In TMT bars, the grade refers to the specified yield strength of the steel. It indicates the minimum amount of stress that the bar can withstand before it begins to deform permanently. The grade of TMT bars is typically denoted as Fe-415, Fe-500, Fe-550, Fe-600, etc., where the number indicates the yield strength in megapascals (MPa). For example, Fe-500 TMT bars have a minimum yield ... https://bit.ly/3KV51a1