Investigation On Hot Stamping Process Of 22NnB5 High Strength Boron Steel

In the automotive industry, the light-weight of car is one of the methods to reduce the fuel consumption. Using high strength steel to manufacture the automotive parts is one of the effective ways. The car body becomes light meanwhile the passive safety is enchanced. Usually hot stamping process is used to process high strength steel,which means die forming at high temperature with pressure holding quenching, finally hot stamping parts with high strength obtained. The research use the high strength of 22 Mn B5 boron steel and the steel that based on 22 Mn B5 boron steel(97# steel), with the experiment of hot stamping of 22 Mn B5 boron steel and 97# steel, the reasonable selected process parameters, and the design of 22 Mn B5 boron steel door anti-collision beam parts for hot stamping die and its cooling system, the research contents as follow:1. The optimization of process parameters: austenitizition temperature 950℃, austenitizition time 5min, pressure holding time 60 s. The result show: under optimal process parameters, the tensile strength can reach 1600 MPa, the elongation is 11±1%. Compared with the current commercial 22 Mn B5 hot stamping parts, the tensile strength is increased about 100 MPa, the elongation is increased about 3~5%.2.Based on the selection of hot stamping process parameters, the mould temperature maintain 200℃ in the 5min with the process of quenching, can make 97# steel’s tensile strength reach 1975 MPa, the elongation reach 10.4%, the product of strength and ductility reach 20GPa·%. The workpiece can have more excellent performance.3.Through the feature analysis of the vehicle door anti-collision beam part. Integrate the requirements of hot stamping die design, the key parameters(mould material, clearance between punch and die, stamping direction of the vehicle door anti-collision beam) of the vehicle door anti-collision beam of hot stamping die are overall designed.4.Through research on the door anti-collision beam hot stamping die colling system with multi-field coupled numerical simulation method, of workpiece are analyzed. The results show that the most of the mold cooling waterway geometry parameters of die and cooling effect is distance between cooling waterway and die surface(H), followed by the pipe distance(S), pipe diameter(D) has minimal effect. The influence of geometric parameters of the essence is: the more cooling water close to the workpiece, the better cooling effect have.