RU2618594C1 - Method for producing artificial roughness detail surface by combined treatment method - Google Patents

Abstract

FIELD: machine engineering.

SUBSTANCE: method involves processing the part with a fiber laser on a precision laser complex in the first stage, after which the final processing of the irregularities is performed by electrochemical method in the final mode. As a result of the proposed dimensional combination treatment, the working parts of the part in the cooling channels can be obtained with the necessary technological parameters without reducing the quality of the surface layer and the reliability of the product.

EFFECT: reduced time in the technological preparation before processing, reduce labour intensity is not less than 2 times.

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Description

The method relates to the field of mechanical engineering and can be used when applying artificial roughness to the surface of the part, for example, on the straight sections and side surfaces of the cooling channels of the heat-loaded part - the shell that is part of the rocket engine.

The known method [1], in which for controlled rough surfaces using the electrothermal action of moving cathode spots in a vacuum arc discharge. The dimensions of the roughness are regulated by the current and time of the discharge, the pressure in the vacuum chamber and a number of other parameters.

The disadvantages of the method are a possible violation of the quality of the surface layer (for example, the side surfaces of the grooves in the heat-loaded parts) with a pulse of high energy, limiting the area of heat transfer, low productivity.

The closest way to apply artificial roughness is the method [2], which includes processing the part with an electrode tool on electrical discharge equipment, while the processing is carried out in two stages, at the first stage in rough mode by an electric pulse method, irregularities in the form of contacting depressions are applied to the working part of the electrode tool after which, in the finishing mode by electrospark treatment with an electrode-tool, a roughness is formed on the treated area.

The disadvantages of the method are the relatively large wear of the electrode tool (for example, the amount of wear of brass electrodes is 25-30% of the volume of metal removed from the part), which significantly increases the cost of this type of processing and makes it difficult to obtain the necessary accuracy, requires high energy consumption, and productivity is relatively low.

The technical result of the proposed method is to obtain artificial roughness in a high-performance way using a pulsed fiber laser without reducing the quality of the surface layer of the product with the necessary technological parameters and expanding the scope of use of the method.

A method of obtaining artificial roughness on the surface of a part using a combined processing method involves processing the part in two stages: initially, a roughness is formed on the surface of the part, then final processing is performed, and at the first stage, the part is processed by a pulsed fiber laser on a precision laser complex, and at the second stage perform electrochemical surface treatment of the part.

In FIG. 1 shows a laser treatment pattern for a pulsed fiber laser to produce artificial roughness. In FIG. - 2 scheme of electrochemical processing.

In FIG. 1 part 1 and a pulsed fiber laser 2 are installed on the desktop 3 of a precision laser complex with a rotary device 4. Laser 2 at the first stage of processing is located at a certain focal length L, depending on the type of fiber laser. After that, energy is supplied to the laser 2 and the working part 5 is processed. The arrangement of the part 1 and the laser 2 relative to each other is controlled by the rotary device 4.

In figure 2, at the second stage of processing, the working part 5 of part 1 is set relative to the cathode device 6 on the work table 3 opposite the working part 5 obtained in the first stage by a fiber laser 2. The electrolyte 7 is fed into the space between the part 1 and the cathode device 6. Through the rectifier supply current to the electrolyte 7, while the part 1 and the cathode device 6 are turned on according to the direct polarity scheme.

The method is as follows. Set part 1 and fiber laser 2 on the desktop 3 of a precision laser complex with a rotary device 4. Set the laser 2 at the required focal length from part 1 (Fig. 1). The control is due to the rotary device 4. Mounting, alignment and automatic adjustment of the laser 2 are provided on the equipment. Then bring the laser 2 to the part 1, adjust the focal length between them, while forming a profile in the form of irregularities.

In the second stage (Fig. 2), part 1 is placed on the desktop 3. Install the cathode device 6 to ensure that on the working part 5 of part 1 of the profile of irregularities. Connect part 1 and the cathode device 6 according to the scheme of direct polarity, while part 1 is the anode (+). Set the finishing mode on the rectifier, which ensures that on the working part 5 of part 1 of the profile of irregularities with a defect-free surface layer. The electrolyte 7 is fed into the space between the part 1 and the cathode device 6. A current is supplied through the rectifier to obtain the necessary irregularities on the working part 5.

An example implementation of the method.

In the cooling channels of the shell of the combustion chamber of the BrHTsrTV alloy of the rocket engine, it is necessary to perform a local section in the bottom of the channel for additional cooling. According to the requirements of technical documentation, the depth of the protrusions should be 0.4 ± 0.03 mm, width 0.8 ± 0.1 mm. Combined methods of laser and electrochemical processing for these purposes have not been previously used. Less productive methods of mechanical, electroerosive and electrochemical treatment were used. Using the above methods is very time-consuming and requires significant costs for technological preparation before starting work.

The experiments showed that with a laser power of up to 50 W, sections with uneven heights of 0.41 mm and a width of 0.82 mm are formed in 0.1 minutes on the working part of the part in the cooling channel. When a surface layer is exposed to temperature influences, it is removed by electrochemical treatment at the following technological conditions: voltage 12 V, current strength 70 ... 190 A, pressure 3 ... 6 kg 6s / cm ² , electrode gap 0.5 mm. Metallographic and X-ray structural studies did not reveal a violation of the quality of the surface layer in the channel on the finished part. Measurement of the profile of sites showed compliance with the requirements of technical documentation.

Thus, the time for technological preparation before processing was reduced, productivity increased by at least 2 times in relation to mechanical, electroerosive and erosion-chemical treatment without reducing the quality of the surface layer of the product.

Information sources

1. Obtaining adjustable roughness of metal surfaces in a vacuum arc discharge. / Anikeev V.N., Dokukin M.Yu. // Engineering Bulletin: FSBEI HPE Moscow State Technical University named after N.E. Bauman ", 02/02/2013.

2. RF patent No. 2464137. A method of obtaining a local cooling section of a heat-loaded part. / V.P. Smolentsev et al. Published on October 20, 2012, Bulletin No. 29.

Claims (1)

A method of obtaining artificial roughness on the surface of a part using a combined processing method, comprising processing the part in two stages, in which the roughness is initially formed on the surface of the part, and then final processing is performed in the finishing mode, characterized in that the first stage is used to process the part with a precision fiber laser laser complex, and at the second stage they perform electrochemical processing of the surface of the part.

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