Crystallizer protective slag for effectively controlling carbon steel cracks in compact strip production (CSP)

Abstract

The invention discloses crystallizer protective slag for effectively controlling carbon steel cracks in a compact strip production (CSP). The crystallizer protective slag comprises the following chemical components in percentage by mass: 35 to 38 percent of CaO, 28 to 31 percent of SiO2, 1 to 3 percent of Al2O3, 1 to 2 percent of MgO, 0.5 to 1.5 percent of Fe2O3, 10 to 11.5 percent of F, 9 to 11.5 percent of Na2O, 1.5 to 3.5 percent of MnO, 5 to 8 percent of fixed carbon, and the balance of inevitable trace elements. Through the crystallizer protective slag for controlling the carbon steel cracks in the CSP, the alkalinity is improved by 0.04 to 0.09, the alkalinity is controlled to be 1.20 to 1.25, the constraint that the alkalinity cannot be more than 1.16 in the field is broken, the viscosity is controlled to be 0.08 to 0.09Pa.S, and the melting point is from 1,155 to 1,185 DEG C; capabilities of dissolving and absorbing inclusions are improved, and heat transfer is retarded by reducing a vitreous body, so that an aim of reducing longitudinal cracks is fulfilled; and by adjusting the proportioned carbon and controlling the thickness of a liquid slag layer, bonding steel leakage caused by high crystallization temperature and deteriorated lubricating performance due to over high alkalinity of the protective slag is relieved.

Description

technical field [0001] The invention relates to a crystallizer powder suitable for controlling thin slab continuous casting cracks in steelmaking and continuous casting technologies, in particular to a crystallizer powder for effectively controlling cracks in carbon steel in CSP. Background technique [0002] Compared with slab continuous casting, the casting conditions faced by thin slab continuous casting are very strict and harsh , It brings great difficulties to improve billet quality and stabilize continuous casting operation. The impact of each characteristic of CSP thin slab continuous casting technology is directly related to mold flux. In recent years, slab quality accidents and mold breakout accidents have occurred frequently due to mold slag, which has seriously affected the smooth operation of CSP production. [0003] CN1060050A Thin slab continuous casting mold flux and its manufacturing method invented by General Institute of Iron and Steel Research, its comp...

AI Technical Summary

Problems solved by technology

[0005]CN1927502A Tangshan Iron and Steel Co., Ltd. invented a low-carbon steel mold powder for thin slab continuous casting and its preparation method, which is used to solve the problem of FTSC continuous casting machine producing low-carbon steel Longitudinal cracks or bonding problems on the surface of the slab

[0006]CN1411931A The CSP thin slab continuous casting mold mold slag invented by Guangzhou Zhujiang Iron and Steel Co., Ltd. overcomes the sharp drop in slag consumption in the thin slab continuous casting process of the prior art, Causes poor lubrication and uneven heat transfer, resulting in bonded breakouts and poor surface quality of the slab

However, the alkalinity of the mold slag is too high, resulting in high crystallization temperature, which is easy to deteriorate the lubrication of the billet shell and cause the billet shell to stick to breakout