WO2012032610A1 - Titanium material - Google Patents
Titanium material Download PDFInfo
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- WO2012032610A1 WO2012032610A1 PCT/JP2010/065369 JP2010065369W WO2012032610A1 WO 2012032610 A1 WO2012032610 A1 WO 2012032610A1 JP 2010065369 W JP2010065369 W JP 2010065369W WO 2012032610 A1 WO2012032610 A1 WO 2012032610A1
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- 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
- C22F1/183—High-melting or refractory metals or alloys based thereon of titanium or alloys based thereon
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- 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
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- 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
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- 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, and more particularly, to a titanium material excellent in strength and workability.
- plate-like or rod-like members formed of materials such as titanium alloys and pure titanium have been widely used.
- plate-like titanium materials hereinafter also referred to as “titanium plates”
- titanium plates are widely used for industrial products, and various processes involving plastic deformation such as bending, overhanging, drawing, etc. are applied to the titanium plates.
- Various products have been formed. Titanium plates subjected to such processing are required to have excellent workability.
- Non-Patent Document 1 below shows the results of evaluating the workability of titanium thin plates having different components and crystal grain sizes by a cylindrical deep drawing test, and the finer the crystal grains, the better the workability.
- Patent Document 1 below discloses a method for producing a pure titanium thin plate, and final annealing is performed by continuous annealing for (600 to 800) ° C. ⁇ (2 to 5) in an air atmosphere. It is described that a pure titanium thin plate having a glossy surface is produced by performing pickling treatment and adjusting the average crystal grain size (hereinafter referred to as grain size) of the product to 3 to 60 ⁇ m.
- Patent Document 2 discloses pure titanium for building materials, a pure titanium plate, and a method for producing the same.
- the oxygen content is 900 ppm or less
- Fe is 100 ppm or more and 600 ppm or less
- Ni and Cr are described.
- Patent Document 2 describes a titanium material for building materials having an average crystal grain size of 70 ⁇ m or less that has been subjected to pickling treatment with a nitric hydrofluoric acid aqueous solution after cold rolling annealing.
- Patent Documents 1 and 2 there is hardly any data evaluated for a crystal grain size of 5 ⁇ m or less, and in Patent Document 2, an example in which the crystal grain size is 3 ⁇ m is shown.
- paragraph [0026] states that “the lower limit is about 5 ⁇ m in actual production”, and there is a negative statement that the crystal grain size should be 5 ⁇ m or less. Yes. This is because these documents aim to obtain an excellent titanium material for building materials with suppressed gloss, and the workability in overhanging, deep drawing, etc. has not been sufficiently studied. it is conceivable that.
- the titanium plate excellent in workability is indicated by the following patent document 4, although these are excellent in workability, the intensity
- Japanese Unexamined Patent Publication No. 63-103056 Japanese Laid-Open Patent Publication No. 9-3573 Japanese Unexamined Patent Publication No. 2006-316323 Japanese Unexamined Patent Publication No. 63-60247
- the present invention has an object to provide a titanium plate having high strength and excellent workability.
- the titanium material can increase strength (yield strength) mainly by adding oxygen (O) or iron (Fe), but if these are added, ductility is lowered and workability is also lowered.
- titanium materials specified in JIS class 1 have low oxygen and iron contents, so titanium plates using this JIS class 1 material generally have low strength (yield strength) but excellent ductility and workability.
- Use of JIS type 2 titanium material, which contains more oxygen and iron than JIS type 1 increases the strength (yield strength) and lowers ductility than titanium material using JIS type 1 titanium material. Tend to decrease.
- JIS type 3 and type 4 having a high oxygen and iron content further increase in strength (yield strength), but further reduce ductility and greatly reduce workability. That is, there is a certain relationship between strength (yield strength) and workability (hereinafter, this relationship is also referred to as “strength (yield strength) -workability” balance).
- plate material and wire which consist of titanium materials are formed by performing the process accompanying plastic deformation, such as rolling and wire drawing.
- plate materials and wires that have undergone processing with plastic deformation have a processed structure formed inside as they are, so a process called finish annealing is performed to recrystallize the structure.
- finish annealing is performed to recrystallize the structure.
- a titanium plate after performing cold rolling or the like to adjust the thickness to a predetermined thickness, batch annealing or continuous annealing is performed to recrystallize the internal processing structure, and equiaxed crystal grains (Hereinafter referred to as “recrystallized grains”) is performed.
- recrystallized grains grow greatly with the lapse of time of annealing, etc., especially immediately after the start of recrystallization with a small recrystallized grain size, the recrystallized grains have a high growth rate and are relatively short in time.
- the particle size becomes larger than 5 ⁇ m.
- the present inventors have adjusted the structure that has not been noticed as a means for improving the strength (proof strength) in the past (by leaving an unrecrystallized part). It was found that the strength (yield strength) of the titanium material can be improved by refining the crystal grains.
- the inventors of the present invention have made a variety of different structures by subjecting an industrial pure titanium plate cold-rolled to a predetermined thickness to finish annealing in vacuum using an electric furnace and changing its temperature and time. These titanium plates were made as prototypes, and their strength (yield strength) and workability (ductility) were evaluated by a tensile test and an Eriksen test to complete the present invention.
- the finer the crystal grains the greater the strength (yield strength), and the workability (Erichsen value) tended to decrease, but the average grain size of the recrystallized grains was below a predetermined size. It has been found that the Erichsen value does not decrease so much and the “strength (yield strength) -workability balance” can be improved as compared with conventional titanium materials.
- the workability (Erichsen value) is reduced, and the “strength (proof stress) -workability balance” can be improved over the conventional titanium material. There was a case where it was not possible.
- the “strength (yield strength) -workability balance” was examined. In particular, when the area ratio of the non-recrystallized portion in the cross-sectional area of the titanium plate exceeded 30%, the workability was improved. We found that it drops extremely.
- the non-recrystallized portion means a portion where a plastically worked structure remains.
- the present invention according to the titanium material for solving the above-mentioned problems is that the iron content is 0.60% by mass or less, the oxygen content is 0.15% by mass or less, and the balance is titanium and inevitable impurities.
- a titanium material having a processed structure formed by processing with plastic deformation, and a recrystallized structure formed by annealing after the processing, and the crystal grains of the recrystallized structure The average grain size is 1 ⁇ m or more and 5 ⁇ m or less, and the area of the non-recrystallized portion occupying the cross-sectional area is more than 0% and 30% or less.
- a titanium material having high strength and excellent workability can be provided.
- the titanium plate in this embodiment has an iron (Fe) content of 0.60 mass% or less, an oxygen (O) content of 0.15 mass% or less, and the balance being titanium (Ti) and inevitable impurities. It is made of material.
- the titanium plate is formed by being annealed after being processed with plastic deformation, and has a processed structure accompanying the processing inside and a recrystallized structure accompanying the annealing, The average grain size of the crystal grains of the recrystallized structure is 1 ⁇ m or more and 5 ⁇ m or less, and the area of the non-recrystallized portion in the cross-sectional area is more than 0% and 30% or less.
- the iron (Fe) is contained at a ratio of 0.60% by mass or less.
- the upper limit of the Fe content is 0.60% by mass in the titanium material
- Fe is a ⁇ -phase stabilizing element, and if the Fe content exceeds 0.60% by mass, the titanium plate is formed. This is because there is a possibility that many ⁇ phases other than the ⁇ phase may be generated in the tissue. That is, depending on the size of the ⁇ phase to be formed, the ductility is greatly reduced or the corrosion resistance is lowered. Therefore, the content of Fe contained in the titanium material forming the titanium plate of this embodiment is reduced to 0. .60 mass% or less is important in terms of forming a titanium plate having high strength and excellent workability.
- the lower limit of the Fe content is not particularly required, but a titanium plate having Fe of less than 0.01% by mass will be manufactured. Then, expensive high purity sponge titanium must be used as a raw material, which may increase the material cost of the titanium plate. Therefore, from the viewpoint of the cost of the titanium plate, the Fe content is preferably set to 0.01% by mass or more and 0.60% by mass or less.
- the titanium plate in the present embodiment can use most of the sponge titanium material by the crawl method when the content of iron is 0.01 to 0.60% by mass. That is, it can be said that the titanium plate in the present embodiment is suitable as a consumer material in that there is almost no restriction on the use site of sponge titanium.
- the oxygen (O) is contained in the titanium material at a content of 0.15% by mass or less.
- the content of O in the titanium material forming the titanium plate of the present embodiment is 0.15% by mass or less because when the O content exceeds 0.15% by mass, the crystal grains are made finer. Titanium plate that is suitable for processing such as overhanging and deep drawing, because there is a possibility that even if it tries to improve the “strength-workability balance”, the strength is too high and the workability may not be sufficiently imparted. Because it becomes difficult to do.
- the lower limit of the O content is not particularly defined, but if the O content in the titanium material constituting the titanium plate is to be less than 0.015% by mass, an expensive high purity sponge titanium is used as a raw material. There is a risk of having to. Therefore, the O content is preferably 0.015% by mass or more and 0.15% by mass or less.
- the content should be less than or equal to JIS type 2. is important. More specifically, it is important that the contents of C, N, and H are each less than 0.02% by mass. More preferably, the C content is 0.01% by mass or less, the N content is 0.01% by mass or less, and the H content is 0.01% by mass or less. From the viewpoint of the workability of the titanium plate, there is no lower limit to the contents of C, N, and H. However, if these contents are extremely reduced, the production cost of the titanium plate is greatly increased. There is a fear. From the viewpoint of suppressing the cost increase, it is preferable that the C content is 0.0005 mass% or more, the N content is 0.0005 mass% or more, and the H content is 0.0005 mass% or more.
- the titanium plate of the present invention has a processed structure and a recrystallized structure therein, and the average grain size of the crystal grains of the recrystallized structure is 1 ⁇ m or more and 5 ⁇ m or less.
- the area of the non-recrystallized portion in the cross-sectional area is formed so as to be more than 0% and not more than 30%.
- the upper limit of the average grain size of the recrystallized structure is set to 5 ⁇ m because when the average crystal grain size of the equiaxed ⁇ grains produced by recrystallization exceeds 5 ⁇ m, the effect of refining the crystal grains This is because it becomes difficult to achieve an excellent “strength-workability balance”.
- the lower limit value is set to 1 ⁇ m, when processing (rolling, forging, etc.) is performed in actual production (industrially practicable method), and then annealing is performed, when the average crystal grain becomes smaller than 1 ⁇ m, This is because the area ratio of the non-recrystallized portion (processed structure) described in (2) increases and the strength becomes very large, but the ductility is greatly reduced and it becomes difficult to realize an excellent “strength-workability balance”.
- the non-recrystallized portion is formed by a processed structure in which the crystal grains are crushed by plastic deformation by processing (cold rolling, forging, etc.), and the strength is improved by leaving the processed structure in the titanium plate. be able to.
- a titanium plate composed of a processed structure formed by cold rolling or the like exhibits high strength while having very low ductility. For this reason, conventionally, it has been practiced to recrystallize the processed structure by annealing to form an equiaxed structure, and a sufficient annealing time is provided so that the processed structure does not remain on the titanium plate.
- the processed structure is left in the titanium plate by employing the annealing conditions described later, and the grain size of the recrystallized grains is as described above. It has been adjusted.
- the non-recrystallized portion (processed structure) is important in that it is provided in such a way that an excellent “strength-workability balance” is provided so that the area ratio in the cross section of the titanium plate is 30% or less.
- the area ratio of the non-recrystallized portion is larger than 30%, the strength of the titanium plate is increased, but the ductility is lowered and it becomes difficult to exhibit excellent workability on the titanium plate. As a result, there is a possibility that an excellent “strength-workability balance” cannot be obtained.
- the area ratio of the non-recrystallized portion is preferably 10% or less.
- the lower limit is not particularly limited, but when there is no unrecrystallized portion (the area ratio becomes 0%), the grain size of the recrystallized grains rapidly increases. Therefore, it is preferable that the area ratio of the non-crystal part is 0.1% or more in that the grain size of the recrystallized grains can be adjusted more surely within the aforementioned range.
- the titanium plate is adjusted to a desired thickness by a general rolling process and then finished under predetermined conditions.
- the method of implementing annealing is mentioned.
- the annealing methods that can be employed in the finish annealing can be broadly classified into a continuous type and a batch type.
- continuous finish annealing is a method of annealing by expanding a cold-rolled coil and passing a titanium plate through the annealing furnace at a constant speed, and the holding time of the heating temperature can be controlled by the passing speed.
- the heating temperature is 700 to 800 ° C.
- the heating time is about several tens of seconds to 2 minutes.
- batch-type finish annealing is a method in which a coil of titanium plate is heated in an annealing furnace in the state of a coil, and it is slowly performed in order to reduce the difference in how heat is applied between the surface layer of the coil and the inside. It is heated and the cooling rate is very slow.
- the heating temperature is 550 to 650 ° C., and the heating time is about 3 to 30 hours.
- the finish annealing performed when producing the titanium plate of the present embodiment for example, in the case of a continuous type, heating is performed at a temperature of 580 ° C. or higher and lower than 600 ° C. for 1 minute or longer and 10 minutes or shorter. It is preferable to carry out the heating under the conditions or at a temperature of 600 ° C. or higher and 650 ° C. or lower for 10 seconds to less than 2 minutes. As this preferable heating condition, the time of 10 seconds or more is selected because when the time for holding the temperature is shorter than 10 seconds, the predetermined annealing is performed on the titanium plate, the plate passing speed, the heating temperature, etc.
- the condition of 10 minutes or less is preferable as the heating time because if the time exceeding 10 minutes is taken, the sheet feeding speed must be slowed, and the productivity is lowered.
- a temperature of 580 ° C. or higher is selected. It is difficult to cause a predetermined recrystallization on the titanium plate with a holding time of 10 minutes or shorter at a heating temperature lower than 580 ° C. This is because the area ratio of the non-recrystallized portion often exceeds 30%.
- the heating temperature of 650 ° C. or lower is selected because the recrystallization of the titanium plate is completed even when the heating temperature is higher than 650 ° C. for 10 seconds, and the recrystallized grains have an average grain size of 5 ⁇ m or more. This is because there is a possibility of growing to a diameter.
- the finish annealing performed when the titanium plate of the present embodiment is manufactured is preferably a heating condition of not less than 3 hours and not more than 50 hours at a temperature of 420 ° C. or more and less than 550 ° C. in the case of a batch type. .
- the heating time is preferably 3 hours or longer because if the heating time is shorter than 3 hours, the temperature inside the coil may not reach a predetermined temperature, depending on the size of the coil. It is.
- the condition of 50 hours or less is preferable as the heating time because if the time exceeding 50 hours is taken, the time required for annealing becomes too long and the productivity of the titanium plate decreases.
- the heating temperature is 420 ° C. or higher. It is difficult to cause predetermined recrystallization on the titanium plate with a holding time of 50 hours or less at a heating temperature lower than 420 ° C. This is because the area ratio often exceeds 30%.
- the time to reach the target temperature varies from several tens of minutes to several hours. For this reason, even if the heating time is slightly different, it is important that the recrystallized grain size does not differ much, that is, it is heated to a temperature range where the growth rate of the recrystallized grains is slow.
- the heating temperature is less than 550 ° C. Since the growth rate of the recrystallized crystal grains is large at a temperature of 550 ° C. or higher, if the heating time is shortened according to the coil surface layer portion, the target is still within the coil. If the heating time is increased according to the inside of the coil, the coil surface layer portion is recrystallized. This is because the grains grow too much and the average crystal grain size may become 5 ⁇ m or more.
- the finish annealing is performed in a vacuum or in an inert gas atmosphere in both continuous and batch processes.
- a titanium plate having an excellent “strength-workability balance” can be obtained by adjusting the average grain size of recrystallization and the remaining ratio of the non-recrystallized portion (worked structure) according to the annealing conditions. Can do.
- a titanium plate is cited as an example of the titanium material.
- the present invention is not limited to the titanium plate. The same applies to various forms of titanium materials such as pipe materials, and these titanium materials are also within the scope of the present invention.
- ⁇ Evaluation 1> (Sample Nos. 1-45) (Production of test piece) An ingot ( ⁇ 140 mm) was produced by small vacuum arc melting, and the ingot was heated to 1050 ° C. and then forged to produce a slab having a thickness of 50 mm. The slab was hot-rolled to a thickness of 5 mm at 850 ° C., and then annealed at 750 ° C., shot and pickled, and the surface scale was removed to prepare a plate material. Further, this plate material was cold-rolled to produce a plate-like sample (titanium plate) having a thickness of 0.5 mm. The 0.5 mm thick titanium plate was subjected to finish annealing for 48 hours or less at a temperature of 400 to 800 ° C. in an argon gas atmosphere to prepare a test piece with adjusted crystal grains.
- Component measurement The amount of iron and the amount of oxygen contained in the titanium plate were measured using the plate material after hot rolling whose surface scale was cut. The iron content was measured according to JIS H1614, and the oxygen content was measured according to JIS H1620.
- test piece titanium plate whose crystal grain size was adjusted as described above was measured according to JIS Z 2241.
- FIG. 1 An example of a structure photograph observed with a transmission electron microscope is shown in FIG. 1 (microstructure of sample No. 28). In this structural photograph, recrystallized ⁇ grains and unrecrystallized parts are shown. (In the photograph shown in FIG.
- Example Nos. A to H (Real machine test) (Production of test coil)
- An ingot ( ⁇ 750 mm) was produced by vacuum arc melting, and the ingot was heated to 850 to 1000 ° C. and then forged to produce a slab having a thickness of 170 mm.
- the slab is heated to a temperature of 850 ° C., then hot-rolled to a thickness of 3.5 mm, and the hot-rolled material is annealed at a temperature of 750 ° C., then shot, pickled, and scaled on the surface.
- the hot rolled coil was produced by removing. This hot rolled coil was cold rolled to form a cold rolled coil having a thickness of 0.4 to 0.8 mm.
- This cold-rolled coil was inserted into a vacuum annealing furnace after washing and removing oils and fats such as cold-rolled oil.
- the inside of the vacuum annealing furnace containing the cold-rolled coil is evacuated, then replaced with argon gas, heated to 450 to 650 ° C. and held for 4 to 36 hours, and recrystallized grains The size of was adjusted. From the obtained titanium plate, “sample measurement”, “tensile strength measurement”, “workability evaluation”, and “structural investigation” are collected in the same size as in the above evaluation 1, and a sample of the required size is collected. Carried out. The results are shown in Table 2.
- Sample No. above. A to E are those in which the average grain size of recrystallized grains is 5 ⁇ m or less, and an unrecrystallized portion is observed in an area ratio of less than 30% in the cross section of the titanium plate.
- F to H are in a state where no non-recrystallized portion remains as in a conventional titanium plate.
- Sample No. above. In A, B, and C a titanium plate excellent in workability having a yield strength of 200 MPaa or more and an Erichsen value of about 13 mm is obtained.
- Sample No. In D and E a high-strength titanium plate having a yield strength of about 400 MPa and a good workability titanium plate having an Erichsen value of about 10 mm is obtained.
- sample no. In F to H although the workability is excellent, the proof stress is smaller than 200 MPa, and the strength is not sufficient. This also shows that according to the present invention, a titanium plate having high strength and excellent workability can be provided.
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Abstract
The present invention addresses the problem of providing a titanium material having high strength and superior workability. To solve this problem, the present invention provides a titanium material having an iron content of 0.60% by mass or less and an oxygen content of 0.15% by mass or less with the remainder being formed from titanium and inevitable impurities. In this titanium material, there are a deformation texture formed by processing that is accompanied by plastic deformation and a recrystallization texture formed by annealing after that processing. The titanium material is formed such that the average grain size of the crystal grains for this recrystallization texture is 1 µm - 5 µm, and the area of the portion of the cross-sectional area that is not recrystallized is greater than 0% and less than or equal to 30%.
Description
本発明は、チタン材に関し、より詳しくは、強度と加工性とに優れたチタン材に関する。
The present invention relates to a titanium material, and more particularly, to a titanium material excellent in strength and workability.
従来、チタン合金や純チタンなどの材料で形成された板状や棒状の部材が広く用いられている。
例えば、工業製品には板状のチタン材（以下「チタン板」ともいう）が、幅広く用いられており、折り曲げ加工、張出し加工、絞り加工などといった塑性変形を伴う種々の加工が前記チタン板に施されて各種の製品が形成されている。
このような加工が施されるチタン板には、優れた加工性が求められている。 Conventionally, plate-like or rod-like members formed of materials such as titanium alloys and pure titanium have been widely used.
For example, plate-like titanium materials (hereinafter also referred to as “titanium plates”) are widely used for industrial products, and various processes involving plastic deformation such as bending, overhanging, drawing, etc. are applied to the titanium plates. Various products have been formed.
Titanium plates subjected to such processing are required to have excellent workability.
例えば、工業製品には板状のチタン材（以下「チタン板」ともいう）が、幅広く用いられており、折り曲げ加工、張出し加工、絞り加工などといった塑性変形を伴う種々の加工が前記チタン板に施されて各種の製品が形成されている。
このような加工が施されるチタン板には、優れた加工性が求められている。 Conventionally, plate-like or rod-like members formed of materials such as titanium alloys and pure titanium have been widely used.
For example, plate-like titanium materials (hereinafter also referred to as “titanium plates”) are widely used for industrial products, and various processes involving plastic deformation such as bending, overhanging, drawing, etc. are applied to the titanium plates. Various products have been formed.
Titanium plates subjected to such processing are required to have excellent workability.
また、最近では、材料コストの低減や、製品の軽量化などの観点からチタン板の薄肉化が求められている。
その結果、チタン板の強度を向上させることが求められるようになってきている。
しかし、従来、チタン板における加工性と強度とはトレードオフの関係にあり、これらを同時に満足させることが困難な状況となっている。
すなわち、従来のチタン板は、耐力が大きくなると、成形加工が難しくなる（加工性が劣る）という問題を有している。 Recently, there has been a demand for thinner titanium plates from the viewpoint of reducing material costs and reducing the weight of products.
As a result, it has been demanded to improve the strength of the titanium plate.
However, conventionally, there is a trade-off relationship between workability and strength in a titanium plate, and it is difficult to satisfy these simultaneously.
That is, the conventional titanium plate has a problem that when the yield strength is increased, the forming process becomes difficult (the workability is inferior).
その結果、チタン板の強度を向上させることが求められるようになってきている。
しかし、従来、チタン板における加工性と強度とはトレードオフの関係にあり、これらを同時に満足させることが困難な状況となっている。
すなわち、従来のチタン板は、耐力が大きくなると、成形加工が難しくなる（加工性が劣る）という問題を有している。 Recently, there has been a demand for thinner titanium plates from the viewpoint of reducing material costs and reducing the weight of products.
As a result, it has been demanded to improve the strength of the titanium plate.
However, conventionally, there is a trade-off relationship between workability and strength in a titanium plate, and it is difficult to satisfy these simultaneously.
That is, the conventional titanium plate has a problem that when the yield strength is increased, the forming process becomes difficult (the workability is inferior).
このことに対し、下記非特許文献１には、成分や結晶粒径の異なるチタン薄板を円筒深絞り試験で加工性を評価した結果が示されており、結晶粒が微細なほど加工性が良好であることが記載されている（第１０３頁、第５行目～）。
そして、下記特許文献１には、純チタン薄板の製造方法が開示されており、最終的な焼鈍を大気雰囲気下、（６００～８００）℃×（２～５）分の連続焼鈍で行い、さらに酸洗処理を施し、製品の平均結晶粒径（以下、粒径という）を３～６０μmに調整して表面の光沢をおさえた純チタン薄板を製造することが記載されている。 On the other hand, Non-Patent Document 1 below shows the results of evaluating the workability of titanium thin plates having different components and crystal grain sizes by a cylindrical deep drawing test, and the finer the crystal grains, the better the workability. (From page 103, line 5).
Patent Document 1 below discloses a method for producing a pure titanium thin plate, and final annealing is performed by continuous annealing for (600 to 800) ° C. × (2 to 5) in an air atmosphere. It is described that a pure titanium thin plate having a glossy surface is produced by performing pickling treatment and adjusting the average crystal grain size (hereinafter referred to as grain size) of the product to 3 to 60 μm.
そして、下記特許文献１には、純チタン薄板の製造方法が開示されており、最終的な焼鈍を大気雰囲気下、（６００～８００）℃×（２～５）分の連続焼鈍で行い、さらに酸洗処理を施し、製品の平均結晶粒径（以下、粒径という）を３～６０μmに調整して表面の光沢をおさえた純チタン薄板を製造することが記載されている。 On the other hand, Non-Patent Document 1 below shows the results of evaluating the workability of titanium thin plates having different components and crystal grain sizes by a cylindrical deep drawing test, and the finer the crystal grains, the better the workability. (From page 103, line 5).
Patent Document 1 below discloses a method for producing a pure titanium thin plate, and final annealing is performed by continuous annealing for (600 to 800) ° C. × (2 to 5) in an air atmosphere. It is described that a pure titanium thin plate having a glossy surface is produced by performing pickling treatment and adjusting the average crystal grain size (hereinafter referred to as grain size) of the product to 3 to 60 μm.
また、下記特許文献２には、建材用純チタン、純チタン板およびその製造方法が開示されており、含有される酸素を９００ｐｐｍ以下、Ｆｅを１００ｐｐｍ以上、６００ｐｐｍ以下とし、さらに、ＮｉとＣｒの含有量の制約された建材用チタン材が記載されている。
また、特許文献２には、冷延焼鈍後に硝フッ酸水溶液で酸洗処理を施した平均結晶粒径７０μｍ以下の建材用チタン材について記載されている。
しかし、この特許文献１、２には、５μｍ以下の微小な結晶粒径のものが評価されたデータが殆ど示されてはおらず、特許文献２において、結晶粒径が３μｍの実施例が示されてはいるものの同時に段落〔００２６〕においては、「実生産上、下限は５μｍ程度となる。」と記載されており、結晶粒径を５μｍ以下とすることに対して否定的な記載がなされている。
これは、これらの文献が、光沢の抑制された建材用として優れたチタン材を得ることを目的としており、張出しや深絞り等における加工性については十分な検討がなされたものではないためであると考えられる。 Patent Document 2 below discloses pure titanium for building materials, a pure titanium plate, and a method for producing the same. The oxygen content is 900 ppm or less, Fe is 100 ppm or more and 600 ppm or less, and further, Ni and Cr. Titanium materials for building materials with limited content are described.
Patent Document 2 describes a titanium material for building materials having an average crystal grain size of 70 μm or less that has been subjected to pickling treatment with a nitric hydrofluoric acid aqueous solution after cold rolling annealing.
However, in Patent Documents 1 and 2, there is hardly any data evaluated for a crystal grain size of 5 μm or less, and in Patent Document 2, an example in which the crystal grain size is 3 μm is shown. However, at the same time, paragraph [0026] states that “the lower limit is about 5 μm in actual production”, and there is a negative statement that the crystal grain size should be 5 μm or less. Yes.
This is because these documents aim to obtain an excellent titanium material for building materials with suppressed gloss, and the workability in overhanging, deep drawing, etc. has not been sufficiently studied. it is conceivable that.
また、特許文献２には、冷延焼鈍後に硝フッ酸水溶液で酸洗処理を施した平均結晶粒径７０μｍ以下の建材用チタン材について記載されている。
しかし、この特許文献１、２には、５μｍ以下の微小な結晶粒径のものが評価されたデータが殆ど示されてはおらず、特許文献２において、結晶粒径が３μｍの実施例が示されてはいるものの同時に段落〔００２６〕においては、「実生産上、下限は５μｍ程度となる。」と記載されており、結晶粒径を５μｍ以下とすることに対して否定的な記載がなされている。
これは、これらの文献が、光沢の抑制された建材用として優れたチタン材を得ることを目的としており、張出しや深絞り等における加工性については十分な検討がなされたものではないためであると考えられる。 Patent Document 2 below discloses pure titanium for building materials, a pure titanium plate, and a method for producing the same. The oxygen content is 900 ppm or less, Fe is 100 ppm or more and 600 ppm or less, and further, Ni and Cr. Titanium materials for building materials with limited content are described.
Patent Document 2 describes a titanium material for building materials having an average crystal grain size of 70 μm or less that has been subjected to pickling treatment with a nitric hydrofluoric acid aqueous solution after cold rolling annealing.
However, in Patent Documents 1 and 2, there is hardly any data evaluated for a crystal grain size of 5 μm or less, and in Patent Document 2, an example in which the crystal grain size is 3 μm is shown. However, at the same time, paragraph [0026] states that “the lower limit is about 5 μm in actual production”, and there is a negative statement that the crystal grain size should be 5 μm or less. Yes.
This is because these documents aim to obtain an excellent titanium material for building materials with suppressed gloss, and the workability in overhanging, deep drawing, etc. has not been sufficiently studied. it is conceivable that.
また、下記特許文献４には、加工性に優れたチタン板が開示されているが、これらは加工性には優れるものの強度（耐力）が低く、加工性と強度とを両立させ得るものではない。
Moreover, although the titanium plate excellent in workability is indicated by the following patent document 4, although these are excellent in workability, the intensity | strength (yield strength) is low, and it cannot make workability and intensity | strength compatible. .
本発明は、高強度であり、しかも、加工性に優れたチタン板の提供を課題としている。
The present invention has an object to provide a titanium plate having high strength and excellent workability.
チタン材は、主に酸素（Ｏ）や鉄（Ｆｅ）を添加して強度（耐力）を大きくすることができるが、これらを添加すると延性が低下して加工性も低下する。
たとえば、ＪＩＳ１種に規定されているチタン材料では、酸素や鉄の含有量が少ないため、このＪＩＳ１種の材料を用いたチタン板は、一般に強度（耐力）は低いが延性に優れ、加工性に優れている。
このＪＩＳ１種よりも酸素や鉄の含有量が多いＪＩＳ２種のチタン材料を用いると、ＪＩＳ１種のチタン材料が用いられたチタン材よりも強度（耐力）が大きくなる一方で延性が低下して加工性が低下する傾向にある。
さらに酸素や鉄の含有量が多いＪＩＳ３種や４種は、さらに強度（耐力）が大きくなるが延性はさらに低下して加工性が大きく低下する。
すなわち、強度（耐力）と加工性はある一定の関係がある（以下、この関係を「強度（耐力）－加工性」バランスともいう）。 The titanium material can increase strength (yield strength) mainly by adding oxygen (O) or iron (Fe), but if these are added, ductility is lowered and workability is also lowered.
For example, titanium materials specified in JIS class 1 have low oxygen and iron contents, so titanium plates using this JIS class 1 material generally have low strength (yield strength) but excellent ductility and workability. Are better.
Use of JIS type 2 titanium material, which contains more oxygen and iron than JIS type 1, increases the strength (yield strength) and lowers ductility than titanium material using JIS type 1 titanium material. Tend to decrease.
Furthermore, JIS type 3 and type 4 having a high oxygen and iron content further increase in strength (yield strength), but further reduce ductility and greatly reduce workability.
That is, there is a certain relationship between strength (yield strength) and workability (hereinafter, this relationship is also referred to as “strength (yield strength) -workability” balance).
たとえば、ＪＩＳ１種に規定されているチタン材料では、酸素や鉄の含有量が少ないため、このＪＩＳ１種の材料を用いたチタン板は、一般に強度（耐力）は低いが延性に優れ、加工性に優れている。
このＪＩＳ１種よりも酸素や鉄の含有量が多いＪＩＳ２種のチタン材料を用いると、ＪＩＳ１種のチタン材料が用いられたチタン材よりも強度（耐力）が大きくなる一方で延性が低下して加工性が低下する傾向にある。
さらに酸素や鉄の含有量が多いＪＩＳ３種や４種は、さらに強度（耐力）が大きくなるが延性はさらに低下して加工性が大きく低下する。
すなわち、強度（耐力）と加工性はある一定の関係がある（以下、この関係を「強度（耐力）－加工性」バランスともいう）。 The titanium material can increase strength (yield strength) mainly by adding oxygen (O) or iron (Fe), but if these are added, ductility is lowered and workability is also lowered.
For example, titanium materials specified in JIS class 1 have low oxygen and iron contents, so titanium plates using this JIS class 1 material generally have low strength (yield strength) but excellent ductility and workability. Are better.
Use of JIS type 2 titanium material, which contains more oxygen and iron than JIS type 1, increases the strength (yield strength) and lowers ductility than titanium material using JIS type 1 titanium material. Tend to decrease.
Furthermore, JIS type 3 and type 4 having a high oxygen and iron content further increase in strength (yield strength), but further reduce ductility and greatly reduce workability.
That is, there is a certain relationship between strength (yield strength) and workability (hereinafter, this relationship is also referred to as “strength (yield strength) -workability” balance).
ところで、チタン材料が用いられてなる板材や線材は、圧延や線引といった塑性変形を伴う加工が施されて形成されている。
このような塑性変形を伴う加工が施された板材や線材は、通常、そのままの状態では内部に加工組織が形成されていることから、組織の再結晶化を行うべく仕上げ焼鈍と呼ばれる工程が実施されて市場に提供されている。
例えば、チタン板であれば、冷間圧延等の加工を行って所定の厚みに調整した後にバッチ焼鈍や連続焼鈍などを実施して、内部の加工組織を再結晶化させ等軸状の結晶粒（以下、「再結晶粒」という）を形成させることが行われている。
そして、この再結晶粒は、焼鈍の時間経過などに伴って大きく成長し、特に再結晶粒の粒径が小さな再結晶開始直後においては、再結晶粒の成長速度が大きく、比較的短時間に５μｍを超える大きな粒径となってしまう。
そして、このような大きさにまで再結晶粒が成長すると、通常、未再結晶部（加工組織）が残存しておらず再結晶粒による等軸状の組織のみがチタン材内部に形成されることとなる。 By the way, the board | plate material and wire which consist of titanium materials are formed by performing the process accompanying plastic deformation, such as rolling and wire drawing.
Usually, plate materials and wires that have undergone processing with plastic deformation have a processed structure formed inside as they are, so a process called finish annealing is performed to recrystallize the structure. Has been offered to the market.
For example, in the case of a titanium plate, after performing cold rolling or the like to adjust the thickness to a predetermined thickness, batch annealing or continuous annealing is performed to recrystallize the internal processing structure, and equiaxed crystal grains (Hereinafter referred to as “recrystallized grains”) is performed.
These recrystallized grains grow greatly with the lapse of time of annealing, etc., especially immediately after the start of recrystallization with a small recrystallized grain size, the recrystallized grains have a high growth rate and are relatively short in time. The particle size becomes larger than 5 μm.
When the recrystallized grains grow to such a size, normally, no unrecrystallized portion (processed structure) remains, and only an equiaxed structure formed by the recrystallized grains is formed inside the titanium material. It will be.
このような塑性変形を伴う加工が施された板材や線材は、通常、そのままの状態では内部に加工組織が形成されていることから、組織の再結晶化を行うべく仕上げ焼鈍と呼ばれる工程が実施されて市場に提供されている。
例えば、チタン板であれば、冷間圧延等の加工を行って所定の厚みに調整した後にバッチ焼鈍や連続焼鈍などを実施して、内部の加工組織を再結晶化させ等軸状の結晶粒（以下、「再結晶粒」という）を形成させることが行われている。
そして、この再結晶粒は、焼鈍の時間経過などに伴って大きく成長し、特に再結晶粒の粒径が小さな再結晶開始直後においては、再結晶粒の成長速度が大きく、比較的短時間に５μｍを超える大きな粒径となってしまう。
そして、このような大きさにまで再結晶粒が成長すると、通常、未再結晶部（加工組織）が残存しておらず再結晶粒による等軸状の組織のみがチタン材内部に形成されることとなる。 By the way, the board | plate material and wire which consist of titanium materials are formed by performing the process accompanying plastic deformation, such as rolling and wire drawing.
Usually, plate materials and wires that have undergone processing with plastic deformation have a processed structure formed inside as they are, so a process called finish annealing is performed to recrystallize the structure. Has been offered to the market.
For example, in the case of a titanium plate, after performing cold rolling or the like to adjust the thickness to a predetermined thickness, batch annealing or continuous annealing is performed to recrystallize the internal processing structure, and equiaxed crystal grains (Hereinafter referred to as “recrystallized grains”) is performed.
These recrystallized grains grow greatly with the lapse of time of annealing, etc., especially immediately after the start of recrystallization with a small recrystallized grain size, the recrystallized grains have a high growth rate and are relatively short in time. The particle size becomes larger than 5 μm.
When the recrystallized grains grow to such a size, normally, no unrecrystallized portion (processed structure) remains, and only an equiaxed structure formed by the recrystallized grains is formed inside the titanium material. It will be.
本発明者らは、先述のような課題に対して鋭意検討を行った結果、従来強度（耐力）を向上させる手段として着目されることがなかった組織の調整（未再結晶部を残すことでの結晶粒の微細化）によってチタン材の強度（耐力）の向上を図りうることを見出した。
具体的には、本発明者らは、所定の厚みにまで冷延した工業用純チタン板を、電気炉を用いて真空中で仕上げ焼鈍し、その温度及び時間を変更して組織の異なる種々のチタン板を試作し、これらの強度（耐力）と加工性（延性）を引張試験及びエリクセン試験によって評価し本発明を完成させた。 As a result of earnest studies on the problems as described above, the present inventors have adjusted the structure that has not been noticed as a means for improving the strength (proof strength) in the past (by leaving an unrecrystallized part). It was found that the strength (yield strength) of the titanium material can be improved by refining the crystal grains.
Specifically, the inventors of the present invention have made a variety of different structures by subjecting an industrial pure titanium plate cold-rolled to a predetermined thickness to finish annealing in vacuum using an electric furnace and changing its temperature and time. These titanium plates were made as prototypes, and their strength (yield strength) and workability (ductility) were evaluated by a tensile test and an Eriksen test to complete the present invention.
具体的には、本発明者らは、所定の厚みにまで冷延した工業用純チタン板を、電気炉を用いて真空中で仕上げ焼鈍し、その温度及び時間を変更して組織の異なる種々のチタン板を試作し、これらの強度（耐力）と加工性（延性）を引張試験及びエリクセン試験によって評価し本発明を完成させた。 As a result of earnest studies on the problems as described above, the present inventors have adjusted the structure that has not been noticed as a means for improving the strength (proof strength) in the past (by leaving an unrecrystallized part). It was found that the strength (yield strength) of the titanium material can be improved by refining the crystal grains.
Specifically, the inventors of the present invention have made a variety of different structures by subjecting an industrial pure titanium plate cold-rolled to a predetermined thickness to finish annealing in vacuum using an electric furnace and changing its temperature and time. These titanium plates were made as prototypes, and their strength (yield strength) and workability (ductility) were evaluated by a tensile test and an Eriksen test to complete the present invention.
その評価の結果においては、結晶粒が細かいほど強度（耐力）が大きくなり、加工性（エリクセン値）は低下する傾向にあったものの再結晶粒の平均粒径が所定の大きさ以下であれば、エリクセン値があまり低下せず、「強度（耐力）－加工性バランス」を従来のチタン材に比べて向上させ得ることが見出された。
As a result of the evaluation, the finer the crystal grains, the greater the strength (yield strength), and the workability (Erichsen value) tended to decrease, but the average grain size of the recrystallized grains was below a predetermined size. It has been found that the Erichsen value does not decrease so much and the “strength (yield strength) -workability balance” can be improved as compared with conventional titanium materials.
また、再結晶粒の平均結晶粒径が所定以下であっても加工性（エリクセン値）が低下してしまって「強度（耐力）－加工性バランス」を従来のチタン材よりも向上させることが出来ない場合があった。
そして、このチタン板のミクロ組織を詳細に調査した結果、仕上げ焼鈍により再結晶した粒の他に、未再結晶部が多く認められた。
この未再結晶部の量に基づいて「強度（耐力）－加工性バランス」を検討したところ、特に、チタン板の断面積に占める未再結晶部の面積率が３０％を超えると加工性が極端に低下することを見出した。
なお、ここで未再結晶部とは、塑性加工された加工組織が残存している部分を意味する。 In addition, even if the average crystal grain size of the recrystallized grains is below a predetermined value, the workability (Erichsen value) is reduced, and the “strength (proof stress) -workability balance” can be improved over the conventional titanium material. There was a case where it was not possible.
As a result of detailed investigation of the microstructure of the titanium plate, many non-recrystallized portions were recognized in addition to the grains recrystallized by finish annealing.
Based on the amount of the non-recrystallized portion, the “strength (yield strength) -workability balance” was examined. In particular, when the area ratio of the non-recrystallized portion in the cross-sectional area of the titanium plate exceeded 30%, the workability was improved. We found that it drops extremely.
Here, the non-recrystallized portion means a portion where a plastically worked structure remains.
そして、このチタン板のミクロ組織を詳細に調査した結果、仕上げ焼鈍により再結晶した粒の他に、未再結晶部が多く認められた。
この未再結晶部の量に基づいて「強度（耐力）－加工性バランス」を検討したところ、特に、チタン板の断面積に占める未再結晶部の面積率が３０％を超えると加工性が極端に低下することを見出した。
なお、ここで未再結晶部とは、塑性加工された加工組織が残存している部分を意味する。 In addition, even if the average crystal grain size of the recrystallized grains is below a predetermined value, the workability (Erichsen value) is reduced, and the “strength (proof stress) -workability balance” can be improved over the conventional titanium material. There was a case where it was not possible.
As a result of detailed investigation of the microstructure of the titanium plate, many non-recrystallized portions were recognized in addition to the grains recrystallized by finish annealing.
Based on the amount of the non-recrystallized portion, the “strength (yield strength) -workability balance” was examined. In particular, when the area ratio of the non-recrystallized portion in the cross-sectional area of the titanium plate exceeded 30%, the workability was improved. We found that it drops extremely.
Here, the non-recrystallized portion means a portion where a plastically worked structure remains.
すなわち、前記課題を解決するためのチタン材にかかる本発明は、鉄の含有量が０．６０質量％以下、酸素の含有量が０．１５質量％以下であり、残部がチタンおよび不可避不純物からなるチタン材であって、塑性変形を伴う加工が施されて形成された加工組織と、前記加工後に焼鈍が施されて形成された再結晶組織とを有し、該再結晶組織の結晶粒の平均粒径が１μｍ以上５μｍ以下であり、断面積に占める未再結晶部の面積が０％を超え３０％以下となるように形成されていることを特徴としている。
That is, the present invention according to the titanium material for solving the above-mentioned problems is that the iron content is 0.60% by mass or less, the oxygen content is 0.15% by mass or less, and the balance is titanium and inevitable impurities. A titanium material having a processed structure formed by processing with plastic deformation, and a recrystallized structure formed by annealing after the processing, and the crystal grains of the recrystallized structure The average grain size is 1 μm or more and 5 μm or less, and the area of the non-recrystallized portion occupying the cross-sectional area is more than 0% and 30% or less.
本発明によれば、高強度であり、しかも、加工性に優れたチタン材を提供し得る。
According to the present invention, a titanium material having high strength and excellent workability can be provided.
以下に、本発明に係るチタン材の好ましい実施の形態についてチタン板を例に説明する。
本実施形態におけるチタン板は、鉄（Ｆｅ）の含有量が０．６０質量％以下、酸素（Ｏ）の含有量が０．１５質量％以下、残部がチタン（Ｔｉ）および不可避不純物からなるチタン材料によって形成されている。
該チタン板は、塑性変形を伴う加工が施された後に焼鈍が施されて形成されたものであり、内部に前記加工に伴う加工組織と、前記焼鈍にともなう再結晶組織とを有し、しかも、該再結晶組織の結晶粒の平均粒径が１μｍ以上５μｍ以下であるとともにその断面積に占める未再結晶部の面積が０％を超え３０％以下となるように形成されている。 Hereinafter, a preferred embodiment of the titanium material according to the present invention will be described using a titanium plate as an example.
The titanium plate in this embodiment has an iron (Fe) content of 0.60 mass% or less, an oxygen (O) content of 0.15 mass% or less, and the balance being titanium (Ti) and inevitable impurities. It is made of material.
The titanium plate is formed by being annealed after being processed with plastic deformation, and has a processed structure accompanying the processing inside and a recrystallized structure accompanying the annealing, The average grain size of the crystal grains of the recrystallized structure is 1 μm or more and 5 μm or less, and the area of the non-recrystallized portion in the cross-sectional area is more than 0% and 30% or less.
本実施形態におけるチタン板は、鉄（Ｆｅ）の含有量が０．６０質量％以下、酸素（Ｏ）の含有量が０．１５質量％以下、残部がチタン（Ｔｉ）および不可避不純物からなるチタン材料によって形成されている。
該チタン板は、塑性変形を伴う加工が施された後に焼鈍が施されて形成されたものであり、内部に前記加工に伴う加工組織と、前記焼鈍にともなう再結晶組織とを有し、しかも、該再結晶組織の結晶粒の平均粒径が１μｍ以上５μｍ以下であるとともにその断面積に占める未再結晶部の面積が０％を超え３０％以下となるように形成されている。 Hereinafter, a preferred embodiment of the titanium material according to the present invention will be described using a titanium plate as an example.
The titanium plate in this embodiment has an iron (Fe) content of 0.60 mass% or less, an oxygen (O) content of 0.15 mass% or less, and the balance being titanium (Ti) and inevitable impurities. It is made of material.
The titanium plate is formed by being annealed after being processed with plastic deformation, and has a processed structure accompanying the processing inside and a recrystallized structure accompanying the annealing, The average grain size of the crystal grains of the recrystallized structure is 1 μm or more and 5 μm or less, and the area of the non-recrystallized portion in the cross-sectional area is more than 0% and 30% or less.
上記のように前記鉄（Ｆｅ）は、０．６０質量％以下となる割合で含有されている。
なお、Ｆｅの含有量の上限値が０．６０質量％であるのは、チタン材料において、Ｆｅはβ相安定化元素でありＦｅの含有量が０．６０質量％を超えるとチタン板を構成する組織においてα相以外にβ相が多く生成されるおそれを有するためである。
すなわち、形成されるβ相の大きさによっては、延性を大きく低下させたり、耐食性を低下させたりするため、本実施形態のチタン板を形成しているチタン材料に含まれるＦｅの含有量を０．６０質量％以下とすることが高強度且つ加工性に優れたチタン板を形成させるという点において重要である。 As described above, the iron (Fe) is contained at a ratio of 0.60% by mass or less.
Note that the upper limit of the Fe content is 0.60% by mass in the titanium material, Fe is a β-phase stabilizing element, and if the Fe content exceeds 0.60% by mass, the titanium plate is formed. This is because there is a possibility that many β phases other than the α phase may be generated in the tissue.
That is, depending on the size of the β phase to be formed, the ductility is greatly reduced or the corrosion resistance is lowered. Therefore, the content of Fe contained in the titanium material forming the titanium plate of this embodiment is reduced to 0. .60 mass% or less is important in terms of forming a titanium plate having high strength and excellent workability.
なお、Ｆｅの含有量の上限値が０．６０質量％であるのは、チタン材料において、Ｆｅはβ相安定化元素でありＦｅの含有量が０．６０質量％を超えるとチタン板を構成する組織においてα相以外にβ相が多く生成されるおそれを有するためである。
すなわち、形成されるβ相の大きさによっては、延性を大きく低下させたり、耐食性を低下させたりするため、本実施形態のチタン板を形成しているチタン材料に含まれるＦｅの含有量を０．６０質量％以下とすることが高強度且つ加工性に優れたチタン板を形成させるという点において重要である。 As described above, the iron (Fe) is contained at a ratio of 0.60% by mass or less.
Note that the upper limit of the Fe content is 0.60% by mass in the titanium material, Fe is a β-phase stabilizing element, and if the Fe content exceeds 0.60% by mass, the titanium plate is formed. This is because there is a possibility that many β phases other than the α phase may be generated in the tissue.
That is, depending on the size of the β phase to be formed, the ductility is greatly reduced or the corrosion resistance is lowered. Therefore, the content of Fe contained in the titanium material forming the titanium plate of this embodiment is reduced to 0. .60 mass% or less is important in terms of forming a titanium plate having high strength and excellent workability.
なお、高強度且つ加工性に優れたチタン板を形成させるという点においては、Ｆｅの含有量における下限値が特に求められるものではないが、Ｆｅが０．０１質量％未満のチタン板を製造しようとすると高価な高純度のスポンジチタンを原料としなければならず、チタン板の材料コストを増大させてしまうおそれを有する。
したがって、チタン板のコストなどの観点からは、Ｆｅの含有量が０．０１質量％以上０．６０質量％以下とされることが好ましい。 In addition, in terms of forming a titanium plate having high strength and excellent workability, the lower limit of the Fe content is not particularly required, but a titanium plate having Fe of less than 0.01% by mass will be manufactured. Then, expensive high purity sponge titanium must be used as a raw material, which may increase the material cost of the titanium plate.
Therefore, from the viewpoint of the cost of the titanium plate, the Fe content is preferably set to 0.01% by mass or more and 0.60% by mass or less.
したがって、チタン板のコストなどの観点からは、Ｆｅの含有量が０．０１質量％以上０．６０質量％以下とされることが好ましい。 In addition, in terms of forming a titanium plate having high strength and excellent workability, the lower limit of the Fe content is not particularly required, but a titanium plate having Fe of less than 0.01% by mass will be manufactured. Then, expensive high purity sponge titanium must be used as a raw material, which may increase the material cost of the titanium plate.
Therefore, from the viewpoint of the cost of the titanium plate, the Fe content is preferably set to 0.01% by mass or more and 0.60% by mass or less.
例えば、クロール法においては、通常、０．６０質量％以上のＦｅ含有量を示すチタン材料は、容器の近くの僅かな領域にしか形成されない。
したがって、本実施形態におけるチタン板は、その成分として鉄の含有量が、０．０１～０．６０質量％とされることで、クロール法によるスポンジチタンの殆どの材料が利用可能である。
すなわち、本実施形態におけるチタン板は、スポンジチタンの使用部位に殆ど制約が加えられないという点において消費材として好適なものであるといえる。 For example, in the crawl method, a titanium material having an Fe content of 0.60% by mass or more is usually formed only in a small region near the container.
Therefore, the titanium plate in the present embodiment can use most of the sponge titanium material by the crawl method when the content of iron is 0.01 to 0.60% by mass.
That is, it can be said that the titanium plate in the present embodiment is suitable as a consumer material in that there is almost no restriction on the use site of sponge titanium.
したがって、本実施形態におけるチタン板は、その成分として鉄の含有量が、０．０１～０．６０質量％とされることで、クロール法によるスポンジチタンの殆どの材料が利用可能である。
すなわち、本実施形態におけるチタン板は、スポンジチタンの使用部位に殆ど制約が加えられないという点において消費材として好適なものであるといえる。 For example, in the crawl method, a titanium material having an Fe content of 0.60% by mass or more is usually formed only in a small region near the container.
Therefore, the titanium plate in the present embodiment can use most of the sponge titanium material by the crawl method when the content of iron is 0.01 to 0.60% by mass.
That is, it can be said that the titanium plate in the present embodiment is suitable as a consumer material in that there is almost no restriction on the use site of sponge titanium.
前記酸素（Ｏ）は、チタン材料中に０．１５質量％以下の含有量で含まれる。
本実施形態のチタン板を形成しているチタン材料中のＯ含有量が０．１５質量％以下とされているのは、Ｏ含有量が０．１５質量％を超えると、結晶粒を細かくして「強度－加工性バランス」の向上を図ろうとしても、強度が向上し過ぎるあまりに加工性の付与が十分なものとならないおそれを有し、張出しや深絞り等の加工に適したチタン板とすることが難しくなるためである。 The oxygen (O) is contained in the titanium material at a content of 0.15% by mass or less.
The content of O in the titanium material forming the titanium plate of the present embodiment is 0.15% by mass or less because when the O content exceeds 0.15% by mass, the crystal grains are made finer. Titanium plate that is suitable for processing such as overhanging and deep drawing, because there is a possibility that even if it tries to improve the “strength-workability balance”, the strength is too high and the workability may not be sufficiently imparted. Because it becomes difficult to do.
本実施形態のチタン板を形成しているチタン材料中のＯ含有量が０．１５質量％以下とされているのは、Ｏ含有量が０．１５質量％を超えると、結晶粒を細かくして「強度－加工性バランス」の向上を図ろうとしても、強度が向上し過ぎるあまりに加工性の付与が十分なものとならないおそれを有し、張出しや深絞り等の加工に適したチタン板とすることが難しくなるためである。 The oxygen (O) is contained in the titanium material at a content of 0.15% by mass or less.
The content of O in the titanium material forming the titanium plate of the present embodiment is 0.15% by mass or less because when the O content exceeds 0.15% by mass, the crystal grains are made finer. Titanium plate that is suitable for processing such as overhanging and deep drawing, because there is a possibility that even if it tries to improve the “strength-workability balance”, the strength is too high and the workability may not be sufficiently imparted. Because it becomes difficult to do.
なお、Ｏ含有量の下限量は特に定めるものではないが、チタン板を構成するチタン材料におけるＯ含有量を０．０１５質量％未満にしようとすると高価な高純度のスポンジチタンを原料として製造しなければならなくなるおそれを有する。
したがって、Ｏ含有量は、０．０１５質量％以上０．１５質量％以下であることが好ましい。 The lower limit of the O content is not particularly defined, but if the O content in the titanium material constituting the titanium plate is to be less than 0.015% by mass, an expensive high purity sponge titanium is used as a raw material. There is a risk of having to.
Therefore, the O content is preferably 0.015% by mass or more and 0.15% by mass or less.
したがって、Ｏ含有量は、０．０１５質量％以上０．１５質量％以下であることが好ましい。 The lower limit of the O content is not particularly defined, but if the O content in the titanium material constituting the titanium plate is to be less than 0.015% by mass, an expensive high purity sponge titanium is used as a raw material. There is a risk of having to.
Therefore, the O content is preferably 0.015% by mass or more and 0.15% by mass or less.
また、炭素（Ｃ）、窒素（Ｎ）、水素（Ｈ）などの不可避不純物については、成形加工における良好なる加工性を確保する目的からは、ＪＩＳ ２種に相当する含有量以下とされることが重要である。
より具体的には、Ｃ、Ｎ、Ｈの含有量は、それぞれ、０．０２質量％未満とされることが重要である。
さらに、好ましくは、Ｃの含有量を０．０１質量％以下、Ｎの含有量を０．０１質量％以下、Ｈの含有量を０．０１質量％以下とすることが好ましい。
チタン板の加工性の観点からは、上記Ｃ、Ｎ、Ｈの含有量に下限を定めるものではないが、これらの含有量を極端に低下させようとするとチタン板の製造コストを大幅に増大させるおそれがある。
このコストアップ抑制の観点からは、Ｃ含有量を０．０００５質量％以上、Ｎの含有量を０．０００５質量％以上、Ｈの含有量を０．０００５質量％以上とすることが好ましい。 In addition, for inevitable impurities such as carbon (C), nitrogen (N), and hydrogen (H), for the purpose of ensuring good processability in the molding process, the content should be less than or equal to JIS type 2. is important.
More specifically, it is important that the contents of C, N, and H are each less than 0.02% by mass.
More preferably, the C content is 0.01% by mass or less, the N content is 0.01% by mass or less, and the H content is 0.01% by mass or less.
From the viewpoint of the workability of the titanium plate, there is no lower limit to the contents of C, N, and H. However, if these contents are extremely reduced, the production cost of the titanium plate is greatly increased. There is a fear.
From the viewpoint of suppressing the cost increase, it is preferable that the C content is 0.0005 mass% or more, the N content is 0.0005 mass% or more, and the H content is 0.0005 mass% or more.
より具体的には、Ｃ、Ｎ、Ｈの含有量は、それぞれ、０．０２質量％未満とされることが重要である。
さらに、好ましくは、Ｃの含有量を０．０１質量％以下、Ｎの含有量を０．０１質量％以下、Ｈの含有量を０．０１質量％以下とすることが好ましい。
チタン板の加工性の観点からは、上記Ｃ、Ｎ、Ｈの含有量に下限を定めるものではないが、これらの含有量を極端に低下させようとするとチタン板の製造コストを大幅に増大させるおそれがある。
このコストアップ抑制の観点からは、Ｃ含有量を０．０００５質量％以上、Ｎの含有量を０．０００５質量％以上、Ｈの含有量を０．０００５質量％以上とすることが好ましい。 In addition, for inevitable impurities such as carbon (C), nitrogen (N), and hydrogen (H), for the purpose of ensuring good processability in the molding process, the content should be less than or equal to JIS type 2. is important.
More specifically, it is important that the contents of C, N, and H are each less than 0.02% by mass.
More preferably, the C content is 0.01% by mass or less, the N content is 0.01% by mass or less, and the H content is 0.01% by mass or less.
From the viewpoint of the workability of the titanium plate, there is no lower limit to the contents of C, N, and H. However, if these contents are extremely reduced, the production cost of the titanium plate is greatly increased. There is a fear.
From the viewpoint of suppressing the cost increase, it is preferable that the C content is 0.0005 mass% or more, the N content is 0.0005 mass% or more, and the H content is 0.0005 mass% or more.
上記に示したように、本発明のチタン板は、内部に加工組織と、再結晶組織とを有し、しかも、該再結晶組織の結晶粒の平均粒径が１μｍ以上５μｍ以下であるとともにその断面積に占める未再結晶部の面積が０％を超え３０％以下となるように形成されている。
As described above, the titanium plate of the present invention has a processed structure and a recrystallized structure therein, and the average grain size of the crystal grains of the recrystallized structure is 1 μm or more and 5 μm or less. The area of the non-recrystallized portion in the cross-sectional area is formed so as to be more than 0% and not more than 30%.
前記再結晶組織の平均粒径の上限値が５μｍとされているのは、再結晶して生成する等軸状のα粒の平均結晶粒径が、５μｍを超えると結晶粒の微細化の効果が小さくなり、優れた「強度－加工性バランス」を実現させることが難しくなるためである。
また、下限値が１μｍとされているのは実生産上（工業的に実施可能な方法）で加工（圧延、鍛造等）を行い、その後焼鈍する場合において平均結晶粒が１μｍより小さくなると、後段において述べる未再結晶部（加工組織）の面積率が多くなり、強度が非常に大きくなるが、延性が大きく低下し優れた「強度－加工性バランス」を実現させることが難しくなるためである。 The upper limit of the average grain size of the recrystallized structure is set to 5 μm because when the average crystal grain size of the equiaxed α grains produced by recrystallization exceeds 5 μm, the effect of refining the crystal grains This is because it becomes difficult to achieve an excellent “strength-workability balance”.
In addition, the lower limit value is set to 1 μm, when processing (rolling, forging, etc.) is performed in actual production (industrially practicable method), and then annealing is performed, when the average crystal grain becomes smaller than 1 μm, This is because the area ratio of the non-recrystallized portion (processed structure) described in (2) increases and the strength becomes very large, but the ductility is greatly reduced and it becomes difficult to realize an excellent “strength-workability balance”.
また、下限値が１μｍとされているのは実生産上（工業的に実施可能な方法）で加工（圧延、鍛造等）を行い、その後焼鈍する場合において平均結晶粒が１μｍより小さくなると、後段において述べる未再結晶部（加工組織）の面積率が多くなり、強度が非常に大きくなるが、延性が大きく低下し優れた「強度－加工性バランス」を実現させることが難しくなるためである。 The upper limit of the average grain size of the recrystallized structure is set to 5 μm because when the average crystal grain size of the equiaxed α grains produced by recrystallization exceeds 5 μm, the effect of refining the crystal grains This is because it becomes difficult to achieve an excellent “strength-workability balance”.
In addition, the lower limit value is set to 1 μm, when processing (rolling, forging, etc.) is performed in actual production (industrially practicable method), and then annealing is performed, when the average crystal grain becomes smaller than 1 μm, This is because the area ratio of the non-recrystallized portion (processed structure) described in (2) increases and the strength becomes very large, but the ductility is greatly reduced and it becomes difficult to realize an excellent “strength-workability balance”.
前記未再結晶部は、加工（冷延や鍛造等）により塑性変形し、結晶粒がつぶれた加工組織で形成されており、該加工組織をチタン板中に残存させることによってその強度を向上させることができる。
冷延等によって形成された加工組織で構成されているチタン板は、高い強度を示す一方で延性が非常に小さい。
そのため、従来は焼鈍によって加工組織を再結晶化させて等軸状の組織にすることが行われており、チタン板に加工組織が残存されない程度に十分な焼鈍時間が設けられていた。
一方で、本実施形態におけるチタン板には、後段において述べるような焼鈍条件を採用することによって前記加工組織をチタン板中に残存されており、しかも、再結晶粒の粒径が上記のように調整されている。 The non-recrystallized portion is formed by a processed structure in which the crystal grains are crushed by plastic deformation by processing (cold rolling, forging, etc.), and the strength is improved by leaving the processed structure in the titanium plate. be able to.
A titanium plate composed of a processed structure formed by cold rolling or the like exhibits high strength while having very low ductility.
For this reason, conventionally, it has been practiced to recrystallize the processed structure by annealing to form an equiaxed structure, and a sufficient annealing time is provided so that the processed structure does not remain on the titanium plate.
On the other hand, in the titanium plate in the present embodiment, the processed structure is left in the titanium plate by employing the annealing conditions described later, and the grain size of the recrystallized grains is as described above. It has been adjusted.
冷延等によって形成された加工組織で構成されているチタン板は、高い強度を示す一方で延性が非常に小さい。
そのため、従来は焼鈍によって加工組織を再結晶化させて等軸状の組織にすることが行われており、チタン板に加工組織が残存されない程度に十分な焼鈍時間が設けられていた。
一方で、本実施形態におけるチタン板には、後段において述べるような焼鈍条件を採用することによって前記加工組織をチタン板中に残存されており、しかも、再結晶粒の粒径が上記のように調整されている。 The non-recrystallized portion is formed by a processed structure in which the crystal grains are crushed by plastic deformation by processing (cold rolling, forging, etc.), and the strength is improved by leaving the processed structure in the titanium plate. be able to.
A titanium plate composed of a processed structure formed by cold rolling or the like exhibits high strength while having very low ductility.
For this reason, conventionally, it has been practiced to recrystallize the processed structure by annealing to form an equiaxed structure, and a sufficient annealing time is provided so that the processed structure does not remain on the titanium plate.
On the other hand, in the titanium plate in the present embodiment, the processed structure is left in the titanium plate by employing the annealing conditions described later, and the grain size of the recrystallized grains is as described above. It has been adjusted.
前記未再結晶部（加工組織）は、チタン板の断面に占める面積割合が３０％以下となるように設けられることが優れた「強度－加工性バランス」を得る点において重要である。
この未再結晶部の面積率が３０％より大きくなるとチタン板の強度は、より大きくなるが、延性が低下し、優れた加工性をチタン板に発揮させることが難しくなる。
その結果、優れた「強度－加工性バランス」を得ることができなくなるおそれを有する。
この優れた「強度－加工性バランス」をより確実にチタン板に付与させうる点においては、未再結晶部の面積率は１０％以下であることが好ましい。
なお、下限値は、特に限定されるものではないが未再結晶部がなくなる（面積率が０％になる）と、再結晶粒の粒径が急速に大きくなる。
そのため、再結晶粒の粒径をより確実に先述の範囲内に調整させ得る点において未結晶部の面積率は０．１％以上とすることが好ましい。 The non-recrystallized portion (processed structure) is important in that it is provided in such a way that an excellent “strength-workability balance” is provided so that the area ratio in the cross section of the titanium plate is 30% or less.
When the area ratio of the non-recrystallized portion is larger than 30%, the strength of the titanium plate is increased, but the ductility is lowered and it becomes difficult to exhibit excellent workability on the titanium plate.
As a result, there is a possibility that an excellent “strength-workability balance” cannot be obtained.
From the viewpoint that this excellent “strength-workability balance” can be more reliably imparted to the titanium plate, the area ratio of the non-recrystallized portion is preferably 10% or less.
The lower limit is not particularly limited, but when there is no unrecrystallized portion (the area ratio becomes 0%), the grain size of the recrystallized grains rapidly increases.
Therefore, it is preferable that the area ratio of the non-crystal part is 0.1% or more in that the grain size of the recrystallized grains can be adjusted more surely within the aforementioned range.
この未再結晶部の面積率が３０％より大きくなるとチタン板の強度は、より大きくなるが、延性が低下し、優れた加工性をチタン板に発揮させることが難しくなる。
その結果、優れた「強度－加工性バランス」を得ることができなくなるおそれを有する。
この優れた「強度－加工性バランス」をより確実にチタン板に付与させうる点においては、未再結晶部の面積率は１０％以下であることが好ましい。
なお、下限値は、特に限定されるものではないが未再結晶部がなくなる（面積率が０％になる）と、再結晶粒の粒径が急速に大きくなる。
そのため、再結晶粒の粒径をより確実に先述の範囲内に調整させ得る点において未結晶部の面積率は０．１％以上とすることが好ましい。 The non-recrystallized portion (processed structure) is important in that it is provided in such a way that an excellent “strength-workability balance” is provided so that the area ratio in the cross section of the titanium plate is 30% or less.
When the area ratio of the non-recrystallized portion is larger than 30%, the strength of the titanium plate is increased, but the ductility is lowered and it becomes difficult to exhibit excellent workability on the titanium plate.
As a result, there is a possibility that an excellent “strength-workability balance” cannot be obtained.
From the viewpoint that this excellent “strength-workability balance” can be more reliably imparted to the titanium plate, the area ratio of the non-recrystallized portion is preferably 10% or less.
The lower limit is not particularly limited, but when there is no unrecrystallized portion (the area ratio becomes 0%), the grain size of the recrystallized grains rapidly increases.
Therefore, it is preferable that the area ratio of the non-crystal part is 0.1% or more in that the grain size of the recrystallized grains can be adjusted more surely within the aforementioned range.
上記のような再結晶粒の粒径の調整や、未再結晶部の形成を行うためには、一般的な圧延工程等によってチタン板を所望の厚みに調整した後に、所定の条件での仕上げ焼鈍を実施する方法が挙げられる。
In order to adjust the grain size of the recrystallized grains as described above and to form the non-recrystallized portion, the titanium plate is adjusted to a desired thickness by a general rolling process and then finished under predetermined conditions. The method of implementing annealing is mentioned.
前記仕上げ焼鈍において採用しうる焼鈍方法は、連続式とバッチ式とに大別することができる。
この内、連続式の仕上げ焼鈍は、冷延コイルを展開して焼鈍炉内にチタン板を一定速度で通板させることにより焼鈍する方法であり、通板速度によって加熱温度の保持時間を制御できる。
従来のチタン板における仕上げ焼鈍では、連続式の場合、加熱温度は７００～８００℃で、加熱時間は数十秒から２分間程度とされている。
一方でバッチ式の仕上げ焼鈍は、チタン板のコイルをコイルの状態のまま焼鈍炉内で加熱する方法であり、コイルの表層部と内部との熱の加わり方の差を小さくするためにゆっくりと加熱され、冷却速度も非常に遅い。
従来のチタン板における仕上げ焼鈍では、バッチ式の場合、加熱温度は５５０～６５０℃で、加熱時間は３時間から３０時間程度とされている。 The annealing methods that can be employed in the finish annealing can be broadly classified into a continuous type and a batch type.
Among these, continuous finish annealing is a method of annealing by expanding a cold-rolled coil and passing a titanium plate through the annealing furnace at a constant speed, and the holding time of the heating temperature can be controlled by the passing speed. .
In the conventional finish annealing of a titanium plate, in the case of the continuous type, the heating temperature is 700 to 800 ° C., and the heating time is about several tens of seconds to 2 minutes.
On the other hand, batch-type finish annealing is a method in which a coil of titanium plate is heated in an annealing furnace in the state of a coil, and it is slowly performed in order to reduce the difference in how heat is applied between the surface layer of the coil and the inside. It is heated and the cooling rate is very slow.
In the conventional finish annealing on a titanium plate, in the case of the batch method, the heating temperature is 550 to 650 ° C., and the heating time is about 3 to 30 hours.
この内、連続式の仕上げ焼鈍は、冷延コイルを展開して焼鈍炉内にチタン板を一定速度で通板させることにより焼鈍する方法であり、通板速度によって加熱温度の保持時間を制御できる。
従来のチタン板における仕上げ焼鈍では、連続式の場合、加熱温度は７００～８００℃で、加熱時間は数十秒から２分間程度とされている。
一方でバッチ式の仕上げ焼鈍は、チタン板のコイルをコイルの状態のまま焼鈍炉内で加熱する方法であり、コイルの表層部と内部との熱の加わり方の差を小さくするためにゆっくりと加熱され、冷却速度も非常に遅い。
従来のチタン板における仕上げ焼鈍では、バッチ式の場合、加熱温度は５５０～６５０℃で、加熱時間は３時間から３０時間程度とされている。 The annealing methods that can be employed in the finish annealing can be broadly classified into a continuous type and a batch type.
Among these, continuous finish annealing is a method of annealing by expanding a cold-rolled coil and passing a titanium plate through the annealing furnace at a constant speed, and the holding time of the heating temperature can be controlled by the passing speed. .
In the conventional finish annealing of a titanium plate, in the case of the continuous type, the heating temperature is 700 to 800 ° C., and the heating time is about several tens of seconds to 2 minutes.
On the other hand, batch-type finish annealing is a method in which a coil of titanium plate is heated in an annealing furnace in the state of a coil, and it is slowly performed in order to reduce the difference in how heat is applied between the surface layer of the coil and the inside. It is heated and the cooling rate is very slow.
In the conventional finish annealing on a titanium plate, in the case of the batch method, the heating temperature is 550 to 650 ° C., and the heating time is about 3 to 30 hours.
これに対して、本実施形態のチタン板を作製する場合に実施される仕上げ焼鈍としては、例えば、連続式であれば、５８０℃以上６００℃未満の温度で、１分以上１０分以下の加熱条件、あるいは、６００℃以上６５０℃以下の温度で、１０秒以上２分未満の加熱条件で実施することが好ましい。
この好ましい加熱条件として、１０秒以上の時間が選択されているのは、温度を保持する時間が１０秒間より短いと、所定の焼鈍をチタン板に実施するために、通板速度や加熱温度等の操業条件の適正な範囲が非常に狭くなって、装置やその操作に精度の高い管理が要求されることになるためである。
一方で、加熱時間として、１０分以下の条件が好ましいのは、１０分間を超える時間を掛けると、通板速度を遅くしなければならず、生産性が低下するためである。 On the other hand, as the finish annealing performed when producing the titanium plate of the present embodiment, for example, in the case of a continuous type, heating is performed at a temperature of 580 ° C. or higher and lower than 600 ° C. for 1 minute or longer and 10 minutes or shorter. It is preferable to carry out the heating under the conditions or at a temperature of 600 ° C. or higher and 650 ° C. or lower for 10 seconds to less than 2 minutes.
As this preferable heating condition, the time of 10 seconds or more is selected because when the time for holding the temperature is shorter than 10 seconds, the predetermined annealing is performed on the titanium plate, the plate passing speed, the heating temperature, etc. This is because the appropriate range of the operating conditions becomes very narrow, and high-precision management is required for the apparatus and its operation.
On the other hand, the condition of 10 minutes or less is preferable as the heating time because if the time exceeding 10 minutes is taken, the sheet feeding speed must be slowed, and the productivity is lowered.
この好ましい加熱条件として、１０秒以上の時間が選択されているのは、温度を保持する時間が１０秒間より短いと、所定の焼鈍をチタン板に実施するために、通板速度や加熱温度等の操業条件の適正な範囲が非常に狭くなって、装置やその操作に精度の高い管理が要求されることになるためである。
一方で、加熱時間として、１０分以下の条件が好ましいのは、１０分間を超える時間を掛けると、通板速度を遅くしなければならず、生産性が低下するためである。 On the other hand, as the finish annealing performed when producing the titanium plate of the present embodiment, for example, in the case of a continuous type, heating is performed at a temperature of 580 ° C. or higher and lower than 600 ° C. for 1 minute or longer and 10 minutes or shorter. It is preferable to carry out the heating under the conditions or at a temperature of 600 ° C. or higher and 650 ° C. or lower for 10 seconds to less than 2 minutes.
As this preferable heating condition, the time of 10 seconds or more is selected because when the time for holding the temperature is shorter than 10 seconds, the predetermined annealing is performed on the titanium plate, the plate passing speed, the heating temperature, etc. This is because the appropriate range of the operating conditions becomes very narrow, and high-precision management is required for the apparatus and its operation.
On the other hand, the condition of 10 minutes or less is preferable as the heating time because if the time exceeding 10 minutes is taken, the sheet feeding speed must be slowed, and the productivity is lowered.
また、好ましい加熱温度の条件として、５８０℃以上の温度が選択されているのは、５８０℃よりも低い加熱温度では１０分間以下の保持時間でチタン板に所定の再結晶を起こさせることが難しく、未再結晶部の面積率が３０％を超えてしまう場合が多くなるためである。
さらに、６５０℃以下の加熱温度が選択されているのは、６５０℃よりも高い温度では１０秒間の加熱時間でもチタン板の再結晶が完了してしまって、再結晶粒が５μｍ以上の平均粒径にまで成長するおそれを有するためである。 Further, as a preferable heating temperature condition, a temperature of 580 ° C. or higher is selected. It is difficult to cause a predetermined recrystallization on the titanium plate with a holding time of 10 minutes or shorter at a heating temperature lower than 580 ° C. This is because the area ratio of the non-recrystallized portion often exceeds 30%.
Furthermore, the heating temperature of 650 ° C. or lower is selected because the recrystallization of the titanium plate is completed even when the heating temperature is higher than 650 ° C. for 10 seconds, and the recrystallized grains have an average grain size of 5 μm or more. This is because there is a possibility of growing to a diameter.
さらに、６５０℃以下の加熱温度が選択されているのは、６５０℃よりも高い温度では１０秒間の加熱時間でもチタン板の再結晶が完了してしまって、再結晶粒が５μｍ以上の平均粒径にまで成長するおそれを有するためである。 Further, as a preferable heating temperature condition, a temperature of 580 ° C. or higher is selected. It is difficult to cause a predetermined recrystallization on the titanium plate with a holding time of 10 minutes or shorter at a heating temperature lower than 580 ° C. This is because the area ratio of the non-recrystallized portion often exceeds 30%.
Furthermore, the heating temperature of 650 ° C. or lower is selected because the recrystallization of the titanium plate is completed even when the heating temperature is higher than 650 ° C. for 10 seconds, and the recrystallized grains have an average grain size of 5 μm or more. This is because there is a possibility of growing to a diameter.
また、本実施形態のチタン板を作製する場合に実施される仕上げ焼鈍としては、バッチ式であれば４２０℃以上５５０℃未満の温度で、３時間以上５０時間以下の加熱条件であることが好ましい。
この加熱時間として、３時間以上の条件が好ましいのは、加熱時間が３時間より短いと、コイルの大きさにもよるが、コイルの内部の温度が所定の温度まで到達しない可能性があるためである。
一方で、加熱時間として、５０時間以下の条件が好ましいのは、５０時間を超える時間を掛けると、焼鈍に要する時間が長くなりすぎてチタン板の生産性が低下するためである。 Further, the finish annealing performed when the titanium plate of the present embodiment is manufactured is preferably a heating condition of not less than 3 hours and not more than 50 hours at a temperature of 420 ° C. or more and less than 550 ° C. in the case of a batch type. .
The heating time is preferably 3 hours or longer because if the heating time is shorter than 3 hours, the temperature inside the coil may not reach a predetermined temperature, depending on the size of the coil. It is.
On the other hand, the condition of 50 hours or less is preferable as the heating time because if the time exceeding 50 hours is taken, the time required for annealing becomes too long and the productivity of the titanium plate decreases.
この加熱時間として、３時間以上の条件が好ましいのは、加熱時間が３時間より短いと、コイルの大きさにもよるが、コイルの内部の温度が所定の温度まで到達しない可能性があるためである。
一方で、加熱時間として、５０時間以下の条件が好ましいのは、５０時間を超える時間を掛けると、焼鈍に要する時間が長くなりすぎてチタン板の生産性が低下するためである。 Further, the finish annealing performed when the titanium plate of the present embodiment is manufactured is preferably a heating condition of not less than 3 hours and not more than 50 hours at a temperature of 420 ° C. or more and less than 550 ° C. in the case of a batch type. .
The heating time is preferably 3 hours or longer because if the heating time is shorter than 3 hours, the temperature inside the coil may not reach a predetermined temperature, depending on the size of the coil. It is.
On the other hand, the condition of 50 hours or less is preferable as the heating time because if the time exceeding 50 hours is taken, the time required for annealing becomes too long and the productivity of the titanium plate decreases.
また、加熱温度が４２０℃以上であるのが好ましいのは、４２０℃よりも低い加熱温度では５０時間以下の保持時間でチタン板に所定の再結晶を起こさせることが難しく、未再結晶部の面積率が３０％を超えてしまう場合が多くなるためである。
あるいは、所定の生産量を確保するには、焼鈍炉（加熱設備）を何基も保有しなければならず設備費が高価になるとともに焼鈍炉の設置のための広いスペースも必要なるためである。
なお、バッチ式ではコイル状態のままで加熱するため、コイルの表層部と内部で温度の上昇速度が異なり、目標とする温度に到達するまでの時間も異なる。
コイルの大きさ、加熱温度や焼鈍炉の加熱能力によるが、一般には、目標温度に到達する時間には数十分から数時間もの差がある。
このため、加熱時間が多少異なっても、再結晶した粒径にあまり差が生じない、すなわち、再結晶粒の成長速度が遅い温度範囲に加熱することが重要である。 Further, it is preferable that the heating temperature is 420 ° C. or higher. It is difficult to cause predetermined recrystallization on the titanium plate with a holding time of 50 hours or less at a heating temperature lower than 420 ° C. This is because the area ratio often exceeds 30%.
Alternatively, in order to secure a predetermined production amount, it is necessary to have several annealing furnaces (heating equipment), which increases the equipment cost and requires a large space for installing the annealing furnace. .
In the batch method, heating is performed in the coil state, so the temperature rising speed is different between the surface layer portion and the inside of the coil, and the time until reaching the target temperature is also different.
Depending on the size of the coil, the heating temperature, and the heating capability of the annealing furnace, generally, the time to reach the target temperature varies from several tens of minutes to several hours.
For this reason, even if the heating time is slightly different, it is important that the recrystallized grain size does not differ much, that is, it is heated to a temperature range where the growth rate of the recrystallized grains is slow.
あるいは、所定の生産量を確保するには、焼鈍炉（加熱設備）を何基も保有しなければならず設備費が高価になるとともに焼鈍炉の設置のための広いスペースも必要なるためである。
なお、バッチ式ではコイル状態のままで加熱するため、コイルの表層部と内部で温度の上昇速度が異なり、目標とする温度に到達するまでの時間も異なる。
コイルの大きさ、加熱温度や焼鈍炉の加熱能力によるが、一般には、目標温度に到達する時間には数十分から数時間もの差がある。
このため、加熱時間が多少異なっても、再結晶した粒径にあまり差が生じない、すなわち、再結晶粒の成長速度が遅い温度範囲に加熱することが重要である。 Further, it is preferable that the heating temperature is 420 ° C. or higher. It is difficult to cause predetermined recrystallization on the titanium plate with a holding time of 50 hours or less at a heating temperature lower than 420 ° C. This is because the area ratio often exceeds 30%.
Alternatively, in order to secure a predetermined production amount, it is necessary to have several annealing furnaces (heating equipment), which increases the equipment cost and requires a large space for installing the annealing furnace. .
In the batch method, heating is performed in the coil state, so the temperature rising speed is different between the surface layer portion and the inside of the coil, and the time until reaching the target temperature is also different.
Depending on the size of the coil, the heating temperature, and the heating capability of the annealing furnace, generally, the time to reach the target temperature varies from several tens of minutes to several hours.
For this reason, even if the heating time is slightly different, it is important that the recrystallized grain size does not differ much, that is, it is heated to a temperature range where the growth rate of the recrystallized grains is slow.
そして、加熱温度が５５０℃未満であるのが好ましいのは５５０℃以上の温度では再結晶した結晶粒の成長速度が大きいため、コイル表層部に合わせて加熱時間を短くすると、コイル内部ではまだ目標とする温度に到達しておらず、再結晶しない未再結晶部が３０％より多い状態になってしまうおそれがあり、逆にコイル内部に合わせて加熱時間を長くすると、コイル表層部は再結晶粒が成長しすぎて平均結晶粒径が５μｍ以上となるおそれがあるためである。
And it is preferable that the heating temperature is less than 550 ° C. Since the growth rate of the recrystallized crystal grains is large at a temperature of 550 ° C. or higher, if the heating time is shortened according to the coil surface layer portion, the target is still within the coil. If the heating time is increased according to the inside of the coil, the coil surface layer portion is recrystallized. This is because the grains grow too much and the average crystal grain size may become 5 μm or more.
なお、連続式でもバッチ式でも仕上げ焼鈍は、真空中あるいは不活性ガス雰囲気下で実施することが望ましい。
以上のようにして、再結晶の平均粒径と、未再結晶部（加工組織）の残存割合を焼鈍条件によって調整することによって、優れた「強度－加工性バランス」を有するチタン板を得ることができる。 In addition, it is desirable that the finish annealing is performed in a vacuum or in an inert gas atmosphere in both continuous and batch processes.
As described above, a titanium plate having an excellent “strength-workability balance” can be obtained by adjusting the average grain size of recrystallization and the remaining ratio of the non-recrystallized portion (worked structure) according to the annealing conditions. Can do.
以上のようにして、再結晶の平均粒径と、未再結晶部（加工組織）の残存割合を焼鈍条件によって調整することによって、優れた「強度－加工性バランス」を有するチタン板を得ることができる。 In addition, it is desirable that the finish annealing is performed in a vacuum or in an inert gas atmosphere in both continuous and batch processes.
As described above, a titanium plate having an excellent “strength-workability balance” can be obtained by adjusting the average grain size of recrystallization and the remaining ratio of the non-recrystallized portion (worked structure) according to the annealing conditions. Can do.
なお、ここでは詳述しないが、従来のチタン板ならびにチタン板製造方法において公知の事項を、本発明の効果を著しく損ねない範囲において、本発明においても採用することが可能である。
また、本実施形態においては、チタン材の例としてチタン板を挙げているが、優れた「強度－加工性バランス」が発揮される点においては、チタン板に限らず、例えば、線材、棒材、管材等種々の形態のチタン材においても同じであり、これらのチタン材も本発明が意図する範囲のものである。 Although not described in detail here, known matters in the conventional titanium plate and titanium plate manufacturing method can be employed in the present invention as long as the effects of the present invention are not significantly impaired.
Further, in the present embodiment, a titanium plate is cited as an example of the titanium material. However, in terms of exhibiting an excellent “strength-workability balance”, the present invention is not limited to the titanium plate. The same applies to various forms of titanium materials such as pipe materials, and these titanium materials are also within the scope of the present invention.
また、本実施形態においては、チタン材の例としてチタン板を挙げているが、優れた「強度－加工性バランス」が発揮される点においては、チタン板に限らず、例えば、線材、棒材、管材等種々の形態のチタン材においても同じであり、これらのチタン材も本発明が意図する範囲のものである。 Although not described in detail here, known matters in the conventional titanium plate and titanium plate manufacturing method can be employed in the present invention as long as the effects of the present invention are not significantly impaired.
Further, in the present embodiment, a titanium plate is cited as an example of the titanium material. However, in terms of exhibiting an excellent “strength-workability balance”, the present invention is not limited to the titanium plate. The same applies to various forms of titanium materials such as pipe materials, and these titanium materials are also within the scope of the present invention.
次に実施例を挙げて本発明をさらに詳しく説明するが、本発明はこれらに限定されるものではない。
Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.
＜評価１＞
（サンプルＮｏ．１～４５）
（テストピースの作製）
小型真空アーク溶解によって鋳塊（φ１４０ｍｍ）を作製し、該鋳塊を１０５０℃に加熱後、鍛造して厚さ５０ｍｍのスラブを作製した。
該スラブを８５０℃で厚さ５ｍｍまで熱延した後、７５０℃で焼鈍し、ショット、酸洗し表面のスケールを除去して板材を作製した。
さらに、この板材を冷延して厚さ０．５ｍｍの板状試料（チタン板）を作製した。
この厚さ０．５ｍｍのチタン板に対して、４００～８００℃の温度で、４８時間以下の仕上げ焼鈍をアルゴンガス雰囲気中で実施し結晶粒の調整されたテストピースを作製した。 <Evaluation 1>
(Sample Nos. 1-45)
(Production of test piece)
An ingot (φ140 mm) was produced by small vacuum arc melting, and the ingot was heated to 1050 ° C. and then forged to produce a slab having a thickness of 50 mm.
The slab was hot-rolled to a thickness of 5 mm at 850 ° C., and then annealed at 750 ° C., shot and pickled, and the surface scale was removed to prepare a plate material.
Further, this plate material was cold-rolled to produce a plate-like sample (titanium plate) having a thickness of 0.5 mm.
The 0.5 mm thick titanium plate was subjected to finish annealing for 48 hours or less at a temperature of 400 to 800 ° C. in an argon gas atmosphere to prepare a test piece with adjusted crystal grains.
（サンプルＮｏ．１～４５）
（テストピースの作製）
小型真空アーク溶解によって鋳塊（φ１４０ｍｍ）を作製し、該鋳塊を１０５０℃に加熱後、鍛造して厚さ５０ｍｍのスラブを作製した。
該スラブを８５０℃で厚さ５ｍｍまで熱延した後、７５０℃で焼鈍し、ショット、酸洗し表面のスケールを除去して板材を作製した。
さらに、この板材を冷延して厚さ０．５ｍｍの板状試料（チタン板）を作製した。
この厚さ０．５ｍｍのチタン板に対して、４００～８００℃の温度で、４８時間以下の仕上げ焼鈍をアルゴンガス雰囲気中で実施し結晶粒の調整されたテストピースを作製した。 <Evaluation 1>
(Sample Nos. 1-45)
(Production of test piece)
An ingot (φ140 mm) was produced by small vacuum arc melting, and the ingot was heated to 1050 ° C. and then forged to produce a slab having a thickness of 50 mm.
The slab was hot-rolled to a thickness of 5 mm at 850 ° C., and then annealed at 750 ° C., shot and pickled, and the surface scale was removed to prepare a plate material.
Further, this plate material was cold-rolled to produce a plate-like sample (titanium plate) having a thickness of 0.5 mm.
The 0.5 mm thick titanium plate was subjected to finish annealing for 48 hours or less at a temperature of 400 to 800 ° C. in an argon gas atmosphere to prepare a test piece with adjusted crystal grains.
（成分測定）
表面のスケールが切削された熱延後の板材を用いて、チタン板に含有される鉄量と酸素量とを測定した。
鉄含有量は、ＪＩＳ Ｈ１６１４に準じて測定し、酸素含有量は、ＪＩＳ Ｈ１６２０に準じて測定した。 (Component measurement)
The amount of iron and the amount of oxygen contained in the titanium plate were measured using the plate material after hot rolling whose surface scale was cut.
The iron content was measured according to JIS H1614, and the oxygen content was measured according to JIS H1620.
表面のスケールが切削された熱延後の板材を用いて、チタン板に含有される鉄量と酸素量とを測定した。
鉄含有量は、ＪＩＳ Ｈ１６１４に準じて測定し、酸素含有量は、ＪＩＳ Ｈ１６２０に準じて測定した。 (Component measurement)
The amount of iron and the amount of oxygen contained in the titanium plate were measured using the plate material after hot rolling whose surface scale was cut.
The iron content was measured according to JIS H1614, and the oxygen content was measured according to JIS H1620.
（引張強度測定）
また、上記のごとく結晶粒度が調整されたテストピース（チタン板）の引張強度をＪＩＳ Ｚ ２２４１に準じて測定をした。 (Tensile strength measurement)
Moreover, the tensile strength of the test piece (titanium plate) whose crystal grain size was adjusted as described above was measured according to JIS Z 2241.
また、上記のごとく結晶粒度が調整されたテストピース（チタン板）の引張強度をＪＩＳ Ｚ ２２４１に準じて測定をした。 (Tensile strength measurement)
Moreover, the tensile strength of the test piece (titanium plate) whose crystal grain size was adjusted as described above was measured according to JIS Z 2241.
（加工性評価）
また、上記のごとく結晶粒度が調整されたテストピース（チタン板）の加工性を評価した。
評価は、ＪＩＳ Ｚ２２４７に準じて、潤滑剤としてグラファイトグリースを用いたエリクセン値の測定により実施した。 (Processability evaluation)
Moreover, the workability of the test piece (titanium plate) whose crystal grain size was adjusted as described above was evaluated.
Evaluation was carried out according to JIS Z2247 by measuring the Erichsen value using graphite grease as a lubricant.
また、上記のごとく結晶粒度が調整されたテストピース（チタン板）の加工性を評価した。
評価は、ＪＩＳ Ｚ２２４７に準じて、潤滑剤としてグラファイトグリースを用いたエリクセン値の測定により実施した。 (Processability evaluation)
Moreover, the workability of the test piece (titanium plate) whose crystal grain size was adjusted as described above was evaluated.
Evaluation was carried out according to JIS Z2247 by measuring the Erichsen value using graphite grease as a lubricant.
（組織調査）
チタン板のミクロ組織を観察して結晶粒（再結晶したα粒）や未再結晶部（加工組織）の組織写真を得た。
なお、観察には、光学顕微鏡あるいは透過型電子顕微鏡を用いた。
透過型電子顕微鏡により観察した組織写真の例を図１（サンプルＮｏ.２８のミクロ組織）に示す。
この組織写真においては、再結晶したα粒と未再結晶部が写っている。
（この図１に示す写真においては、“Ａ”で示すような箇所が未再結晶部である。）
この写真を、画像解析ソフトを用いて未再結晶部以外の面積を求めて、再結晶しているα粒の平均面積を求め、該平均面積と同じ面積を有する円の直径を計算により求めて再結晶粒の平均粒径とした。
また、未再結晶都の面積より、未再結晶部の面積率を求めた。
以上の結果を、表１に示す。 (Organizational survey)
The microstructure of the titanium plate was observed to obtain a structure photograph of crystal grains (recrystallized α grains) and non-recrystallized parts (processed structure).
For observation, an optical microscope or a transmission electron microscope was used.
An example of a structure photograph observed with a transmission electron microscope is shown in FIG. 1 (microstructure of sample No. 28).
In this structural photograph, recrystallized α grains and unrecrystallized parts are shown.
(In the photograph shown in FIG. 1, the portion indicated by “A” is an unrecrystallized portion.)
Using this image analysis software, obtain the area other than the unrecrystallized part, obtain the average area of the recrystallized α grains, and calculate the diameter of a circle having the same area as the average area. The average grain size of recrystallized grains was used.
Moreover, the area ratio of the non-recrystallized part was calculated | required from the area of the non-recrystallized capital.
The results are shown in Table 1.
チタン板のミクロ組織を観察して結晶粒（再結晶したα粒）や未再結晶部（加工組織）の組織写真を得た。
なお、観察には、光学顕微鏡あるいは透過型電子顕微鏡を用いた。
透過型電子顕微鏡により観察した組織写真の例を図１（サンプルＮｏ.２８のミクロ組織）に示す。
この組織写真においては、再結晶したα粒と未再結晶部が写っている。
（この図１に示す写真においては、“Ａ”で示すような箇所が未再結晶部である。）
この写真を、画像解析ソフトを用いて未再結晶部以外の面積を求めて、再結晶しているα粒の平均面積を求め、該平均面積と同じ面積を有する円の直径を計算により求めて再結晶粒の平均粒径とした。
また、未再結晶都の面積より、未再結晶部の面積率を求めた。
以上の結果を、表１に示す。 (Organizational survey)
The microstructure of the titanium plate was observed to obtain a structure photograph of crystal grains (recrystallized α grains) and non-recrystallized parts (processed structure).
For observation, an optical microscope or a transmission electron microscope was used.
An example of a structure photograph observed with a transmission electron microscope is shown in FIG. 1 (microstructure of sample No. 28).
In this structural photograph, recrystallized α grains and unrecrystallized parts are shown.
(In the photograph shown in FIG. 1, the portion indicated by “A” is an unrecrystallized portion.)
Using this image analysis software, obtain the area other than the unrecrystallized part, obtain the average area of the recrystallized α grains, and calculate the diameter of a circle having the same area as the average area. The average grain size of recrystallized grains was used.
Moreover, the area ratio of the non-recrystallized part was calculated | required from the area of the non-recrystallized capital.
The results are shown in Table 1.
上記サンプルＮｏ．１～３０は、再結晶粒の平均粒径が５μｍ以下で、チタン板の断面に未再結晶部が３０％未満の面積率で観察されるものであり、Ｎｏ．３１～４２は、従来のチタン板のごとく、未再結晶部が残存していない状態のものである。
また、サンプルＮｏ．４３～４５は、未再結晶部をあえて残存させるように焼鈍条件を調整したものであるが、未再結晶部をその面積率が３０％を超える状態で残存させたものである。
上記サンプルＮｏ．１～３０とＮｏ．３１～４２は、酸素含有量、鉄含有量がほぼ同一のチタン材料を用いながらも焼鈍条件の違いによって結晶粒の大きさ（α相の円相当平均粒径）と未再結晶部の量とを調整したものである。
この表１からもわかるように未再結晶部が含まれることにより平均粒径を小さく抑えることができ、大きな耐力が発揮されるようになっている。
上記の評価においては、総じて、耐力が大きくなるほど、加工性（エリクセン値）は低下する傾向にあるが、同程度の加工性（エリクセン値）で比較すると、未再結晶部を存在させることで耐力が大きくなっており、高強度であることがわかる（例えば、サンプルＮｏ．１と３１、９と３４、１５と３９との比較参照）。
すなわち、結晶粒が５μｍ以下の大きさで未再結晶部が３０％以下であれば、「耐力－加工性バランス」が良好であることがわかる。
一方で、サンプルＮｏ．４３～４５に示したように、仕上げ焼鈍後に未再結晶部の面積が３０％よりも多いと、加工性（エリクセン値）が大きく低下している。
このことからも、本発明によれば高強度であり、しかも、加工性に優れたチタン板が提供され得ることがわかる。 Sample No. above. In Nos. 1 to 30, the average grain size of recrystallized grains is 5 μm or less, and an unrecrystallized part is observed in the cross section of the titanium plate with an area ratio of less than 30%. Nos. 31 to 42 are in a state where no non-recrystallized portion remains as in a conventional titanium plate.
Sample No. In Nos. 43 to 45, the annealing conditions were adjusted so as to leave unrecrystallized portions, but the non-recrystallized portions remained in a state where the area ratio exceeded 30%.
Sample No. above. 1-30 and no. Nos. 31 to 42 show that the size of the crystal grains (α-phase equivalent circle average grain size) and the amount of the non-recrystallized portion are different depending on the annealing conditions while using titanium materials having substantially the same oxygen content and iron content. Is adjusted.
As can be seen from Table 1, the inclusion of the non-recrystallized portion makes it possible to keep the average grain size small and to exert a large proof stress.
In the above evaluation, generally, as the yield strength increases, the workability (Ericsen value) tends to decrease. However, when compared with the same degree of workability (Erichsen value), the yield strength is obtained by the presence of an unrecrystallized part. Is large and it is understood that the intensity is high (for example, refer to comparison between sample Nos. 1 and 31, 9 and 34, and 15 and 39).
That is, it can be seen that if the crystal grain size is 5 μm or less and the non-recrystallized portion is 30% or less, the “balance of yield strength-workability” is good.
On the other hand, sample no. As shown in 43 to 45, when the area of the non-recrystallized portion is more than 30% after finish annealing, the workability (Ericsen value) is greatly reduced.
This also shows that according to the present invention, a titanium plate having high strength and excellent workability can be provided.
また、サンプルＮｏ．４３～４５は、未再結晶部をあえて残存させるように焼鈍条件を調整したものであるが、未再結晶部をその面積率が３０％を超える状態で残存させたものである。
上記サンプルＮｏ．１～３０とＮｏ．３１～４２は、酸素含有量、鉄含有量がほぼ同一のチタン材料を用いながらも焼鈍条件の違いによって結晶粒の大きさ（α相の円相当平均粒径）と未再結晶部の量とを調整したものである。
この表１からもわかるように未再結晶部が含まれることにより平均粒径を小さく抑えることができ、大きな耐力が発揮されるようになっている。
上記の評価においては、総じて、耐力が大きくなるほど、加工性（エリクセン値）は低下する傾向にあるが、同程度の加工性（エリクセン値）で比較すると、未再結晶部を存在させることで耐力が大きくなっており、高強度であることがわかる（例えば、サンプルＮｏ．１と３１、９と３４、１５と３９との比較参照）。
すなわち、結晶粒が５μｍ以下の大きさで未再結晶部が３０％以下であれば、「耐力－加工性バランス」が良好であることがわかる。
一方で、サンプルＮｏ．４３～４５に示したように、仕上げ焼鈍後に未再結晶部の面積が３０％よりも多いと、加工性（エリクセン値）が大きく低下している。
このことからも、本発明によれば高強度であり、しかも、加工性に優れたチタン板が提供され得ることがわかる。 Sample No. above. In Nos. 1 to 30, the average grain size of recrystallized grains is 5 μm or less, and an unrecrystallized part is observed in the cross section of the titanium plate with an area ratio of less than 30%. Nos. 31 to 42 are in a state where no non-recrystallized portion remains as in a conventional titanium plate.
Sample No. In Nos. 43 to 45, the annealing conditions were adjusted so as to leave unrecrystallized portions, but the non-recrystallized portions remained in a state where the area ratio exceeded 30%.
Sample No. above. 1-30 and no. Nos. 31 to 42 show that the size of the crystal grains (α-phase equivalent circle average grain size) and the amount of the non-recrystallized portion are different depending on the annealing conditions while using titanium materials having substantially the same oxygen content and iron content. Is adjusted.
As can be seen from Table 1, the inclusion of the non-recrystallized portion makes it possible to keep the average grain size small and to exert a large proof stress.
In the above evaluation, generally, as the yield strength increases, the workability (Ericsen value) tends to decrease. However, when compared with the same degree of workability (Erichsen value), the yield strength is obtained by the presence of an unrecrystallized part. Is large and it is understood that the intensity is high (for example, refer to comparison between sample Nos. 1 and 31, 9 and 34, and 15 and 39).
That is, it can be seen that if the crystal grain size is 5 μm or less and the non-recrystallized portion is 30% or less, the “balance of yield strength-workability” is good.
On the other hand, sample no. As shown in 43 to 45, when the area of the non-recrystallized portion is more than 30% after finish annealing, the workability (Ericsen value) is greatly reduced.
This also shows that according to the present invention, a titanium plate having high strength and excellent workability can be provided.
＜評価２＞
（サンプルＮｏ．Ａ～Ｈ）
（実機試験）
（テストコイルの作製）
真空アーク溶解によって鋳塊（φ７５０ｍｍ）を作製し、該鋳塊を８５０～１０００℃に加熱後、鍛造して厚さ１７０ｍｍのスラブを作製した。
該スラブを８５０℃の温度になるまで加熱した後、厚さ３．５ｍｍまで熱延し、該熱延されたものを７５０℃の温度で焼鈍した後、ショット、酸洗して表面のスケールを除去し熱延コイルを作製した。
この熱延コイルを冷延して厚さ０．４～０．８ｍｍの冷延コイルとした。
この冷延コイルは、冷延油等の油脂類を洗浄除去した後、真空焼鈍炉に挿入した。
冷延コイルを収容させた真空焼鈍炉の炉内を真空にした後、アルゴンガスで置換して４５０～６５０℃に加熱して４～３６時間保持するバッチ式の焼鈍を実施して再結晶粒の大きさを調整した。
得られたチタン板から「成分測定」、「引張強度測定」、「加工性評価」、「組織調査」を上記の評価１と同様に評価すべく必要な大きさの試料を採取し、前記評価を実施した。結果を、表２に示す。 <Evaluation 2>
(Sample Nos. A to H)
(Real machine test)
(Production of test coil)
An ingot (φ750 mm) was produced by vacuum arc melting, and the ingot was heated to 850 to 1000 ° C. and then forged to produce a slab having a thickness of 170 mm.
The slab is heated to a temperature of 850 ° C., then hot-rolled to a thickness of 3.5 mm, and the hot-rolled material is annealed at a temperature of 750 ° C., then shot, pickled, and scaled on the surface. The hot rolled coil was produced by removing.
This hot rolled coil was cold rolled to form a cold rolled coil having a thickness of 0.4 to 0.8 mm.
This cold-rolled coil was inserted into a vacuum annealing furnace after washing and removing oils and fats such as cold-rolled oil.
The inside of the vacuum annealing furnace containing the cold-rolled coil is evacuated, then replaced with argon gas, heated to 450 to 650 ° C. and held for 4 to 36 hours, and recrystallized grains The size of was adjusted.
From the obtained titanium plate, “sample measurement”, “tensile strength measurement”, “workability evaluation”, and “structural investigation” are collected in the same size as in the above evaluation 1, and a sample of the required size is collected. Carried out. The results are shown in Table 2.
（サンプルＮｏ．Ａ～Ｈ）
（実機試験）
（テストコイルの作製）
真空アーク溶解によって鋳塊（φ７５０ｍｍ）を作製し、該鋳塊を８５０～１０００℃に加熱後、鍛造して厚さ１７０ｍｍのスラブを作製した。
該スラブを８５０℃の温度になるまで加熱した後、厚さ３．５ｍｍまで熱延し、該熱延されたものを７５０℃の温度で焼鈍した後、ショット、酸洗して表面のスケールを除去し熱延コイルを作製した。
この熱延コイルを冷延して厚さ０．４～０．８ｍｍの冷延コイルとした。
この冷延コイルは、冷延油等の油脂類を洗浄除去した後、真空焼鈍炉に挿入した。
冷延コイルを収容させた真空焼鈍炉の炉内を真空にした後、アルゴンガスで置換して４５０～６５０℃に加熱して４～３６時間保持するバッチ式の焼鈍を実施して再結晶粒の大きさを調整した。
得られたチタン板から「成分測定」、「引張強度測定」、「加工性評価」、「組織調査」を上記の評価１と同様に評価すべく必要な大きさの試料を採取し、前記評価を実施した。結果を、表２に示す。 <Evaluation 2>
(Sample Nos. A to H)
(Real machine test)
(Production of test coil)
An ingot (φ750 mm) was produced by vacuum arc melting, and the ingot was heated to 850 to 1000 ° C. and then forged to produce a slab having a thickness of 170 mm.
The slab is heated to a temperature of 850 ° C., then hot-rolled to a thickness of 3.5 mm, and the hot-rolled material is annealed at a temperature of 750 ° C., then shot, pickled, and scaled on the surface. The hot rolled coil was produced by removing.
This hot rolled coil was cold rolled to form a cold rolled coil having a thickness of 0.4 to 0.8 mm.
This cold-rolled coil was inserted into a vacuum annealing furnace after washing and removing oils and fats such as cold-rolled oil.
The inside of the vacuum annealing furnace containing the cold-rolled coil is evacuated, then replaced with argon gas, heated to 450 to 650 ° C. and held for 4 to 36 hours, and recrystallized grains The size of was adjusted.
From the obtained titanium plate, “sample measurement”, “tensile strength measurement”, “workability evaluation”, and “structural investigation” are collected in the same size as in the above evaluation 1, and a sample of the required size is collected. Carried out. The results are shown in Table 2.
上記サンプルＮｏ．Ａ～Ｅは、再結晶粒の平均粒径が５μｍ以下で、チタン板の断面に未再結晶部が３０％未満の面積率で観察されるものであり、Ｎｏ．Ｆ～Ｈは、従来のチタン板のごとく、未再結晶部が残存していない状態のものである。
上記サンプルＮｏ．Ａ、Ｂ、Ｃでは耐力が２００ＭＰａa以上でエリクセン値が１３ｍｍ程度の加工性に優れたチタン板が得られている。
また、サンプルＮｏ．Ｄ、Ｅでは、耐力が４００ＭＰａ程度の高強度でありながら、エリクセン値が１０ｍｍ程度の加工性の良いチタン板が得られている。
一方で、サンプルＮｏ．Ｆ～Ｈでは、加工性が優れているものの耐力が２００ＭＰａよりも小さく強度が十分でない。
このことからも、本発明によれば高強度であり、しかも、加工性に優れたチタン板が提供され得ることがわかる。 Sample No. above. A to E are those in which the average grain size of recrystallized grains is 5 μm or less, and an unrecrystallized portion is observed in an area ratio of less than 30% in the cross section of the titanium plate. F to H are in a state where no non-recrystallized portion remains as in a conventional titanium plate.
Sample No. above. In A, B, and C, a titanium plate excellent in workability having a yield strength of 200 MPaa or more and an Erichsen value of about 13 mm is obtained.
Sample No. In D and E, a high-strength titanium plate having a yield strength of about 400 MPa and a good workability titanium plate having an Erichsen value of about 10 mm is obtained.
On the other hand, sample no. In F to H, although the workability is excellent, the proof stress is smaller than 200 MPa, and the strength is not sufficient.
This also shows that according to the present invention, a titanium plate having high strength and excellent workability can be provided.
上記サンプルＮｏ．Ａ、Ｂ、Ｃでは耐力が２００ＭＰａa以上でエリクセン値が１３ｍｍ程度の加工性に優れたチタン板が得られている。
また、サンプルＮｏ．Ｄ、Ｅでは、耐力が４００ＭＰａ程度の高強度でありながら、エリクセン値が１０ｍｍ程度の加工性の良いチタン板が得られている。
一方で、サンプルＮｏ．Ｆ～Ｈでは、加工性が優れているものの耐力が２００ＭＰａよりも小さく強度が十分でない。
このことからも、本発明によれば高強度であり、しかも、加工性に優れたチタン板が提供され得ることがわかる。 Sample No. above. A to E are those in which the average grain size of recrystallized grains is 5 μm or less, and an unrecrystallized portion is observed in an area ratio of less than 30% in the cross section of the titanium plate. F to H are in a state where no non-recrystallized portion remains as in a conventional titanium plate.
Sample No. above. In A, B, and C, a titanium plate excellent in workability having a yield strength of 200 MPaa or more and an Erichsen value of about 13 mm is obtained.
Sample No. In D and E, a high-strength titanium plate having a yield strength of about 400 MPa and a good workability titanium plate having an Erichsen value of about 10 mm is obtained.
On the other hand, sample no. In F to H, although the workability is excellent, the proof stress is smaller than 200 MPa, and the strength is not sufficient.
This also shows that according to the present invention, a titanium plate having high strength and excellent workability can be provided.
Claims (1)
- 鉄の含有量が０．６０質量％以下、酸素の含有量が０．１５質量％以下であり、残部がチタンおよび不可避不純物からなるチタン材であって、
塑性変形を伴う加工が施されて形成された加工組織と、前記加工後に焼鈍が施されて形成された再結晶組織とを有し、該再結晶組織の結晶粒の平均粒径が１μｍ以上５μｍ以下であり、断面積に占める未再結晶部の面積が０％を超え３０％以下となるように形成されていることを特徴とするチタン材。 The iron content is 0.60% by mass or less, the oxygen content is 0.15% by mass or less, and the balance is titanium material consisting of titanium and inevitable impurities,
It has a processed structure formed by processing with plastic deformation and a recrystallized structure formed by annealing after the processing, and the average grain size of the recrystallized structure is 1 μm or more and 5 μm The titanium material is characterized in that it is formed so that the area of the non-recrystallized portion in the cross-sectional area is more than 0% and 30% or less.
Priority Applications (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US13/820,768 US20130164166A1 (en) | 2010-09-08 | 2010-09-08 | Titanium material |
| KR1020137004532A KR20130059399A (en) | 2010-09-08 | 2010-09-08 | Titanium material |
| CN2010800687875A CN103069027A (en) | 2010-09-08 | 2010-09-08 | Titanium material |
| PCT/JP2010/065369 WO2012032610A1 (en) | 2010-09-08 | 2010-09-08 | Titanium material |
| EP10856960.9A EP2615186A4 (en) | 2010-09-08 | 2010-09-08 | Titanium material |
| RU2013115113/02A RU2544976C2 (en) | 2010-09-08 | 2010-09-08 | Titanium material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/JP2010/065369 WO2012032610A1 (en) | 2010-09-08 | 2010-09-08 | Titanium material |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2012032610A1 true WO2012032610A1 (en) | 2012-03-15 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/JP2010/065369 WO2012032610A1 (en) | 2010-09-08 | 2010-09-08 | Titanium material |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US20130164166A1 (en) |
| EP (1) | EP2615186A4 (en) |
| KR (1) | KR20130059399A (en) |
| CN (1) | CN103069027A (en) |
| RU (1) | RU2544976C2 (en) |
| WO (1) | WO2012032610A1 (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5937865B2 (en) * | 2011-05-30 | 2016-06-22 | 株式会社神戸製鋼所 | Production method of pure titanium plate with excellent balance of press formability and strength, and excellent corrosion resistance |
| JP5973975B2 (en) * | 2013-09-24 | 2016-08-23 | 株式会社神戸製鋼所 | Titanium plate |
| JP6265037B2 (en) * | 2014-05-01 | 2018-01-24 | 新日鐵住金株式会社 | Titanium welded tube and manufacturing method thereof |
| FR3024160B1 (en) * | 2014-07-23 | 2016-08-19 | Messier Bugatti Dowty | PROCESS FOR PRODUCING A METAL ALLOY WORKPIECE |
| RU2017134929A (en) * | 2015-03-23 | 2019-04-09 | Кабусики Кайся Кобе Сейко Се (Кобе Стил, Лтд.) | TITANIUM PLATE, PLATE FOR HEAT EXCHANGER AND SEPARATOR FOR FUEL ELEMENT |
| JP6356084B2 (en) * | 2015-03-25 | 2018-07-11 | 株式会社神戸製鋼所 | Method for producing cold rolled rolled plate and method for producing pure titanium plate |
| CN105624464B (en) * | 2015-12-28 | 2017-08-29 | 湖南湘投金天钛金属有限公司 | A kind of titanium hanger titanium strip coil and preparation method thereof |
| CN105734474B (en) * | 2016-03-29 | 2017-05-24 | 浙江大学 | Treatment process used for improving cold rolling performance of titanium and zirconium alloy high in zirconium content |
| JP7385941B2 (en) * | 2019-08-23 | 2023-11-24 | 国立大学法人東京海洋大学 | Titanium material, titanium products processed from the titanium material, and method for manufacturing the titanium material |
| CN112593171B (en) * | 2020-12-09 | 2021-08-24 | 四川大学 | Fine-grained pure titanium with high toughness and excellent osseointegration performance and preparation method thereof |
| KR102589875B1 (en) * | 2021-04-22 | 2023-10-13 | 한국재료연구원 | Fine grained pure titanium and manufacturing method for the same |
| CN115612955B (en) * | 2022-10-24 | 2023-05-16 | 四川大学 | Recrystallized high-strength and high-toughness superfine crystal pure titanium and preparation method thereof |
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| RU2246556C1 (en) * | 2004-01-22 | 2005-02-20 | Федеральное государственное унитарное предприятие "Всероссийский научно-исследовательский институт авиационных материалов" (ФГУП "ВИАМ") | Method for production of strained feed from titanium-based alloy and product made from the same |
| JP2008106323A (en) * | 2006-10-26 | 2008-05-08 | Sumitomo Metal Ind Ltd | Titanium alloy |
| JP4666271B2 (en) * | 2009-02-13 | 2011-04-06 | 住友金属工業株式会社 | Titanium plate |
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2010
- 2010-09-08 EP EP10856960.9A patent/EP2615186A4/en not_active Withdrawn
- 2010-09-08 KR KR1020137004532A patent/KR20130059399A/en not_active Application Discontinuation
- 2010-09-08 CN CN2010800687875A patent/CN103069027A/en active Pending
- 2010-09-08 US US13/820,768 patent/US20130164166A1/en not_active Abandoned
- 2010-09-08 RU RU2013115113/02A patent/RU2544976C2/en not_active IP Right Cessation
- 2010-09-08 WO PCT/JP2010/065369 patent/WO2012032610A1/en active Application Filing
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| JPH01252747A (en) * | 1987-12-23 | 1989-10-09 | Nippon Steel Corp | High strength titanium material having excellent ductility and its manufacture |
| JPH0835046A (en) * | 1994-07-19 | 1996-02-06 | Nkk Corp | Industrially pure titanium and its production |
| JPH08164195A (en) * | 1994-10-11 | 1996-06-25 | Japan Energy Corp | Fastening titanium wire for living body and its production |
| JP2009161816A (en) * | 2008-01-08 | 2009-07-23 | Sumitomo Metal Ind Ltd | Titanium material |
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Also Published As
| Publication number | Publication date |
|---|---|
| EP2615186A4 (en) | 2017-10-18 |
| CN103069027A (en) | 2013-04-24 |
| KR20130059399A (en) | 2013-06-05 |
| US20130164166A1 (en) | 2013-06-27 |
| RU2013115113A (en) | 2014-10-20 |
| RU2544976C2 (en) | 2015-03-20 |
| EP2615186A1 (en) | 2013-07-17 |
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