Prestressing Steel Wire With Wire Rods Experimental Study

The problems of technology and quality in producing high carbon hot rolled wire rods for prestressed steel wire in Nanjing Iron and Steel Group Co. Ltd are studied. Started with the analysis of the fracture reason of prestressed wire, the research carry on lab and factory experimentation and producing test. The main conclusions are:The cause for prestressed wires breaking in drawing is the metallographic structure which is admixture of sorbide, troostite, bainite, and Martensite; the quantity of Martensite in center being more than that of inside is caused by the segregation ofMn.In 77B hot rolled wire rods for prestressed steel wires, there is segregational strip of C Mn, microcrack and microhole. The causes are segregation , residual shrink hole and porosity of continuous cast steel billets.Nb refines dendrite and influences the segregation of C strongly in the range of 0.040%. The segregation of C is alleviated by V in the range of 0.060%~0.095%. Ti influences the segregation of C little, but alleviates that of Mn strongly in the range of 0.020%. The segregation of Mn Si P and S is alleviated by V Nb and Ti in different degree.Applying the rebuilt producing line and sound range of components, for 77B hot rolled wire rods for prestressed steel wires, the optimal control-rolling and control-cooling parameters are: temperature of beginning rolling 1000~1050癈, finishing rolling temperature 850℃, spinning temperature 820~850癈, the speed of cooling 10 ~13℃/s. And the technics have been industrialized.