Development of flux-cored wire for surfacing of parts operating under conditions of wear

Abstract

Powder wire for surfacing of abrasive-wearing products of Fe - C - Si - Мп - Cr -Ni - Mo system (type A according to IIW classification) was developed and investigated. Studies in laboratory conditions were performed according to the following scheme: multilayer surfacing of the samples was carried out with preheating of plates up to 350 °C and subsequent slow cooling (after surfacing). Surfacing was made by ASAW-1250 welding tractor with manufactured cored wire in six layers on plates of 09G2S steel. Instead of amorphous carbon, carbon-fluorine-containing dust containing 21 - 46 % Al2O3; 18 - 27 % F; 8 - 15 % Na2O; 0.4 - 6.0 % K2O; 0.7 - 2.3 % CaO; 0.5 - 2.5 % SiO2; 2.1 - 3.3 % Fe2O3; 12.5 - 30.2 % Cgen ; 0.07 - 0.90 % MnO; 0.06 -- 0.90 % MgO; 0.09 - 0.19 % S; 0.10 - 0.18 % P was introduced into the wire. The following powder materials were used as filler: iron powder PZhV1 as per GOST 9849 - 86, ferrosilicon powder FS 75 as per GOST 1415 - 93, high carbon ferrochrome powder F99A as per GOST 4757 - 91, carbon ferromanganese powder FMN 78(A) as per GOST 4755 - 91, PNK-1L5 nickel powder PNK-1L5 as per GOST 9722 - 97, ferromolybdenum powder FMo60 as per GOST 4759 - 91, ferrovanadium powder FV50U 0.6 as per GOST 27130 - 94, cobalt powder PC-1U as per GOST 9721 - 79, tungsten powder PVN as per PS 48-19-72 - 92. Studies of the deposited layer have shown that within the obtained limits, carbon, chromium, molybdenum, nickel, manganese and to a lesser extent vanadium simultaneously increase hardness of the deposited layer and reduce rate of wear of the samples. Increase in concentration of tungsten increases hardness of the deposited metal but reduces wear resistance. Low viscosity of matrix does not allow tungsten carbides to be kept on surface, as a result, wear occurs not according to the uniform surface abrasion scheme, but is reasoned by pitting high-strength carbide particles from the matrix, resulting in additional cracks formed in matrix, contributing to additional wear of matrix. Introduction of cobalt to the mixture composition does not have significant effect on hardness and abrasive wear of the deposited layer, which is associated with obtaining more viscous, but less solid matrix. In case of absence of solid particles of carbides embedded in matrix, the effect of introduction of cobalt is negative. According to the results of multivariate correlation analysis, dependences of hardness of the deposited layer and its wear resistance on mass fraction of elements included in flux-cored wires of the Fe - C - Si - Mn - Cr - Mo - Ni - V - Co system were determined.