RU2538849C2 - Spark application of coating - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to machine building, particularly, to application of coatings. Proposed process comprises contact surface processing of the part connected to current source negative pole by rotary electrode connected to current source positive pole. Contact processing is conducted by disc-shaped electrode with inclined crosswise helical grooves. Note here that during application abrasive tool is used for continuous removal of faulted ply from disc-shaped electrode working surface and processing of electrode and applied coating by brushes.

EFFECT: higher quality of surface coating.

2 dwg

Description

The proposed method relates to mechanical engineering and can be used for coating.

A known method of restoring and hardening worn steel parts [Patent No. 2383420], adopted as an analogue, comprising machining the worn surface of the part and machining the deposited layer.

A disadvantage of the known technical solution is the low productivity of the process and the high cost of the coating due to the significant number of operations and the use of alloying elements.

There is also known a method of electric spark alloying and a device for its implementation [Patent No. 2175594], adopted as a prototype, including contact surface treatment of a part connected to the negative pole of a current source, a rotating electrode connected to the positive pole of a current source.

The disadvantages of this technical solution are the complexity of the device and the high cost of the proposed method with low productivity and quality of the coating.

In [1], [2], [3] it was noted that with electrospark deposition, the coating thickness grows in time along a curve with saturation, i.e. coating speed decreases. The closer the processing time to the saturation time, the worse the surface quality.

The reason for this is the counter transfer of the material of the part (cathode) to the electrode (anode) as a result of cathodic sputtering, as well as due to diffusion at the moment of contact between the electrode and the surface of the part.

In this regard, as well as as a result of thermal action on the surface layers of the disk electrode during a spark discharge, a certain volume of it is saturated with the chemical elements of the material of the part and changes its physicochemical properties, resulting in the formation of a defective layer up to 0.2 mm deep. The consequence of this is a decrease in processing productivity and quality (wear resistance) of the hardened surface.

The technical result of the proposed method is to increase the productivity and quality of the process of the processed surface in combination with low cost and simplicity of design.

Obviously, the removal of the defective layer (cleaning) in the process of electrospark coating, that is, the constant updating of the working surface of the electrode and the workpiece in order to maintain the original properties of the materials will increase the productivity of the process and the quality of the workpiece surface.

The essence of the proposed method consists in electrospark coating on a part, including contact processing by a rotating disk electrode.

In contrast to the prototype, during the coating process, the defective layer is continuously removed from the working surface of the disk electrode and from the surface of the workpiece, and the quality of the applied layer and sparking are improved due to the continuity of contact with the disk electrode part by means of inclined transverse grooves made along a helical line.

The objective of the invention is achieved by the fact that in the method of electrospark coating on a part, including contact processing of the surface of the part connected to the negative pole of the current source, a rotating electrode connected to the positive pole of the current source, according to the invention, the contact processing is performed by a disk electrode with inclined transverse grooves made along a helical line, while during the coating process, a defective layer is continuously removed with an abrasive tool with the working surface of the disk electrode and brushing the disk electrode and the applied coating layer

In FIG. 1. shows a method of electrospark coating a part. In FIG. 2 is a section along AA in FIG. one.

The method consists in the fact that the disk electrode 1 (made, for example, of white unalloyed cast iron) with inclined transverse grooves made along a helical line, connected to the positive pole of the current source, is rotated and moved along the surface of the part 2 connected to the negative pole of the current source while at the same time during the coating process from the working surface of the disk electrode, the defective layer is continuously removed with a cleaning tool 3 (for example, a grinding wheel) rotating in spring-loaded fork-shaped base 4. There are also brushes 5 for processing the applied layer and the disk electrode to remove the defective layer and abrasive dirt. The inclined transverse grooves of the disk electrode 1 are made along a helical line at an angle to the center line so that they overlap by at least fifty percent for smooth and continuous contact with the workpiece. Inclined transverse grooves are also necessary to maintain constant sparking with a given quality and uniformity of the deposition of the layer on the surface of the part.

The method allows during the coating process to continuously remove the defective layer from the working surface of the disk electrode and from the surface of the workpiece, as well as to improve the quality of the applied layer due to the continuity of contact with the part of the disk electrode by means of inclined transverse grooves made along a helical line.

Information sources

1. Verkhoturov A.D., Mukha I.M. Technology of electrospark alloying of metal coatings / A.D. Verkhoturov, I.M. Fly. - Kiev: Technics, 1982. - 181 p.

2. Burumkulov F.Kh., Lyalyakin V.P., Ivanov V.I. Improving the wear resistance of tools with spark hardening: Technique in agriculture, No. 4, 2001, S.29-34.

3. Restoration of machine parts: Handbook / F.I. Panteleenko, V.P. Lyalyakin, V.P. Ivanov et al .; under the editorship of V.P. Ivanova. - M.: Mechanical Engineering, 2003 .-- 672 p., Ill.

Claims (1)

The method of electrospark coating on a part, including contact processing of the surface of the part connected to the negative pole of the current source, a rotating electrode connected to the positive pole of the current source, characterized in that the contact processing is performed by a disk electrode with inclined transverse grooves made along a helical line, this in the process of coating carry out continuous removal with an abrasive tool of a defective layer from the working surface of the disk electrode and brushing the disk electrode and the applied coating layer.

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