Research On Processings And Microstructure And Properties Of HRB400MPa

Wire products is the largest in our country's production and consumption of steel products. To improve comprehensive properties of ribbed bar, China mainly uses the technology line with alloying elements added, resulting in resource consumption and high production costs, and product market competition is not strong. Thus, researching and developing new ribbed bar production technology to produce high-strength ribbed steel and wire without micro-alloyed or minimum conditions of micro-alloying elements, would greatly enhance the core competitiveness of enterprises, while also conserving resources, improving the environment to make significant contributions to society.This article takes 20MnSi as a raw material, obtaining ultrafine grain without any micro-alloying elements in order to maintain toughness enhances the intensity through the combination of deformation induced ferrite transformation and critical austenitic controlled rolling and controlled cooling technology. Making a count and regressing the relations of chemical composition and mechanics performance by MINITAB software in order to provide reference for component design of steel; Researching on the influence of deformation parameters for deformation induction exhalation through carrying on hot compression experiment with the single through the Gleeble1500 thermal simulation testing machine; Simulating and analyzing temperature field and stress field after finish rolling by ANSYS finite element software; Intending to roll 400MPa steel bar through the original equipment transformation and the chemical composition adjustment. This article mainly draws the following conclusions:(1) Single factor variance analysis: Mn, Ni, P, S, Cu and C+(Mn+Si )/6 affect obviously to ReL, C, Si and Cr are not remarkable to the ReL; Cr is not remarkable to the Rm, other elements affect obviously to Rm; Mn and P affect obviously to A; C, Si, S, Cr, Ni, Cu and C+(Mn+Si)/6 are not remarkable to the A. Regression analysis: Mn and Cu's influence are biggest to ReL, next is P , next is Ni again, finally is S; P, S and Cu's influence is biggest to Rm, next is Mn and Ni, next is Si again, finally is C.(2)Deformation induced transformation is completed in the process of deformation. Cumulative deformation above 50% helps induced precipitation; The large deformation and high strain rate help to DIFT at high temperature; The large deformation and low strain rate help to DIFT at low temperature.(3)The temperature and stress field of wires after finishing rolling simulated by ANSYS, the result is basically consistent with reality.(4)Final chemical compositions are: C+(Mn+Si)/6≥0.38, C(0.21~0.25), Mn(0.90~1.05), Si(0.20~0.40); Optimum production technology: rolling speed for 74m/s, NTM/RSM/LH outlet temperature is 740~770/740~770/700℃, fan opened 12×99%. Aging experiments shows that strain aging sensitivity is low, basically no prescription.