“HYSD” stands for High Yielding Strength Deformed Bars. There are different types of HYSD Steel Bars.
- Tor Steel Bars
- CTD Steel Bars (Cold Twisted Deformed Steel Bars)
HYSD Bars are manufactured under heat treatment. During HYSD Bar manufacturing post heat treatment process, steel bars are either heat rolled or cold twisted for shaping.
Previously the steel bars were low in tensile strength for which HYSD has been introduced in market. When HYSD Bars were introduced to the market it was highly accepted because it has properties such as
- Residual Stress
- Corrosion Resistance
With time construction industry has grown extensively and the criteria for selecting the Steel bars has gone up. HYSD Bars were not able to meet the criteria with growing market therefore TMT Bar has been introduced that has
- Superior Ductility
- Excellent Bend and Re-bend capacity
- Earthquake Resistance
- Corrosion Resistance
- Fire Resistance
HYSD Bars (High Yielding Strength Deformed Bars)
- Surface flaws in Twisting
- Normal Steel Consumption
- Heavy weight, Transportation cost is high
- Lesser Ductility
- Resistant to Corrosion (In scale moderate)
- Low Tensile Strength
TMT Bars (Thermo mechanically Treated Bars)
- No Surface flaws in Twisting
- Save upto 17% to 20% steel
- Lighter in weight, Transportation cost is low
- Superior Ductility. Highly appropriate for modern construction industry
- Highly Resistant to Corrosion
- Earthquake Resistant for High Tensile Strength
10 Important facts why TMT Bar is best other than HYSD Bars
- For high ductility and uniform ribs in exterior surface, TMT Bars bond in RCC other than HYSD Bars.
- During the cooling process of Thermo mechanical treatment, TMT Bars turns into ferrite-pearlite structure for which it is highly ductile.
- In HYSD Bars residual stress is high and tensile strength is low that causes deformation. In TMT Bars residual stress is low and tensile strength is high for which it do not undergo any deformation.
- TMT Bars can bend and re-bend as per construction requirement. In HYSD torsional stress occurs during bending that causes surface defects.
- Due to low intake of carbon, sulphur & phosphorus TMT Bars are highly resistant to corrosion
- TMT Bars consume upto 17% to 20% less amount of steel than HYSD Bars. TMT Bars reduces the transportation cost and it is cost effective too.
- TMT Bars are Earthquake Resistant. For Ferrite pearlite structure tmt bars are strong in outer periphery and softer in core, it provides desired tensile strength with high elongation and ductility as required. TMT Bars has the ability to absorb extra energy during an earthquake and hold the structure from its core.
- TMT Bars increases the longevity of the structure. TMT Bars do not reacts with the structures quickly inside the RCC that is why it helps to prevent rust other than HYSD Bars.
- TMT Bars can absorb 400 to 600 degree Celsius of heat. TMT Bars are highly Fire Resistant.
- As per IS Standards Fe 500d Grade TMT Bar has the best combination of strength & ductility and that is Fe 500d Grade TMT Bar is most recommended for all type of construction purposes.
The reasons stated above are clearing the fact why TMT Bars are better over HYSD Bars. With technological advancement and modern age construction requirement usage of TMT Bars are mandatory. It is very important to know the facts on best quality TMT Bars.