| Because of its excellent mechanical properties, TWIP steel was used as the most popular kind of steel in the modern military manufacturing, automobile manufacturing and other industries, it can shows up a very high intensity as well as good toughness. This steel properties of product of tensile strength and elongation are many times better than other steel, so those characteristics have became its symbol. In order to get the same content of Mn, TWIP steel under different system performance and microstructure of differences. The Fe-C-Mn and Fe-Mn-Si-Al system TWIP steel were smelted and carried out the tests of chemical composition, impact strength and ensile property of the steel after the heat treatment.The impact properties of four groups of TWIP steel were measured after the impact test at 20 ?, the highest impact absorbing energy can up to 94 J and the highest impact toughness can reach 177 J/cm2. The maximum value measured in the tensile test was Sample no. 3, whose ductility was 47%, tensile strength was 927 MPa and product of tensile strength and elongation reached 43700 MPa?%.In microstructure observation of the TWIP cast steel by Zeiss microscope, the interior of the TWIP steel was austenite completely, so the TWIP steel is non-magnetic.The impact fracture morphology was observed with sem.the fracture morphology for the ductile fracture. In fracture analysis of toughening nest type on the basic observation of scanning electron microscopy(sem) images for shaft such as toughening and uniform number form. On rolling deformation after TWIP steel specimen for tem observation can be obtained that after rolling deformation within the grain to produce a large number of dislocation tangles, appear deformation twin also found each other into 60 ° two twin system exists. Elongation promotes the growth of strain induced twin mechanical twin induced plasticity, namely the TWIP effect. Steel good extensibility is caused by TWIP effect. |
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