Efficacy and recovery of calcium during CaSi cored wire injection in steel melts

Abstract

Deoxidation, desulphurisation and inclusion modification are some of the essential features in secondary steel refining through injection of calcium alloy in the form of a cored wire. It is imperative that the filling material must be consumed by the melt to the maximum extent in order to make this cored wire alloy addition cost effective and efficient. In this connection study of calcium recovery is an important issue, which may provide guidelines to select the optimum operating parameters from a fundamental basis. The present study is based on plant data from Tata Steel, Jamshedpur, India. The results demonstrate that maximum calcium recovery is achievable at an optimum speed of the cored wire. Dimensional analysis was carried out to analyse the plant data and the calcium recovery was found to correlate well with physically sound dimensionless numbers such as Biot number, the dimensionless bath temperature and the relative rate of silicon to sulphur transfer from/to the added calcium silicide in the melt. A correlation has also been obtained between the calcium recovery and various dimensionless parameters. The efficacy of calcium addition is also assessed through characterisation of inclusions by scanning electron microscopy and energy dispersive X-ray spectroscopy.

Inclusion characterisation for clean steelmaking and quality control

“…It is possible that the melting of wire and the subsequent Ca reaction are delayed in the ladle when wire C is used, yielding a higher recovery, but an exact explanation is not available at present. Although a higher Ca recovery can be achieved with optimising the speed of addition of the wire in the melt, 11 the addition rate of metallic Ca/ton of liquid steel is important and was kept the same for all the three wires during trials. It seems from Fig.…”

Effect of Types of Calcium‐Containing Cored Wires on the Inclusion Modification by Calcium Treatment

“…1) The calcium yield was the highest when using the SiCa-type wire and was the lowest under the use of pure Ca-type wire. The detailed calcium yield was 4.62%, 1.96%, and 0.49%, respectively, under the use of SiCa wire, CaAl wire, and Zheng et al [37] Xie et al [38] Liu [39] Ji et al [40] Basak et al [41] Zheng et al [37] Wen et al [41] Liu [39] Ji et al [40] Wang et al [43] Content of [Al] in steel (wt%) on the solubility of calcium in steel. [44] Table 2.…”

Heat transfer of calcium cored wires and CFD simulation on flow and mixing efficiency in the argon-stirred ladle

“…To ensure good performance of steel product, the cored-wire feeding technology has been widely used to improve the cleanliness of molten steel and accurately control the alloy's component in steelmaking process [1,2]. The argon bottom blowing method was applied to enhance the mixing efficiency by stirring the molten steel, such as in the LF refining treatment [3,4]. However, there is still no effective approach to real-time monitor the state of molten steel and its property variation, so that it is difficult to assess and control the mixing efficiency [5,6].…”