A Study On The Process And Properties Of SPHD And SPCD Stamping Steel

With the rapid development of domestic appliances,automobile and mechanical industry,the demand of high value-added,high quality and high technology steel is increasing.Deep drawing steel can be excellent manufacturing raw materials for related industries,and also can create good economic benefits for the iron and steel enterprises.Cold rolled deep drawing steel SPHD is a board widely used in automobile and home appliances.It has high yield strength and excellent elongation,and higher requirements in strength,toughness,plasticity,scalability and size accuracy.With the development of metallurgical technology and metallurgical production technology,it provides a broad development space for the production of SPHD.Many steel enterprises compete to develop such products,optimize the distribution ratio and production process,develop the SPHD cold rolling mill with strength,toughness,plasticity,deep pulse and easiness to control.In this paper,the production practice of SPHD steel in 1450 production line of company,ltd.is introduced.The microstructure evolution of cold rolled and cold stamping steel during hot rolling was studied,and its production process was optimized,including coiling temperature,laminar cooling mode,and the annealing process required by customers.The main research contents and conclusions are as follows:(1)The average component content of SPHD is controlled within the design range.With good control level of N and O,the content of free cementite and pearlite in SPHD steel is very few,and the quantity of inclusions in SPHD steel is small,which has little effect on the properties of SPHD steel.(2)Effect of cold rolling,annealing on the microstructure and mechanical property of SPCD steel was studied.The amount of carbides in the grain boundary after annealing is less than SPCC after annealing.When the annealing temperature increased from 630℃ to 650℃,the grain size became coarsening and the number of cementite on the grain boundary increased.The higher the coiling temperature is,the lower the strength and the higher plastic,forming properties of SPCD have.(3)The influence of different coiling temperature and laminar cooling mode on the microstructure and properties of SPHD hot rolled plate is compared and analyzed.According to the characteristics of the short laminar cooling in Gupfeng production line,it is determined that the coiling temperature of SPHD hot rolling plate is about 600℃.SPCD cold rolled plate has the best comprehensive mechanical properties in this condition.(4)Aiming at the defects of SPHD and plate in SPHD production,a series of SPHD steel rolling control measures are taken to control the temperature of the reheating furnace,improve the precision of the finishing rolling equipment and change the parameters of the coiling equipment.The stability of SPHD steel is gradually improved after field process improvement.