Thermodiffusion zinc coating |
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IPC classes for russian patent Thermodiffusion zinc coating (RU 2557045):
Composition for thermodiffusion galvanising of steel products / 2539888
Invention relates to method of thermodiffusion galvanising of steel products. Preparation of composition for thermodiffusion galvanising, containing zinc powder, inert filling agent and activator, and processing of steel products in said composition by heating at temperature 420°C are carried out. Preparation of composition for thermodiffusion galvanising is carried out by addition of 0.5-0.8% of tetrachloromethane of weight content of zinc powder as activator into composition, which contains 25-75 wt % of zinc powder and 75-25% of inert filling agent, with heating in the process of processing of steel products in said composition being carried out for 90 minutes.
 Zinc coating method and apparatus therefor / 2533400
Invention relates to anticorrosive treatment of metal articles and specifically to depositing a zinc coating on articles made of ferromagnetic materials by thermodiffusion zinc coating and an apparatus used to carry out the method. The method includes loading a batch of articles into the retort of an electric heating apparatus, pouring a saturating zinc-containing mixture in amount of 8-16% of the weight of the articles to be zinc coated, which contains 20-25% zinc powder and 75-80% alumina, sealing the retort, placing the retort inside the inductors of the heating apparatus and heating to 350-550°C depending on the required coating thickness and the weight of the articles with eddy currents while rotating the retort to the required temperature, holding the retort, removing the retort from the inductors and cooling while rotating on a process table to a temperature not higher than 250°C. Excess pressure in the retort is continuously released during the coating process. The moment at which the given temperature is reached is monitored, upon which a signal is output for longitudinal displacement of the retort by a value equal to the distance between the inductors. Heating is continued until the given temperature is reached in the displaced areas of the retort while rotating the retort.
 Method of thermodiffusion galvanising of products from ferromagnetic materials / 2527593
Retort is placed inside inducers by means of additional mechanisms of a longitudinal movement, heating of the retort surface to a specified value is performed in two stages, at the first stage it is heated to a temperature, equal to 85-90% of the specified value, which is measured in a zone of inducers by means of thermocouples, additionally installed in the said zones. When the value of the said range is achieved in the zone of inducers, electrical power supply of the inducers is switched off and the retort is moved towards the output from the heating installation by a value, equal to the distance between the inducers, after that, electrical power supply of the inducers and additional mechanism of the retort rotation is switched on at the moment when the mechanisms touch the retort surface, and heating of the retort with eddy currents is continued until achievement of the specified value of temperature in displaced zones of the retort, which constitutes 250-550°C depending on zinc content, constituting 10-50 wt % in the zinc mixture, and weight of loaded into the retort products, time of the retort exposure in a heating installation is determined depending on the zinc mixture composition and required thickness of the coating, constituting from 30 to 300 mcm. In the process of galvanising a continuous relief of overpressure in the retort is carried out. After that, the retort is removed from the inducers, subjected to cooling and the galvanised products are discharged.
 Application method of thermal diffusion zinc coating, and coupling with thermal diffusion zinc coating / 2507300
Chemical and heat treatment is performed at the temperature of 380-420°C in a rotating vessel in a suspended layer of modified zinc powder, which has a surface film of active zinc oxide. Content in the powder of a fraction with the powder size of less than 40 mcm is 10-40%. Treatment is started from loading of products into the vessel with powder heated up to the temperature of 330-360°C and ended with a stage of vacuum cooling to the temperature of 320-360°C during at least 50 minutes. Residual pressure at the cooling stage is maintained in the range of 0.1-0.3 kgf/sq.cm. Weight ratio of steel products to the modified powder is maintained on the level of 1.5 to 4.0. A steel coupling with a threaded surface has a thermal diffusion zinc coating with thickness of 31-60 mcm, which has a deviation from an average value of thickness on the threaded surface of not more than 20% and which has been applied by means of the above method. The coating has the ratio of G-phase thickness to δ-phase thickness in the range of 0.4 to 1.0; with that, δ-phase has a homogeneous structure and includes G-phase inclusions in the range of 5-10% by weight. Size of G-phase inclusions in δ-phase layer is 0.05 to 0.2 mcm.
Application method of corrosion protection coating onto metal products by thermodiffusion zinc plating / 2500833
Corrosion protection coating is applied onto metal products in a sealed container arranged in a muffle furnace. Treated parts are arranged in the container in a regular manner in accessories with supporting surfaces, which fix them and prevent their direct contact between each other and movement relative to each other at movement of the container so that minimum distance between treated surfaces of parts is 3-5 mm. During zinc plating process, treated parts can perform movements relative to supporting surfaces of the accessories in the container by not more than 5-10 mm. Saturating mixture contains zinc crystals with purity of 0.97-0.99% of needle shape with coefficient of effective surface area of 10. Saturating mixture has particle size distribution at the interval of 3-7 mcm, and its weight is 1-4% of the weight of treated parts or 130-140% of the weight of the required coating on surface of treated parts.
 Method of diffusion titanising of cast iron products / 2493289
Method of diffusion titanising of cast iron products includes saturation of the surface with titanium upon heating to 1000-1100°C in contact with titanium oxide, exposure at this temperature during 2-4 hours with further quick cooling in hardening medium.
Zinc impregnation method of metal parts surface / 2451109
Surface of items is cleaned from impurities; container is filled with items and zinc powder and arranged in heated furnace. Container is filled with items to 0.2-0.7 of its volume; zinc powder is loaded to container in quantity of 0.005-0.15 of mass of loaded items. In addition, zinc oxide is loaded to container in quantity of 0.005-0.2 of zinc powder mass, absorbent carbon powder in quantity of 0.005-0.1 of zinc powder mass, ammonia sulphate in quantity of 0.007-0.3 of zinc powder mass, ammonium chloride in quantity of 0.001-0.1 of zinc powder mass, and abrasive powder in quantity of 0.1-0.5 of zinc powder mass. After container is filled with items and enriching mixture, container is sealed, installed on the bench with possibility of being rotated about vertical axis and rotated during 5-10 minutes. Then, container is installed in furnace heated to temperature of 1.2-1.5 of zinc fusion temperature; container is rotated in furnace during 1-4 hours; after that, container is removed from furnace, installed on the bench and rotated with simultaneous air blowing during 1-5 hours; after that, items are removed from container; excess zinc powder is removed from their surface; items are placed into solution containing orthophosphoric acid; then, items are washed and dried.
 Procedure for application of zinc coating and installation for its implementation / 2424351
Procedure consists in loading batch of items into vessel of electric heating installation, in charging saturated zinc containing mixture, in vessel sealing, in its heating, in vessel conditioning in heating installation, and in unloading items from vessel. During galvanisation excessive pressure in the vessel is continuously released. As a zinc containing mixture there is used the mixture containing the following components wt %: zinc powder - 20-25 and alumina - 75-80. The saturating mixture is charged into the vessel with uniform distribution of charge above whole length of the vessel at amount of 8-16 % of weight of galvanised items. Upon sealing the vessel is positioned inside an inductor. A case of the vessel is heated with eddy currents to temperature 300-400°C, while items - to temperature 768-910°C with vessel rotation. There are performed from one to eight fluctuations of temperature in a zone of magnetic transformations of material causing magnet-striction effects by means of alternate cooling and heating the case of the vessel to the said temperature due to alternate inductor turning on and off. Further the vessel is withdrawn from the inductor and is subjected to forced cooling to temperature as high, as 250°C at its rotation of a process table.
Method of zincing steel parts / 2401320
Parts are loaded into retort, and saturating mixture is loaded therein containing the following components, in wt % 35-60 of zinc in the form of finely-dispersed powder, 2-5 of aluminium chloride AlCl3 as activator and aluminium oxide or fire-clay grog, or quartz sand as an inert filler. Heating and extracting the parts is carried out at the temperature of 360-450°C.
 Zinc impregnation method of metal parts / 2386723
Invention refers to procedures of application of protective corrosion-resistant coatings. Method involves preparation of part surfaces, simultaneous loading of parts and mixture of powdered components to working chamber, heating of working chamber up to temperature of diffusion interaction of the charge material with the surface of treated metal parts within 350-450°C, exposure and chemical passivation in water solution medium of phosphorus compound. Before heating, vacuum treatment of working chamber is performed up to residual pressure of 0.1 kPa. Then there performed is contact of the parts throughout the surface with powdered mixture at vibration, and inert gas is pumped to working chmaber. Mixture of powdered components contains the following ingredient ratio, wt %: powdered zinc 55-85, inert filler - silicon dioxide or aluminium oxide - the rest. Mixture of powdered components has degree of dispersion of not less than 0.01 mcm.
Protective coating of metal work surface / 2353707
Invention relates to protective coating and can be used in mechanical engineering, transport, chemical and other industries. Protective coating of the metallic working surface and metal products contains internal thermodiffusion zinc layer, which is covered by particles of fine-dispersed zinc oxide with grain sizes from 0.05 till 5 mcm and external polymeric or varnish-and-paint layer.
Modified zinc powder for thermo-diffusion zincing, procedure for application of coating and clutch with thermo-diffusion zinc coating / 2383413
Modified zinc powder with specific surface not less, than 0.8 m2/g with zinc contents up to 99 % has surface film of active zinc oxide on particles of zinc of 10-60 mcm dimension. Surface film of active zinc oxide has fine grain dendrite-flaky structure and thickness not less, than two microns. The procedure for application of thermo-diffusion zinc coating on metallic items consists in performing chemical-thermal treatment of items in a rotating retort in a suspended layer of modified zinc powder at reverse motion of the retort with a period of 2-4 minutes between change of rotation direction at frequency of retort rotation 2-3.5 rev/min. A clutch is subject to zincing; the clutch is made with threaded surface and has thermo-diffusion coating of not less, than 20 mcm thickness. Thickness of coating is 31-60 mcm; deviation from average value of thickness coating on threaded surface is not more, than 20 %.
Zinc impregnation method of metal parts / 2386723
Invention refers to procedures of application of protective corrosion-resistant coatings. Method involves preparation of part surfaces, simultaneous loading of parts and mixture of powdered components to working chamber, heating of working chamber up to temperature of diffusion interaction of the charge material with the surface of treated metal parts within 350-450°C, exposure and chemical passivation in water solution medium of phosphorus compound. Before heating, vacuum treatment of working chamber is performed up to residual pressure of 0.1 kPa. Then there performed is contact of the parts throughout the surface with powdered mixture at vibration, and inert gas is pumped to working chmaber. Mixture of powdered components contains the following ingredient ratio, wt %: powdered zinc 55-85, inert filler - silicon dioxide or aluminium oxide - the rest. Mixture of powdered components has degree of dispersion of not less than 0.01 mcm.
Method of zincing steel parts / 2401320
Parts are loaded into retort, and saturating mixture is loaded therein containing the following components, in wt % 35-60 of zinc in the form of finely-dispersed powder, 2-5 of aluminium chloride AlCl3 as activator and aluminium oxide or fire-clay grog, or quartz sand as an inert filler. Heating and extracting the parts is carried out at the temperature of 360-450°C.
Procedure for application of zinc coating and installation for its implementation / 2424351
Procedure consists in loading batch of items into vessel of electric heating installation, in charging saturated zinc containing mixture, in vessel sealing, in its heating, in vessel conditioning in heating installation, and in unloading items from vessel. During galvanisation excessive pressure in the vessel is continuously released. As a zinc containing mixture there is used the mixture containing the following components wt %: zinc powder - 20-25 and alumina - 75-80. The saturating mixture is charged into the vessel with uniform distribution of charge above whole length of the vessel at amount of 8-16 % of weight of galvanised items. Upon sealing the vessel is positioned inside an inductor. A case of the vessel is heated with eddy currents to temperature 300-400°C, while items - to temperature 768-910°C with vessel rotation. There are performed from one to eight fluctuations of temperature in a zone of magnetic transformations of material causing magnet-striction effects by means of alternate cooling and heating the case of the vessel to the said temperature due to alternate inductor turning on and off. Further the vessel is withdrawn from the inductor and is subjected to forced cooling to temperature as high, as 250°C at its rotation of a process table.
Zinc impregnation method of metal parts surface / 2451109
Surface of items is cleaned from impurities; container is filled with items and zinc powder and arranged in heated furnace. Container is filled with items to 0.2-0.7 of its volume; zinc powder is loaded to container in quantity of 0.005-0.15 of mass of loaded items. In addition, zinc oxide is loaded to container in quantity of 0.005-0.2 of zinc powder mass, absorbent carbon powder in quantity of 0.005-0.1 of zinc powder mass, ammonia sulphate in quantity of 0.007-0.3 of zinc powder mass, ammonium chloride in quantity of 0.001-0.1 of zinc powder mass, and abrasive powder in quantity of 0.1-0.5 of zinc powder mass. After container is filled with items and enriching mixture, container is sealed, installed on the bench with possibility of being rotated about vertical axis and rotated during 5-10 minutes. Then, container is installed in furnace heated to temperature of 1.2-1.5 of zinc fusion temperature; container is rotated in furnace during 1-4 hours; after that, container is removed from furnace, installed on the bench and rotated with simultaneous air blowing during 1-5 hours; after that, items are removed from container; excess zinc powder is removed from their surface; items are placed into solution containing orthophosphoric acid; then, items are washed and dried.
Method of diffusion titanising of cast iron products / 2493289
Method of diffusion titanising of cast iron products includes saturation of the surface with titanium upon heating to 1000-1100°C in contact with titanium oxide, exposure at this temperature during 2-4 hours with further quick cooling in hardening medium.
Application method of corrosion protection coating onto metal products by thermodiffusion zinc plating / 2500833
Corrosion protection coating is applied onto metal products in a sealed container arranged in a muffle furnace. Treated parts are arranged in the container in a regular manner in accessories with supporting surfaces, which fix them and prevent their direct contact between each other and movement relative to each other at movement of the container so that minimum distance between treated surfaces of parts is 3-5 mm. During zinc plating process, treated parts can perform movements relative to supporting surfaces of the accessories in the container by not more than 5-10 mm. Saturating mixture contains zinc crystals with purity of 0.97-0.99% of needle shape with coefficient of effective surface area of 10. Saturating mixture has particle size distribution at the interval of 3-7 mcm, and its weight is 1-4% of the weight of treated parts or 130-140% of the weight of the required coating on surface of treated parts.
Application method of thermal diffusion zinc coating, and coupling with thermal diffusion zinc coating / 2507300
Chemical and heat treatment is performed at the temperature of 380-420°C in a rotating vessel in a suspended layer of modified zinc powder, which has a surface film of active zinc oxide. Content in the powder of a fraction with the powder size of less than 40 mcm is 10-40%. Treatment is started from loading of products into the vessel with powder heated up to the temperature of 330-360°C and ended with a stage of vacuum cooling to the temperature of 320-360°C during at least 50 minutes. Residual pressure at the cooling stage is maintained in the range of 0.1-0.3 kgf/sq.cm. Weight ratio of steel products to the modified powder is maintained on the level of 1.5 to 4.0. A steel coupling with a threaded surface has a thermal diffusion zinc coating with thickness of 31-60 mcm, which has a deviation from an average value of thickness on the threaded surface of not more than 20% and which has been applied by means of the above method. The coating has the ratio of G-phase thickness to δ-phase thickness in the range of 0.4 to 1.0; with that, δ-phase has a homogeneous structure and includes G-phase inclusions in the range of 5-10% by weight. Size of G-phase inclusions in δ-phase layer is 0.05 to 0.2 mcm.
Method of thermodiffusion galvanising of products from ferromagnetic materials / 2527593
Retort is placed inside inducers by means of additional mechanisms of a longitudinal movement, heating of the retort surface to a specified value is performed in two stages, at the first stage it is heated to a temperature, equal to 85-90% of the specified value, which is measured in a zone of inducers by means of thermocouples, additionally installed in the said zones. When the value of the said range is achieved in the zone of inducers, electrical power supply of the inducers is switched off and the retort is moved towards the output from the heating installation by a value, equal to the distance between the inducers, after that, electrical power supply of the inducers and additional mechanism of the retort rotation is switched on at the moment when the mechanisms touch the retort surface, and heating of the retort with eddy currents is continued until achievement of the specified value of temperature in displaced zones of the retort, which constitutes 250-550°C depending on zinc content, constituting 10-50 wt % in the zinc mixture, and weight of loaded into the retort products, time of the retort exposure in a heating installation is determined depending on the zinc mixture composition and required thickness of the coating, constituting from 30 to 300 mcm. In the process of galvanising a continuous relief of overpressure in the retort is carried out. After that, the retort is removed from the inducers, subjected to cooling and the galvanised products are discharged.
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FIELD: oil and gas industry. SUBSTANCE: thermodiffusion zinc coating of steel parts includes loading into a sealed rotating reactor steel parts and saturating mixture consisting of inert support, activator and 30 - 60 wt % of fine-grained zinc powder in quantity to weight of the loaded parts, heating of the reactor with parts and saturating mixture, withholding at 360-380°C in inert atmosphere and subsequent cooling down up to temperature of 20-36°C. Fine-grained powder is used with grain size of 4-60 mcm in quantity of 0.05-0.18 kg per 1m2 of the coated surface of steel parts. Saturating mixture is loaded to the reactor in quantity of 40 - 100 wt % to the weight of parts while inert support is used with grain size of 60-140 mcm. EFFECT: non-waste method of thermodiffusion zinc coating with simultaneous cheapening of the process.
The invention relates to chemical-thermal treatment method of thermal diffusion galvanizing couplings for casing and tubing in powder environments to protect the threads from corrosion in atmospheric conditions, harsh environments, performance improvement parts, increasing the number of cycles of the screwing-unscrewing. The known method of thermal diffusion galvanizing of steel products in powder mixtures containing zinc dust in an amount of 20 wt.% zinc or more and an inert filler (sand, aluminum oxide, refractory clay) - the rest. Details along with zinc dust loads in welded steel or having flanges and asbestos gasket cartridges and LinkOut at a temperature of 350-600°C. When using zinc dust without filler thermodiffusion saturation is carried out at a temperature of 350-400°C, and when using zinc dust with aluminum oxide, at a temperature of 500-600°C (Zilberfarb M. I., Prikhodko, L. N. Diffusion galvanizing. Proceedings of all-Union scientific-research and design Institute of chemical engineering. - 1959, vol. 28, p. 95-123). The disadvantage of this method is the high cost of the process due to the use of the mixture of a large number of expensive zinc (20 wt.% and more). In addition, when using zinc dust with up to 50 wt% of zinc oxide, decreasing the thickness of the coatings obtained. In addition, at temperatures above 400°C the holiday heat-treated coupling, which leads to lower strength characteristics. Closest to the proposed method to the technical essence and the achieved result is a method of thermal diffusion galvanizing powder mixtures containing zinc powder and inert materials (thinners) such as aluminum oxide, silica sand, fireclay in the amount of 25 wt.%. Perhaps galvanised steel powder mixtures containing 90 wt.% quartz sand, but it greatly reduced the thickness of the coating. When using a homogeneous mixture of zinc powder with an average diameter portion 100 μm using silica sand with a particle diameter of 140 microns, fireclay - 150 μm, alumina - 156 μm. The powder mixture can be used repeatedly, however, this reduces its coverts activity due to partial oxidation of the zinc powder. To maintain the activity of the powder mixture into it periodically add new portions of zinc powder to 10 wt.% (Proskurnin E. V., Popovich, V. A., Moroz A. T. Galvanizing. Guide. - M.: metallurgy, 1988, p. 403-406). The disadvantage of this method is the high cost of the process due to the use of honey in it a mixture, comprising from 10 to 75 wt.% dear paroxetine, and at repeated using a mixture of reduced coating thickness. The object of the present invention is to provide a waste-free method of thermal diffusion galvanizing with simultaneous cost reduction. To solve this problem in the known method of thermal diffusion galvanizing, including loading in a sealed rotating reactor steel parts and saturating mixture consisting of an inert carrier, an activator, and from 30 to 60 wt.% highly dispersed zinc powder in amount to the weight of the loaded parts, reactor parts and saturating the mixture is heated and maintained at 360-380°C in an inert atmosphere, then cooled to a temperature of 20-36°C, with loads of finely dispersed zinc powder with grain size 4-60 μm in an amount of 0.05-0.18 kg per 1 m2the coated surface of steel parts. Another feature of the method is that saturating the mixture was charged into the reactor from 40 to 100 wt.% to the weight of the parts. Another feature of the method is that an inert carrier is used the grain size 60-140 microns. The method is as follows. In a sealed rotating steel reactor was charged with the parts to be diffusion galvanizing, and saturating the mixture of the inert carrier, the activator and superfine zinc powder, in an amount of from 30 to 60 mA�.% to the weight of the loaded parts taking into account the configuration of the product and its weight. The reactor was closed with a lid with a hermetic seal. The reactor is set into a rotating heater installation that is performed in the heating of the reactor with details and saturating the mixture to a temperature of 360-380°C. After reaching the set temperature of the reactor parts and saturating the mixture was incubated at the specified temperature for 1-3 hours, depending on the desired thickness of the zinc coating, and then cooled to a temperature of 20-36°C. After completion of the diffusion process of galvanizing the reactor is open, the details and the mixture is extracted. When you load the following volumes of parts every time you add additional portions of superfine zinc powder with grain size 4-60 μm, necessary for obtaining a predetermined thickness of the coating rate of 0.05-0.18 kg per 1 m2the coated surface, wherein the amount of inert carrier remains constant. Thus, each time the zinc is completely consumed in the formation of the diffusion layer. As the inert carrier (diluent) used abrasive nephroscope materials not entering into chemical reaction with the zinc and iron, size 80-140 microns. Such dispersion diluent is optimal for producing high-quality coverage thread couplings casing and pump-compressor pipes, e�Ohm no buildup cinchouse mixture onto the threaded portions of the parts. If you take zinc powder with grain size less than 25 μm, the coverage is small because of the increase of the oxide film on the surface of zinc powder. The coating is non-uniform and small thickness. To an inert carrier scored the threads on the hardware, the optimal size of it is taken 60-140 μm. With increasing particle size of the powder of the carrier of more than 140 μm galvanizing process slows down and even stops altogether. The optimal number of carrier is used from 30 to 60 wt.% to the weight of the loaded parts, which allows to obtain a uniform coating over the entire surface of the threads of the couplings casing and tubing. If the media in the container is less than 30%, then the thread can receive parcels without zinc coating. To increase the number of carrier is more than 100% of the weight of the parts is impractical due to the rising cost of galvanizing. Economic efficiency and waste-free method is achieved in that the content of superfine zinc powder in a mixture, 0.10-0.20 kg per 1 m2the surface of the parts, conforms to the required thickness of the coating, and the amount of added superfine powder of zinc for galvanizing each of the next batch of thread couplings casing and tubing equal to its consumption at a given coating thickness. Thus, for applying �innovage coating on a new batch of couplings used fresh superfine zinc powder, not reduced the coverage cinchouse mixture and no waste. Sinkula mixture is constantly in use, and does not generate waste production. Coating anti-corrosion properties are not inferior to other methods of thermal diffusion galvanizing of steel parts and can withstand repeated screwing and unscrewing (50 cycles) couplings tubing. The present invention can be used in the oil and gas industry to improve the corrosion resistance of coupling of pump-compressor pipes. Galvanized diffusion method of coupling will allow you to make more than 50 tripping operation with pump-compressor pipes, wherein the screwing and unscrewing of the thread without losing the tightness and geometrical parameters of the thread profile, and in the repair and engineering works for oil and gas wells, also help to make maintaining the ability to easily otvincivatmisa when lifting pipes even after several years of operation. The method of thermal diffusion galvanizing of steel parts, including loading in a sealed rotating reactor steel parts and saturating mixture consisting of inert carrier, the activator and from 30 to 60 wt.% superfine zinc powder in amount to the weight of the loaded parts, the heating of the reactor � details and saturating the mixture, the holding at 360-380°C in an inert atmosphere and subsequent cooling to a temperature of 20-36°C, characterized in that the finely dispersed zinc powder with grain size 4-60 μm in an amount of 0.05-0.18 kg per 1 m2the coated surface of steel parts, saturating the mixture was charged into the reactor from 40 to 100 wt.% to the weight of the parts, and an inert carrier is used the grain size 60-140 μm.
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