HRB400 is a steel reinforcement material with high strength and good plasticity. HR stands for "hot rolling", which essentially refers to the heating and rolling process of steel bars in the production process. B represents that its yield strength is 400 megapascals (MPa) higher than that of ordinary carbon steel. HRB400 steel bars are mainly composed of alloys of carbon, sulfur, phosphorus, manganese and other elements, which have weather resistance, corrosion resistance and high tensile strength.