| The history of steels for bridge construction at home and abroad has exhibited the developing route of plain carbon steel→ low alloy steel→ high strength steel→ high performance steel (HPS) . The high performance micro-alloying steels for bridge construction have been broad applied and developed at home and abroad and that shows good market prospect.Firstly, the chemical composition design of Q370qE steel plate is determined by means of melting in vacuum furnace and selecting after experiment rolling mill. Then, the hot simulation test of experiment materials is conducted on MMS-100 Thermal/Mechanical simulator and the CCT curve of steel can be determined. The microstructures gained under the condition of different cooling rates, different deforming temperature and different deformation are analyzed. The rule of phrase transformation is researched and the mathematics model of resistance of deformation has been established for this steel. Lastly, the process parameters for production of Q370qE steel are designed through combining the simulation test results with the equipment condition of workshop. The properties of steel plates at the states of control rolling & control cooling and normalizing heat treatment were tested, and the microstructure and the precipitates of steel plates were observed and analyzed using the optical microscope, scanning electronic microscope(SEM), transforming electronic microscope(TEM) and the energy spectrum analysis. In addition, the development of normalizing examination in laboratory provided the basis for working-out the process parameters of practical production.The systematic study on Q370qE steel plates has been made in laboratory and...
|
PDF Full Text Request