WO2017018521A1 - Matériau de titane pour laminage à chaud - Google Patents

Matériau de titane pour laminage à chaud Download PDF

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Publication number
WO2017018521A1
WO2017018521A1 PCT/JP2016/072343 JP2016072343W WO2017018521A1 WO 2017018521 A1 WO2017018521 A1 WO 2017018521A1 JP 2016072343 W JP2016072343 W JP 2016072343W WO 2017018521 A1 WO2017018521 A1 WO 2017018521A1
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Prior art keywords
titanium
surface layer
base material
slab
hot rolling
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PCT/JP2016/072343
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English (en)
Japanese (ja)
Inventor
森　健一
藤井　秀樹
一浩 ▲高▼橋
知徳 國枝
吉紹 立澤
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新日鐵住金株式会社
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Priority to JP2016567285A priority Critical patent/JP6086178B1/ja
Publication of WO2017018521A1 publication Critical patent/WO2017018521A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
    • B21B1/02—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling heavy work, e.g. ingots, slabs, blooms, or billets, in which the cross-sectional form is unimportant ; Rolling combined with forging or pressing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B3/00—Rolling materials of special alloys so far as the composition of the alloy requires or permits special rolling methods or sequences ; Rolling of aluminium, copper, zinc or other non-ferrous metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K15/00—Electron-beam welding or cutting
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K20/00—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating
    • B23K20/04—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating by means of a rolling mill
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C14/00—Alloys based on titanium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/16—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of other metals or alloys based thereon
    • C22F1/18—High-melting or refractory metals or alloys based thereon

Definitions

  • the present invention relates to a titanium material for hot rolling.
  • Titanium material has excellent properties such as corrosion resistance, oxidation resistance, fatigue resistance, hydrogen embrittlement resistance, and neutron blocking properties. These properties can be achieved by adding various alloying elements to titanium.
  • Industrially pure titanium is mainly composed of an ⁇ phase having an hcp (dense hexagonal lattice) structure, and it is known that when a large amount of hydrogen is absorbed in the ⁇ phase, a hydride is formed and embrittles. For this reason, depending on the use environment, there is a case where an accident occurs in which hydrogen is absorbed and becomes brittle and breaks.
  • Non-Patent Document 1 for example, accidents due to hydrogen absorption in a plant that handles non-oxidizing acids, or in a urea / ammonia environment or a hydrogen gas environment are reported. For this reason, a titanium alloy material excellent in hydrogen embrittlement resistance has been proposed.
  • Patent Document 1 discloses a titanium alloy containing 50% by volume or more of a ⁇ phase and containing 500 to 6000 ppm of hydrogen and having a large elongation at break. Even if it contains a large amount of hydrogen, it is brittle. An example is shown that does not.
  • the titanium material is usually manufactured by the method shown below.
  • the raw material titanium oxide is chlorinated to titanium tetrachloride by the crawl method, and then reduced with magnesium or sodium to produce a lump-like sponge-like metal titanium (sponge titanium).
  • This sponge titanium is press-molded to form a titanium consumable electrode, and a titanium ingot is manufactured by vacuum arc melting using the titanium consumable electrode as an electrode.
  • an alloy element is added as necessary to produce a titanium alloy ingot.
  • the titanium alloy ingot is divided, forged and rolled into a titanium slab, and the titanium slab is further subjected to hot rolling, annealing, pickling, cold rolling, and vacuum heat treatment to produce a titanium thin plate.
  • titanium ingot is smashed, hydroground, dehydrogenated, powder crushed, and classified to produce titanium powder, and titanium powder is powder-rolled, sintered, and cold-rolled.
  • the manufacturing method is also known.
  • Patent Document 2 discloses that a titanium powder is produced directly from sponge titanium, not a titanium ingot, and a titanium thin plate is produced from the obtained titanium powder.
  • Sintered compacts are manufactured by sintering pre-sintered compacts made of viscous compositions containing agents and solvents into thin sheets, and sintered compacts are manufactured by compacting the sintered compacts.
  • a method is disclosed in which the fracture elongation of the sintered thin plate is 0.4% or more, the density ratio is 80% or more, and the density ratio of the sintered compacted plate is 90% or more. ing.
  • Patent Document 3 discloses a composite powder obtained by adding an appropriate amount of iron powder, chromium powder or copper powder to titanium alloy powder using titanium alloy scrap or titanium alloy ingot as a raw material. After extruding the carbon steel capsule, the capsule on the surface of the obtained round bar is dissolved and removed, and further solution treatment or solution treatment and aging treatment are performed to produce a titanium alloy with excellent quality by the powder method A method is disclosed.
  • Patent Document 4 discloses a method in which a titanium sponge powder is filled in a copper capsule and then subjected to warm extrusion at an extrusion ratio of 1.5 or more and an extrusion temperature of 700 ° C. or less.
  • a method for producing a titanium molded body in which 20% or more of the total length of the grain boundary of the molded body is in metal contact is performed by performing outer peripheral processing excluding copper.
  • a pack rolling method is known as a technique for rolling the sheet.
  • the pack rolling method is a method in which a core material such as a titanium alloy having poor workability is covered with a cover material such as inexpensive carbon steel having good workability and hot rolling is performed.
  • a release agent is applied to the surface of the core material, and at least two upper and lower surfaces thereof are covered with a cover material, or the four peripheral surfaces are covered with a spacer material in addition to the upper and lower surfaces, and the surroundings are welded. Assembled and hot rolled.
  • a core material which is a material to be rolled, is covered with a cover material and hot rolled. Therefore, the core material surface does not directly contact a cold medium (atmosphere or roll), and the temperature drop of the core material can be suppressed, so that even a core material with poor workability can be manufactured.
  • Patent Document 5 discloses a method for assembling a hermetically sealed box
  • Patent Document 6 discloses a degree of vacuum of 10 ⁇ 3 torr or higher.
  • Patent Document 7 discloses a method of covering the carbon steel (cover material) with an order of 10 ⁇ 2 torr.
  • a method for producing a hermetic coated box by sealing by high energy density welding under the following vacuum is disclosed.
  • Patent Document 8 a steel material is used as a base material and titanium or a titanium alloy is used as a mating material, and the joint surface between the base material and the mating material is evacuated and then welded and assembled.
  • a method for manufacturing a titanium clad steel sheet in which an assembly slab for rolling is joined by hot rolling is disclosed.
  • Patent Document 9 discloses that pure nickel, pure iron, and carbon content are 0.01 mass% or less on the surface of a base steel material containing 0.03 mass% or more of carbon. After the titanium foil material is laminated by interposing an insert material made of any one of the above-mentioned low carbon steels with a thickness of 20 ⁇ m or more, a laser beam is irradiated from either side of the lamination direction, A method of manufacturing a titanium-coated steel material by melting and joining at least the vicinity of the edge with a base steel material over the entire circumference is disclosed.
  • JP-A-2015-045040 Patent Document 10
  • the surface of a porous titanium raw material (sponge titanium) formed into an ingot shape is melted using an electron beam under vacuum to make the surface layer portion dense titanium.
  • the titanium ingot is manufactured and hot rolled and cold rolled to form a porous portion in which the porous titanium raw material is formed into an ingot shape, and the entire surface of the porous portion composed of dense titanium.
  • a method for producing a dense titanium material (titanium ingot) having a dense coating portion for coating with very little energy is exemplified.
  • Patent Document 11 describes that a surface effect treatment of an engine member for an automobile is performed by thermal spraying.
  • JP 2013-163840 A JP 2011-42828 A JP 2014-19945 A JP 2001-131609 A JP-A-63-207401 Japanese Patent Laid-Open No. 09-136102 JP 11-057810 A Japanese Patent Laid-Open No. 08-141754 Japanese Patent Laid-Open No. 11-170076 Japanese Patent Laying-Open No. 2015-045040 JP 62-270277 A
  • Titanium processing technology edited by Japan Titanium Association, Nikkan Kogyo Shimbun, p. 214-230, issued in November 1992
  • sponge titanium is press-molded to form a titanium consumable electrode, and a titanium ingot is manufactured by vacuum arc melting using the titanium consumable electrode as an electrode.
  • the titanium slab was forged and rolled into a titanium slab, and the titanium slab was manufactured by hot rolling, annealing, pickling, and cold rolling.
  • a process of dissolving titanium and producing a titanium ingot was always added.
  • a method of producing titanium powder by powder rolling, sintering, and cold rolling is also known, but in the method of producing titanium powder from a titanium ingot, a step of dissolving titanium is also added.
  • the core material covered with the cover material is slab or ingot to the last, and has undergone a melting process or is made of expensive titanium powder, and the manufacturing cost cannot be reduced.
  • a dense titanium material can be manufactured with very little energy, but the surface of the titanium sponge formed into an ingot shape is dissolved, and the dense titanium surface layer portion and the internal components are the same kind of pure titanium. Or it is prescribed
  • thermal spraying is a method in which a film is formed by melting a metal, ceramics, or the like and spraying it on the surface of a titanium material.
  • thermal spraying is performed while shielding with an inert gas in order to avoid oxidation of the film.
  • inert gases are entrained in the pores of the coating.
  • Such pores containing the inert gas are not pressed by hot working or the like.
  • vacuum heat treatment is generally carried out, but during this treatment, the inert gas in the pores may expand and the film may be peeled off.
  • the abundance ratio (porosity) of pores generated by thermal spraying is several vol. % Or more and 10 vol. % May be exceeded.
  • a titanium material having a high porosity in the film has a risk of peeling in the manufacturing process, and there is a risk that a defect such as a crack during processing may occur.
  • melt resolidification process As a process for melting and resolidifying the surface layer of the slab using an electron beam.
  • the melted and re-solidified surface layer is removed in a pickling step after hot rolling.
  • the present inventors paid attention to this melt resolidification treatment. That is, the present inventors can form a surface layer portion containing a specific alloy element in the slab by melting a specific alloy element when melting the slab surface layer and solidifying it with a slab-derived component. I thought.
  • the melt resolidification treatment for the purpose of suppressing surface flaws during hot rolling cannot be used as it is to form a surface layer portion containing a specific alloy element in the slab. This is because the conventional melt resolidification treatment is based on the premise that the formed surface layer is removed by pickling, and no consideration was given to segregation of alloy components in the surface layer portion.
  • the present invention reduces the content of alloying elements added to improve hydrogen embrittlement resistance (the amount of specific alloying elements that express target characteristics) and suppresses the production cost of titanium materials Thus, it is an object to obtain a titanium material for hot rolling having desired characteristics at a low cost.
  • the present invention has been made to solve the above-mentioned problems, and the gist thereof is the following titanium material for hot rolling.
  • Titanium for hot rolling comprising a base material made of industrial pure titanium or a titanium alloy, and a surface layer portion having a chemical composition different from that of the base material formed on at least one rolling surface of the base material.
  • the surface layer portion has a thickness of 2.0 to 20.0 mm, the ratio of the total thickness to 40% or less per side, and the chemical composition of the surface layer portion is increased from the base material.
  • the Mo equivalent calculated by the following formula (1) is 8.0 to 20.0, and the content of the elements contained in the surface layer portion
  • / C AVE ⁇ 100 Is a titanium material for hot rolling, having a content of 40% or less.
  • Mo equivalent Mo content (% by mass) + V content (% by mass) /1.5+Nb content (% by mass) /3.6 (1)
  • Other surface layer portions are formed on a surface other than the rolling surface of the base material,
  • the other surface layer portion has the same chemical composition and metal structure as the surface layer portion.
  • Titanium material for hot rolling is formed on a surface other than the rolling surface of the base material.
  • the titanium material for hot rolling according to the present invention includes a base material made of pure industrial titanium or a titanium alloy and a surface layer portion having a chemical composition different from that of the base material, and is thus manufactured using the base material. Compared with a titanium material made entirely of the same titanium alloy, the titanium composite material has equivalent hydrogen embrittlement resistance, but can be manufactured at low cost.
  • FIG. 1 is an explanatory view showing an example of the configuration of a titanium material for hot rolling according to the present invention.
  • FIG. 2 is an explanatory view showing another example of the structure of the titanium material for hot rolling according to the present invention.
  • FIG. 3 is an explanatory diagram showing an example of the configuration of the titanium composite material according to the present invention.
  • FIG. 4 is an explanatory diagram showing an example of the configuration of the titanium composite material according to the present invention.
  • FIG. 5 is an explanatory diagram showing a method of melt re-solidification.
  • FIG. 6 is an explanatory diagram showing a method of melt re-solidification.
  • FIG. 7 is an explanatory view showing a method of melt re-solidification.
  • FIG. 5 is an explanatory diagram showing a method of melt re-solidification.
  • FIG. 8 is an explanatory view schematically showing that a titanium rectangular slab (slab) and a titanium plate are bonded together by welding in a vacuum.
  • FIG. 9 is an explanatory view schematically showing that a titanium plate is bonded to not only the surface of a titanium rectangular cast slab (slab) but also a side surface thereof.
  • the titanium material for hot rolling of the present invention is a material (slabs such as slabs, blooms and billets) subjected to hot working, and after hot working, cold working, heat treatment, etc. are performed as necessary. And processed into a titanium composite.
  • the titanium material for hot rolling according to the present invention will be described with reference to the drawings.
  • “%” regarding the content of each element means “mass%”.
  • a titanium material for hot rolling 1 includes a base material 1b and a surface layer portion 1a on the rolling surface of the base material 1b.
  • the surface layer portion includes a predetermined intermediate layer (not shown).
  • the base material 1b is made of industrial pure titanium or a titanium alloy, and the surface layer portion 1a has a chemical composition different from that of the base material 1b.
  • the titanium material 1 for hot rolling according to the present invention may include surface layer portions 1aa and 1ab on both rolling surfaces of the base material 1b.
  • the hydrogen embrittlement resistance of the titanium material 1 for hot rolling is secured by the surface layer portion 1a (1aa, 1ab in the example shown in FIG. 2) in contact with the external environment.
  • This titanium material for hot rolling 1 has equivalent hydrogen embrittlement resistance as compared with a titanium material made entirely of the same titanium alloy, but can be manufactured at a low cost.
  • the dimension in case the titanium material for hot rolling is a rectangular titanium cast piece will not be specifically limited if it is a dimension which can be used for hot rolling as it is.
  • the rectangular titanium cast piece has a thickness of about 50 to 300 mm, a length of about 3000 to 10000 m, and a width of 600. It may be about ⁇ 1500 mm.
  • the thickness of the surface layer portion is set to 2.0 to 20.0 mm.
  • the ratio of the thickness of the surface layer part to the total thickness is 40% or less per side.
  • Base material Base material 1 consists of industrial pure titanium or a titanium alloy. However, by using a titanium alloy, mechanical properties (strength, ductility, etc.) superior to the case of using industrial pure titanium can be obtained.
  • JIS 1 to 4 types of industrial pure titanium can be used among the pure titanium specified in JIS. That is, it contains 0.1% or less C, 0.015% or less H, 0.4% or less O, 0.07% or less N, 0.5% or less Fe, and the balance is Ti. Pure titanium for industrial use. If these JIS 1 to 4 kinds of industrial pure titanium are used, a titanium material that has sufficient workability, does not generate cracks, and is integrated with the surface titanium alloy after hot working can be obtained.
  • ⁇ -type, ⁇ + ⁇ -type, and ⁇ -type titanium alloys can be used as the base material 1.
  • the ⁇ -type titanium alloy for example, Ti-0.5Cu, Ti-1.0Cu, Ti-1.0Cu-0.5Nb, Ti-1.0Cu-1.0Sn-0.3Si-0. 25Nb, Ti-0.5Al-0.45Si, Ti-0.9Al-0.35Si, Ti-3Al-2.5V, Ti-5Al-2.5Sn, Ti-6Al-2Sn-4Zr-2Mo, Ti- Examples thereof include 6Al-2.75Sn-4Zr-0.4Mo-0.45Si.
  • Examples of ⁇ + ⁇ type titanium alloys include Ti-6Al-4V, Ti-6Al-6V-2Sn, Ti-6Al-7V, Ti-3Al-5V, Ti-5Al-2Sn-2Zr-4Mo-4Cr, and Ti.
  • -6Al-2Sn-4Zr-6Mo Ti-1Fe-0.35O, Ti-1.5Fe-0.5O, Ti-5Al-1Fe, Ti-5Al-1Fe-0.3Si, Ti-5Al-2Fe, Ti Examples are -5Al-2Fe-0.3Si, Ti-5Al-2Fe-3Mo, Ti-4.5Al-2Fe-2V-3Mo, and the like.
  • ⁇ -type titanium alloy for example, Ti-11.5Mo-6Zr-4.5Sn, Ti-8V-3Al-6Cr-4Mo-4Zr, Ti-10V-2Fe-3Mo, Ti-13V-11Cr-3Al Ti-15V-3Al-3Cr-3Sn, Ti-6.8Mo-4.5Fe-1.5Al, Ti-20V-4Al-1Sn, Ti-22V-4Al, and the like.
  • the base material may be manufactured by a known manufacturing method such as a melting method or a powder metallurgy method, and is not particularly limited.
  • the base material can be manufactured by cutting and refining an ingot into a slab or billet shape by breakdown.
  • breakdown since the surface is relatively flat by breakdown, it is easy to disperse the element containing the alloy element relatively uniformly, and it is easy to make the element distribution of the alloy phase uniform.
  • an ingot directly produced during casting can be used as a base material.
  • the cutting and refining process can be omitted, it can be manufactured at a lower cost.
  • the surface is cut and refined after the ingot is manufactured, the same effect can be expected when it is manufactured through breakdown.
  • the surface layer portion of the titanium material for hot rolling is Various alloy elements listed below may be included.
  • the layer for obtaining hydrogen absorption resistance is a titanium alloy layer containing a certain range of ⁇ -stabilizing elements.
  • the reason for prescribing the formation of the ⁇ phase is that the ⁇ phase of titanium forms a hydride even at a hydrogen concentration of only a few tens of ppm, whereas the ⁇ phase of the titanium alloy can dissolve about 1000 ppm or more of hydrogen, This is because it has the characteristic that it is difficult to cause embrittlement due to hydrogen.
  • the lower limit of the Mo equivalent is the amount of alloy necessary to obtain a sufficient amount of ⁇ phase.
  • the upper limit was determined because a titanium alloy with a large amount of alloy addition is not suitable for use because of its high cost.
  • Impurities can be contained within a range that does not hinder the target characteristics, and other impurities include Ta, Si, Mn, and Cu as impurity elements mainly mixed from scrap, and C, which are general impurity elements, In combination with N, Fe, O and H, a total amount of 5% or less is allowed.
  • Titanium composite material The titanium material for hot rolling of the present invention is a material (slab, slab, bloom, billet, etc.) subjected to hot working, and after hot working, if necessary, cold working, It is processed into titanium composite by heat treatment.
  • the titanium composite material includes an inner layer derived from the base material of the titanium material for hot rolling according to the present invention and a surface layer derived from the surface layer portion. (thickness) If the thickness of the surface layer in contact with the external environment is too thin, sufficient hydrogen absorption resistance cannot be obtained. On the other hand, when the surface layer is thick, there is no problem in hydrogen absorption resistance, but the manufacturing cost increases because the ratio of the surface layer to the entire material increases. For this reason, the ratio of the thickness of the surface layer to the total thickness of the titanium composite (surface layer occupancy) is 2 to 20% per side.
  • the thickness of the surface layer depends on the thickness of the surface layer portion 1a and the processing rate at the time of hot processing performed thereafter.
  • the porosity of the surface layer is preferably 0.1% or less. When the porosity exceeds 0.1%, the surface layer may be swollen or peeled off during hot rolling.
  • the porosity can be easily measured by taking a photograph of the cross section of the material by observing it with an optical microscope and processing the photograph. An arbitrary 10 to 20 points in the cross section are observed, the porosity is measured, and the average can be set as the overall porosity.
  • the porosity of the material which performed hot rolling or after cold rolling is equivalent to the porosity of the titanium material for hot rolling.
  • the specific element in the surface layer portion can be measured using EPMA or GDS. Specifically, arbitrary 10 to 20 locations on the surface layer portion are measured, and the average value of the increased content from the base material at each measured location is defined as the increased content C 0 at each measured location, and the increased content C 0. May be the average value C AVE of the increased content in the surface layer portion.
  • the surface layer includes an intermediate layer in the vicinity of the inner layer. That is, the titanium material for hot rolling of the present invention is provided with a surface layer portion formed by, for example, melt resolidification treatment on the surface of the base material, and the surface layer portion is then subjected to hot rolling heating, and In the heat treatment step after cold rolling, diffusion occurs at the interface between the base material and the surface layer portion, and when the titanium composite material is finally finished, it is between the inner layer derived from the base material and the surface layer derived from the surface layer portion. An intermediate layer is formed. This intermediate layer bonds the inner layer and the surface layer to each other and bonds them firmly. Further, since a continuous element gradient is generated in the intermediate layer, the difference in strength between the inner layer and the surface layer can be reduced, and cracks during processing can be suppressed.
  • the thickness of this intermediate layer is preferably 0.5 ⁇ m or more.
  • the thickness of the intermediate layer can be measured using EPMA or GDS. If GDS is used, more detailed measurement is possible. In the case of GDS, after removing the surface layer to some extent by polishing, the thickness of the intermediate layer can be measured by performing GDS analysis in the depth direction from the surface.
  • the intermediate layer is the increased content from the base material (in the case of an element not included in the base material, its content, in the case of an element also included in the base material, the increase in content from the base material) ) Is C MID, and the average of the increased content in the surface layer portion is C AVE , it means a region of 0 ⁇ C MID ⁇ 0.8 ⁇ C AVE .
  • the titanium material for hot rolling of the present invention is specified as a base material by melting the surface layer of the base material, melting a specific alloy element at that time, and solidifying it together with components derived from the base material. It can manufacture by forming the surface layer part containing these alloy elements.
  • FIGS. 5 to 7 are explanatory views showing a method of melt resolidification.
  • a method for melting and resolidifying the surface of the base material of the titanium material for hot rolling there are laser heating, plasma heating, induction heating, electron beam heating, etc., and any method may be used.
  • electron beam heating since it is performed in a high vacuum, even if a void or the like is formed in this layer during the melt resolidification treatment, it can be made harmless by pressure bonding in subsequent rolling because it is a vacuum.
  • the degree of vacuum in the case of melting in a vacuum is desirably higher than 3 ⁇ 10 ⁇ 3 Torr.
  • the number of times of melting and resolidifying the surface layer of the titanium material for hot rolling is not particularly limited, and even if the number of times is increased as necessary, the thickness of the alloy layer on the surface layer portion of the material and the amount of additive elements added are not limited. If it is within the above range, there is no problem. However, as the number of times increases, the processing time becomes longer and the cost increases.
  • the melt resolidification method of the surface layer is carried out as shown in FIG. 5 in the case of a rectangular slab. That is, among the outer surfaces of the rectangular slab 10, at least two wide surfaces 10A and 10B that become the rolling surfaces (surfaces in contact with the hot rolling roll) in the hot rolling process are irradiated with an electron beam, and the surfaces on the surfaces are irradiated. Only melt the layer.
  • the surface 10A is one of the two surfaces 10A and 10B.
  • the area of the electron beam irradiation region 14 by the single electron beam irradiation gun 12 on the surface 10A of the rectangular slab 10 is compared with the total area of the surface 10A to be irradiated.
  • the electron beam irradiation is actually performed while continuously moving the electron beam irradiation gun 12 or continuously moving the rectangular slab 10. It is normal.
  • the shape and area of this irradiation area can be adjusted by adjusting the focus of the electron beam or by using an electromagnetic lens to oscillate a small beam at a high frequency (oscillation Oscillation) to form a beam bundle. can do.
  • the moving direction of the electron beam irradiation gun is not particularly limited, it is generally continuous along the length direction (usually the casting direction D) or the width direction (usually the direction perpendicular to the casting direction D) of the rectangular slab 10.
  • the irradiation region 14 is continuously irradiated in a band shape with a width W (in the case of a circular beam or beam bundle, a diameter W).
  • the electron beam irradiation is performed in a belt shape while continuously moving the irradiation gun 12 in the reverse direction (or the same direction) in the adjacent unirradiated belt region.
  • a plurality of irradiation guns may be used to simultaneously perform electron beam irradiation on a plurality of regions.
  • FIG. 5 the case where a rectangular beam is continuously moved along the length direction (usually casting direction D) of the rectangular slab 10 is shown.
  • the surface (surface 10A) of the rectangular titanium cast piece 10 is irradiated with an electron beam by such a surface heat treatment step and heated to melt the surface, the rectangular titanium as shown in the left side of the center of FIG.
  • the surface layer of the surface 10A of the slab 10 is melted at the maximum by a depth corresponding to the heat input.
  • the depth from the direction perpendicular to the irradiation direction of the electron beam is not constant as shown in FIG. 7, and the depth becomes the largest at the central part of the electron beam irradiation, and the thickness increases toward the strip-shaped end part. Decreases, resulting in a downwardly convex curved shape.
  • the surface layer of the material for hot rolling is alloyed by melting and resolidifying together with the material composed of the target alloy element.
  • a material used in this case one or more of powder, chip, wire, thin film, cutting powder, and mesh may be used.
  • the component and amount of the material to be arranged before melting are determined so that the component in the element concentration region after melting and solidifying together with the material surface becomes the target component.
  • the melt resolidification treatment After the melt resolidification treatment, it is preferable to hold at a temperature of 100 ° C. or higher and lower than 500 ° C. for 1 hour or longer. If it is cooled rapidly after melting and resolidification, fine cracks may occur in the surface layer due to strain during solidification. In the subsequent hot rolling process and cold rolling process, the fine cracks may be the starting point, and the surface layer may be peeled off, or a part having a partially thin alloy layer may be generated. Further, if the inside is oxidized due to fine cracks, it is necessary to remove in the pickling process, and the thickness of the alloy layer is further reduced. By maintaining at the above temperature, fine cracks on the surface can be suppressed. At this temperature, atmospheric oxidation hardly occurs even if the temperature is maintained.
  • the titanium material for hot rolling provided with a surface layer portion formed by melt re-solidification treatment on the surface of the base material is used at the interface between the base material and the surface layer portion in the subsequent heat treatment process during hot rolling and after cold rolling.
  • This intermediate layer makes the said inner layer and the said surface layer metal-bond, and joins firmly.
  • a continuous element gradient is generated in the intermediate layer, the difference in strength between the inner layer and the surface layer can be reduced, and cracks during processing can be suppressed.
  • the shape of the melted portion is curved as described above, so that the shape is also inherited in the final product.
  • the alloy element diffuses and joins from the interface with the curved base material, so if the element diffusion direction is only in the depth direction In addition, diffusion also occurs in the width direction. Therefore, the gradient of the alloy element in the intermediate portion between the base material and the alloy layer occurs not only in the depth direction but also in the width direction.
  • the surface of the base material may be melted and re-solidified, and a titanium plate containing a predetermined alloy component may be attached to the surface layer portion to manufacture a titanium material for hot rolling.
  • FIG. 8 is an explanatory view schematically showing that a titanium rectangular cast piece (slab) 6 and a titanium plate 7 in which a surface layer portion is formed by melting and resolidifying the surface of a base material are bonded together by welding in a vacuum.
  • FIG. 9 is an explanatory view schematically showing that the titanium plates 7 and 8 are bonded together by welding not only on the surface of the titanium rectangular cast slab (slab) 6 but also on the side surfaces.
  • the titanium rectangular slab 6 (slab) 6 in which the surface of the base material is formed by melting and re-solidifying the base material surface is referred to as “titanium slab 6”.
  • the surface layer 3 of the titanium composite material is bonded by hot rolling cladding. , 4 are alloyed. That is, after the titanium plate 7 containing the alloy element is bonded to the surface corresponding to the rolling surface of the titanium slab 6, the titanium slab 6 and titanium are preferably welded at least in the periphery by the weld 9 in a vacuum vessel. The space between the plates 7 is sealed with a vacuum, and the titanium slab 6 and the titanium plate 7 are bonded together by rolling. In welding the titanium plate 7 to the titanium slab 6, for example, as shown in FIGS. 8 and 7, the entire circumference is welded so that air does not enter between the titanium slab 6 and the titanium plate 7.
  • Titanium is an active metal and forms a strong passive film on the surface when left in the atmosphere. It is impossible to remove the oxidized layer on the surface. However, unlike stainless steel, etc., oxygen easily dissolves in titanium. Therefore, when heated in a vacuum and sealed without external oxygen supply, oxygen on the surface diffuses into the solid solution. Therefore, the passive film formed on the surface disappears. Therefore, the titanium slab 6 and the titanium plate 7 on the surface thereof can be completely adhered to each other by the hot-rolled clad method without any inclusions being generated therebetween.
  • the titanium slab 6 when an as-cast slab is used as the titanium slab 6, surface defects are generated in the subsequent hot rolling process due to coarse crystal grains generated during solidification.
  • the titanium plate 7 when the titanium plate 7 is bonded to the rolled surface of the titanium slab 6 as in the present invention, the bonded titanium plate 7 has a fine structure, so that surface defects in the hot rolling process can be suppressed.
  • a titanium plate 7 is bonded to only one surface of the titanium slab 6 in a vacuum as shown in FIG. You may hot-roll without sticking 7.
  • a titanium plate 7 may be bonded to both sides of the titanium slab 6 instead of just one side.
  • production of the hot rolling in a hot rolling process can be suppressed as mentioned above.
  • at least a part of the side surface of the titanium slab 6 usually wraps around the surface side of the hot-rolled sheet by being rolled down by the titanium slab 6. Therefore, if the structure of the surface layer on the side surface of the titanium slab 6 is coarse or a large number of defects are present, surface flaws may occur on the surface near both ends in the width direction of the hot-rolled sheet. For this reason, as shown in FIG.
  • the same standard titanium plate 8 is preferably bonded and welded to the side surface of the titanium slab 6 on the edge side during hot rolling as well as the rolled surface. Thereby, generation
  • This welding is preferably performed in a vacuum.
  • the amount of the side surface of the titanium slab 6 that wraps around during hot rolling varies depending on the manufacturing method, but is usually about 20 to 30 mm. Therefore, it is not necessary to attach the titanium plate 8 to the entire side surface of the titanium slab 6 and manufacture. It is only necessary to attach the titanium plate 8 only to a portion corresponding to the amount of wraparound according to the method.
  • the base material-derived component can be contained in the titanium composite material. For example, heat treatment at 700 to 900 ° C. for 30 hours is exemplified.
  • Methods for welding the titanium slab 6 and the titanium plates 7 and 8 include electron beam welding and plasma welding.
  • electron beam welding can be performed under high vacuum, the space between the titanium slab 6 and the titanium plates 7 and 8 can be made high vacuum, which is desirable.
  • the degree of vacuum when the titanium plates 7 and 8 are welded in a vacuum is desirably a higher degree of vacuum of the order of 3 ⁇ 10 ⁇ 3 Torr or less.
  • the titanium slab 6 and the titanium plate 7 are not necessarily welded in a vacuum vessel.
  • a vacuum suction hole is provided in the titanium plate 7 and the titanium plate 7 is overlapped with the titanium slab 6.
  • the titanium slab 6 and the titanium plate 7 may be welded while evacuating the titanium slab 6 and the titanium plate 7 using a vacuum suction hole, and the vacuum suction hole may be sealed after welding.
  • Base material of hot-rolling titanium material The base material of the hot-rolling titanium material is usually manufactured by cutting and refining an ingot into a slab or billet shape by breakdown. In recent years, rectangular slabs that can be hot-rolled directly at the time of ingot production are sometimes produced and used for hot-rolling. When manufactured by breakdown, since the surface is relatively flat by breakdown, it is easy to disperse the material containing the alloy element relatively uniformly, and it is easy to make the element distribution of the alloy phase uniform.
  • the cutting and refining process can be omitted, so that it can be manufactured at a lower cost.
  • the ingot is manufactured and then used after the surface is cut and refined, the same effect can be expected when it is manufactured through breakdown.
  • an alloy layer may be stably formed on the surface layer, and an appropriate material may be selected according to the situation.
  • the base material is not particularly limited.
  • the slab and welding the surroundings After assembling the slab and welding the surroundings, it is heated to 700 to 850 ° C. and subjected to 10-30% joint rolling, and then heated at the ⁇ -zone temperature for 3 to 10 hours to diffuse the base material components to the surface layer. It is preferable to perform hot rolling later. This is because by performing hot rolling at a ⁇ -region temperature, the deformation resistance becomes low and rolling becomes easy.
  • Hot rolling process Also in the hot rolling process, if the surface temperature is too high, a large amount of scale is generated during sheet passing, and the scale loss increases. On the other hand, if it is too low, the scale loss is reduced, but surface flaws are likely to occur. Therefore, it is necessary to remove by surface pickling, and it is desirable to perform hot rolling in a temperature range in which surface flaws can be suppressed. . Therefore, it is desirable to perform rolling in the optimum temperature range. In addition, since the surface temperature of the titanium material decreases during rolling, it is desirable to minimize roll cooling during rolling and suppress the decrease in the surface temperature of the titanium material.
  • the hot-rolled plate has an oxide layer on its surface
  • the oxide layer is generally removed by pickling with a nitric hydrofluoric acid solution.
  • the surface may be ground by grinding with a grindstone after pickling.
  • a two-layer or three-layer structure including an inner layer and a surface layer derived from the base material and the surface layer portion of the titanium material for hot rolling may be used.
  • a shot blast treatment is performed as a pretreatment for the pickling treatment to remove a part of the scale on the surface, and at the same time, cracks are formed on the surface, and in the subsequent pickling step The liquid penetrates into the cracks and removes part of the base material.
  • a slab which is a base material for manufacturing the titanium composite material 2 having the surface layers 3 and 4 containing a predetermined alloy, is cut by hot forging a Ti-5Al-1Fe alloy manufactured by vacuum arc melting.
  • the produced 28-143 mm thick slab was used.
  • the chemical component of the titanium ingot in a present Example is Al: 5%, Fe: 1%, O: 0.15%.
  • Mo, V, Nb alloy element material is sprinkled on the slab surface, melted and re-solidified, and a region (alloy layer) in which the alloy element is solid solution on the entire surface of the slab is 1 to 15 mm deep. Formed.
  • the slab is heated to 950 ° C. and hot-rolled to a thickness of 5 mm, then heat-treated at 700 ° C. for 2 hours in an air atmosphere, and then descaled on both the front and back surfaces using shot blasting and nitric hydrofluoric acid. Processed.
  • Each titanium plate produced above was exposed at 500 ° C. for 5 hours in a 1% by volume H 2 + 99% by volume Ar atmosphere as a hydrogen absorption environment.
  • the alloy element concentration of the surface layers 3 and 4 of each titanium plate is an average value as a result of performing a line analysis on the range from the surface to the lower end of the alloy concentrated portion using EPMA.
  • the remainder is a component contained in industrial pure titanium except for contamination components such as O and C.
  • an impact test piece having a thickness (4.8 to 5.0 mm) ⁇ 10 mm ⁇ 55 mm and 2 mmV notch was prepared.
  • the longitudinal direction of the test piece was the rolling direction, and the notch direction was the plate thickness penetration direction. Hydrogen brittleness was evaluated by impact value.
  • the surface layer portion includes an element derived from a slab (base material).
  • the “surface layer composition” in the table indicates the content of elements that are not included in the slab, and for elements that are also included in the slab, if there is an increase in the content, increase the content. The content is shown, and “ ⁇ ” is shown when there is no increase in content.
  • No. 1 is a case where a surface layer portion (alloy concentrated layer) is not formed, and the impact value after exposure to a hydrogen environment is as low as 13 J / cm 2 .
  • the thickness of the surface layer portion is within the range of the present invention, but the Mo equivalent is low, and the impact value after exposure to a hydrogen environment is also low.
  • Mo equivalent is within the scope of the present invention, but segregation of the surface layer part is outside the scope of the present invention, and the impact value after exposure to a hydrogen environment is low.
  • the surface layer thickness and Mo equivalent satisfy the scope of the present invention, and the impact value is as high as 16 J / cm 2 or more.
  • No. 11 to 14 are within the scope of the present invention, and the impact value after exposure to a hydrogen environment is high.
  • a 70 mm thickness of Ti-6Al-4V produced by vacuum arc melting, forging and cutting processes was used for the slab as the base material.
  • the alloy element material of Mo, V, and Nb is sprinkled on the slab surface, melted and re-solidified, and the depth (3 to 10 mm) of the region (surface layer part) where the alloy element is solid-solved on the entire surface of the slab Formed.
  • the slab is heated to 950 ° C. and hot-rolled to a thickness of 5 mm, then heat-treated at 700 ° C. for 2 hours in an air atmosphere, and then descaled on both the front and back surfaces using shot blasting and nitric hydrofluoric acid. Processed.
  • the surface layer portion includes an element derived from a slab (base material).
  • the “surface layer composition” in the table indicates the content of elements that are not included in the slab, and for elements that are also included in the slab, if there is an increase in the content, increase the content. The content is shown, and “ ⁇ ” is shown when there is no increase in content.
  • No. 1 is a case where a surface layer portion (alloy concentrated layer) is not formed, and the impact value after exposure to a hydrogen environment is as low as 14 J / cm 2 .
  • the thickness of the surface layer portion and the Mo equivalent are within the range of the present invention, and the impact value after exposure to a hydrogen environment is 15 J / cm 2 or more and is high.
  • the slab was heated to 850 ° C. and hot-rolled to a thickness of 4.8 to 5.0 mm, and then annealed at 600 to 650 ° C. for 4 to 10 hours in a vacuum atmosphere.
  • descaling treatment was performed on both the front and back surfaces using shot blasting and nitric hydrofluoric acid.
  • Each titanium plate produced above was exposed at 500 ° C. for 5 hours in a 1% by volume H 2 + 99% by volume Ar atmosphere as a hydrogen absorption environment.
  • the alloy element concentration of the surface layers 3 and 4 of each titanium plate is an average value as a result of performing a line analysis on the range from the surface to the lower end of the alloy concentrated portion using EPMA.
  • the remainder is a component contained in industrial pure titanium except for contamination components such as O and C.
  • an impact test piece having a thickness (4.8 to 5.0 mm) ⁇ 10 mm ⁇ 55 mm and 2 mmV notch was prepared.
  • the longitudinal direction of the test piece was the rolling direction, and the notch direction was the plate thickness penetration direction. Hydrogen brittleness was evaluated by impact value.
  • the surface layer portion includes an element derived from a slab (base material).
  • the “surface layer composition” in the table indicates the content of elements that are not included in the slab, and for elements that are also included in the slab, if there is an increase in the content, increase the content. The content is shown, and “ ⁇ ” is shown when there is no increase in content.
  • the thickness of the surface layer portion and the Mo equivalent are within the range of the present invention, and the impact value after exposure to a hydrogen environment is 15 J / cm 2 or more and is high.
  • Titanium materials for hot rolling 1a, 1aa, 1ab.
  • Base material 2. Titanium composite 3,4.

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Abstract

L'invention concerne un matériau de titane pour laminage à chaud (1) qui est équipé d'un matériau de base (1b) constitué d'un titane industriel pur ou d'un alliage de titane, et d'une partie couche superficielle (1a) qui est formée sur au moins une face laminage du matériau de base (1b), et qui possède une composition chimique différente du matériau de base (1b). La partie couche superficielle (1a) est telle que lorsque son épaisseur est comprise entre 2,0 et 20,0mm, que sa proportion par rapport à toute l'épaisseur est inférieure ou égale à 40% pour une face, et que la teneur en éléments chimiques qu'elle contient est mesurée en une pluralité de points, la relation entre la valeur moyenne ＣAVE d'une quantité d'augmentation à partir du matériau de base (1b), et la quantité d'augmentation Ｃ0 à partir du matériau de base (1b) en chaque point de mesure, est telle que |ＣAVE－Ｃ0|／ＣAVE×１００ est inférieur ou égal à 40%. La composition chimique de ladite partie couche superficielle (1a) comprend un élément ou plus choisi parmi Mo, V et Nb, en tant que quantité d'augmentation à partir du matériau de base (1b), et un équivalent Mo est compris entre 8,0 et 20,0. Ce matériau de titane pour laminage à chaud (1) possède les caractéristiques requises indépendamment de son bas coût.
PCT/JP2016/072343 2015-07-29 2016-07-29 Matériau de titane pour laminage à chaud WO2017018521A1 (fr)

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Cited By (1)

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Publication number Priority date Publication date Assignee Title
CN111560539A (zh) * 2020-06-04 2020-08-21 成都先进金属材料产业技术研究院有限公司 一种tb14钛合金熔炼用自耗电极的制备方法

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JP2009041065A (ja) * 2007-08-08 2009-02-26 Nippon Steel Corp 高温疲労強度および耐クリープ性に優れた耐熱部材用チタン合金
WO2014163087A1 (fr) * 2013-04-01 2014-10-09 新日鐵住金株式会社 Pièce coulée de titane pour utilisation dans le laminage à chaud, et son procédé de production
JP2014233753A (ja) * 2013-06-05 2014-12-15 新日鐵住金株式会社 分塊工程や精整工程を省略しても熱間圧延後の表面性状に優れた工業用純チタンインゴットおよびその製造方法

Patent Citations (3)

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Publication number Priority date Publication date Assignee Title
JP2009041065A (ja) * 2007-08-08 2009-02-26 Nippon Steel Corp 高温疲労強度および耐クリープ性に優れた耐熱部材用チタン合金
WO2014163087A1 (fr) * 2013-04-01 2014-10-09 新日鐵住金株式会社 Pièce coulée de titane pour utilisation dans le laminage à chaud, et son procédé de production
JP2014233753A (ja) * 2013-06-05 2014-12-15 新日鐵住金株式会社 分塊工程や精整工程を省略しても熱間圧延後の表面性状に優れた工業用純チタンインゴットおよびその製造方法

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111560539A (zh) * 2020-06-04 2020-08-21 成都先进金属材料产业技术研究院有限公司 一种tb14钛合金熔炼用自耗电极的制备方法

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