Journey of TMT Bar: From Iron Ore To TMT, The Process Is Long & Detailed. To Produce High-Quality TMT Rebars, Every Step In Manufacturing Has To Be Aced. Here’s How It Is Done! Thermo mechanically treated bars have brought about a revolution in construction due to its high yield strength, high ductility, high weldability and most importantly resistance to the corrosive and seismic forces of nature.