Estimation of the influence of melt processing with Ca- and Ba-containing wire on the phase composition and contamination with non-metallic inclusions during ladle furnace treatment and casting of 26KhMFBA steel

Abstract

The increasing requirements of the customer to the quality of the metal of the casing pipes necessitate the search for new technological solutions that make it possible to ensure a stable level of strength and corrosion-resistant properties of the resulting blanks. The main factor affecting the quality of the metal of the casing pipes (strength properties and corrosion resistance) is metallurgical inheritance, namely, the contamination of steel with non-metallic inclusions. At present, to reduce the negative effect of inclusions on the quality of steel, out-offurnace treatment methods at atmospheric and reduced pressure, as well as methods for modifying liquid steel with alkaline earth metals, are quite effectively used. The paper presents the results of a study showing the effect of Ca and Ba-containing master alloy on the phase composition and contamination with non-metallic inclusions during out-of-furnace treatment and casting (ladle furnace evacuator continuous casting) of 26KhMFBA steel. It is shown that the use of SK30wire, after evacuation, leads to incomplete modification of refractory aluminate inclusions. The use of SKB-15Rwire before evacuation leads to a maximum reduction in the total contamination with fusible inclusions. Sequential processing of SKB-15Rwire and SK30wire after evacuation leads to a maximum reduction in refractory aluminate inclusions. The presence of low-melting inclusions (12СaO ∙ 7Al2O3) is more preferable, since this type of inclusions does not deposit on the walls of the nozzle and does not adversely affect the casting of steel.