Page 11 - НАЦІОНАЛЬНА АКАДЕМІЯ НАУК УКРАЇНИ

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it due to the formation of chromium-containing borides. The matrix phases of the

developed coatings are Cr, Mn and Si alloyed ferrite, martensite and austenite in the

volume of which there are up to 25 wt.% of finely dispersed precipitates of borides

Fe(Cr)2B. It was found that in the structure of coatings from CW 90Cr6MnSi, CW

90Cr6BMnSi, CW 90Cr10MnSi and CW 90Cr10BMnSi, sprayed using the supersonic

mode, the content of austenite (γ-Fe(Cr) decreased and the content of martensite

increased, which is due to more intensive burning of C from droplets of molten CW

during the spraying process, and in coatings from CW 90Cr17BMnSi and CW

90Cr17B2MnSi, the content of ferrite (α -Fe(Cr)) increases and the content of austenite

(γ -Fe(Cr) decreases. The content of Fe(Cr) 2B borides in the structure of the coatings

practically does not depend on the spraying mode of the coatings.

The mechanism of the wear of friction pairs of ASCs and counterbodies made of

cast iron, bronze or babbitt was established. It was shown that the wear of a cast iron as

a counterbody occurred through the elastic-plastic deformation and the uniform

abrasion of its surface layer. While the wear of a bronze counterbody occurs due to

microcutting of bronze by oxide protrusions on the ASC surface. The soft babbitt, due

to the frictional interaction, was rubbed with particles torn off from the ASC surface,

which ensured grinding of the surfaces during the friction. Such friction pairs are

suitable for the use up to the specific loads of 10 MPa.

The technological regulation for the restoration of shaft-type parts by the method

of the arc spraying of the coatings from CWs of the Fe-Cr-Si-Mn-B-C alloying system

was developed for the needs of the agricultural, food processing, municipal, transport

and defense industries. The coatings from the developed CWs have undergone

experimental and industrial testing at enterprises in Ukraine and were introduced into

production. The total volume of work on the restoration of shaft-type parts by the

developed CWs, performed within the framework of the economic contracts in the

laboratory of methods of gas thermal spraying of coatings, reached 3.2 million UAH.

Based on the results of experimental studies and pilot tests carried out on real
products of different enterprises, three variants of CWs for restoration of shaft-type

parts were proposed: