Open AccessStructure and hardness of wear-resistant coatings with low-frequency current modulation deposited on low carbon steel
Author(s) -
Ю. Н. Сараев,
В. С. Безбородов,
М. В. Перовская,
В. М. Семенчук
Publication year - 2020
Publication title -
izvestiâ vysših učebnyh zavedenij. černaâ metallurgiâ
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.3
H-Index - 7
eISSN - 2410-2091
pISSN - 0368-0797
DOI - 10.17073/0368-0797-2020-6-469-473
Subject(s) - materials science , metallurgy , microstructure , coating , composite material , overheating (electricity) , physics , quantum mechanics
Influence of the modes of manual electric arc surfacing of coatings with T-590 electrodes on low-alloy steel 09G2S on their structure and hardness was investigated. It is shown that the pulsed arc surfacing of coatings by electrodes forms a fine-dendritic structure of the deposited metal. Microstructure of the heat-affected zone after surfacing consists of several sections: the overheating zone with a widmanstett structure and the normalization zone with a characteristic fine-grained ferrite-perlite structure. In the initial state, the base metal (steel 09G2S) has a hardness of ~2500 MPa. The hardness of the deposited coating material due to strong mixing with the steel metal is ~ 2700 – 3000 MPa, and of thermal impact zone: 2100 – 2300 MPa. When applying the coating on DC mode, heating temperature of the surfacing bath is higher; this, as a consequence, causes grain growth. When coating on pulse modes, a structure with smaller component sizes is formed by directed low-frequency high-energy impact of the electric arc on the formed metal and due to the constant reciprocating motion of the melt with the frequency of current modulation. It was established that the application of the pulse-arc surfacing method allows preserving the previously formed hardening phases in the deposited coatings.