Study On The Production Process Of HRB400 Hot-rolled Ribbed Steel Bar

HRB400 Hot-rolled ribbed bar is popularized and applied in China, compare to HRB335, it have higher strength and favorable elongation. In comparison with HRB335, the application of HRB400 can save 10~15% reinforced bar consumption, in the meanwhile , save social resources in great extent.The microalloying and alloying and afterheat treatment after rolling production process of HRB400 Hot-rolled ribbed bar are researched by production experiment, in the meanwhile, the advantage and disadvantage of different kinds of production process are analysed: the microalloying process is maturing, the mechanical property of HRB400 bars is stable by it, but its production cost is expensive; the mechanical property of HRB400 bars is unstable by afterheat treatment after rolling process, the aging of bars are strong , the aging of big specification bars is much more outstanding. Based on analysis conclusions, HRB400 production process on microalloying and rolling water-cooling is put forward and has application in production, the process have some characteristic as follows: adding microalloy element, overcome aging and welding performance of bars.The rolling water-cooling process is important means of improving bar's strength, the strength of bars is greatly increased by it.HRB400 Hot-rolled ribbed bar is produced by microalloying and rolling water-cooling process, in spite of tensile strength and elongation of bars meet national standard, cold bending and recurvation performance is qualified, but the production cost is relative expensive, it brings about disadvantageous affect on product sale and production. As a consequence, the new alloying method to decrease production cost is put forward.The thesis summarize the usage and technical requirements and performance character of HRB400 Hot-rolled ribbed bars, analyse technique situation and theoretical basis of developing HRB400 bars, account for principles of microalloying process,control-rolling process,SiC alloying process,MnSiN alloying process. The production practice and product quality and cost of KISC HRB400 are analyzed and investigated, in the meanwhile , the composition and fracture and metallographic structure of HRB400 bars by the different production process are also researched. The research and production results indicate: the performance of ribbed bars completely meet requirements of standard and customer, the production cost is also greatly reduced.