THE CHOICE OF MATERIALS FOR HARDFACING OF METALLURGICAL EQUIPMENT PARTS, WORKING AT ABRASIVE WEAR CONDITIONS AT HIGH TEMPERATURES

Abstract

The paper presents the results of the modern research analysis in the areas of development of promising materials for surfacing of metallurgical equipment parts, which require high resistance to abrasive wear (parts of blast furnace loading devices, gas distribution valves, bunkers and sieves). The basic systems for such applications are Fe – Cr – C, Fe – Cr – C – B, Ni – Cr – C – B, which are additionally alloyed with strong carbide-forming elements (Mo, W, V, Nb, Ti). When choosing materials, it should be considered that the real characteristics of materials for surfacing depend not only on the chemical composition, but also on the microstructure formed during the surfacing process. In addition to the chemical composition, an effective tool for controlling the formation of the microstructure and the complex of alloy properties is the control of the energy parameters of the coating formation process, the surfacing temperature regime, and the geometric parameters of the layers in a multilayer coating structure. It is proposed to distinguish the main groups of materials for surfacing: economically alloyed high-chromium high-carbon materials based on iron, high-chromium materials with additional alloying with strong carbide-forming elements for operation at high temperatures. In cases where the keeping of hardness, wear resistance and resistance to thermocyclic loading of the surfacing layer at high temperatures is of great importance, nickel-based alloys are promising. In conditions of relatively low temperatures, low-carbon materials with a reduced chromium content are promising, the wear resistance of which is ensured by the formation of not only a carbide phase, but also a hard martensitic matrix. Examples of specific materials of the specified groups for the surfacing are given.