SU633703A1 - Electric spark alloying method - Google Patents

Description

I

The invention relates to electric methods of processing materials and is intended for the electric-spark doping of products from conductive materials.

Electrospark doped coatings are known to have an increased roughness, therefore, they are subjected to grinding, for example, electric spark coating, at which the polarity of the technological current source I | changes.

However, first, the repeated processing of the doped surface is carried out after hardening and crystallization of the aaaaaaa layer of material, which requires an increase in the power of the “grinding current” source and reduces the quality of the “polished surface”; secondly, the repeated passage of the tool along the surface requires additional time.

The aim of the invention is to reduce power consumption and improve surface quality.

It is achieved by the fact that in the process of processing the electrospark doping is combined with electrospark grinding by applying alternating polarity pulses alternating in time; moreover, the amplitude of the forward pulse (1) and the reverse pulse () is chosen in the ratio

g-fc v

During the alloying, a rotation is reported to the electrode holder and supplied to it and

detail pulse voltage. The contact of the electrodes with the part is accompanied by the passage of current pulses, the direction and amplitude of which is due to the applied voltage.

An initial current impulse passes through the contact point, accompanied by the transfer of material from the electrodes to the part. The transferred material is disposed on the surface of the part in separate microvolumes. Height microvolume .. with-one

side determines the thickness of the applied layer, on the other - the surface roughness. The material from the electrode to the part is transferred, as a rule, in the liquid phase. Contacting a cold surface, the material is cooled. Supercooling of the melt is accompanied by crystallization.

When doping with this method, a pulse and a lifting current is applied while the material is still in the liquid phase. In this case, on the one hand, energy is not expended on melting the removed part of the material, on the other hand, the conditions for the distribution by the electrode of the molten material mass on the surface of the workpiece are improved.

The ratio of the amplitudes of the forward and reverse current pulses is selected from the following considerations. The higher the requirements for surface roughness, the more material will come to remove the surface of the part with pulses of reverse polarity. Experiments have established that already with respect to I; 0.5 roughness obtained as a result of grinding, commensurate with roughness obtained by doping. In the case of high requirements for surface cleanliness, the process is performed at an amplitude ratio of close to 1: 0.4. If it is necessary to obtain openings of sufficient thickness, running, there are stringent requirements for surface cleanliness, the process is carried out with an amplitude ratio within I: 0.1-0.2.

Preliminary tests have shown that the proposed method allows reducing consumption by 20–30% and improving the quality of processing (reducing the height of irregularities in the profile of the coating — roughness) by 1L, 25 times compared with the known methods.

Claims (1)

Invention Formula A method of electrospark doping with current pulses flowing through a vec- ture gap that differs in heme, in order to reduce electrical energy consumption and improve the quality of the alloyed surface, the process is alternated with forward and reverse field pulses at a ratio of pulse amplitude-direct polarity to pulse amplitude reverse polarity in the range of 2.5 to 10. Sources of information taken into account in the examination: I. USSR Copyright Certificate No. 75592, cl. B 23 P 1/18, 1948.