Analysis On Mechanical Property And Microstructure Of Low Carbon Al-killed Steel DC04for Deep Drawing

As the quality representative of the second generation of deep drawing steel sheet, DC04steel plate deoxygenated adequately by aluminum is a typical kind of low carbon Al-killed steel. Cause its characteristics of low yield strength and tensile strength, good plasticity and stamping property, DC04steel plate has been widely used in the production of complex parts such as automotive parts which require high ductility. The production processes of DC04steel plate include smelting, hot rolling, pickling, cold rolling, annealing and flattening. At room temperature, the matrix structure is constituted by ferrite and free cementite. The grain size of ferrite, same as the species and distribution of free cementite has significant impacts on the strength, n value and r value of DC04steel plate. Moreover, the product performance is also related with the level of inclusions and precipitation characteristics of second phase particles.This topic studied the impacts on performance by composition and microstructure under technological conditions including hot rolling, cold rolling and annealing. In order to provide theoretical guidance for the enterprise production, on the scene, we selected samples of DC04steel plate which own three different component content and rolled by single stand reversing mill to carry out experimental study under these different process such as steelmaking, hot rolling and annealing. For example, we tested the mechanical properties of low-carbon aluminium killed steel sample by uniaxial tensile testing machine; observed microstructures of hot rolled and annealed plate specimen, inclusion and precipitation of second phase particles by means of metallographic microscope, SEM and TEM; studied the specific influence rules of grain with different form, cementite with different distribution characteristics, inclusions and second phase particle with different types and numbers exert on the deep drawing performance of low carbon steel. This topic analyzed the possible effects each production processes exert on product from the micro level. We basically achieved the comprehensive experiment about the analysis of microstructure and mechanical property of DC04. The topic provides the fundamental basis for formulating the control standards of composition and the adjustment of the smelting process, provides data reference about possible effects of low carbon steel’s deep drawing performance exert by precipitates. The ultimate goal is to conclude the best technology roadmap of production of DC04combining the influencing mechanism of smelting, hot rolling, cold rolling and annealing under the premise of guaranteeing the performance of deep drawing of low carbon steel.