Research On Sand Slurry Abrasion Mechanisms Of Dredging Conditions And New Wear-Resistant Materials

Wear is one of three main failures (wear, corrosion and fatigue). It occurs frequently and inevitably. Therefore, it is a "perpetual" program to study wear and develop new wear-resistant materials continuously. Through the research, we can find the practical causes of wear failures of workpieces, so as to be able to select and use materials correctly, economize the cost, minimize the expenditure, enhance the reliability of the equipment operation, and obtain the higher economic, social and environmental benefits. It will be ultimately beneficial to the continuable development.The paper's accomplishments are sponsored by the 95' State Pivot Scientific Project (Key Problem), the State Nature Science Foundation, of PRC, and so on. In the paper the author relates systematically the research fruits in the program of Research on Sand Slurry Abrasion Mechanisms of Dredging Conditions and New Wear-Resistant Materials. The main contents and innovations are listed as follows.Summarized and analyzed are the wear researches and developments, and the methods of increasing materials wear-resistance. From the viewpoint of the characteristics of two-phase liquid sand slurry wear, combined with the examination and study on easily damaged workpieces, the wear failure's basic rules are pointed out, of the pump shell and the cutter-piece on service, and the general principles of material wear-resistant designs put forward. The sand slurry abrasion tester has been designed and developed which can simulate general dredging conditions. Summarized and presented are the position-exchange measuring method of sand slurry abrasion test and the experiment specification of sand slurry wear test of dredging conditions.With the induction depositing process especially, as well as the overlaying deposit and the adhesive coating process for wear resistance, in consideration of the material manufacture and application, some types of new wear-resistant materials, including metallic materials, their composites and polymers are designed and developed. The research results on wear-resistant properties, microstructures and worn morphologies show that these materials possess their own characteristics, present the excellent and synthetic properties.The research results show that, from the viewpoint of second phase morphologies, there exist quite differences between the grain-type materials (such as WC/BCu brazing deposit material, WRS1000 and 1ZT tungsten carbide strengthening overlaying material, as well as the wear-resistant material of polymer adhesive coating etc.), and the aggregation-type as well as dispersion-type ones (such as ZG35SiMn, WRD-1 and KHC-K2 depositing material) in the wear-resistance and sand slurry abrasion mechanism. The sand slurry abrasion mechanisms are brought forward, of new wear-resistant materials with the features of grain-type second phase morphologies. Another research finds that the ball mechanic milling on high-Cr alloy powders has obvious effects on strengthening and toughening of the material. It is an effective approach for the materials' strengthening and toughening.Based on the technical requirements of manufacture, application and repair of the pump shell and cutter piece of the cutterhead pipeline dredge, put forward are the re-manufacture three principles on easily damaged workpieces of dredge engineering. With the inter-clamped structures on the pump liners, the gradient wear-resisting design on the cutter piece, and the new techniques in the process of re-manufacture, new wear-resistant materials, including high-Cr alloy, overlaying and brazing deposits, and polymer adhesive coatings have been successfully applied to the re-manufacture dredge pump shell and cutter piece. The application results show that their wear-resistant lifetimes and the dredging profits have been increased remarkably. The practical applications of new wear-resistant materials to the dredges have exploited a new aspect for manufacturing; using and repairing of easily damaged workpieces in dredge engineering. It displays...