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

Microstructure is defined as the structure of a prepared surface of material asrevealed 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.