Welcome to International Journal of Emerging Technologies in Engineering Research (IJETER)

Volume 7, Issue 9, September (2019)

S.No	Title & Authors	Full Text
1	Evaluation of Hardness of Gas and Tig Welded Sheet Metals Dr.R.Uday Kumar Abstract - Hardness is the resistance to indentation, and it is determined by measuring the permanent depth of the indentation. More simply put, when using a fixed load and a given indenter, the smaller the indentation, the harder the material. Indentation hardness value is obtained by measuring the depth or the area of the indentation using different test methods. The Rockwell test is generally easier to perform, and more accurate than other types of hardness testing methods. The Rockwell method measures the permanent depth of indentation produced by a load on an indenter. Initially a preliminary test force (commonly referred to as preload or minor load) is applied to a sample using a diamond or ball indenter. This preload breaks through the surface to reduce the effects of surface finish. After holding the preliminary test force for a specified dwell time, the baseline depth of indentation is measured. After the preload, an additional load, call the major load, is added to reach the total required test load. This force is held for a predetermined amount of time (dwell time) to allow for elastic recovery. This major load is then released, returning to the preliminary load. After holding the preliminary test force for a specified dwell time, the final depth of indentation is measured. The Rockwell hardness value is derived from the difference in the baseline and final depth measurements. This distance is converted to a hardness number. The preliminary test force is removed and the indenter is removed from the test specimen. In this method the specimens consists of hot rolled and cold rolled sheets with thickness and also these rolled sheets with TIG and Gas welding. The Rockwell hardness number is evaluated experimentally for those cases and studied. The Rockwell scale is a hardness scale based on indentation hardness of a material.	Download