SU387005A1 - METHOD OF THERMOMECHANICAL TREATMENT OF METAL COATINGS - Google Patents

Description

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The invention relates to methods for hardening metal platings applied by overlaying and can be used for repairing metal plastics in repair shops.

The known method of thermomechanical treatment of metal coatings applied by vibro-arc welding, according to which the deposited layer undergoes plastic deformation during the deposition process.

The purpose of the invention is to increase the strength and wear resistance of the weld metal.

This is achieved by the fact that the deposited metal is again subjected to plastic deformation at the temperature of stability of supercooled austenite.

FIG. 1 shows a scheme for the implementation of the process of surfacing and pre-deforming the weld metal; in fig. 2 shows a scheme for carrying out low-temperature thermomechanical hardening of the weld metal.

The part / which is subjected to fusing is installed in the centers of the converted screw-cutting machine 2, on the support of which the surfacing head 3, the two-roller tool 4 for deforming the weld metal and the cooling system are mounted. Surfacing is performed by welding wires, the chemical composition of which provides greater stability of supercooled austenite in the low temperature range (for example, welding wire made of YuKhPNVMF steel provides greater stability of supercooled austenite at a temperature of 700 to 300 ° C). Initially, the weld metal is deformed in the process of surfacing with rollers 4 in the high temperature range (900–950 ° C) with a compressing force Pi of 250–300 kg, with the aim of

elimination of metallurgical defects-pores, various kinds of cracks, etc. After the surfacing, the part is cooled by air at a temperature that provides the necessary stability and ductility of supercooled austenite. Then, the deposited metal is subjected to secondary deformation by the rollers 4 with a squeezing force of 2 1200-1300 kg with simultaneous cooling using system 5.

The appearance of the metal coating 6 in the case of deformation of the weld metal in the high temperature range takes a smoother appearance compared to conventional surfacing, but traces of surfacing remain.

Under secondary deformation, the appearance of the surface of the metal-coating 7 resembles the surface after the usual rolling of the metal. Traces of hardfacing are completely absent, depending on the geometry of the strengthening

The tool can get a different roughness class (from V3 to V8).

The deformation of the deposited metal in the range of high and low temperatures leads to the elimination of metallurgical defects and the formation of a crushed structure, and the subsequent cooling results in hardening much more than the sum of the hardening from the effect of these factors separately.

The use of this method will increase the strength and wear resistance of the metal coating, as well as the technical and economic efficiency of the restoration of machine parts.

Subject invention

The method of thermomechanical treatment of metal coatings deposited by cladding, including plastic deformation during the cladding process, characterized in that, in order to increase strength and wear resistance, the weld metal is again subjected to plastic deformation during cooling at the temperature of resistance of supercooled austenite.

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