STEEL SLAB, METHOD FOR PRODUCING STEEL SLAB, AND HIGH-TENSION STEEL PLATE

• Main Authors: KIJIMA TAKESHI, AKATSUKA TAKAO
• Format: Patent
• Language: English; Japanese
• Published: 13.12.2018
• Subjects: ALLOYS; CASTING; CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES; CHEMISTRY; FERROUS OR NON-FERROUS ALLOYS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; PERFORMING OPERATIONS; POWDER METALLURGY; TRANSPORTING; TREATMENT OF ALLOYS OR NON-FERROUS METALS

To provide steel slab, where, carbide and nitride which have been deposited in the steel slab can be dissolved in a solid state in the steel slab in short time without increasing a heating temperature, at a heating stage before hot rolling, and a high-tension steel plate with excellent workability can be obtained stably.SOLUTION: Steel slab contains, in mass%, C: 0.02-0.15%, Si: 2.0% or less, Mn: 0.5-2.0%, P: 0.08% or less, S: 0.0060% or less, N: 0.006% or less, Al: 0.005-0.1%, Ti: 0.05-0.3%, B: 0.0005-0.005% with the balance being Fe and inevitable impurities, where ferrite grains have an average crystal grain size of 70 μm or more, and deposited TiN and MnS have an average particle size of more than 10 μm.SELECTED DRAWING: Figure 3 【課題】鋼スラブ中に析出していた炭化物や窒化物を、熱間圧延前の加熱段階で、加熱温度を高くすることなく短時間で鋼スラブ中に固溶させることができ、加工性に優れた高張力鋼板を安定して得ることのできる鋼スラブを提供すること。【解決手段】質量％で、Ｃ：０．０２〜０．１５％、Ｓｉ：２．０％以下、Ｍｎ：０．５〜２．０％、Ｐ：０．０８％以下、Ｓ：０．００６０％以下、Ｎ：０．００６％以下、Ａl：０．００５〜０．１％、Ｔi：０．０５〜０．３％、Ｂ：０．０００５〜０．００５％を含有し、残部がＦｅ及び不可避的不純物からなり、フェライト粒の平均結晶粒径が７０μｍ以上であり、析出したＴｉＮおよびＭｎＳの平均粒径が１０μｍ超であることを特徴とする鋼スラブ。【選択図】図３