Study Of BWELDOX700E Steel For Square Storehouse Of Special Off-road Vehicle In Wide And Thick Plate Production Line

The paper BWELDOX700E high strength and toughness steel plate as the research object,the composition design,smelting,rolling,heat treatment process determination,microstructure analysis and mechanical properties testing were systematically studied by SEM and mechanical testing.The research process includes laboratory research,small industrial trial production and explosion-proof test.The experimental results show that the suitable heat treatment system is 880?for quenching and560?for tempering without adding rare earth.The inclusions in the test steel are mainly Ca S,Al₂O₃and tin,and some Cao with the size of 4-5?m.At this time,all indexes of the test steel have reached the level of imported steel plate of the same grade;When the rare earth content is 10ppm,the rare earth content in the steel is 5ppm,and the appropriate heat treatment system is 880?quenching+560?tempering,the Al₂O₃inclusions in the steel can be modified,and the cerium aluminate inclusions with low hardness can be produced.In addition,some cerium sulfide can be formed,and the size of inclusions will be reduced.At this time,the mechanical properties meet the requirements of SSAB technical specifications.The results of small-scale trial production show that the suitable outlet temperature of reheating furnace for hot-rolled slab is 1180?±20?In the rolling stage,the starting temperature of rough rolling is more than or equal to 1100?,and the finishing temperature of finishing rolling is 820-870?.There is no need for controlled cooling for thin gauge.The heat treatment system is:880±10?,After 20 min quenching,the tempering temperature is 580?±10?,After tempering,the microstructure is tempered sorbite,the yield strength of hot rolled plate is 730?770MPa,the tensile strength is 830?821mpa,the impact energy at-40?is above 69J,and the mechanical properties of cold bending meet the requirements.The results of explosion-proof test show that the V-shaped bottom of BT700E protection component deforms under the action of explosion,and the deformation state is basically the same.The maximum deformation is 24 cm,25 cm and 24 cm respectively,and there is no crack due to explosion.The anti explosion performance of BT700E steel is similar to that of imported WELDOX 700E steel.Through the research of this paper,it fills the blank of Baotou Steel's WELDOX series steel plate,provides technical guidance for Baotou Steel's production of WELDOX series steel plate,and has great application value.