TMT (thermo-mechanically treated) bars are critical in residential construction due to their superior strength, durability, and flexibility. These bars primarily reinforce concrete and enhance buildings' structural integrity. Here's a detailed look at the role and benefits of TMT bars in residential construction:
What are TMT bars?
TMT bars are high-strength reinforcement bars with a rigid outer layer and soft inner core. The manufacturing process involves:
- Thermo-mechanical treatment: this process combines mechanical deformation and thermal processing to improve the properties of the steel.
- Quenching: right after rolling, a red hot steel bar is passed through a rapid water-cooling system to enhance the strength of the outer layer while the core remains softer. This cooling happens very fast, so the outside becomes hard while the inside remains hot. The quick cooling forms a hard layer called martensite outside the bar.
- Self-tempering: the bar's inside, which is still hot, cools down slowly. As it cools, the inside changes into different types of steel phase mixtures called ferrite and perlite, which are not as hard as martensite but are more flexible.
- Self-Tempering: The heat from the inside of the bar moves outwards, making the hard outer layer even more challenging with improved ductility and free from residual stress.
- Atmospheric cooling: final cooling at room temperature retains the core's ductility and flexibility.