INGOT CONSISTING OF ALLOY OF HIGH MELTING POINT ACTIVE METAL AND MANUFACTURING METHOD THEREFOR

• Main Authors: NAKAOKA TAKEHIRO, KANEHASHI HIDEKATSU, KUROSAWA EISUKE
• Format: Patent
• Language: English; Japanese
• Published: 29.11.2018
• Subjects: ALLOYS; BLASTING; CASTING; CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES; CHEMISTRY; DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS,IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KINDOF FURNACE; FERROUS OR NON-FERROUS ALLOYS; FURNACES; HEATING; KILNS; LIGHTING; MECHANICAL ENGINEERING; METALLURGY; OVENS; PERFORMING OPERATIONS; POWDER METALLURGY; PRETREATMENT OF RAW MATERIALS; PRODUCTION AND REFINING OF METALS; RETORTS; TRANSPORTING; TREATMENT OF ALLOYS OR NON-FERROUS METALS; WEAPONS

PROBLEM TO BE SOLVED: To provide an ingot consisting of alloy of a high melting point active metal less in deviation of alloy contents, and a manufacturing method therefor.SOLUTION: A maximum value θ with sharp angle by growth direction of columnar crystal structure CO formed outer side of the center of an ingot 16 and inside of the ingot, and a central axis O of the ingot 16 is threshold θsatisfying following formulae (1) to (4) or less, wherein permissible value of segregation degree of an alloy element in a radial direction of the ingot 16 is γ[%], equilibration partition coefficient of the alloy element to a high melting point active metal is k[-], material constant of the alloy element is α [sec./m], casting speed of the ingot 16 is V[m/sec.], dissolution rate of a raw material is M [kg/sec.], density of alloy of the high melting point active metal is ρ [kg/m], cross section area of the ingot 16 is A [m], diameter of the ingot 16 is d [m]. γ=abs(1-β)×100 [%] Formula (1), β={k+(1-k)exp(-αV)}/{k+(1-k)exp(-αVcosθ)} Formula (2), V=M/ρA Formula (3), A=πd/4 Formula (4).SELECTED DRAWING: Figure 6 【課題】合金成分の偏りが少ない高融点活性金属の合金からなる鋳塊、および、その製造方法を提供する。【解決手段】鋳塊１６の半径方向における合金元素の偏析度の許容値をγcr［％］、高融点活性金属に対する合金元素の平衡分配係数をｋ0［−］、合金元素の材料定数をα［秒／ｍ］、鋳塊１６の鋳造速度をＶc［ｍ／秒］、原料の溶解速度をＭ［ｋｇ／秒］、高融点活性金属の合金の密度をρ［ｋｇ／ｍ3］、鋳塊１６の断面積をＡ［ｍ2］、鋳塊１６の直径をｄ［ｍ］とすると、鋳塊１６の内部であって、前記鋳塊の中央よりも外側に形成された柱状晶組織ＣＯの成長方向と、鋳塊１６の中心軸Ｏとがなす鋭角の最大値θが、以下の式（１）〜（４）を満たす閾値θcr以下にされている。γcr＝ａｂｓ（１−βcr）×１００[％] ・・・式（１）、βcr＝｛ｋ0＋（１−ｋ0）ｅｘｐ（−αＶc）｝／｛ｋ0＋（１−ｋ0）ｅｘｐ（−αＶcｃｏｓθcr）｝ ・・・式（２）、Ｖc＝Ｍ／ρＡ ・・・式（３）、Ａ＝πｄ2／４ ・・・式（４）【選択図】図６