Effect of carbon-fluorine additive to flux on the structure, defective substructure and fracture surface of electric arc surfacing of low-carbon wire

Abstract

By the methods of transmission and scanning electron microscopy the effect of a carbon-fluorine containing additive in a flux of a silicomanganese slag with a low content of manganese oxide on the structural-phase state, defect substructure and fracture surface of an electric arc surfacing of low-alloy steel is investigated. A quantitative analysis of the parameters of structure, phase composition, dislocation substructure of the surfacing with the additive into a flux and without it is made. It is shown that the deposited metal with the additive into a flux has a layer surface structure. It is detected that a predominant fracture mechanism is a ductile fracture with a formation of the pit structure of the fracture. The areas of a quasibrittle fracture are much more rarely detected. The main structural constituent of the deposited metal are the α-phase grains. The second structural constituent of the surfacing is the pearlite grains of lamellar morphology whose relative content in the surfacing with the carbon-fluorine containing additive to a flux is three-fold higher than in the surfacing to a flux without it. In most cases the α-phase grains are fragmentary. The particles of iron carbide of a round shape of 20–80 nm in size are revealed in the α-phase grains of the deposited metal with the carbon-fluorine containing additive to a flux. The metal of the surfacing with the additive to a flux is characterized by the higher values of scalar and excess dislocation density and the amplitude of curvature-torsion of a crystal lattice.