Development And Research Of DC06EK Cold-rolled Steel For Enamelling Use

The microstructure,mechanical properties and precipitate analysis have been carried out based on Ti-bearing ultra low carbon(ULC)steels with alloying element contents and processing parameters.By means of electro-chemical method,the hydrogen diffusion coefficient and hydrogen permeation time of this steel had been measured to study the hydrogen storage behavior in the steel.The results had been laid the foundation of a special technology process on the production of ULC steel for enameling use.For DC06EK Ti-bearing steel sheet after annealing,the average Rp0.2 is less than 190MPa,the Rm is between 270 to 350MPa,the total elongation is more than 38%.the average r value is greater than 1.6,the hydrogen permeation time parameter is bigger than 6.7,and the carbon content is less than 0.02%,the manganese content is less than 0.5%,the phosphorus content is less than 0.02%,the sulfur content is less than 0.05%,the titanium content is less than 0.3%.Therefore,the mechanical property and chemical composition of the steel matches the requirements of the EN DC06EK Standard.The micro-structure of steels after annealing is composed of pure ferritic,with the grain size level of ASTM 7-8.The precipitates mainly consist of TiC and Ti4C2S2 in the DC06EK steel.The hydrogen permeation behavior is related to the density and average size of the dispersive second particles,which depend on the contents of alloy elements.The enameling test shows that the bubble structure of enamel layer was good,the cohesion between the base metal and the enamel layer was excellent.In regard to the surface quality,no defect or fish-scale was found on the surface.An integration control method is established in relationship of element composition,process,micro-structure,mechanical property and hydrogen permeation in industry production of DC06EK ULC Ti-bearing steel for enameling use.The research results show that the steel sheet with excellent enameling properties and extra deep drawability can satisfy the needs of manufacture such as bathtub,cooker and construction decorative panel.