Under the standard of Q/02GTZ012-2005, the main grade of the hot rolled wire coil for prestressing steel bar ( PC steel bar ) produced by QIS is 30MnSi with the main diameters of φ8mm,φ10mm and φ12 mm. With the advantages of excellent tensile strength, percentage reduction of area and the microstructure of the wire coil after process of smelting outside stove, electromagnetic stirring continuous casting and cold and rolling control of the liquid steel, the prestressing concrete steel bar made from it, which has the advantages of high strength, low looseness and high plasticity, is mainly used in the basic constructions such as the prestressing concrete pipe pile, high rise in coast are, dock and harbor and bridge, another little is used to make prestressing concrete components such as large roof board.