High-temperature graphite carbon bush and production method

Abstract

The invention discloses a high-temperature graphite carbon bush and a production method, wherein the high-temperature graphite carbon bush is suitable for carrying out heat treatment on a high-trademark cold rolling silicon steel sheet under the condition of high temperature (950-1,050 DEG C). The method comprises the following steps: mixing and kneading raw materials; molding; and dipping the raw materials by an antioxidant, wherein the raw materials comprise the following components in percentage by weight: 65-70 percent of powder with the grain diameter of 300-400 meshes and 30-35 percent of modified asphalt; the powder comprises the following components in percentage by weight: 99.5-99.8 percent of needle coke, 0.3-0.5 percent of titanium nitride and 0.2-0.3 percent of molybdenum disilicide; the modified asphalt is prepared by melting and dewatering high-temperature coal tar pitch and then adding phenolic resin to modify the coal tar pitch, and the weight ratio of the high-temperature coal tar pitch to the phenolic resin is 100:(3-5). The manufactured graphite carbon bush has the characteristics of high strength, wear resistance, good thermal shock resistance and good beading resistance and oxidation resistance; in addition, the working temperature can reach more than 1,050 DEG C.

Description

Technical field: [0001] The invention relates to a graphite carbon sleeve and a production method, in particular to a high-temperature graphite carbon sleeve suitable for heat treatment of high-grade cold-rolled silicon steel sheets under high temperature conditions (above 950-1050°C) and a production method. Background technique: [0002] The heat treatment conditions for high-grade cold-rolled silicon steel sheets are: N 2 -H 2 The dry atmosphere is 950-1050°C, and the operating speed is greater than or equal to 70 m / min. Under such high temperature conditions, the various indicators of the graphite carbon sleeve that is in direct friction contact with the silicon steel sheet will directly affect the quality and output of the silicon steel sheet production. The existing graphite carbon sleeves use petroleum coke or pitch coke as aggregates, and after crushing, grinding and screening, carry out particle size classification, and mix large, small and fine particles according...

AI Technical Summary

Problems solved by technology

Due to the transfer process of the extruded paste from the material chamber to the extrusion nozzle, the paste at the center of the extrusion nozzle is subject to less resistance and moves faster, and the paste close to the inner wall of the extrusion nozzle With high resistance and slow moving speed, this "layered movement" leads to the following defects in the quality of pressed products: first, the product density gradually decreases from the surface layer to the center, that is, the density of different parts along the radial direction is uneven; The radial coarse and fine particle size distribution is uneven (the surface layer has more fine particles, and the center has more coarse particles); the third is that the structure is a layered structure

The above three defects will make the graphite carbon sleeve poor in strength, wear resistance and thermal shock resistance, not only easy to break, fast consumption, short service life, but also prone to "nodules" and "peeling", which will cause the silicon steel sheet to be damaged due to surface damage. Roll printing, scratching and scrapping, at the same time, the occurrence of "nodules" will force the annealing furnace to stop working and affect the production schedule

[0004] 2. Chromic acid is used as the anti-oxidation impregnating liquid. Because of its certain toxicity, it affects environmental protection and endangers the health of operators. The dispersibility and permeability are poor, so that it is difficult to impregnate graphite particles that have been roasted two or three times and impregnated with asphalt. In the hole, resulting in low impregnation weight gain rate and poor thermal oxidation resistance

[0005] 3. Due to the lack of reasonable design of the graphitization power transmission power curve, during the temperature rise process, the product often cracks due to severe expansion and contraction, resulting in low product yield

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