Method for electron-beam surfacing of multimodal-structure coatings
FIELD: electron-beam surfacing of flat and cylindrical surfaces, possibly manufacture of new parts and restoration of worn surfaces of parts operating at condition of intensified abrasive wear in combination with impact loads.
SUBSTANCE: in order to enlarge manufacturing possibilities of method, on surface of welded-on article melting zone by means of electron beam is created. Powder composition material for surfacing is fed to melting zone. Surfaced article is moved and powder material for surfacing is fed normally relative to motion direction of article. As coating is applied unfocused electron beam is used for acting upon surface of said coating without supply of material for surfacing. It provides separation of dispersed particles of strengthener from solid solution and formation of multimodal structure of surfacing along its whole thickness.
EFFECT: enlarged manufacturing possibilities of method.
1 dwg, 1 ex
The invention relates to welding, and in particular to methods of electron-beam welding of flat and cylindrical surfaces, and can be used for manufacturing new and restoring the surface of worn parts, working in conditions of intensive abrasive wear in combination with impact loads.
At the present time to increase the wear resistance of the working surfaces of parts of mechanisms and machines by their manufacturing and repair process, as fused powder mixtures are typically used hard and superhard composite materials such as Stellite, Carmit, the FTC [Gulyaev A.P.]. - M.: metallurgy 1986, 544 S.]. Data surfacing materials have found wide application in the mining industry, metallurgy, where there are no strict requirements on the quality of the structure welding. As a strengthening phase they contain 30...90% expensive carbides of titanium, tungsten, molybdenum, are very unevenly distributed over the volume of the deposited layer, especially when their content up to 30...50%. The main drawback of the composite cladding is fragile due to the high content of reinforcing particles, which limits their applications in heavy-duty friction with large contact loads, accompanied by the blow.There is a method of electron-beam welding (RF Patent No. 2118243 from 1998.08.27, MKI UK 15/00), wherein on the surface of the fused product creates a zone of melting beam with linear sweep, clean the product move, and fusible powder material is fed into the gap between the lines of the beam sweep.
The disadvantage of this method is that it is applicable only for surfacing materials, not containing in its composition dispersed hardening phases. At low content of reinforcing particles is strong irregularity of their distribution surfaced in the material, resulting in reduced performance properties of the coatings. To increase the uniformity of distribution of the reinforcing phase it is necessary to increase the number of more than 40 vol.%, that limits the technological possibilities of the method and leads to increased fragility of the deposited coatings.
The closest way to the same destination to the claimed invention by a combination of traits is a method of electron-beam welding (RF Patent No. 2205094, from 2003.05.27, MKI UK 9/04, UK 15/00, UK 35/368), in which the protected surface metal products creates a zone of melting electron beam with a linear scan in the form of several parallel lines, facing material is fed to the zone melting, and the product is moved when the protected surface is pre-cleaned by melting electron beam without filing fused material the scan of the electron beam performs perpendicular to the direction of movement of the product, and as the fused material use of composite powders, or a mixture of heat-sensitive powders.
The disadvantage of this known method is that when forming the cladding of the composite powder of the refractory material particles partially (TiC) or fully (WC) dissolved in the liquid metal bath melt and rapid further crystallization and cooling do not have time to completely stand out from the solid solution. Any insoluble particles of concrete and partially segregated grains are unevenly distributed throughout the thickness of the hardened layer due to the significant difference in their densities with the density of the liquid metal bath melt. The formation of heterogeneous structures surfacing on the basis of αor γ- solid solution on its thickness contributes to uneven wear, failure to monitor and predict its performance, which ultimately leads to premature failure of the product.
The primary object of the present invention is the expansion of technological capabilities of the method of electron-beam welding and the improvement of physico-mechanical properties of fused products. In particular the improvement of wear resistance of low-alloy to positionnow surfacing and structural uniformity throughout the thickness of the hardened layer by creating a multimodal distribution of reinforcing particles in α or γsolid solution iron-based.
This object is achieved in that in the method of electron beam welding on the surface of the fused product creates a zone of melt electron beam fused powder composite material serves in the area of the melt, fuse product move, and fusible powder material serves perpendicular to the movement surfaced products. After coating on the additional passage is heat welding, which is an additional temperature effects defocused electron beam on the surface of the deposited coating without feeding the fused material. The current focus of the electron beam 10...20% less than the current focus, which is surfacing coating that provides the heating temperature of the coating 650 700...°S. This leads to the separation of dispersed particles of the hardener of the solid solution and formation of multimodal patterns surfacing throughout its thickness.
An example of a specific implementation.
The method of electron-beam welding is implemented on the basis of the welding electron-beam installation ELU-5, is additionally equipped with a powder feeder and the scanner beam. For surfacing, use the following powder materials, for example:
1. e - 20% Ni - 4% V - 4% Mo - 10% TiC;
2. Fe - 20% Mn - 4% V - 4% Mo - 1% - 15% WC;
3. steel R6M5 - 10% TiC;
4. steel R6M5-15% WC.
The mixture of the source powder is poured into a ceramic crucible and subjected to sintering in a vacuum at a temperature of 1050 1120...°C for 30 to 40 minutes. After cooling in the furnace resulting spectra are subjected to crushing and sieving into fractions. For welding use a fraction of composite powder 90...250 μm. Welding takes place by feeding the powder material from the powder feeder to the zone of melt generated by an electron beam with a linear scan, which is formed by using a scanner beam. After deposition of the coating on the additional pass is carried out, heat treatment, which is an additional temperature effect of the electron beam on the surface of the deposited coating. The current focus of the electron beam when the processing is put on 10...20% less than the current focus, which was conducted surfacing coating. The current of the electron beam is set such size that in his area the temperature was 650-700°S, which is controlled by a thermocouple on the sample-witnesses.
The drawing shows the microstructure of the coatings (Fe - 20% Ni - 4% V - 4% Mo - 10% TiC) and the distribution of the particles of the solid phase in size after welding (a, b) and subsequent aging (b, d). Acerage (a) shows the microstructure of the coating immediately after electron-beam welding. You can see the uneven distribution of carbide particles in the austenite matrix in the form of separate linear discharge. The average size of these particles is equal to 1.1 μm (see drawing). Heat treatment welding due to the additional temperature effects defocused electron beam leads to additional release of particles reinforcer (see drawing b). This contributes to the creation of a uniform multimodal distribution of particles of hardener in the solid solution (see drawing d). On the distribution of particles reinforcer dimensions (see drawing d) obvious three maxima in the distribution (d1=1.2 µm d2=2.5 μm, d3=4,1 μm), the average particle size of 1.8 μm. Thus formed multi-modal structure allows to increase the hardness of surfacing from 6 to 8.3 GPA, to reduce the variance of the distribution from 3.5 to 0.5 HPa, to reduce the wear material with 6×10-4to 3.7×10-4cm3per hour and keep it uniform throughout the thickness of the surfacing. The abrasive wear resistance was determined when worn about not gestazione abrasive particles (GOST 23.208-79). As the abrasive material was used quartz sand grain sizes 160...350 μm when the load on the sample 44±0,25 N.
The method of electron-beam welding, in which the surface of the product, the cat is the ROI napravlyayut floor, pre-cleaned by melting electron beam without the filing of fused material, then on the surface of the fused product creates a zone of melt electron beam surfaced product move, and fusible powder material is fed into the area of the melt in the feed direction perpendicular to the relative movement surfaced product, characterized in that the coating is formed in multiple passes, with the last pass perform defocused electron beam without filing surfaced material, providing the heating temperature of the coating 650-700°C.
FIELD: method of application of metal coats on detachable contact connectors.
SUBSTANCE: proposed method is used for stabilization of contact resistance of connectors at level of initial assembly during entire period of operation in parts made from copper, aluminum and their alloys during assembly, operation and repair of electrical plants and plants manufacturing electrical equipment. Proposed method includes cleaning and degreasing the contact surfaces, applying liquid flux on these surfaces, preheating the surfaces and applying the metal coat; preheating is continued to temperature of 40-45C; metal coat is applied by means of local contact fusion and gallium alloy having melting point not above 30C is applied as metal coat at thickness not exceeding 0.1 mm.
EFFECT: reduction of contact resistance.
6 cl, 1 dwg
FIELD: foundry, centrifugal casting in particular; manufacture of multi-layer vessels, pipe lines, bottles, connecting parts and other articles.
SUBSTANCE: proposed method includes placing the thermit mixture in cavities of article, followed by rotation, initiating of exothermic reaction, melting of thermit mixture, cooling of external surface of article and crystallization of molten thermit mixture. Thermit mixture contains additionally fluid material. Cooling of external surface of article is continued till temperature of its internal surface gets equal to melting point of metal of article.
EFFECT: reduced thickness of coat; improved control of heat removal.
FIELD: many branches of industry; methods of fritting and polymerization in the furnace of the powder coatings.
SUBSTANCE: the invention is pertaining to the method of heating and fritting of the polymeric powder coatings applied on articles and may be used in many branches of industry for painting articles of the various configurations. The method includes: charging by batches of the articles in the furnace, heating with realization of polymerization of their powdery coatings and refrigeration. Before the heating operation in the working space of the furnace create rarefaction by means of preliminary switching on the ventilation and circulation system. After the heating up to the preset temperature conduct the periodical switching-on / switching-off of the electric heater of the furnace. At that the blowout of the air from the furnace is conducted. For keeping the preset temperature over the whole operational volume of the furnace through at least one pilot hole in the furnace the portions of the cold air are periodically pumped in. Then conduct refrigeration, at which the electric heater is finally switched off, and the air saturated with the products of polymerization is removed from the furnace, create the rarefaction and feed the new batch of the cold air into the furnace. For realization of the heating they use the electric heater made out of the steel sheets and the square-shaped metallic tubes. The tubes have holes used for arrangement in them of the tubular rods supporting the spirals. The tubular rods supporting the spirals of the electric heater are made out of the mullitesiliceous ceramics. The technical result of the invention is improvement of the quality of the articles treated in the furnace with simultaneous improvement of the process of heating of the furnace, the air ventilation and circulation.
EFFECT: the invention ensures improvement of the quality of the articles treated in the furnace at simultaneous improvement of the process of heating of the furnace, the air ventilation and circulation.
8 cl, 3 dwg, 1 ex
FIELD: processes and equipment for joining by rolling different type liquid and solid metals, possibly manufacture of clad metallic sheets and articles in different branches of industry.
SUBSTANCE: method comprises steps of pouring melt metal onto surface of different solid main metal coated with flux for soldering; rolling metals under pressure for rapid cooling of melt metal, crystallizing it and joining with surface of solid main metal due to metallurgical joining between two or more metals. Plant for performing the method includes mounted according to desired order: machine for uncoiling sheet metal from coil; vessel with soldering flux; unit for drying and heating; casting nozzle; rolls with inner cooling and machine for coiling sheet metal. Ladle for melt metal is arranged over casting nozzle. Main frame of plant is arranged under said ladle.
EFFECT: enhanced strength of different metals joints, low cost of products, improved efficiency, high quality of sheet metal, relatively small cost of plant, decreased power consumption.
14 cl, 6 dwg, 3 ex
FIELD: mechanical engineering, restoration of machine parts.
SUBSTANCE: method is realized by applying at least one coating by means of electric spark alloying. Wear resistance coating is applied with use of electrode of boron alloyed intermetallide Ni3Al containing, mass %: Al, 2 - 15; B, 0.02 - 02; Ni, the balance. In variants of invention electrode contains in addition dispersed particles of Si3 N4. Before applying on part layer of wear resistant coating, nickel layer with thickness 20 - 50 micrometers is applied as intermediate adhesion barrier. Coated parts are subjected to mechanical working. Restoration is realized for parts with wear degree up to 100 micrometers or with wear degree 100 - 300 micrometers.
EFFECT: possibility for restoring parts, improving their wear resistance and increasing adhesion strength of applied coating with base material of part.
6 cl, 3 tbl, 3 ex
FIELD: ferrous metallurgy; methods of the thermal treatment of the connecting elements of the pipelines made out of the low-alloy steel.
SUBSTANCE: the invention is pertaining to the field of ferrous metallurgy, in particular, to the engineering process of the thermal treatment of the pipes made out of the low-alloy constructional steel and may be used at manufacture of the welded connecting elements and the assemblies of the main pipelines and the field pipelines of the large diameter (up to 1420 mm) of the facilities of the petroleum industry and the natural gas industry transporting the non-aggressive petroleum, the oil products and the gas. For improvement of reliability of the connecting elements at simultaneous reduction of the power inputs conduct simultaneously normalization and hardening with heating in the austenitic area up toАс3+80-100°С (940-960°С), aging at this temperature within 1 hour and cooling in the water with application of the water bubbling by the compressed air, the backing of the connecting elements within the interval of the temperatures of 300±10°С, their aging at this temperature within 1 hour with the further cooling in the open air. The connecting elements of the pipelines have the mechanical properties corresponding to the К60 strength class and the heightened impact elasticity at the negative temperatures (-60°C).
EFFECT: the invention ensures the improved reliability of the connecting elements at simultaneous reduction of the power inputs.
2 tbl, 1 ex
FIELD: heat treatment of welded joints, namely joints of welded structures operating at lo temperatures.
SUBSTANCE: method comprises steps of slow cooling of welded joint together with furnace during three stages. At first stage cooling is realized only till temperature exceeding less than 150 C temperature value of starting formation of coherent to matrix tertiary cementite. At second stage accelerated cooling is realized at rate 30 - 50 m/h till temperature 250 ± 50°C and then welded joint is cooled in air. In such case tertiary cementite at stage of beginning its formation has small size and in the result stresses between matrix and reinforcing phase are occurred to be weak. It allows eliminate embitterment of welded joint. Low rate of cooling allows eliminate warping of welded structures.
EFFECT: increased cold resistance of zone of thermal influence of welded joints due to slow cooling of welded joint together with furnace during three stages.
1 ex, 2 tbl
FIELD: pipe rolling process; cooling welded joints of drill pipes during heat treatment in production lines.
SUBSTANCE: proposed device includes water and air supply passages with mixing chamber connected to them; mixing chamber is provided with water and air inlet branch pipes; mixing chamber is connected with nozzles by means of outlet branch pipe. Air inlet branch pipe is made in form of inner and outer branch pipes located coaxially one in other in mixing chamber; these branch pipes are provided with individual air supply passages. Inner branch pipe is connected with water inlet branch pipe through nozzle orifice; outer branch pipe is provided with spraying screen on outlet side; mixing chamber is provided with flow distributor located symmetrically along its axis and provided with outlet branch pipes with contraction tube mounted inside them before nozzles. Inner air inlet branch pipe is movable; mixing chamber is telescopic in construction. Nozzle is mounted at outlet of air inlet branch pipes.
EFFECT: enhanced control of cooling drill pipes in heat treatment lines.
4 cl, 3 dwg, 1 tbl
FIELD: processes for welding austenite steels.
SUBSTANCE: method comprises steps of applying to near-seam zone ultrasonic oscillations in frequency range 22.1 - 22.7 kHz. As melt is degassed and thermal equilibrium is set in crystal lattice, seam metal crystallizes at improved condition that is why welded joints practically have no residual stresses.
EFFECT: improved quality of welded joints.
FIELD: mechanical engineering and metalworking; methods of manufacture of cold strain dies.
SUBSTANCE: proposed method includes welding-on the welding material on working section of die of the following chemical composition: C, 0.5-1.5%; Si, 0.2-2.0%; Mn, 0.3-6.0%; Cr, 0.3-10%; Co, 0.3-10%; V, 0.3-2.0%; Mo, 5.0-10.0%, unavoidable admixtures; the remainder being Fe. Welded-on metal is cooled down at rate above critical rate of hardening in temperature interval of Ar1-600°C. Welded-on working part is subjected to machining for obtaining required geometry and to treatment by cold of welded-on metal. After machining and treatment by cold, welded-on metal is tempered at temperature of 480-520°C ensuring separation of dispersed carbides and intermetallic compounds without coagulation.
EFFECT: enhanced hardness of working part of die; enhanced reliability; increased productivity.
2 cl, 4 dwg, 3 tbl
FIELD: metallurgy; methods and devices for heat treatment of circular welded seams of large-sized thick-walled hollow articles.
SUBSTANCE: proposed method includes smooth delivery of heat-transfer agent at maintenance of preset temperature in heating zone not only by control of heat-transfer agent parameters but by control of parameters of heat-transfer agent discharged from heating zone; to this end, heat-transfer agent supply branch pipe is provided with flow swirler and holes for escape of waste heat-transfer agent are provided with dampers for control of flow section of exhaust holes; flow swirler is mounted in plane of welded seam being treated. Proposed method ensures smooth heating of welded seam and near-seam zone at reduced power requirements.
EFFECT: reduction of power requirements.
3 cl, 2 dwg
FIELD: welding technology; removal of residual stresses arising in welded joints in the course of welding.
SUBSTANCE: in the course of welding, ultrasonic oscillations at frequency of 22.1-22.7 kHz are introduced into near-seam zone.
EFFECT: enhanced efficiency of removal of residual stresses.
FIELD: mechanical engineering, in particular, manufacture of welded parts, in particular, repair of spherical gas valves.
SUBSTANCE: method involves providing annealing for relieving of welding voltage at temperature of 450-5000C and holding for 4.5-5.0 hours to prevent separation in steel microstructure of coarse carbide lattice determining toughness drop. Temperature is optimized by thermal processing and by testing of toughness samples.
EFFECT: stabilized toughness values and elimination of delay in spherical gas valve repair works.
FIELD: machine engineering, namely processes and equipment for fusion welding, possibly of different-structure parts, for example providing fluid-tightness of active zones of nuclear reactors at usual condition and from remote places.
SUBSTANCE: method comprises steps of supplying energy to welding zone by pulses; performing welding by several passes while controlling energy density in heating spot of heat source during process of forming seam; selecting relation of pulse energy density in heating spot to pulse duration at first pass in range ( 5 - 350) x 102 J/(mm2 s); selecting less values of said relation for lowered thickness of welded edges and selecting larger value of said relation for increased thickness of welded edges in given range. At each next pass relation of energy density of pulse in heating spot to pulse duration is set equal to or less than value of said relation in first pass.
EFFECT: possibility for improving quality and operational reliability of welded joints of different structures due to lowered size of pores and of oxide inclusions and due to their partial removal.