Effect of Strain Rate 10-4 to 103 s-1 on Room Temperature TensileProperties and Notched Plastic Zone of Type 304 Stainless Steel

摘要

Quasi-static, rapid and impact tensile test of cylindrical smooth and notched specimensrnwas carried out at room temperature at strain rate (ε) range 10-4 to 103 s-1 of type 304 stainless steel.rnThe yield strength increases gradually with strain rate, while the ultimate tensile strength decreasesrnto the minimum at (ε) = ～10-1 s-1 then increases gradually. The high strength at the lower strain rate isrndue to the beneficial effect of the martensite formation. The notched ultimate tensile strengthrnincreases gradually as the yield strength. The beneficial effect of the martensite formation is little.rnFurthermore, the applicability of the recrystallization technique (an experimental technique ofrnplastic zone) to high strain rate deformation was examined using tapered cylindrical specimen. It isrnfound that the technique can be applied well to (ε) = 103s-1,I.e. the plastic zone with plastic strainrnabove 0.12 and the plastic zone with plastic strain above 0.02 can be measured. It is shown that therntwo plastic zones in the fractured notched specimen decrease with increasing strain rate.