The influence of sulfur on both slag and melt is very important in steelmaking. have researched PK304 steel, its main property is improved machinability. Machinability can be achieved by alloying sulfur at the end of the secondary processing of the steel melt. These are steels that form small chips and shavings during mechanical processing by cutting, which is more appropriate and favorable for both the workpiece and the processing tool and machine.
Since the yield of additional sulfur wire varies greatly in each batch, we delved into understanding the interaction between melt and slag using empirical numerical models and simulation of the process path with the ThermoCalc software tool.
We calculated the yield of sulfur additions and thus defined the influencing factors on the efficiency of the sulfur addition, based on industrial batches. We then took three samples from the selected batches, namely, the 1st sample after degassing, the 2nd sample 5 minutes after the addition of sulfur and the 3rd sample just before casting. Melt and slag samples were taken. Chemical analysis of steel and slag was carried out using an X-ray fluorescence spectrometer XRF. With the help of these results, we then analyzed and evaluated some existing numerical models for determining the sulfide capacity, calculated the activities of oxides, oxygen and sulfur, then finally calculated the distribution ratio for sulfur and the basicity of the slag.
With the help of calculations, we have more clearly defined the influence of individual thermodynamic and process parameters. Based on the results, we found a great influence of the slag chemical composition and basicity on the recovery of the added sulfur. The experimental results were also compared with thermodynamic simulations of phase equilibria, and their values were meaningfully evaluated.
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