Which of the following statement is correct regarding 'HYSD' bars?

I. HYSD bars have lugs, ribs or deformation on the surface

II. HYSD bar have a definite yield point 

Explanation:

HYSD Bars: HYSD (High Yield Strength Deformed) bars are commonly used in reinforced concrete construction due to their high strength and improved bonding with concrete. These bars are characterized by their physical and mechanical properties.

The characteristics of HYSD bars include:

• Lugs, ribs, or deformation on the surface (I): HYSD bars have surface deformations such as lugs or ribs that improve the bond with concrete, providing better anchorage compared to plain bars.
• To minimize the problem of yield plateau in the mild steel, mild steel is stressed by the process of either stretching or twisting beyond the yield plateau, and then it is unloaded which causes some permanent strain on the material then it is again reloaded. This process is called the cold working process.
• All the HYSD bars are essentially mild steel.
• The yield strength for Fe415 is 415 N/mm2 and for Fe500 is 500 N/mm2.
• The percentage elongation is less than that of mild steel.
• Ductility is comparatively less.
• The yield point is not well defined.

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Mild steel has a definite yield point and the plastic strain may extend up to a train 0.15. Cold worked high strength deformed bars do not have a definite yield point and the characteristic strength refers to 0.2% proof stress. Their plastic strain is less than that of mild steel bars.