A NEW PROCESS TO PROTECT STEEL PARTS FROM HYDRO ABRASIVE WEAR USING ENVIRONMENTALLY SAFE TECHNOLOGICAL METHODS

Abstract

The goal of this work was to achieve improved durability of steel parts by developing a technology for creating coatings on wear surfaces, which would increase the ability to make a stand against wear, guarantee the reliability and durability of their operation in aggressive media, be environmentally safe and reduce the cost of their production. The paper proposes a new environmentally safe process for protecting steel parts from hydro abrasive wear. The process relates to the field of mechanical engineering and machine repair, in particular to strengthening of steel parts, and it can be used to protect them from hydro abrasive wear using electrospark alloying (ESA) method. The technology based on the new process is as follows. First, the steel part surfaces are ground to Ra = 0.5 μm, then, while carburizing the ground surfaces of the part with the use of the electrospark alloying (ESA) method, the electrospark coating (ESC) is formed on the ground surface, after that there is performed an aluminizing process of the carburized layer using the ESA method by an aluminum electrode-tool with the subsequent application thereon of the electrospark coating (ESC) by the electrode-tool made of a wear-resistant composite material obtained using the powder metallurgy (PM) composition consisting of 90% VK6 + 10% 1M, where 1M is 70% Ni + 20% Cr + 5% B + 5% Si. Further, the surface of the formed combined electrospark coating is subjected to polymerization with a metal-polymer material (MPM), which has been being reinforced in the course of the polymerization process with tungsten carbide powder WC and/or zirconium nitride ZnN or their mixture WC+ZnN. Then a part of the surface layer of the MPM is removed until the appearance of the roughness protrusions of the coating made of the hydro resistant composite material of 90% VK6 + 10% 1M. For practical use, in order to protect steel parts from hydro abrasive wear, there are proposed the coatings formed in the sequence of CESA → ESA Al → ESA (90% VK6 + 10% 1M) → application of MPM reinforced with WC powder, or ZnN, or a mixture thereof. It has been experimentally established that the samples made of the corrosion-resistant stainless steel of the 12Х18Н10Т grade have the best resistance to hydro abrasive wear. As compared to the specimens made of steel 45, their wear is 37.3% less.