High Speed Casting Technology of Hypo-peritectic Steel for Round Billet Caster

摘要

The advanced round billet casting technologies have been developed at Wakayama Steel Works.The round billet casting is efficient in comparison with bloom one,because round billets are directly supplied to seamless pipe mill without billeting process.In the round-shaped mold,solidified shell does not bulge and tends to easily make a gap to the mold wall,which induces uneven solidification,especially in the case of hypo-peritectic steel.In this case,high viscosity is necessary for filling the gap with mold flux,because of round shape of the mold.Thus,in order to realize high speed casting of hypo-peritectic steel round billets of high quality,compatibility of adequate lubrication with effective mild cooling is important.We have been focused the lubrication by measurement of frictional force in the mold and improved the mold flux for hypo-peritectic steel.Applying the improved flux,surface cracking on the surface of billets or sticking in the mold has been prevented,and as a result,high speed casting of 3.6m/min has been realized for hypo-peritectic round billet of 191 mm in diameter.The quality of the billets is fine and they are contributing the increase of seamless pipe production.