Slide board lubricating coating and preparation method thereof
Technical field
The present invention relates to a kind of slide gate nozzle slide board lubricating coating, particularly relate to a kind of slide plate mouth of a river, the revolution mouth of a river, filling pipe end and continuous cast mold etc. of being used for, can improve the slip coating of its surface lubrication performance, belong to the slip coating field.
Background technology
Slide gate nozzle is a vitals of steel-making continuous casting equipment, the quality of its performance will directly have influence on the control of molten steel in the casting process, directly have influence on the bleed-out situation of casting cycle, the quality of continuously cast bloom and to pollution of molten steel etc., therefore, performance and the quality to slide gate nozzle proposed more and more higher technical requirements.The working conditions of slide gate nozzle specifically has: (1) needs to contact with high-temperature molten steel for a long time; (2) satisfying under the different casting process requirement conditions, need stand violent chemical erosion of molten steel and physics erosion repeatedly; (3) mechanical wear in the time of need bearing violent thermal shocking of high-temperature molten steel and switching between slide plate etc.Therefore, require slide plate must possess good thermal-shock resistance, erosion resistance, abrasion resistance and hot strength etc.Simultaneously, for switching that realizes slide plate smoothly and the function of controlling molten steel flow, planeness, parallelism and the size etc. of sled surface all there is the technical requirements of strictness.Slide plate is as the slide unit of control molten steel flow in the slide gate nozzle, after watering time use more, because the frequent friction of contact surface will bring the wearing and tearing of sled surface inevitably, destroyed the integrity of the tight zone of sled surface, reduced the corrosion resistance of slide plate flexible movements degree and slide plate, simultaneously, the increase of slide plate contact surface friction will influence the degree of flexibility of its slip and the accuracy of molten steel flow control.
By covering high temperature resistant, anti-molten steel erosive slip coating, can improve the surface finish and the slickness of slide plate, thereby make slide plate obtain longer work-ing life and more excellent performance in sled surface.Just carried out the research work of relevant slide board lubricating coating abroad in the eighties in 20th century.For example, the big new Chemical Co., Ltd of Japan has worked out the DSS slide board lubricating coating, this coating adopts the high-purity natural crystalline flake graphite after gelatinizing, mixes refining forming with water-soluble wedding agent, by brushing or spraying, form the slip coating of the smooth densification of one deck in sled surface, and can fill up the convex-concave defective of the sled surface that causes because of mechanical workout, make sled surface smooth smooth, and under low friction load, slide neatly, simultaneously, also has the good anti-wetting property of anti-dry slag.But the prescription and the production technique of external slide board lubricating coating hold in close confidence, and import price is very expensive, and obviously domestic refractory materials and iron and steel producer is difficult to bear, so the import slip coating can only use in high-end slide plate upper limit amount.
At this present situation, domestic relevant enterprise and scientific research institutions have carried out the research about the slide board lubricating coating aspect.Find by literature search, patent " sliding plate lubricant coating and preparation method thereof the " (application number: 200410012887.2) reported a kind of sliding plate lubricant coating and preparation method thereof that Ouyang De has just waited, system adopts inorganic bentonite, water-soluble graphite dispersion agent, silicon sol, ethylene glycol, ethanol and water-soluble siccative, water-soluble polypropylene acid resin or polyurethane latex or two kinds of composite emulsions constitute organic bond and trolamine, in colloidal mill, mix, adding the natural flake graphite micro mist again stirs, treat that it mixes back adding silicon carbide micro-powder and alumina powder mixes, finally obtain sliding plate lubricant coating, the use properties of this lubricant is better, than with lubricator slide plate life-span does not improve once/cover.But because the antioxidant property of the natural flake graphite that is adopted is poor, so limited for the protective capability of slide plate, simultaneously, the additive types that is adopted is various, makes the process for preparation of slip coating comparatively loaded down with trivial details.
Summary of the invention
The present invention is directed to the deficiency of above technology; a kind of aluminium charcoal sliding gate slide board that is mainly used in is provided; and the lubricated and protective cover of the revolution mouth of a river, filling pipe end and continuous cast mold etc.; the oxidation-resistance of raising sliding gate slide board etc. and the high temperature lubricating between slide plate; in sled surface covering protection coating; can reduce the oxidation rate of carbon material in the slide plate; improve the work-ing life of slide plate; can also reduce simultaneously the frictional force of slide plate contact surface; anti-limited slip plate face pull generation with fluffiness, thereby improve the use properties of slide plate.
The objective of the invention is to realize according to following method: a kind of lubricated and protective cover that is mainly used in aluminium charcoal sliding gate slide board, according to weight percent, mainly form: aqueous solution 50-80%, solid micro-powder 20-50% by following component and content.The described aqueous solution is the some kinds of aqueous solution organic and inorganic additives is dissolved in the water and obtains; Described pressed powder comprises the natural flake graphite and the inorganic powder additive that pass through chemical conversion treatment.The aqueous solution wherein comprises mainly that sodium alginate, polyvinylpyrrolidone, silicon sol are proportionally soluble in water to form, and forms and content is: water 70-90%, sodium alginate 5-10%, polyvinylpyrrolidone 1-2%, silicon sol 4-18%; Described pressed powder comprises that particle diameter is the crystalline flake graphite 80-98% of 2.5-20 μ m, and median size is the hexagonal boron nitride powder 2-20% of 1 μ m.Ratio by the aqueous solution in the sight-feed lubricator coating and solid micro-powder is regulated viscosity.Slip coating can adopt the mode of brushing or spraying, and is coated in sled surface and forms lubricated and supercoat.Above unit is a weight percentage.
The crystalline flake graphite that is adopted among the present invention; it is main component as the lubricated and protection of slide plate protective cover; has good self-lubricating property and to the nonwetting property of molten steel and slag; the frictional coefficient between slide plate can be effectively reduced, and the infiltration of molten steel and slag can be prevented effectively to the slide plate face.But tangible oxidation will take place in graphite in the time of 400 ℃ in air, and graphite and water do not soak into, so crystalline flake graphite that is adopted among the present invention, must carry out surface-treated through following process: with crystalline flake graphite and concentration is that the aluminum nitrate aqueous solution of 5-30% carries out ball milling and mixes, the weight ratio of crystalline flake graphite is 30-50%, the weight ratio 50-70% of aluminum nitrate aqueous solution, then slurry is dried down in 100-150 ℃ in baking oven, aluminum nitrate is in the flake graphite's surface crystallization, at last with crystalline flake graphite under 400-500 ℃ in air thermal treatment 1-5 hour, aluminum nitrate decomposites aluminum oxide, covers flake graphite's surface.The crystalline flake graphite that adopts this method to obtain has good hydrophilicity and oxidation-resistance.
Hexagonal boron nitride that the present invention adopts, it is a kind of laminate structure that similar crystalline flake graphite is arranged, performance with good self-lubricating property and anti-molten steel and slag corrosion, simultaneously, because the aerial oxidizing temperature of hexagonal boron nitride is greater than 900 ℃, so its antioxidant property is far above graphite, and can provide the lubricity of slide plate under hot conditions, improve the hot sticky attached performance under hot conditions between slide plate.
The sodium alginate that the present invention adopts is a kind of water-soluble macromolecule dispersing agent and binding agent, and graphite is had good dissemination in water, and at ambient temperature can film-forming; The polyvinylpyrrolidone that adopts is a kind of water-soluble polymeric additive, can improve the flow leveling of slip coating, makes the flat appearance of slide plate coating; The silicon sol that adopts is a kind of inorganic adhesive, and the lubricated and supercoat that slip coating is formed on slide plate has the certain high temperature bonding strength.
The preparation method of above-mentioned sliding plate lubricant coating provided by the invention is characterized in that: (1) aqueous solution preparation: with sodium alginate 5-10%, polyvinylpyrrolidone 1-2%, among the water-soluble 70-90% of silicon sol 4-18%, place standby according to weight percent; (2) be that crystalline flake graphite and the concentration of 2.5-20 μ m is in the aluminum nitrate aqueous solution of 5-30% with particle diameter, by the ball milling mixing after 1-5 hour, in baking oven, dry down in 100-150 ℃, place 400-500 ℃ heat treatment furnace to heat-treat again 1-5 hour, make the aluminum nitrate decomposition and form the alumina-ceramic layer at crystalline flake graphite; (3) will carry out the crystalline flake graphite of chemical conversion treatment and hexagonal boron nitride powder and join in the aqueous solution in the above-mentioned steps (1) according to certain ratio, ball milling mixing 1-8 hour promptly obtains coating for slide plate.
Slide board lubricating coating of the present invention has following advantage:
1. slide board lubricating coating of the present invention is because of having adopted the crystalline flake graphite of surface coverage alumina-ceramic layer, so have good hydrophilicity, make crystalline flake graphite under the effect of macromolecule dispersing agent, stable suspersion has guaranteed that slip coating can long-term storage and do not precipitate in slip coating; Simultaneously, the crystalline flake graphite of surface coverage alumina-ceramic layer is compared with common crystalline flake graphite, has higher antioxidant property.
2. slide board lubricating coating of the present invention, rate of drying is fast at normal temperatures, and slip coating is evenly fine and close, flat appearance is smooth, and under hot conditions, still keeps good lubricating property, especially the anti-coal-tar middle oil excellent property of oozing out of limited slip plate, antioxidant effect is splendid.
3. the raw material of the present invention's employing is domestic procurement, and cost of material is cheap, therefore compares with external product, and is with low cost, compares with external imported product, and cost only is about its 20-30%.
4. slide board lubricating coating of the present invention can still be combined closely with sled surface when slide plate connects sliding 3-4 time, keeps it to lubricate and barrier propterty, has satisfied homemade slide plate at present to the requirement in work-ing life.
Embodiment
Embodiment 1:
Take by weighing 5 kilograms of sodium alginates, 1 kilogram of polyvinylpyrrolidone, 4 kilograms of silicon sol join in 90 kg of water, fully after the stirring and dissolving, obtain 100 kg of water solution (1), and are standby.Take by weighing 5 kilograms of technical pure aluminum nitrates, be dissolved in 95 kg of water, it is standby to obtain the aluminum nitrate mass concentration and be 5% (2) 100 kilograms of the aqueous solution.With 30 kilograms mean particle sizes is that crystalline flake graphite and the above-mentioned aluminum nitrate aqueous solution of 2.5 μ m carried out the ball milling blend 1 hour for (2) 70 kilograms, in baking oven, dry down then in 100 ℃, 400 ℃ of following thermal treatments 5 hours, obtain the crystalline flake graphite of surface coverage alumina-ceramic layer then, standby.
Take by weighing (1) 80 kilogram of the aqueous solution, add 4 kilograms of 16 kilograms of the crystalline flake graphites of surface coverage alumina-ceramic layer and hexagonal boron nitrides that median size is 1 μ m therein, ball milling mixed 1 hour, promptly obtained slip coating of the present invention.Slide board lubricating coating of the present invention is found significantly precipitation after 2 months leave standstill, the four glasss of values that are coated with of coating are 60 seconds.Through on the slide plate working face of the big water-coating port of steelworks, having carried out the commerical test of 50 covers, the mean lifetime of slide plate is 2.6 a times/cover, after the test, sled surface remains with fine and close slip coating, coatingsurface is smooth, find no the scuffing vestige, the oxidative phenomena of carbon material does not take place near the place of coating in the slide plate section.Compare with external imported product, the cost of slip coating of the present invention be about its about 20%.
Embodiment 2:
Take by weighing 7.5 kilograms of sodium alginates, 1.5 kilograms of polyvinylpyrrolidones, 11 kilograms of silicon sol join in 80 kg of water, fully after the stirring and dissolving, obtain 100 kg of water solution (1), and are standby.Take by weighing 15 kilograms of technical pure aluminum nitrates, be dissolved in 85 kg of water, it is standby to obtain the aluminum nitrate mass concentration and be 15% (2) 100 kilograms of the aqueous solution.With 40 kilograms mean particle sizes is that crystalline flake graphite and the above-mentioned aluminum nitrate aqueous solution of 10 μ m carried out the ball milling blend 3 hours for (2) 60 kilograms,, in baking oven, dry down then, then 450 ℃ of following thermal treatments 3 hours in 120 ℃, obtain the crystalline flake graphite of surface coverage alumina-ceramic layer, standby.
Take by weighing (1) 65 kilogram of the aqueous solution, add 3.5 kilograms of 31.5 kilograms of the crystalline flake graphites of surface coverage alumina-ceramic layer and hexagonal boron nitrides that median size is 1 μ m therein, ball milling mixed 5 hours, promptly obtained slip coating of the present invention.Slide board lubricating coating of the present invention is found significantly precipitation after 2 months leave standstill, the four glasss of values that are coated with of coating are 70 seconds.Through on the slide plate working face of the big water-coating port of steelworks, having carried out the commerical test of 50 covers, the mean lifetime of slide plate is 4 a times/cover, after the test, sled surface remains with fine and close slip coating, coatingsurface is smooth, find no the scuffing vestige, the oxidation material phenomenon of charcoal element does not take place near the place of coating in the slide plate section.Compare with external imported product, the cost of slip coating of the present invention be about its about 25%.
Embodiment 3:
Take by weighing 10 kilograms of sodium alginates, 2 kilograms of polyvinylpyrrolidones, 18 kilograms of silicon sol join in 70 kg of water, fully after the stirring and dissolving, obtain 100 kg of water solution (1), and are standby.Take by weighing 30 kilograms of technical pure aluminum nitrates, be dissolved in 70 kg of water, it is standby to obtain the aluminum nitrate mass concentration and be 30% (2) 100 kilograms of the aqueous solution.With 50 kilograms mean particle sizes is that crystalline flake graphite and the above-mentioned aluminum nitrate aqueous solution of 20 μ m carried out the ball milling blend 5 hours for (2) 50 kilograms,, in baking oven, dry down then, then 500 ℃ of following thermal treatments 1 hour in 150 ℃, obtain the crystalline flake graphite of surface coverage alumina-ceramic layer, standby.
Take by weighing (1) 50 kilogram of the aqueous solution, add 1 kilogram of 49 kilograms of the crystalline flake graphites of surface coverage alumina-ceramic layer and hexagonal boron nitride that median size is 1 μ m therein, ball milling mixed 8 hours, promptly obtained slip coating of the present invention.Slide board lubricating coating of the present invention is found significantly precipitation after 2 months leave standstill, the four glasss of values that are coated with of coating are 90 seconds.Through on the slide plate working face of the big water-coating port of steelworks, having carried out the commerical test of 50 covers, the mean lifetime of slide plate is 3.8 a times/cover, after the test, sled surface remains with fine and close slip coating, coatingsurface is smooth, find no the scuffing vestige, the oxidative phenomena of charcoal element does not take place near the place of coating in the slide plate section.Compare with external imported product, the cost of slip coating of the present invention be about its about 28%.