The method of applying a reinforcing coating on items of wrought aluminium alloys
(57) Abstract:The method of applying a reinforcing coating on items of wrought aluminium alloys includes machining the surface of a worn-out plot, degreasing gasoline or acetone, shot blasting, detonation spraying in batches of 10-20 shots with intervals of 0.5 to 3.0 min with continuous blowing of the substrate by compressed air pressure of 2-4 bar. 3 Il., table 1. The invention relates to methods of making and repairing worn surfaces of parts made of wrought aluminium alloys employed in friction pairs.The known method for plasma deposition of hardening coatings, including shot blasting the surface of the part and subsequent coating (see Kostikov and other coatings. M. metallurgy, 1978, S. 160).The disadvantage of this method is overheating basis to a temperature of more than 100oC and the appearance of intergranular corrosion in conditions of high loads and corrosive environments (salt mist) and low adhesion strength.The known method for plasma deposition of hardening coatings on parts made of aluminum alloys, including the preparation of detania coatings on aluminum alloys. Powder metallurgy, No. 12, 1988, pages 37-40).The disadvantage of this method is the low adhesion coating main material, and heating the substrate to a temperature exceeding 100oC, resulting in intergranular corrosion in conditions of high loads and corrosive environments (salt mist) and, as a consequence cracking foundations.The closest known to those proposed by the achieved result is a way to restore parts of detonation method comprising machining the surface of a worn-out plot, degreasing gasoline or acetone, shot blasting the surface of the part and subsequent detonation deposition of hardening coatings (see L. I. Zverev and other Detonation spray coatings, shipbuilding, L. 1979, S. 105-110).The disadvantage of this method is that when the coating temperature of the substrate reaches 200oC and leads to the formation of intergranular corrosion in wrought aluminium alloys in conditions of high loads and corrosive environments (salt mist).The aim of the invention is to reduce the surface temperature and the Oia intergranular corrosion.This objective is achieved in that in the method of applying a reinforcing coating on items of wrought aluminium alloys, including shot blasting the surface details, detonation spray coating in accordance with the invention, the sputtering is performed by the detonation series of shots, each series includes 10-20 shots, this time between batches is 0.5 to 3.0 min, in addition, continuously produce the flapper substrate by compressed air pressure of 2-4 bar.Spraying the detonation series of shots with the certain number of shots in the series, regulated by time between a series of shots, continuous blowing of the substrate with compressed air regulated pressure constitute "significant differences" of the invention.In the operation of aircraft parts from wrought aluminium alloys when working in pairs their friction surface wear by up to 0.5 mm. To restore it is necessary to apply a hardening of the coating and to prevent heating of the surface to temperatures of more than 100oC, as in wrought aluminium alloys develops intergranular corrosion, which is SS="ptx2">The method is as follows:
The wear surface is subjected to mechanical treatment, jobstreet and degrease gasoline or acetone. Detonation spraying carry out a series of shots. After the implementation of a series that includes 10-20 shots, a pause is made of 0.5 to 3.0 min, after which the next series, which includes the same number of shots, and so on until the spray coating of the desired thickness. While the substrate is continuously blown by compressed air pressure of 2-4 bar. and cools it as the deposition and during pauses between each series of shots.When detonation spraying with lots with less than 10 shots is low productivity of the process. The implementation of detonation spraying series, including more than 20 shots leads to heating of the substrate to a temperature of more than 100oC and the occurrence of intergranular corrosion in conditions of high loads and corrosive environments (salt mist).When the time between the series of shots is less than 0.5 min, the substrate does not have time to cool to room temperature, which is the source for the beginning of the detonation spraying in the proposed method. When the time between when the providing compressed air to less than 2 ATM does not give rapid effect its cooling, and blowing substrate pressures greater than 4 bar leads to deflation of the flow of powder particles in detonation spraying, and, as a result, unevenness of the surface coating.An example implementation of the method.During the operation of rod control aircraft alloy D-16 in contact with the rollers appear to develop to a depth of 0.5 mmThe restoration of the worn surface is as follows:
mechanical treatment is carried out using a grinding heads (circles felt the knurled abrasive powder (oxide) grit N 25-16, 10-6 N, N 5-5 GOST 3647-80) along the fiber material D-16, i.e. parallel to the axis of thrust to the elimination of sharp corners.Shot blasting is carried electrocorundum marks 23A.25A 14A or silicon carbide S.55C (grain 40.63).RUB the surface of the substrate is carried out directly before deposition of a napkin cotton, bleached, moistened with acetone GOST 2768-84.Detonation spray coatings based on NiAl type PNU perform the installation of the ADK-1 "Prometheus".Modes detonation spraying:
oxygen flow rate l/min 15-19
flow ACET is to the substrate, mm 19020
According to the Handbook of aeronautical materials (so 2 Nonferrous alloys, part 1, aluminum alloys, vol. 5, 1965, page 107) and the requirements of the all-Russian Institute of aviation materials (VIAM) alloy D-16T is not recommended to heat to a temperature of more than 100oC, as a result, the details of these alloys during operation occurs intergranular corrosion.At the development stage of the technological process during the deposition the samples of alloy D-16 coating thickness of 0.5 mm was found that the substrate is heated to a temperature of 200oC. Blowing compressed air is allowed to reduce the temperature of the substrate, the optimal adopted a pressure of 4 ATM (PL.1).However, after 21 shots the temperature of the substrate has reached a temperature of more than 100oC (Fig.1). When you spray on another sample after 20 shots was taken pause. Measurements of substrate temperature during pause is shown in Fig. 2 (when measuring the temperature of the used thermocouple chromel-Copel, potentiometer PP-63 class 0.05 and graduirovochnye table according to GOST 3044-84). Optimal was adopted pause 1 min After a pause again conducted a series of detonation spraying 20 shots and pause 1 min and so the openings were placed in a cell with a salt fog and was created to cover the increased loads. The results of metallographic analysis of samples with coatings that have passed these tests showed that under the cover of intergranular corrosion was not developed
After recovery, traction control aircraft series 20 shots at intervals of 1 min and blowing compressed air pressure of 4 ATM spent machining the repaired surface to the drawing size.The thrust recovery was tested by Il-76.The proposed method is compared with the known provides restoration of parts of wrought aluminium alloys employed in friction pairs under conditions of corrosive environments (salt mist). The method of applying a reinforcing coating on items of wrought aluminium alloys, including machining the surface of a worn-out plot, degreasing gasoline or acetone, shot blasting and subsequent detonation spraying, characterized in that the detonation spraying carry out a series of shots, each series includes 10 of 20 shots, the time between episodes is 0.5 to 3.0 min, while continuously produce the flapper substrate by compressed air pressure of 2 to 4 atmospheres.
FIELD: portable apparatuses for applying coatings of powder materials by gasodynamic deposition.
SUBSTANCE: apparatus includes compressed gas source, powder meter, deposition unit in the form of portable manual tool with remote control having supersonic nozzle and gas heater rigidly connected with it. Gas heater includes metallic body inside which electric and heat insulation having through mutually parallel pneumatic ducts with inserted in them heating members. Apparatus also includes pneumatic duct for feeding powder from powder meter to supersonic nozzle, locking devices and unit for controlling deposition process, said units are mutually connected through flexible pneumatic ducts and electric connection wires. According to invention electric and heat insulation of gas heater includes inner and outer cylinders coaxially arranged one inside other. Inner cylinder has central through passage for placing pneumatic duct for feeding powder from meter to supersonic nozzle. Pneumatic ducts along its periphery are in the form of grooves. Inner and outer cylinders of electric heat insulation of gas heater are made of heat resistant material having electric and heat insulated coating on surfaces restricting pneumatic ducts.
EFFECT: enlarged manufacturing possibilities, simplified design, lowered mass, improved capability for repairing works, enhanced operational efficiency.
2 cl, 3 dwg
FIELD: finish treatment of precision friction pairs requiring high quality of treatment at retaining starting dimensions, for example, high-precision machines and tools and diesel engine supply equipment.
SUBSTANCE: friction surface is degreased, dried and technological medium is applied to it by means of brush, for example. Brass rod is fitted at angle of 45-60 deg. relative to surface being treated. When rod is pressed at simultaneous switching-on of electric machine, it forms shocks over surface being treated; energy of shock is equal to 0.5-0.7 J.
EFFECT: improved quality of coat at low porosity.
2 cl, 2 dwg, 1 ex
FIELD: machine engineering, other branches of industry, namely deposition of coatings of powder materials for imparting different properties to coated surfaces.
SUBSTANCE: apparatus includes deposition unit having electric heater of compressed gas and supersonic nozzle. The last is rigidly joined with outlet of electric heater and has member for introducing powder to nozzle. Apparatus also includes control unit connected with electric heater of compressed gas by means of flexible pipeline and electric cable; powder feeder whose outlet is connected with member for introducing powder to nozzle by means of flexible pipeline. In order to enhance operational safety of apparatus due to lowered temperature of outer members of electric heater of compressed gas, the last includes casing in which metallic housing is arranged with gap filled with heat insulator. Fuel member is arranged in metallic housing having openings for blowing non-heated gas through casing. Member for introducing powder to nozzle is provides powder feeding to supercritical portion of supersonic nozzle at inclination angle relative to its axis.
EFFECT: enhanced efficiency of apparatus due to uniform distribution of powder along nozzle.
39 cl, 13 dwg
FIELD: equipment for plasma-powder fusing or deposition of powders.
SUBSTANCE: powder feeder comprises casing-chamber, powder hopper arranged in upper part of casing-chamber and equipped with discharge opening, which is aligned with annular charging channel of rotating disk provided within casing-chamber, and drive arranged in lower part of casing-chamber. Ejector is disposed on casing-chamber at opposite side of hopper and equipped with supersonic nozzle and intake branch pipe of intake chamber. Intake branch pipe is aligned with annular charging channel of rotating disk. Agitator mounted within powder hopper is equipped with drive.
EFFECT: improved quality of coating deposited.
FIELD: application of coat on rocket engine manifold.
SUBSTANCE: coat is formed on at least one backing by feeding particles of metal powder through sprayer nozzle; size of particles is sufficient for excluding blowing-off by front of shock wave up to 50 mcm. Particles are passed through sprayer nozzle at rate sufficient for arising of plastic deformation of metal powder particles on at least one surface of backing. Carrier gas is fed to nozzle at flow rate of 0.028 to 1415.84 dm3/min.
EFFECT: avoidance of swelling after soldering at high temperature.
17 cl, 1 dwg
FIELD: application of anti-score coats on sections of oil well tubing.
SUBSTANCE: proposed method consists in rotating the tube along its longitudinal axis and applying the coat on threaded section. Application of coat is performed by at least two air-powder jets. Jets are rectangular in cross-section and are directed in such way that axis of each jet lies in plane passing through axis of tube and is inclined to it at angle of 30-40°. Jets are inclined relative to tube axis to opposite sides. Wide sides of jets have length equal to 0.3-1.0 of length of threaded section; they are positioned along tube axis. Specification contains description of device for realization of this method.
EFFECT: improved quality of spraying due to smooth distribution of metal over thread surface.
9 cl, 3 dwg, 2 ex
FIELD: processes for applying coatings by chemical deposition for obtaining hard wear resistant coatings.
SUBSTANCE: method comprises steps of applying onto surface of steel containing carbon, at least 0.2 mass %, preferably 0.7 -1.2 mass % and chrome, 4 - 12 mass % at least one metal of 5-th Group with atomic number no more than 41. Chemical deposition is realized at rotating article in fluid-tight vessel at temperature 870 - 1110° C practically without air provided with source of powder mixture containing at least one metal of 5-th Group with atomic number no more than 41 and halogen catalyst. Said powder mixture contains up to 50 mass % of inert particles for the total mass of mixture. Such method is used for making rollers of chains with hard coating containing chrome carbide, 1 - 3%. Steel for making articles contains, mass %: carbon, 0.7 - 1.2; chrome, 4 - 8; manganese, 0.25 - 0.45; silicon, 0.25 - 0.55; molybdenum, 0.2 - 0.55; phosphorus, no more than 0.03; sulfur, no more than 0.03; aluminum, no more than 0.05; iron, the balance.
EFFECT: possibility for making article with coating highly resistant against shearing and exfoliation.
20 cl, 4 dwg