FE 550D in the context of TMT bars signifies a higher grade compared to FE 500. The 'FE' stands for 'Ferrum' or iron, denoting it as a reinforced steel bar. The '550' indicates the minimum yield strength in MPa, which is 550 MPa for FE 550D bars, signifying increased tensile strength compared to FE 500 bars. The 'D' denotes that these bars have high ductility, making them suitable for... https://bit.ly/3KV51a1