Study of the operating in conditions of abrasive wear deposited layer obtained with the use of new flux-cored wires

Abstract

The effect of introduction of chromium with increased concentration as a reducing agent was studied at the manufacture of flux cored wire of the Fe – C – Si – Мn – Сr – Ni – Mo system. Metal welding deposition was carried out on the plates of St3 steel with the help of AN-26С flux with preliminary heating of the base metal to 250 – 300 °С. Flux cored wire of5 mmin diameter, made on a laboratory machine, was deposited on ASAW-1250 welding tractor in the following modes: current 420 –520 A, voltage 28 – 32 V, welding speed 7.2 – 9.0 m/h. After it the metal was cooled at room temperature. For manufacture of the samples, the corresponding powdery materials were used as fillers (charge): iron powder PZhV1 according to GOST (State Standards) 9849 – 86, FS 75 ferrosilicon powder according to GOST 1415 – 93, FKh900A high carbon ferrochrome powder according to GOST 4757 – 91, FMn 78(A) carbonaceous ferromanganese powder according to GOST 4755 – 91, PNK-1L5 nickel powder according to GOST 9722 – 97, FMo60 ferromolybdenum powder according to GOST 4759 – 91, FV50U 0.6 ferrovanadium powder according to GOST 27130 – 94, PC-1U cobalt powder according to GOST 9721 – 79 and tungsten powder PVN TU 48-19-72-92. It was determined that carbon, manganese, chromium, molybdenum, nickel and, to a small extent, vanadium, within the limits studied, simultaneously increase hardness of the deposited layer and decrease wear rate of the samples. It is shown that the low viscosity of the matrix does not allow tungsten carbides to be kept on the surface, as a result of which the wear is carried out not according to the uniform abrasion of the surface, but according to the scheme of spalling high-strength carbides particles from the matrix. As a result, new cracks are formed in the matrix, contributing to its additional wear. According to the results of the multifactor correlation analysis, dependences of hardness and wear resistance of the deposited layer on mass fraction of the elements included in the flux-cored wires of the Fe – C – Si – Мn – Сr – Ni – Mo system were determined. The obtained dependences can be used to predict hardness and wear resistance of the deposited layer with a change in the chemical composition of the weld metal.