Characteristics of Alloying and Structure Formation of Wear-Resistant Coatings Carboborite

Abstract

Modern hardfacing methods for machine parts using alloying systems Cr-Mn, Cr-B, Cr-Ni, Cr-W-V based on iron have pushed their functionality to the limit and cannot satisfy the increasing demands of modern machinery, because alloys based on these systems form build-up layers with restricted content of alloying elements: chromium 30-40%; titanium 4-5%; tungsten 18-25%; manganese up to 15%. Cladding materials with such content of alloying elements do not exert due effect for details experiencing severe abrasion working in aggressive media, under high temperatures. During alloying the best effect is obtained when not one but several alloying elements influencing the properties are added, they form an advantageous structure. The authors have developed new cladding compositions with refractory components TiC, (Ti,Cr)B2, B4C, FeV. Laboratory testing of their mechanical properties have proved high efficiency of the studied cladding materials. High resistance to wear is reasoned by a favourable combination of strong cementing austenitic- martensitic matrix and formation of complex carboborides strongly fixed in that matrix. The base of the strengthening phase is a strong and wear-resisting carboboride ((TiB2Fc,Cr,Ti)23(C,B)6); plastic borides CrB2 and TiB2 are present in the structure of the build-up layer, too. Thus, the peculiarities and laws of build-up layers formation suggest that due to high properties and quality refractory compositions are an intense source for creation of new highly efficient classing materials with unique physical and technical properties.