THE EFFECT OF WELD POSITION ON MECHANICAL PROPERTIES OF TMT ROD JOINED BY ARC WELDING

MD Anis Raza, Sudhir Kumar Kashyap, Rakesh

Abstract: There are various welding processes for joining the materials. Arc welding is a prominent joining process in which two steel parts are joined by heat generated due to arc. Many researches have been carried out in joining of different materials by different welding techniques. Our research has been emphasized on TMT bars. A Thermo Mechanical Treated (TMT) bar is commonly used for making reinforced roofs and column of building. They are also used in for industrial purpose such as rock bolting in underground mines etc. Most of TMT bar’s joining process took place with arc welding. In this paper a study has been made for the effect of welding position on strength of joined rods. In this study four Nos. of samples were taken having different locations of welding. They were allowed to cool under ambient condition. The chemical composition of parent material and weld zone were checked and observed that weld zone have different chemical composition compared with parent material. The variations of hardness with respect to distance were also checked using Brinell hardness testing machine and it was found that firstly hardness decreases and then increases with increase in distance from weld centre. From microstructural examination it has been seen that weld zone, HAZ and parent material all have different grain size as well as phase composition. Such change has been due to differential heating during welding. This increase and decrease in hardness has been justified with microstructural changes. Smaller grains have high hardness. Higher the pearlite phase higher is the hardness. There is decrease in hardness and strength in weld zone compared to parent zone and this was justified by lower percentage of carbon in weld zone as well as the microstructure of weld zone.

Keywords: TMT, Tensile strength, HAZ, Hardness, Microstructure.

DOI: https://doi.org/10.15623/ijret.2016.0509010