The method of preparation of the surfaces of the parts
(57) Abstract:Before coating thermal spraying the surface of the product is subjected to electro-processing tool for performing a reciprocating movement in a plane perpendicular to the plane of the work surface. The treatment is carried out by the instrument's profile, allowing you to contact the processing of 1/4 of the surface with periodic off the electric current. 2 C. p. F.-ly, 1 tab., 2 Il. The invention relates to mechanical engineering, in particular to thermal methods of coating, for example, in the repair and restoration of parts of hardened steel.The known method of surface preparation [1, 2] including shot blasting the surface.This method allows you to provide the necessary roughness when machining parts with low hardness, but when machining hardened steel components necessary for high adhesion surface roughness is not ensured.Closest to the proposed invention is a method of surface preparation of parts  mainly of hardened steel prior to coating deposition, IEP form a machining surface of the workpiece by the tool with the profile, corresponding to the profile of the recesses, and deletion at the site of contact of the tool and parts electric current to the local melting of the latter when the pressure of the tool 50 to 80 kgf/cm2and moving it along a helical line.The disadvantages of the known method is relatively low adhesion due to the coincidence of the direction of the turns of the roll with the direction of the tangential stresses at the coating conditions of friction, seeking in the process to tear sprayed coating from the substrate, and reduction in fatigue strength of the workpiece due to the formation on its surface connected by a helix of stress concentrators.The invention aims to improve the adhesion without significant reduction in fatigue strength.The solution of this problem is achieved by the fact that the treatment is carried out by the instrument's profile, allowing you to contact the processing of 1/4 workpiece surface, and the shifting shall be reciprocating in a plane perpendicular to the treated surface with periodic off the electric current. The electric current turns off before moving the instrument wars with the prototype allows to make a conclusion, because the relief in the proposed method, the tool is formed with a profile that provides for brief contact with a multitude of local melting and forcing the metal at the points of contact of the tool with the surface of the part not related to each other, not by squeezing the tool moving relative to the workpiece along a helical line formed in the process craters will not be linked which is not reduced to a significant reduction in fatigue strength. The increase in the area of the substrate surface due to its processing tool, which increases the lengths of the guide and a generatrix line of the surface (Fig. 1) allows to increase the adhesion strength of the coating.In Fig. 1 shows a diagram of the formation of the surface.The surface details are not processed (Fig. 1A). The surface area to be processed is calculated by the formula:
where S1surface area (m2);
R radius (m);
h1the length of the conventional forming surface (m).Since 2R=l1, (2)
where l1the length of the conventional guide surface (m).The expression (1) takes the form:
S1< The surface area is calculated by the formula:
where l>2the length of the conventional guide surfaces treated by the method described in the prototype (m);
h2the length of the conventional forming surface processed by the method described in the prototype (m).Since l2l1h2> h1,
the area of the surface of the substrate processed by the method described in the prototype, there will be more square untreated surface.S2> S1< / BR>The surface details are processed by the proposed method (Fig. 1B).The area of the formed surface is calculated by the formula:
where S3the area of the surface of the substrate processed by the proposed method (m2);
l3the length of the conventional guide surfaces treated by the proposed method (m);
h3the length of the conventional forming surface processed by the proposed method (m).Since l3> l2h3h2,
the area of the surface of the substrate processed by the proposed method, more surface area of the raw and processed by the method described in protot mm. The samples are tempered at the facility HDTV at a depth of 1.5-3.0 mm to hardness RC 56-62. Before deposition, the samples were divided into five groups. Their surfaces were subjected to various kinds of processing.To generate the surface profile of the samples of the first group used the tool that represents the punch with a concave working surface. The length of the arc describing the working surface of the tool is equal to 1/4 of the circumference of the workpiece. The radius of the arc describing the working surface of the tool is equal to 1/2 the diameter of the surface of the workpiece. On the working surface of the tool, made of a refractory alloy VL-4 is cut tetradecene teeth with a pitch of 2.5 mm, the Radius of the top of the teeth is 0.8 mmTool performing reciprocating motion in the plane perpendicular to the plane of the workpiece, for one revolution of the workpiece in contact with it 4 times with a pressure of 50-80 kg/cm2. On the part and the tool was applied current 500-550 And when the voltage 2-6 C. In order to prevent the formation of an electric arc with the disengagement of the tool from the surface, before beginning its upward movement, the electric current is turned off.The processing of the above-described method electric current is shut off immediately after contact of the tool with the workpiece and local melting of the surface. Next tool, continuing to move down, deformed cooling the metal, thereby procrea surface.Surface treatment of samples of the third group was made by the method described in the prototype.Surface samples of the fourth group were subjected to blast processing.Samples of the fifth group were not treated.Flame spraying parts of the first four groups was performed with the powder feeding PLUS-25 (GOST 21448-75), when the particle size of 5-100 μm and the coefficient of its use 70-80% of the Distance of the torch from the workpiece during the coating within 50-100 mm, the flow rate of plasma gas (argon) 2-C m3/PMSamples of the fifth group did not nubilalis.The deposited samples were polished up to a diameter 50,8 mmThe adhesion strength was determined by the force tangential shear segment size of 10 x 5 mmOn fatigue strength in torsion sample was tested on the installation of the MIND-4. For a database of tests taken 1,2x107loading cycles.The results of the tests are presented in the table and shown in Fig. 2, which presents the adhesion strength of the coating and fatigue strength of specimens.
the second strength of the coating without significant reduction in fatigue strength of the part. It can be recommended to use the invention in mechanical engineering, in particular when restoring worn parts.1. The way to prepare the surface before coating thermal spraying, including Electromechanical processing surface of the workpiece by the tool at a pressure of 50 to 80 kgf/cm by passing electric current at the site of contact to melting and movement of the tool, wherein the treatment is carried out by the instrument's profile, allowing you to contact the processing of 1/4 workpiece surface, and the shifting shall be reciprocating in a plane perpendicular to the processed surface with periodic off the electric current.2. The method according to p. 1, characterized in that the electric current is disconnected before moving the instrument up.3. The method according to p. 1, characterized in that the electric current is shut off after the contact of the tool with the surface.
FIELD: oil-producing industry; mining; boring equipment.
SUBSTANCE: the invention is pertaining to the field of boring equipment and may be used at building-up of boreholes in the deep and superdeep drilling, and also at the open-cut mines at the blastholes drilling with blasting of the mine face by air. The method provides for the milling machining of each cog and deposition on it of an abrasive resistant protective coating. Before milling machining it is necessary to exercise turning machining of the inner and outer surfaces of the rolling cutter. After milling machining deposit an anticementing coating on the surfaces requiring protection against cementation. Then exercise cementation of the rolling cutter, its subsequent tempering in the oil, the low tempering, the bearing tracks grinding and coating by vapor deposition of an abrasive resistant protective coating on the cutter teeth and its intercrowned pits of the milling cutter. The protective coating has the hardness in the interval from HRC64 up to HRA72. Deposition of the protective coating is exercised, when the limiting temperature of heating-up of the rolling cutter does not exceed the temperatureof tn=280°C, at which the loss of strength of the cemented surfaces starts. The abrasive resistant protective coating is deposited in one or several layers till reaching the preset project depth of 0.2-0.8 mm. The technical result of the invention is the increased reliability of protection of the surfaces of the milled reinforced items against the wear and the increased mechanical resistance of the drilling bit as a whole.
EFFECT: the invention ensures increased reliability of protection of the surfaces of the milled reinforced items against the wear and the increased mechanical resistance of the drilling bit as a whole.
3 cl, 1 dwg
FIELD: metallurgy; restoration of working surface of crystallizer walls without disassembly of it.
SUBSTANCE: method of restoration of crystallizer walls made from copper and its alloys includes making notch, 0.5 mm deep at depth of wear of working surface no less than 1.0 mm. Then, working surface at depth of wear no less than 0.5 mm is subjected to shot-blasting after which precoat of thermo-reactive material, 0.1-0.2 mm thick and working layer of wear-resistant material are applied by gas thermal spraying. Depth of residual wear is no less than 0.5 mm.
EFFECT: enhanced resistance of coat.
FIELD: chemical industry; other industries; deposition of coatings by the gas-thermal methods.
SUBSTANCE: the invention is pertaining to the field of deposition of coatings by the gas-thermal methods, in particular, to the plasma deposition. The invention presents the method of preparation of the surface before the plasma deposition of chromium carbonyl. The method includes realization of the electrospark doping in the carbonic gas medium with utilization of the electrode formed from the powder on the basis of chromium. The doping is conducted at the following modes: the specific duration of the doping is 2-3 minutes/cm2, the discharge current - 0.6-0.9 A, the amplitude of the electrode vibrations is 60-70 microns, the frequency of the electrode vibrations is IOO Hz. The technical result of the invention is the increase of the cohesion strength of the gas-thermal coating with the substrate.
EFFECT: the invention ensures the increased cohesion strength of the gas-thermal coating with the substrate.
FIELD: metallurgy industry; mechanical engineering; other industries; methods of the vacuum-arc treatment of the metal products.
SUBSTANCE: the invention is pertaining to the field of the vacuum-arc treatment of the metal products before deposition on them of the coatings and may be used in metallurgy industry, mechanical engineering and other industries. The method provides for the vacuum-arc refining of the product-cathode and deposition of the coatings. Before deposition of the coatings the vacuum-arc refining is combined with the simultaneous complete or local oxidation of the surfaces, for example, up to the yellow, blue, violet, brown, black colors and-or tints and the combinations of the colors and tints. During the treatment of the long-sized products the local oxidation can be conducted in the form of the longitudinal and-or transversal straps and areas. The mode of the oxidation is exercised due to vibrations of the arc or the arcs, and-or due to for example the change - the increase of the power of the arc and-or the power emitted by the product caused by the electric current passing through it in the section from the electric current feeder from the power supply or the power supplies feeding the arc or the arcs to the product-cathode up to the electric arc or the arcs. The technical result of the invention is expansion of the technological capabilities of the method of the vacuum-arc treatment, improvement of the quality and the extension of the assortment of the depositing coatings.
EFFECT: the invention ensures expansion of the technological capabilities of the method of the vacuum-arc treatment, improvement of the quality and the extension of the assortment of the depositing coatings.
FIELD: technological process.
SUBSTANCE: invention is related to methods of surface preparation for plasma sputtering of coatings and may be used for cleaning of different surfaces with abrasive materials. Method includes abrasive treatment of surface that is subject to sputtering with thermal abrasive jet directed at the angle of 40...45° to processed surface. Jet is formed from high-temperature gas flow with abrasive loose material with fraction size of 0.3 - 0.7 mm. Processing is carried out until surface roughness is 40-50 micrometer, at that the mentioned surface is heated with high-temperature flow of gases up to 70 - 210°C.
EFFECT: provision of high-quality adhesion of coating with surface subject to sputtering.
SUBSTANCE: invention refers to methods of treatment of planing machine rollers. The method includes preparing of roller body surface and application of strengthening coating. Preliminary preparation of roller body surface is performed by means of its blowing-off under pressure with iron shot of 180...200 mcm fraction. Further two-layer strengthening coating is applied by the method of gas-detonation sputtering. Also the interior layer of coating is applied with powder of tungsten carbide of 55...65 mcm fraction obtaining thickness of the interior layer of 15...25 mcm. The exterior layer is applied with copper powder with additives not more, than 0.6%, obtaining the thickness of the exterior layer of 8...10 mcm.
EFFECT: upgraded wear resistance of sheet planing roller.
FIELD: technological processes, metal working.
SUBSTANCE: invention is related to the field of metal products cleaning, such as rolled wire, wire, strip, forged pieces, foundry and others, in particular, to method for electroarc processing of metal products surfaces and may find application in different branches of machine building industry. Prior to arc discharge treatment, surface is previously coated by thin layer of alkaline, alkali-earth or rare-earth metals or their compounds in process of hot processing or in cold condition. Prior to processing, at atmospheric pressure processed surface is previously coated by material, which is gasified by cathode spots of arc, creating protective or restorative medium above cleaned surface. Result achieved is considerable reduction of metal products processing cost, higher efficiency of processing and lower heating of processed product metal.
EFFECT: reduction of metal products processing cost, higher efficiency of processing and lower heating of processed product metal.
2 cl, 1 tbl
FIELD: textile fabrics; paper.
SUBSTANCE: invention relates to recovery method of diametric dimension of drier of paper-making equipment. After turning cut of cylinder it is implemented thermal processing of surface at temperature 100°C in passage area of electroarc burner. Then one-pass by material M470 it is applied the first adhesion layer of coating of solidity 360-420 HB of thickness 0.1 mm. It is applied the second filling layer by material ST-0002 of solidity 360-420 HB, thickness of which corresponds specified value of increase of diametrical dimension. It is applied the third coating cover of thickness 0.5 mm by material ST-0028 of solidity 250-270 HB, subject to allowance 1-2 mm for complete machining. Application is impregnated by compound "Hartz" in cooled condition, grind and polished the surface by flexible tool with providing of roughness Ra<0.63 micrometre, it is washed workpiece surface by mineral oil. After what it is run in surface of cylinder by edge scraping tool with angle of wedge slope 25°-30° and linear pressure 200-300 N/m.
EFFECT: it can be used in mechanical engineering at repair of driers without removal of it from the operation position.
FIELD: textile fabrics, paper.
SUBSTANCE: invention relates to paper-making manufacturing, particularly to application method of corrosion protection coating on working surface of rolling and creping cylinders and can be used at repair of rolling and creping cylinders without its taking off from operation position. After turning cut and thermal processing of surface one-pass it is applied the first adhesion layer of thickness 0.1 mm by iron alloy with chrome content 10÷13%. Then it is applied the second coating cover of thickness 2.0÷2.2 mm with content 13% of chrome and 27% of nickel. Then is implemented impregnation of coating cover by anticorrosive composition and grinding of operating surface by flexible tool.
EFFECT: receiving of cylinder with high processing characteristics, there are reduced expenditures for equipment repair and it is improved quality of paper, received with usage of mentioned cylinders.
FIELD: technological processes, metal working.
SUBSTANCE: invention is related to methods for preparation of flat steel cutting tools for operation, namely, to strengthening of cutting edges of disk scissors knives. Method includes preliminary processing of cutting edges by means of their blowing with coarse-grained abrasive and application of wear-resistant coat in them with thickness of 10…25 mcm. Coat is applied by means of gas detonation spraying of powdery mixture of chrome carbides on nickel binder with fraction of 55…60 mcm with pressure of 2900…3200 MPa during explosion of propane and oxygen mixture.
EFFECT: higher efficiency of cutting tool.
3 cl, 1 ex