Wear Resistant Structural Steels...

Wear Resistant Structural Steels Wear is described as ‘the phenomenon of metal surfaces that are moving relative to each other getting worn out due to the surfaces scratching each other or due to metallic adhesion’. Wear resistance can be said to be the property in which such a phenomenon is difficult to occur. The properties of wear resistant steels enable them to resist wear, due to rubbing, impact or compressive loads from external agents such as cement, sand, stones etc., and are intended for use in equipment construction and for replacement of wearing parts. Numerous structures, such as dump bodies, materials handling equipment and crushing machines, for instance, are exposed to continuous, abrasive and impact wear, which is costly. As a solution, special structural steels have been developed that are highly resistant to wear and abrasion. Factors affecting wear resistance of steels There are four main factors which have considerable effect on the wear resistance of steels. These are (i) heat treatment, (ii) alloying additions, (iii) influence of carbon content, and (iv) effects of carbides, both primary and secondary. A big factor affecting wear resistance is ‘hardness’. In general, the wear resistance increases as the material becomes harder. There is a direct relationship between hardness and wear resistance. The resistance of a steel surface against wear is primarily a function of the ‘effective hardness’ resulting from the destructive action of the abrasive particles and depend on the strain hardening rate of the steel under the applied conditions. Factors affecting plastic deformation, such as grain size, recrystallization temperature, hardness, strain rate etc. also affect the wear of steels. Unlike single crystals which have free boundaries, the grains of a polycrystalline steel are influenced by their neighours during deformation, their constraining action on deformation is least...