A metallurgical investigation of microstructure of the weld bead in submerged arc welding

摘要

Microstructure is defined as the structure of a prepared surface of material as revealed by a microscope. The microstructure of a material strongly influence physical properties such as strength, toughness, ductility, hardness, corrosion resistance, high/ low temperature behavior, wear resistance, and so on, which in turn govern the application of these materials in industrial practice. The metallurgical and mechanical properties of weld metal depend upon its microstructure which is governed by the rate of heat input. The rate of heat input is further dependant on the welding parameters. Weld metal generally constitutes of grain boundary ferrite, polygonal ferrite and acicular ferrite. In order to have maximum toughness and good strength it is desirable to obtain maximum amount of acicular ferrite in the weld metal. In this paper investigations were carried out to study the microstructure of weld metal.