The production flow sheet of steel S34MnV for marine crank is 100 t Consteel arc furnace-LF-VD + VC (vacuum casting) -ingot process. The observation and analysis on samples of defect region of steel S34MnV ingot are carried out by using scanning electron microscope and numerical simulation to get that the a large amount of non-metallic inclusions enriched at deposit cone of ingot is the cause of rejection of crank by non-destructive test. With using optimum process measures including feeding 2 m/t aluminium wire to deep-deoxidize before refining
feeding Ca-Si wire for end deoxidization
controlling type of inclusions in steel
adjusting slag series and optimizing structure of steel ingot mold etc. the defects at deposit cone of ingot reduce
the rejection rate of ingot is reduced to 6% from original 21% and the oxygen content in steel of ingot bottom decreases to 12 x 10