What is 500d in steeel bars?

500D in steel bars refers to a specific grade of high-strength deformed steel bars used in construction, particularly for reinforced concrete. The "500" indicates the yield strength of the steel, which is 500 megapascals (MPa), while the "D" signifies that the bars have a deformed surface, enhancing their bond with concrete. This grade is commonly used in structural applications due to its strength and durability.