, modified electrode pitch, and low quinoline insoluble content special impregnant pitch, urgently need the attention and active cooperation of my country’s petroleum and coal chemical processing enterprises.

hp 250 graphite electrode application

(1) For electric arc steelmaking furnace

Electric furnace steelmaking is a major user of hp 250 graphite electrode. The output of electric furnace steel in my country accounts for about 18% of the output of crude steel, and the hp 250 graphite electrode for steelmaking accounts for 70% to 80% of the total consumption of the hp 250 graphite electrode. Electric furnace steelmaking uses the hp 250 graphite electrode to introduce current into the furnace, and uses the high temperature heat source generated by the arc between the electrode end and the charge to smelt.

(2) Used in submerged electric furnace

The submerged electric furnace is mainly used for the production of industrial silicon and yellow phosphorus. Its characteristic is that the lower part of the conductive electrode is buried in the charge to form an arc in the charge layer, and the heat energy from the resistance of the charge itself is used to heat the charge, which requires current High-density submerged electric furnaces need hp 250 graphite electrode. For example, hp 250 graphite electrode needs to consume about 100kg to produce 1t of silicon, and hp 250 graphite electrode to produce 1t of yellow phosphorous to consume about 40kg.

(3) For resistance furnace

Graphitization furnaces for the production of graphite products, melting furnaces for melting glass, and electric furnaces for the production of silicon carbide are all resistance furnaces. The materials in the furnace are both heating resistors and objects to be heated. Usually, the conductive hp 250 graphite electrode is embedded In the furnace head wall at the end of the resistance furnace, the hp 250 graphite electrode used here is discontinuously consumed.

(4) Used to prepare special-shaped graphite products

The blank of hp 250 graphite electrode is also used to process various crucibles, molds, boats, heating elements and other special-shaped graphite products. For example, in the quartz glass industry, every production of 1t of fused tubes requires 10t of hp 250 graphite electrode blanks; every production of 1t of quartz bricks requires 100kg of hp 250 graphite electrode blanks.


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