Abstract：Currently, in order to reduce the cost of steelmaking process and improve production efficiency, the most of the domestic steelmaking plants adopt converter direct-top process in the production of common carbon series steel, which is hot metal pretreatment/hot metal→BOF→converter argon blowing→CC. A steel plant with double-stand 230mm×1410 mm slab caster casting Q235B steel grade by converter direct-up process, a large area of longitudinal surface cracks occured on the slab, which seriously affects the normal production and operation of the enterprise. After on-site process tracking of quality defects in the steel plant,and through the comparison and analysis of the key process control points, such as converter process, tapping alloying, argon blowing process, production cycle control, mold water cooling technology, mold flux and submerged nozzle. Finally, some pertinent process improvement methods and slab longitudinal crack improvement measures were obtained, which effectively reduced the occurrence rate of longitudinal crack on slab surface of Q235B steel casted by converter direct-top process.
2019, Vol. 38 