Elemental and phase composition of electric arc coating formed with a flux-cored wire of Fe – C – Si – Mn – Сr – Ni – Mo system

Abstract

The authors have studied the elemental and phase compositions of electric arc coating with a flux-cored wire of Fe – C – Si – Mn – Cr – Ni – Mo system. Formation of electric arc coating was carried out using ASAW-1250 welding tractor with fabricated flux-cored wire on plates made of 09G2S steel. Aluminum production gas cleaning dust has been introduced into the composition of flux cored wire (instead of amorphous carbon). Chemical composition of the deposited metal was determined by X-ray fluorescence method on XRF-1800 spectrometer and by the atomic emission method on DFS-71 spectrometer. Microstructure of the electric arc coatings was studied using OLYMPUSGX-51 optical microscope. Analysis of phase and elemental compositions was performed by scanning electron microscopy using LEO EVO 50 instrument. Segregation of tungsten and molybdenum was revealed in electric arc coating. Concentration of tungsten changes more than 3 times, and molybdenum – more than 2 times. Fractures of the samples are formed as a result of ductile fracture of the material. There are surface layers on the samples fractures, thickness of which is determined by chemical and elemental composition of the electric arc coating. The layer under consideration is characterized by a relatively small diameter of fracture pits compared to the samples volume. Their diameter ranges from tenths to tens of micrometers. The largest pits are formed on particles of the second phase with micron sizes (2 – 3 µm). Contamination of metal of electric arc coatings with non­metallic inclusions was studied. It was established that chemical composition of flux-cored wire of the studied system does not significantly affect the level of contamination with non-metallic inclusions in electric arc coatings. Parameter a of crystal lattice and values of areas of coherent scattering of Fe and CrC phases formed as a result of hardfacing were determined by X-ray phase analysis.