JP6756364B2 - Titanium composite and packaging - Google Patents

Description

The present invention relates to titanium composites and packaging.

Since titanium is a metal material with excellent corrosion resistance, it is used in heat exchangers that use seawater, various chemical plants, and the like. In addition, since its density is lower than that of carbon steel and its specific strength (strength per unit weight) is excellent, it is often used in aircraft fuselage. In addition, by using titanium material for land transportation equipment such as automobiles, the land transportation equipment itself becomes lighter and is expected to improve fuel efficiency.

However, titanium material is more complicated than steel material and is manufactured through a large number of processes. A typical manufacturing process is illustrated below.
(1) Forging process: Titanium oxide, which is a raw material, is chlorinated to obtain titanium tetrachloride, and then reduced with magnesium or sodium to produce spongy (lumpy) metallic titanium (hereinafter referred to as "sponge titanium"). Manufacturing process (2) Melting process: Press molding of sponge titanium to make electrodes, melting in a vacuum arc melting furnace to produce ingots (3) Forging process: Hot forging of ingots to slab ( Process of manufacturing hot-rolled materials) and billets (materials such as hot-extruded and hot-rolled) (4) Hot-working process: Hot rolling and extruding of slabs and billets to make plates and rounds Process for manufacturing rods, etc. (5) Cold processing process: A process for manufacturing thin plates, round bars, wires, etc. by further cold rolling and forging plates and round bars.

Titanium material is very expensive because it is manufactured by such many steps. For this reason, titanium materials are rarely applied to land transportation equipment such as automobiles. Therefore, in order to promote the use of titanium material, it is necessary to increase the productivity of the manufacturing process. In order to deal with this problem, efforts are being made to simplify the manufacturing process of titanium materials.

Patent Document 1 discloses a method for producing a titanium thin plate by molding, drying, sintering, compacting and resintering a composition containing titanium powder, a binder, a plasticizer and a solvent into a thin plate. .. According to this method, the melting step, the forging step, the hot rolling step and the cold rolling step can be omitted.

Patent Document 2 describes a method in which copper powder, chromium powder or iron powder is added to titanium alloy powder, encapsulated in a carbon steel capsule, heated and extruded hot to produce a titanium alloy round bar. It is disclosed. According to this method, the melting step and the forging step can be omitted, so that the manufacturing cost can be reduced.

Patent Document 3 discloses a method for producing a round bar by filling a copper capsule with titanium sponge powder, heating it to 700 ° C. or lower, and performing a warm extrusion process. In this method, since the melting step and the forging step can be omitted, the manufacturing cost can be reduced.

Further, conventionally known pack rolling is a method of hot rolling by covering a core material such as titanium alloy having poor workability with a cover material such as inexpensive carbon steel having good workability. For example, after applying a release agent to the surface of the core material, at least the upper and lower two surfaces thereof are covered with a cover material, or the four peripheral surfaces in addition to the upper and lower surfaces are also covered with a cover material, and the seams are welded to seal the coating. A box is manufactured, and the inside is evacuated to seal it and then hot-rolled.

Regarding pack rolling, Patent Document 4 discloses a method for assembling a sealed coated box, and Patent Document 5 seals (packs) the cover material with a vacuum degree of 10 ^-3 torr (about 0.133 Pa) or more. method of making a sealing cover box Te been disclosed, further, Patent Document 6, covered with carbon steel (cover ^member), by 10 -2 torr (about 1.33 Pa) or less of a high energy density welding under vacuum A method of sealing (packing) to produce a sealed cladding box is disclosed.

In these pack rolling, since the core material to be rolled is covered with a cover material and hot-rolled, the surface of the core material does not come into direct contact with a cold medium (atmosphere or roll), and the temperature of the core material drops. Therefore, it is possible to manufacture a thin plate even with a core material having poor workability.

As the cover material, carbon steel, which is a material different from the core material and has good workability and is inexpensive, is used. Since the cover material becomes unnecessary after hot rolling, a release agent is applied to the surface of the core material in order to facilitate separation from the core material.

Japanese Unexamined Patent Publication No. 2011-042828 Japanese Unexamined Patent Publication No. 2014-019945 Japanese Unexamined Patent Publication No. 2001-131609 JP-A-63-207401 Japanese Unexamined Patent Publication No. 09-136102 Japanese Unexamined Patent Publication No. 11-057810

The method disclosed in Patent Document 1 requires the use of expensive titanium powder (average particle size of 4 to 200 μm) as a raw material and many steps such as sintering and consolidation, so that the obtained titanium thin plate is obtained. Is very expensive and has not yet promoted the use of titanium materials.

In the method disclosed in Patent Document 2, since an expensive titanium powder alloy is used as a raw material, the obtained titanium alloy round bar is expensive and the use of the titanium material has not been promoted. Moreover, since the titanium sponge powder is oxidized when heated, the obtained round bar contains titanium oxide in the surface layer and inside, and the appearance is discolored and the tensile properties are inferior to those of the round bar manufactured in the normal process. There are problems such as.

In the method disclosed in Patent Document 3, since the sponge titanium powder is oxidized when heated, the obtained round bar contains titanium oxide in the surface layer and inside, and has an appearance as compared with a round bar manufactured in a normal process. There are problems such as discoloration and inferior tensile properties.

Further, in the methods disclosed in Patent Documents 4 to 6, since the cover material is peeled off and discarded after rolling as in pack rolling, the manufacturing cost is higher than in the normal process, and the obtained titanium material is high. It's still a cost.

For this reason, titanium materials have not yet been applied to land transportation equipment such as automobiles.

In view of such circumstances, an object of the present invention is to provide a titanium material such as a titanium plate or a titanium round bar at low cost.

In order to solve the above problems, the present inventors diligently studied means capable of producing a titanium material by omitting the melting step and the forging step, and obtained the findings (A) to (F) listed below. The invention was completed.

(A) Instead of powders such as expensive titanium powder and sponge titanium powder, amorphous sponge-like (lumpy) sponge titanium is used as a raw material. Since the sponge-like titanium sponge is conventionally manufactured, it can be obtained at a relatively low cost. Further, since the main impurities such as iron and chlorine are removed from the titanium sponge in the smelting process, there is no problem in the chemical composition even if the titanium material is directly produced from the titanium sponge. In addition, titanium materials such as scraps that cannot be used as products (hereinafter referred to as "titanium scrap") can be obtained at a relatively low cost. However, since titanium scrap has an irregular shape, it cannot be directly processed to produce titanium material.

(B) If it is a titanium packaging body in which a filler such as sponge titanium is housed in a container (hereinafter referred to as "packing material") made of industrial pure titanium material or titanium alloy material and sealed, heat is generated. It is possible to suppress the occurrence of surface defects such as surface cracks and sponge-like shapes during interprocessing. In particular, by making the chemical composition of the filler the same as that of pure titanium, it is not necessary to peel off the cover material after rolling and dispose of it as in conventional pack rolling, and the titanium packing material is hot-worked. Can be effectively used as it is as a part of titanium composite material (product).

(C) To prevent the filler such as titanium sponge from oxidizing when heated before hot working, and to easily reduce the voids between the fillers and between the filler and the packing material during hot working. In addition, it is important to reduce the internal pressure of the packing material as much as possible.

(D) As a filler to be contained in the packing material, a metal other than Ti such as Sn, Zr, Al, Mo, V, Nb, Fe, Cr, Cu, Co, Ni, or a compound thereof, together with a titanium material such as titanium sponge. The tensile strength of the titanium composite material can be increased by filling the powder (hereinafter, also referred to as "powder of metal or the like") of (the compound includes an alloy).

(E) That is, the inside of the titanium packing material, which is a wrought material of pure titanium for industrial use, is filled and sealed with sponge titanium and a powder such as a metal capable of increasing the tensile strength of the titanium composite material. The pressure is reduced to form a titanium package, and the titanium package is hot-worked, and if necessary, cold-worked to form a titanium composite material, which is an assembly of titanium ingots before hot-working. After hot working, the titanium package is compression-molded as a whole to become an integrated titanium composite material (three-layer clad material).

(F) The titanium composite material is a compression molded product of titanium containing a metal other than Ti or a compound thereof (hereinafter, also referred to as “compound or the like”) in which only the inner layer portion can increase the tensile strength of the titanium composite material. However, since the surface layer is a wrought material of industrial pure titanium or titanium alloy material, it has excellent workability and high tensile strength, and it can be manufactured without going through the conventional melting process and forging process. The cost can be significantly reduced.

The present invention is as listed below.

(1) A titanium composite material having an inner layer portion and a surface layer portion covering the inner layer portion.
The surface layer portion is made of an industrial pure titanium material or a titanium alloy material having a chemical composition belonging to any of JIS types 1 to 4.
The inner layer portion includes a portion in which a metal other than titanium or a compound thereof is dispersed in titanium, and the metal element is diffused around the metal or the compound, and the area ratio is more than 0% and 30% or less. Has voids,
Titanium composite material.

(2) The metal is one or more selected from Sn, Zr, Al, Mo, V, Nb, Fe, Cr, Cu, Co and Ni.
The titanium composite material of (1) above.

(3) In the inner layer portion, metals other than titanium or a compound thereof are dispersed in a titanium material as streaky aggregates arranged in the rolling direction.
The titanium composite material of (1) or (2) above.

(4) The chemical composition of the industrial pure titanium material is mass%.
C: 0.08% or less,
H: 0.013% or less,
O: 0.4% or less,
N: 0.05% or less,
Fe: 0.5% or less,
Remaining: Ti and impurities,
The titanium composite material according to any one of (1) to (3) above.

(5) A packing body including a titanium packing material made of an industrial pure titanium material or a titanium alloy material belonging to any of JIS 1 to 4 and a filling material filled inside the titanium packing material.
The filler has one or more selected from titanium sponge, titanium briquette and titanium scrap, and powder of a metal other than titanium or a compound thereof, and the internal pressure is 10 Pa or less.
Packing body for hot processing.

The titanium composite material according to the present invention is excellent in mechanical properties such as tensile strength and Young's modulus, and can be manufactured without going through a melting step and a forging step, so that the manufacturing cost can be significantly reduced. Further, the titanium composite material according to the present invention uses a large amount of titanium material such as cutting and removing many defective parts on the surface layer and bottom surface of the ingot, removing surface cracks after forging and removing front and rear ends (crops) having a bad shape. Since it can be manufactured without cutting or cutting, the manufacturing yield is greatly improved, and from this point as well, the manufacturing cost is greatly reduced.

FIG. 1 is an explanatory diagram showing an example of the configuration of the titanium composite material according to the present invention. FIG. 2 is a diagram schematically showing an aggregate 42a such as a streak compound. In the figure showing the concept of the distance in the thickness direction of one grain and the element concentration distribution around it in the cross section (thickness cross section) parallel to the length direction (rolling direction) and the thickness direction of the titanium composite material 1. is there. FIG. 4 is an explanatory view showing an example of the configuration of a titanium package which is a material for hot processing of a titanium composite material according to the present invention. FIG. 5 is an explanatory diagram showing an example of the configuration of the titanium briquette. FIG. 6 is an explanatory view showing an example of another configuration of the titanium package according to the present invention. FIG. 7 is a photograph of the cross-sectional microstructure of the titanium composite material (Sample No. 14: Ti-5.0% Fe plate) according to the present invention.

The titanium composite material according to the present invention and the titanium package for hot working thereof will be described with reference to the accompanying drawings. In the following description, "%" relating to the chemical composition means "mass%" unless otherwise specified.

1. 1. Configuration of Titanium Composite Material 1 According to the Present Invention FIG. 1 is an explanatory diagram showing an example of the configuration of the titanium composite material 1 according to the present invention.

As shown in FIG. 1, the titanium composite material 1 includes surface layer portions 2 and 3 and an inner layer portion 4. Hereinafter, each layer will be described.

(A) Surface layer 2, 3
(A-1) Chemical Composition of Surface Layers 2 and 3 As the industrial pure titanium material forming the surface layers 2 and 3, an industrial pure titanium material having a chemical composition belonging to any of JIS 1 to 4 can be used. .. For example, the surface layer portions 2 and 3 have C: 0.08% or less, H: 0.013% or less, O: 0.4% or less, N: 0.05% or less, Fe: 0.5% or less, and the balance. It has a chemical composition of Ti and impurities.

It should be noted that the above JIS types 1 to 4 are defined in JIS SH4600: 2012. What is JIS 1 type? C: 0.08% or less, H: 0.013% or less, O: 0.15% or less, N: 0.03% or less, Fe: 0.20% or less, balance Ti and impurity composition Have. JIS2 types are C: 0.08% or less, H: 0.013% or less, O: 0.20% or less, N: 0.03% or less, Fe: 0.25% or less, balance Ti and impurities. Has a composition. JIS3 types are C: 0.08% or less, H: 0.014% or less, O: 0.30% or less, N: 0.05% or less, Fe: 0.30% or less, balance Ti and impurities. Has a composition. JIS4 types are C: 0.08% or less, H: 0.013% or less, O: 0.40% or less, N: 0.05% or less, Fe: 0.50% or less, balance Ti and impurities. Has a composition.

On the other hand, as the titanium alloy material forming the surface layer portions 2 and 3, an α-type titanium alloy, an α + β-type titanium alloy, or a β-type titanium alloy can be used.

Examples of the α-type titanium alloy include Ti-0.06% Pd, Ti-0.2Pd, Ti-0.02Pd-0.05Mm (where Mm refers to misch metal) and Ti-0.5Ni. -0.05Ru, Ti-0.5Cu, Ti-1.0Cu, Ti-1.0Cu-0.5Nb, Ti-1.0Cu-1.0Sn-0.3Si-0.25Nb, Ti-0.5Al -0.45Si, Ti-0.9Al-0.35Si, Ti-3Al-2.5V, Ti-5Al-2.5Sn, Ti-6Al-2Sn-4Zr-2Mo, Ti-6Al-2.75Sn-4Zr There are −0.4Mo −0.45Si and the like.

Examples of the α + β type titanium alloy include Ti-6Al-4V, Ti-6Al-6V-2Sn, Ti-6Al-7V, Ti-3Al-5V, Ti-5Al-2Sn-2Zr-4Mo-4Cr, Ti-6Al. -2Sn-4Zr-6Mo, Ti-1Fe-0.35O, Ti-1.5Fe-0.5O, Ti-5Al-1Fe, Ti-5Al-1Fe-0.3Si, Ti-5Al-2Fe, Ti-5Al There are -2Fe-0.3Si, Ti-5Al-2Fe-3Mo, Ti-4.5Al-2Fe-2V-3Mo and the like.

Further, examples of the β-type titanium alloy include Ti-11.5Mo-6Zr-4.5Sn, Ti-8V-3Al-6Cr-4Mo-4Zr, Ti-10V-2Fe-3Mo, and Ti-13V-11Cr-3Al. , Ti-15V-3Al-3Cr-3Sn, Ti-6.8Mo-4.5Fe-1.5Al, Ti-20V-4Al-1Sn, Ti-22V-4Al and the like.

(A-2) Thickness of Surface Layers 2 and 3 If the thickness of the surface layers 2 and 3 of the titanium composite material 1 is too thick, the thickness of the inner layer 4 becomes thin, so that the effect of improving mechanical properties is sufficient. I can't get it. Therefore, the thickness of the surface layer portions 2 and 3 is preferably 40% or less per side, and more preferably 25% or less per side with respect to the total thickness of the titanium composite material 1.

On the other hand, when the surface layer portions 2 and 3 are thin, the thickness of the inner layer portion 4 becomes thick, so that the effect of improving the mechanical characteristics is improved. However, if the surface layer portions 2 and 3 are too thin, when the titanium composite material 1 is processed, the surface layer portions 2 and 3 are cracked and the inner layer portion 4 appears on the surface, and the compounds and the like in the inner layer portion 4 fall off or the surface. Surface cracks and edge cracks occur starting from the compounds appearing in. Further, when a liquid such as water comes into contact with the liquid, there arises a problem that the liquid invades the inner layer portion 4. Therefore, the thickness of the surface layer portions 2 and 3 is preferably 0.1 mm or more.

(B) Inner layer 4
In the inner layer portion 4, compounds and the like 42 are dispersed in titanium 41, and the respective constituent elements (for example, Sn, Zr, Al, Mo, V, Nb, Fe, Cr, Cu, Co) are dispersed around the compound and the like 42. It has a portion (not shown) in which (an element selected from Ni and Ni) is diffused, and has a void 43 having an area ratio of more than 0% and 30% or less.

(B-1) Chemical Composition of Inner Layer 4 As the titanium constituting the inner layer 4 of the titanium composite material 1, for example, JIS 1 to JIS 4 industrial pure titanium can be used. That is, as general impurities, C: 0.08% or less, H: 0.013% or less, O: 0.4% or less, N: 0.05% or less, Fe: 0.5% or less, and the balance It is an industrial pure titanium that is Ti.

In particular, if JIS1 to 3 types of industrial pure titanium are used, they have sufficient workability, cracks do not occur, and industrial pure titanium forming the above-mentioned surface layer portions 2 and 3 after hot working. A titanium composite material 1 integrated with the above can be obtained.

The rest other than the above is impurities. Impurities can be contained within a range that does not diminish the effect of improving processability and mechanical properties. Impurities other than the above include Al, V, Cr, Nb, Si, Sn, Mo, Cu and the like as impurity elements mainly mixed from scrap, and general impurity elements (C, N, Fe, O, H). ), And 5% or less is allowed in total.

As the inner layer portion 4, in order to give the titanium composite material 1 good mechanical properties, a metal other than titanium or a compound thereof is dispersed in titanium. In the inner layer portion 4, examples of the metal element include one or more selected from Sn, Zr, Al, Mo, V, Nb, Fe, Cr, Cu, Co and Ni. The preferable range of the average content of each element and the reason for the limitation are described. The above compounds include alloys.

[Sn: 0.3 to 8.0%]
Since Sn has the effects of improving the mechanical properties (tensile strength) of the titanium composite material 1 and adjusting the Young's modulus, it is preferable to contain Sn in an amount of 0.3% or more. If the average content exceeds 8.0%, the inner layer portion 4 of the titanium composite material 1 becomes brittle, and there is a possibility that the inner layer portion 4 cracks during processing and the titanium composite material 1 is peeled off. Therefore, the average content thereof is preferably 0.3 to 8.0%.

[Zr: 0.3 to 5.0%]
Since Zr has the effects of improving the mechanical properties (tensile strength) of the titanium composite material 1 and adjusting the Young's modulus, it is preferable to contain Zr at 0.3% or more. If the average content exceeds 5.0%, the inner layer portion 4 of the titanium composite material 1 becomes brittle, and there is a possibility that the inner layer portion 4 will crack during processing and the titanium composite material 1 will peel off. Therefore, the average content thereof is preferably 0.3 to 5.0%.

[Al: 0.3 to 8.0%]
Since Al has the effects of improving the mechanical properties (tensile strength) of the titanium composite material 1 and adjusting the Young's modulus, it is preferable to contain Al in an amount of 0.3% or more. If the average content exceeds 8.0%, the inner layer portion 4 of the titanium composite material 1 becomes brittle, and there is a possibility that the inner layer portion 4 cracks during processing and the titanium composite material 1 is peeled off. Therefore, the average content thereof is preferably 0.3 to 8.0%.

[Mo: 0.3-8.0%]
Since Mo has the effects of improving the mechanical properties (tensile strength) of the titanium composite material 1 and adjusting the Young's modulus, it is preferable to contain Mo in an amount of 0.3% or more. If the average content exceeds 8.0%, the inner layer portion 4 of the titanium composite material 1 becomes brittle, and there is a possibility that the inner layer portion 4 will crack during processing and the titanium composite material 1 will peel off. Therefore, the average content thereof is preferably 0.3 to 8.0%.

[V: 0.3-5.0%]
Since V has the effects of improving the mechanical properties (tensile strength) of the titanium composite material 1 and adjusting the Young's modulus, it is preferable to contain V in an amount of 0.3% or more. If the average content exceeds 5.0%, the inner layer portion 4 of the titanium composite material 1 becomes brittle, and there is a possibility that the inner layer portion 4 will crack during processing and the titanium composite material 1 will peel off. Therefore, the average content thereof is preferably 0.3 to 5.0%.

[Nb: 0.3 to 5.0%]
Since Nb has the effects of improving the mechanical properties (tensile strength) of the titanium composite material 1 and adjusting the Young's modulus, it is preferable to contain Nb in an amount of 0.3% or more. If the average content exceeds 5.0%, the inner layer portion 4 of the titanium composite material 1 becomes brittle, and there is a possibility that the inner layer portion 4 will crack during processing and the titanium composite material 1 will peel off. Therefore, the average content thereof is preferably 0.3 to 5.0%.

[Fe: 0.3 to 5.0%]
Since Fe has the effects of improving the mechanical properties (tensile strength) of the titanium composite material 1 and adjusting the Young's modulus, it is preferable to contain Fe in an amount of 0.3% or more. If the average content exceeds 5.0%, the inner layer portion 4 of the titanium composite material 1 becomes brittle, and there is a possibility that the inner layer portion 4 will crack during processing and the titanium composite material 1 will peel off. Therefore, the average content thereof is preferably 0.3 to 5.0%.

[Cr: 0.3 to 5.0%]
Since Cr has the effects of improving the mechanical properties (tensile strength) of the titanium composite material 1 and adjusting the Young's modulus, it is preferable to contain Cr in an amount of 0.3% or more. If the average content exceeds 5.0%, the inner layer portion 4 of the titanium composite material 1 becomes brittle, and there is a possibility that the inner layer portion 4 will crack during processing and the titanium composite material 1 will peel off. Therefore, the average content thereof is preferably 0.3 to 5.0%.

[Cu: 0.3 to 8.0%]
Since Cu has the effects of improving the mechanical properties (tensile strength) of the titanium composite material 1 and adjusting the Young's modulus, it is preferable to contain Cu in an amount of 0.3% or more. If the average content exceeds 8.0%, the inner layer portion 4 of the titanium composite material 1 becomes brittle, and there is a possibility that the inner layer portion 4 cracks during processing and the titanium composite material 1 is peeled off. Therefore, the average content thereof is preferably 0.3 to 8.0%.

[Co: 0.3-5.0%]
Since Co has the effects of improving the mechanical properties (tensile strength) of the titanium composite material 1 and adjusting the Young's modulus, it is preferable to contain Co in an amount of 0.3% or more. If the average content exceeds 5.0%, the inner layer portion 4 of the titanium composite material 1 becomes brittle, and there is a possibility that the inner layer portion 4 will crack during processing and the titanium composite material 1 will peel off. Therefore, the average content thereof is preferably 0.3 to 5.0%.

[Ni: 0.3-5.0%]
Since Ni has the effects of improving the mechanical properties (tensile strength) of the titanium composite material 1 and adjusting the Young's modulus, it is preferable to contain Ni in an amount of 0.3% or more. If the average content exceeds 5.0%, the inner layer portion 4 of the titanium composite material 1 becomes brittle, and there is a possibility that the inner layer portion 4 will crack during processing and the titanium composite material 1 will peel off. Therefore, the average content thereof is preferably 0.3 to 5.0%.

The component analysis of the surface layer portion and the inner layer portion is performed by known methods (for example, JIS H 1614 (1995), JIS H 1622 (1998), JIS H 1624 (2005), JIS H 1630 (1995), JIS H 1631 (2008)). , JIS H 1632 (2014), etc.). At this time, the surface layer portion and the inner layer portion are cut out from the titanium composite material, and then the measurement is performed. It is efficient to collect an analysis sample from chips and the like obtained by processing the surface layer portion and from the residual material after removing the surface layer from the inner layer portion for analysis. As an analysis sample, 0.5 g or more is collected from the central portion of the surface layer portion and the inner layer portion in the plate thickness direction. If the surface layer or inner layer is too thin to obtain a sufficient amount of chips, the entire composition of the titanium composite is analyzed and the analysis value and the analysis value of either the surface layer or the inner layer are analyzed. And, the component of the surface layer or the inner layer portion may be calculated (back calculation) from each plate thickness.

(B-2) Porosity of Inner Layer 4 If the porosity of the void 43 of the titanium composite material 1 is too large, mechanical properties (strength and ductility) as a bulk metal cannot be obtained. On the other hand, the smaller the gap 43 is, the more desirable it is, but in order to completely crimp the gap, a large reduction is required. As a result, the shape (thickness) of the titanium composite material 1 to be manufactured is limited, and the manufacturing cost is increased.

On the other hand, when the void 43 is contained to such an extent that it has sufficient mechanical properties (strength, ductility, etc.) to maintain the structure of the titanium composite material 1, the density of the inner layer portion 4 becomes low, and the titanium composite The weight of the material 1 can be reduced.

As described above, the porosity is lowered when the mechanical properties of the bulk metal are important, while the porosity is raised when the weight reduction of the titanium composite material 1 is prioritized. In this way, the porosity can be selected according to the application. The range of the porosity at this time is preferably more than 0% and 30% or less, and more preferably more than 0% and 10% or less. By setting the porosity to 10% or less, it is possible to provide mechanical properties comparable to those of general industrial pure titanium.

The ratio (porosity) of the voids 43 remaining in the inner layer portion 4 of the titanium composite material 1 is calculated as follows. After embedding the titanium composite material 1 in a resin so that a cross section having a thickness parallel to the length direction (rolling direction) can be observed, the observation surface is polished with a diamond or alumina turbid solution (mirror finish) and observed. Finish as a sample for use.

The mirrored observation sample is photographed with an optical microscope at 20 different thickness centers. Here, the central portion is the center of the plate thickness when the titanium composite material 1 is a plate, and the center of the circular cross section when the titanium composite material 1 is a round bar. The area ratio of the void 43 observed in the optical micrograph is measured, and the result of averaging the values of the porosity of 20 photographs is calculated as the porosity.

When taking a tissue photograph with an optical microscope, an appropriate magnification is selected according to the size of the voids of the titanium composite material 1 or the porosity. For example, when the porosity is 1% or less, the porosity is small, so it is preferable to observe at a high magnification of about 500 times and take a photograph. When the porosity is 10% or more, there are many large voids, so it is preferable to observe at a low magnification of about 20 times and take a photograph. Further, when the porosity such that the void becomes small is 1% or less, it can be observed more clearly than a normal optical microscope by using a differential interference microscope capable of polarization observation.

(B-3) Structure of Inner Layer 4 As shown in FIG. 1, the inner layer 4 in the titanium composite 1 contains a large amount of compounds 42 and the like. The compounds 42 have their respective constituent elements (for example, Sn, Zr, Al, Mo, V, Nb, Fe, Cr, Cu) around the compound 42 due to hot working in the production process of the titanium composite material 1. , Co and elements selected from Co and Ni) diffuse into the titanium 41, but each constituent element that cannot be dissolved in the titanium 41 remains dispersed in the titanium material 41 as a compound or the like 42. At this time, the compounds and the like 42 are lined up in the processing (rolling) direction to form a streak aggregate (hereinafter, referred to as “a streak compound and the like aggregate”) 42a. Further, the compound and the like 42 are completely. In addition to those forming compounds, it also contains compounds in which a metal is present. For example, when a metal such as Sn is used as a material for a compound or the like, the metal reacts with titanium in a manufacturing process such as hot rolling. The compound may be formed, but a metal that has not completely reacted with titanium may remain inside the compound.

(B-3-1) Shape of Compound or The like FIG. 2 is a diagram schematically showing an aggregate 42a such as a streak compound or the like. As shown in FIG. 2, the streak compound or the like aggregate 42a has a plurality of distances D (hereinafter, referred to as “inter-particle distance”) obtained by projecting the distance between the centers of the particles of the compound or the like 42 in the rolling direction to be 20 μm or less. It means an aggregate of 42 such as compounds of. In the present specification, when the interparticle distance exceeds 20 μm, it is treated as another aggregate such as a streak compound.

The thickness t (that is, the size in the compression processing direction) of the streak compound or the like aggregate 42a is preferably 100 μm or less. This is because if this thickness exceeds 100 μm, there is a high possibility that cracks will occur starting from the compound or the like 42 when processing the titanium composite material. On the other hand, the length L (that is, the size in the processing direction) of the aggregate 42a such as streaks is 2.0 times or more (that is, L / t ≧) the size (thickness) t in the thickness direction. 2.0) is preferable, and 3.0 times or more (that is, L / t ≧ 3.0) is more preferable. This is because if the length L is small, the inner layer portion is likely to break from this compound or the like when subjected to tensile stress. It is preferable that L / t ≦ 100, and more preferably L / t ≦ 40.

The size (length L and thickness t) of the aggregate 42a such as streaky compounds is calculated as follows. After embedding the titanium composite material 1 in a resin so that the cross section parallel to the length direction (rolling direction) and the thickness direction (thickness cross section) is the observation surface, the observation surface is made using a diamond or alumina polishing liquid. Polish to finish the sample for observation.

Using an optical microscope, 20 photographs are taken at different positions at the center of the thickness of the observation surface. Here, the thickness center portion is the plate thickness center portion when the titanium composite material 1 is a plate, and is the center of the circular cross section when the titanium composite material 1 is a round bar. In the obtained 20 photographs, the length L and the thickness t of the aggregate 42a such as streaks are measured, and the average value of the respective values is defined as the length L and the thickness t, and L / t is calculated. ..

(B-3-2) Existence of Diffuse Layer Around each grain of the compound or the like 42, each constituent element (for example, Sn, Zr, Al, Mo, V, Nb, Fe, Cr, Cu, Co and There is a diffusion layer of (element selected from Ni). The diffusion layer is a compound or the like 42 dispersed in the titanium 41 of the inner layer portion 4, and its constituent elements (for example, Sn, Zr, etc.) are diffused around the compound or the like 42 in the surrounding titanium 41 to form a concentration gradient. Titanium.

FIG. 3 shows the concept of the distance in the thickness direction of one grain and the concentration distribution of constituent elements around it in the cross section (thickness cross section) parallel to the length direction (rolling direction) and the thickness direction of the titanium composite material 1. It is a figure which showed. When the diffusion layer is heated and held in the process of producing the titanium composite material 1 (heating before hot rolling, heat treatment during hot rolling, heat treatment after hot rolling, etc.), the diffusion layer is formed from the particles of the compound or the like 42 to the surroundings. This is a layer formed by diffusing each constituent element into titanium 41. As shown in FIG. 3, the diffusion layer is contained in a larger amount than the value of each constituent element contained in the titanium 41 of the inner layer portion 4. Due to the presence of this diffusion layer, the particles of the compound or the like 42 in the inner layer portion 4 and the titanium 41 are firmly bonded. Therefore, when the titanium composite material 1 is processed, it does not crack starting from the compound or the like 42.

This diffusion layer can be grasped as follows. After embedding the titanium composite material 1 in a resin so that the cross section parallel to the length direction (rolling direction) and the thickness direction (thickness cross section) is the observation surface, the observation surface is made using a diamond or alumina polishing liquid. Polish to finish the sample for observation. Using EPMA, line analysis is performed in the thickness direction so that the grains of 42 such as compounds observed in the above observation sample are at the center. The object of analysis is each constituent element (that is, Fe in the case of iron particles or iron compound particles, Al in the case of aluminum particles or aluminum compound particles, etc.). Based on the value of titanium 41 in the inner layer portion 4, the concentration is higher than that, and the region excluding the particles is the diffusion layer.

The thickness of the diffusion layer varies depending on various factors. For example, when a compound or the like is added, it is formed by (1) decomposition of the compound or the like and (2) diffusion of each constituent element to the periphery, so that the decomposition rate of the compound or the like and the titanium material of each constituent element are formed. It changes depending on the diffusion rate within. It also changes depending on the heat history at the time of manufacture. Further, it also changes depending on the degree of contact between the sponge titanium or the like and the powder such as metal when the package as the hot-rolled material is heated. Therefore, the thickness of the diffusion layer has various thicknesses of the diffusion layer even in the same material, and it is difficult to uniquely determine it, but compounds and the like and their constituent elements are present or exist. It is formed not a little around the part that has been removed.

(B-4) Thickness of Inner Layer 4 The thicker the inner layer 4 with respect to the total thickness of the titanium composite 1, the better the mechanical properties. Therefore, 20 is obtained with respect to the total thickness of the titanium composite 1. It is preferably more than%, more preferably more than 50%. On the other hand, if it is too thick, the workability deteriorates, so that the thickness of the inner layer portion 4 is preferably 95% or less with respect to the total thickness of the titanium composite material 1.

2. 2. Configuration of Packing Body 5 According to the Present Invention The titanium packing body 5 includes a titanium packing material 6 and fillers 7 and 8. The shape of the titanium packaging body 5 is not limited to a specific shape, but is determined by the shape of the titanium composite material 1 to be manufactured. When the titanium composite material 1 of the plate material is manufactured, a rectangular parallelepiped titanium packing body 5 is used. Further, in the case of manufacturing a round bar, a wire rod, or a titanium composite material 1 as an extruded material, a titanium packing body 5 having a polygonal pillar shape such as a cylinder or an octagonal pillar is used. The size of the titanium packing body 5 is determined by the size (thickness, width and length) of the product and the production amount (mass).

(A) Titanium packing material 6
(A-1) Titanium Packing Material 6 Chemical Composition As the titanium packing material 6, industrial pure titanium or a titanium alloy material belonging to JIS 1 to JIS 4 is used as in the surface layer portions 2 and 3 of the titanium composite material 1.

(A-2) Titanium packing material 6 shape Since the shape of the titanium packing material 6 depends on the shape of the titanium packing body 5 used as a material for hot processing, there is no particular fixed shape, and a plate material, a pipe material, or the like may be used. it can.

In order for the titanium composite material 1 manufactured through manufacturing processes such as hot working, cold working, and annealing to have excellent surface properties, retention of the inner layer portion 4, and workability, the thickness of the titanium packing material 6 is required. Is important.

When the thickness of the titanium packing material 6 is as thin as less than 1 mm, the titanium packing material 6 breaks during the hot working due to the plastic deformation, and a part of the inside of the titanium packing body 5 falls off. In this case, the vacuum is broken at the same time, and the titanium material 7 filled inside the titanium packing body 5 is oxidized. In addition, the undulations of the titanium material 7 filled inside the titanium packaging body 5 may be transferred to the surface of the titanium packaging body 5, causing large surface undulations during hot working.

As a result, the produced titanium composite material 1 deteriorates in mechanical properties such as surface texture or ductility. Further, if the titanium packing material 6 becomes excessively thin, the weight of the titanium material 7 filled therein may not be supported. Therefore, the rigidity of the titanium package 5 may be insufficient and the titanium package 5 may be deformed during room temperature, hot holding, or processing.

In order to produce a titanium composite material 1 which can be hot-worked without causing these problems and has excellent surface properties, retention of the inner layer portion 4 and workability, the thickness of the titanium packing material 6 is increased. , It is preferably 1 mm or more, and more preferably 2 mm or more.

Further, the thickness of the titanium packing material 6 is preferably 25% or less of the total thickness of the titanium packing body 5. If the thickness of the titanium packing material 6 is thicker than 25% of the total thickness of the titanium packing body 5, there is no particular problem in manufacturing, but the ratio of the titanium packing material 6 to the total thickness of the titanium packing body 5 is It becomes larger and the thickness of the inner or inner layer portion 4 becomes thinner. For this reason, the amount of metal equal to the inside of the titanium packaging body 5 is reduced, and the effect of improving mechanical properties is reduced, which is not preferable.

(B) Fillers 7, 8
(B-1) Titanium material 7
The titanium material 7 as a filler is one or more selected from sponge titanium, titanium briquette and titanium scrap.

(B-1-1) Chemical Composition of Titanium Material 7 As the chemical composition of the titanium material 7, industrial pure titanium corresponding to JIS type 1 to JIS type 4 can be used. That is, the chemical composition of C: 0.08% or less, H: 0.013% or less, O: 0.4% or less, N: 0.05% or less, Fe: 0.5% or less, the balance Ti and impurities. Have.

(B-1-2) Shape of Titanium Material 7 As the titanium material 7, ordinary sponge titanium produced by a smelting process such as a conventional Kroll process can be used. The size is preferably 20 mm or less in terms of average particle size. If the average particle size is larger than 20 mm, it is difficult to uniformly mix the powder 8 such as metal, and there is a possibility that the compound or the like may be uneven in the inner layer portion 4 of the titanium composite material 1 produced by hot working. On the other hand, when the average particle size is small, there is no problem in terms of characteristics, but when the average particle size of the titanium material 7 is less than 0.5 mm, it takes time to crush and a large amount of fine dust is scattered. Therefore, the manufacturing efficiency deteriorates. Therefore, the average particle size of the titanium material is preferably 0.5 mm or more.

As the titanium material 7, titanium scrap can be used. For example, titanium scrap is used as scraps that are not produced in the manufacturing process of industrial pure titanium material, titanium chips generated when cutting and grinding industrial pure titanium material to make it into a product shape, and as products. It is an industrial pure titanium material that is no longer needed after it has been used. If the titanium scrap is too large, there are problems that it is difficult to transport it and it is difficult to put it in the titanium packing body 5, so it is desirable to cut it appropriately.

Since titanium sponge or titanium scrap is lumpy, there are gaps 9 between the materials. In order to improve the handleability of titanium sponge or the like or reduce these voids, powder 8 of titanium sponge or the like and metal or the like is mixed in advance and then compression molded to form a briquette 10 as shown in FIG. You may put it in.

(B-2) Metal powder 8
(B-2-1) Chemical composition of powder 8 such as metal The powder 8 such as metal is, for example, a metal other than Ti (for example, Sn, Zr, Al, Mo, V, Nb, Fe, Cr, Cu, Co. Or Ni) powder, as well as its compounds (eg, Ti-Al, Al-V alloys, Al-4.5% Cu alloys, Ti-10% Zr, Zr-2.5% Nb, Al-V, Fe. -13Ni-24Cr, Fe-11Ni-19Cr, Fe-Cr, Fe-Mo, Ni-Cr, Cu-5% Al, Cu-8Al-2Fe, Cu-45% Ni, Ti-2.5% Cu, Ni -Cr, Cu-5% Ni, Ni-5% Al, Ni-16% Cr-6Fe, Ni-28Mo, Ni-32Mo-15Cr, Ni-5% Al, etc.) powders are exemplified. As these powders 8, commercially available powders 8 may be used.

(B-2-2) Shape of powder 8 such as metal When the average particle size of powder 8 such as metal exceeds 100 μm, it is difficult to uniformly mix with the titanium material 7. Therefore, the compound and the like cannot be uniformly dispersed in the inner layer portion 4 of the titanium composite material 1. Therefore, the average particle size of the metal or other powder 8 is preferably 100 μm or less.

On the other hand, if the average particle size of the powder 8 such as metal is smaller, there is no problem in terms of characteristics, but if it is too small, the powder is easily oxidized and the oxygen concentration in the inner layer of the titanium multi-layer material is increased. It becomes difficult to obtain predetermined characteristics. Further, when mixing with the titanium material 7 or filling the titanium packing body 5, dust scattering may become a problem and hinder the work. Therefore, the average particle size of the metal or other powder 8 is preferably 1 μm or more.

(C) Internal pressure of the packing body 5 If air remains in the gap 43 in the titanium packing body 5, the titanium material 7 is oxidized and nitrided during heating before hot working, and the titanium composite material to be manufactured is produced. The ductility of 1 decreases. Therefore, it is effective to reduce the pressure inside the titanium packing body 5 to create a high vacuum.

In order to prevent oxidation and nitriding of the titanium material 7 during hot working, the internal pressure (absolute pressure) of the titanium packing body 5 is preferably 10 Pa or less, preferably 1 Pa or less. If the internal pressure of the titanium packing body 5 is larger than 10 Pa, the titanium material 7 is oxidized or nitrided by the remaining air. Reducing the internal pressure extremely requires improvement of the airtightness of the device and enhancement of the vacuum exhaust device, which leads to an increase in manufacturing cost. Therefore, the lower limit of the internal pressure is set to 1 × 10 ^-3 Pa. Is good.

3. 3. Manufacturing Method of Titanium Composite Material 1 The titanium composite material 1 is manufactured by hot-working or further cold-working the titanium packaging body 5.

(A) Hot working method The hot working method can be selected according to the shape of the product. When the titanium composite material 1 of the plate material is manufactured, the titanium packing body 5 having a rectangular parallelepiped shape (slab) is heated and hot-rolled to obtain a titanium plate. If necessary, as in the conventional step, after hot rolling, the oxide layer on the surface may be removed by pickling or the like, and then cold rolling may be performed to further reduce the thickness.

When manufacturing a titanium composite material 1 of a round bar or a wire rod, the titanium packing body 5 having a cylindrical or polygonal shape (billet) is heated and hot-rolled or hot-extruded to obtain a titanium round bar or a wire rod. .. Further, if necessary, as in the conventional step, the oxide layer may be removed by pickling or the like after hot working, and then cold rolling may be performed to further reduce the thickness.

(A-1) Heating Temperature for Hot Processing Further, when the titanium composite material 1 of the extruded profile is manufactured, the titanium package 5 having a cylindrical or polygonal shape (billet) is heated to perform hot extrusion. , Titanium profiles with various cross-sectional shapes. The heating temperature before hot working may be the same as the heating temperature when hot working a normal titanium slab or billet. The heating temperature varies depending on the size of the titanium package 5 and the degree of hot working (processing rate), but it is preferable to heat the titanium package 5 to 600 ° C. or higher and 1200 ° C. or lower.

If the heating temperature is too low, the high temperature strength of the titanium package 5 is high and the deformability is low, so that cracks are likely to occur during hot working. In particular, if the welded portion of the titanium packaging body 5 is cracked to expose the inside and partly fall off, or if the inside is oxidized, the characteristics required for the titanium composite material 1 cannot be obtained. In addition, the diffusion layer of the constituent elements around the grains of the compound or the like is not formed, and the grains of the compound or the like in the inner layer cannot be sufficiently bonded to titanium. Therefore, when the titanium composite material is processed, cracks may occur starting from a compound or the like. On the other hand, if the heating temperature is too high, the structure of the obtained titanium composite material 1 becomes coarse, and sufficient material properties cannot be obtained. In addition, the packing material 6 on the surface is thinned by oxidation. Therefore, it is recommended that the heating temperature be 600 ° C to 1200 ° C.

(A-2) Processing rate of hot working The degree of processing during hot working, that is, the working rate can be selected in order to control the porosity of the inner layer portion 4 of the titanium composite material 1. The processing ratio referred to here is a ratio (percentage) obtained by dividing the difference between the cross-sectional area of the titanium packaging body 5 and the cross-sectional area of the titanium composite material 1 after hot processing by the cross-sectional area of the titanium packaging body 5.

When this processing rate is low, the voids 43 inside the titanium packing body 5 are not sufficiently crimped, so that the voids 43 remain even after hot processing. The titanium composite material 1 containing a large number of such voids is lighter by the amount of the voids contained therein, and there is no problem in the effect of improving mechanical properties. However, since there are many voids 43 existing in the inner layer portion 4, sufficient mechanical properties cannot be obtained. On the other hand, as the processing rate increases, the porosity decreases and the mechanical properties improve. Therefore, when the mechanical properties of the produced titanium composite material 1 are important, a high processing rate is preferable.

(B) Hot working process After hot rolling, it may be subjected to annealing or cold rolling. The titanium composite material 1 has no significant difference in the effect of improving mechanical properties between a hot-rolled material (for example, hot-rolled plate) and a cold-worked material (for example, cold-rolled plate). Further, the surface condition may be any of the rolled state, the pickling finish and the annealing finish, and the effect of improving the mechanical properties does not change.

4. Method for Manufacturing Titanium Package 5 (a) Mixing of Filling Materials 7 and 8 It is necessary to fill the titanium material 7 with powder 8 such as metal uniformly and at high density. For this purpose, the titanium material 7 and the powder 8 such as metal are filled in a container and rotated or vibrated, and the titanium material 7 inside and the powder 8 such as metal are mixed so as to be uniformly dispersed. Good.

The method of stirring is to rotate the container vertically, tilt it 20 to 70 ° from the horizontal and rotate it diagonally, vibrate the container vertically or horizontally, or insert a stirrer into the container to stir. Examples include a method of rotating the child.

The stirring time varies depending on the size of the container, the amount of the titanium material 7 to be mixed, and the amount of the powder 8 such as metal, but is preferably 1 to 30 minutes. Considering productivity, it is preferable to determine the size of the container and the amount to be processed so that the mixture can be uniformly mixed in a few minutes.

The mixed titanium material 7 and metal powder 8 are filled in the titanium packing body 5 as they are. Alternatively, in order to improve the handleability of the titanium material 7 and reduce these voids, the titanium briquette 10 may be compression-molded as shown in FIG. 5 and then stored in the titanium packing body 5.

(B) Welding Examples of the method of welding the titanium packing material 6 at the welded portion 11 include arc welding such as TIG welding and MIG welding, electron beam welding, laser welding and the like, and are not particularly limited. However, as for the welding atmosphere, it is preferable to perform welding in a vacuum atmosphere or an inert gas atmosphere so that the surfaces of the titanium material 7 and the titanium packing material 6 are not oxidized or nitrided.

When the joint (welded portion 11) of the titanium packing material 6 is finally welded, the titanium packing body 5 is placed in a container (chamber) in a vacuum atmosphere for welding, and the inside of the titanium packing body 5 is kept in a vacuum. Is preferable.

As shown in FIG. 6, the titanium briquette 10 which is mixed with powder 8 such as metal and compression-molded is covered with a titanium wrought material which is a packing material, and the entire circumference of the titanium wrought material is seam welded (resistance using a rotating electrode). The titanium packaging body 12 may be manufactured by welding) and sealing. At this time, the inside of the titanium wrought material is depressurized to a predetermined pressure through a copper tube in which a hole is made in advance at the end and the copper tube is brazed, and after the depressurization, the copper tube is crimped to extend the titanium. The pressure inside the material may be maintained.

5. Applications of Titanium Composite Material 1 Since it has high tensile strength and good workability and can be manufactured at low cost, it can be used as a structural member of land transportation equipment such as automobiles.

The titanium package shown in Table 1 was manufactured, and the titanium composite material 1 (plate material) was manufactured in the titanium package by the manufacturing process shown in Table 1.

As a filler, the particle size produced by the Kroll process is 2.5 mm or more and 6 mm or less, and the chemical composition is equivalent to JIS Class 1 (C: 0.002%, H: 0.001%, O: 0.03%, N: 0.001%, Fe: 0.03%, balance Ti and impurities) sponge titanium was used. Further, as a filler, commercially available Sn powder, Zr powder, Al powder, Mo powder, V powder, Nb powder, Fe powder, Cr powder, Cu powder, Co powder, Ni powder, Fe-10Ni-19Cr powder, Ni- 20Cr powder was used.

The above-mentioned titanium sponge and powder of metal or the like were mixed by putting a predetermined amount into a V-type mixer. The mixed material was put into a mold and compression molded to obtain a titanium briquette shown in FIG. 5 having a thickness of 15 mm, a width of 50 mm, and a length of 60 mm. For comparison, sample No. In No. 11, a titanium briquette was prepared by adding only the sponge titanium grains 7 and not adding the powder raw material 8.

As a titanium packing material, JIS type 1 (TP270C; C: 0.001%, H: 0.005%, O: 0.04%, N: 0.001%, Fe: 0.03%, balance Ti and impurities) Or JIS type 2 (TP340C; C: 0.002%, H: 0.004%, O: 0.09%, N: 0.001%, Fe: 0.05%, balance Ti and impurities) Industrial pure titanium A thin plate having a thickness of 1.0 mm made of wood was used.

As shown in FIG. 6, the titanium briquette was covered with an industrial pure titanium material as a packing material, and the entire circumference of the industrial pure titanium material was sealed by seam welding (resistance welding using a rotating electrode). This industrial pure titanium material was pre-drilled at the ends and brazed to a copper tube. After seam welding, the inside of the industrial pure titanium material is depressurized to a predetermined pressure (0.07 to 1.7 Pa) through a copper tube, and after the decompression, the copper tube is crimped to the inside of the industrial pure titanium material. I kept the pressure. Sample No. In No. 24, when the pressure was reduced to 42 Pa, a copper tube was crimped to form a package.

The produced titanium package was heated at 850 ° C. for 4 hours in an air atmosphere and then hot-rolled to produce a titanium composite material having a thickness of 2.0 mm. The titanium composite material was annealed at 725 ° C. for 15 minutes, then pickled to remove scale on the surface layer, and subjected to microstructure observation and tensile test.

After embedding the titanium composite material in a resin so that the cross section parallel to the length direction (rolling direction) and the thickness direction (thickness cross section) can be observed, the observation surface is polished with a diamond or alumina turbid solution ( Mirror finish), finished as an observation sample. For the porosity, 20 photographs were taken at the center of the thickness of the observation sample with an optical microscope, and the area ratio of the void was measured for each photograph to obtain the average value thereof. The morphology of the aggregates such as streaky compounds was determined by observing the central portion of the thickness of the observation sample with an optical microscope. In addition, the thickness t and the length L of 20 of the observed aggregates such as streak compounds were measured to calculate L / t, and the average value thereof was obtained.

The thickness of the diffusion layer was No. 1 to which Al powder, Mo powder, V powder, Nb powder, Fe powder, Cr powder, Co powder, and Ni powder were added. 5, No. 7, No. 9, No. 11, No. 13, No. 15, No. 19, No. With respect to 21, for 5 aggregates of streaky compounds, etc. observed in the center of the thickness of the above-mentioned observation sample, grains of 3 metals, etc. (metals or compounds of the metals) observed in the aggregates were observed by EPMA. It was measured. Line analysis is performed in the thickness direction so that the particles of metal, etc. are at the center, and the concentration of constituent elements (Al, Mo, V, etc.) such as metal is higher than that based on the value of titanium in the inner layer. , The distance of the region on one side excluding the particles was measured, and they were averaged to obtain the thickness of the diffusion layer of each aggregate such as streaks.

The tensile test was evaluated in the rolling direction of the titanium composite. The tensile speed was 0.4% / min until the yield point was exceeded, and 30% / min after the yield point was exceeded, and the strength was measured. In addition, Young's modulus was obtained from the gradient of the stress-strain curve until yielding.

The results are summarized in Table 1.

FIG. 7 is a photograph of the cross-sectional microstructure of the titanium composite material (Sample No. 14: Ti-5.0% Fe plate) according to the present invention.

As illustrated in FIG. 7, the sample No. which is an example of the present invention. When observing the cross-sectional structure of the titanium composite plate of 14, some compounds appearing black are observed. This black streak aggregate was an aggregate of TiFe compounds, and as a result of measurement by X-ray diffraction, it was TiN.

Sample No. of the example of the present invention in which a compound or the like is dispersed in titanium. Sample Nos. 1 to 24 which do not have a compound or the like. Compared with 25, the strength of the titanium composite material was improved.

On the other hand, the Young's modulus of the titanium composite material can be adjusted by the type and amount of the metal to be added.

Sample No. As shown in 1 to 4, the Young's modulus of the titanium composite material was not significantly different from that of the titanium plate even when Sn and Zr, which are neutral elements that dissolve in a large amount in the α and β phases, were added. Sample No. As shown in 5 and 6, Young's modulus could be increased by adding Al, which is an α-phase stabilizing element of titanium. When Mo, V, Nb, Fe, Cr, Cu, Co, and Ni, which are β-phase stabilizing elements of titanium, are added in a certain amount or more, the titanium β-phase becomes stable, so that the Young's modulus can be reduced. Sample No. to which Mo was added. Sample No. 7, 8 and V added in an amount of 3% or more. 10. Sample No. with 3% or more of Nb added. 12. Sample No. to which 0.06% by mass or more of Fe was added. Sample No. 13, 14 and Cr added in an amount of 0.7% or more. 16. Sample No. with 2% or more of Cu added. 18. Sample No. with 1% or more of Co added. 20. Sample No. with 0.3% or more of Ni added. In 21 and 22, sample No. 21 to which no metal powder was added. Young's modulus could be reduced as compared with 25.

Since V, Nb, Cr, Cu, Co, and Ni, which are β-phase stabilizing elements of titanium, form a titanium α-phase when the amount added is small, the Young's modulus can be increased. Sample No. with less than 3% V added. 9. Sample No. with less than 3% Nb added. 11. Sample No. with less than 0.7% Cr added. 15. Sample No. with less than 2% Cu added. 17. Sample No. with less than 1% of Co added. In No. 19, sample No. 19 to which no metal powder was added. Young's modulus could be increased as compared with 25.

Sample No. 1 in which the reduction rate of the titanium package 5 was small and the porosity of the inner layer portion 4 was large. In 26, the metal compound (TiCu, _Ti 2 Cu) are interspersed directional rather with voids, was cracked in fabricating tensile specimens.

No. to which Al powder was added. In No. 5, the thickness of the diffusion layer of Al was 3 to 6 μm. No. to which Mo powder was added. In No. 7, the thickness of the diffusion layer of Mo was 1 to 3 μm. No. to which V powder was added. In 9, the thickness of the diffusion layer of V was 3 to 5 μm. No. to which Nb powder was added. In No. 11, the thickness of the diffusion layer of Nb was 2 to 4 μm. No. to which Fe powder was added. In No. 13, the thickness of the diffusion layer of Fe was 15 to 21 μm. No. to which Cr powder was added. At 15, the thickness of the Cr diffusion layer was 3 to 6 μm. No. to which Co powder was added. At 19, the thickness of the diffusion layer of Co was 32 to 40 μm. No. to which Ni powder was added. In No. 21, the thickness of the diffusion layer of Ni was 16 to 22 μm.

As shown in Table 2, a titanium composite material was produced from a titanium package.

Titanium sponge used as a filler has a chemical composition equivalent to JIS 1 type (C: 0.001%, H: 0.001%, O: 0.04%, N: 0.001%, Fe) produced by the Kroll process. : 0.03%, balance Ti and impurities), sponge titanium B has a particle size of 6 mm or more and 13 mm or less, sponge titanium C has a particle size of 2.5 mm or more and 6 mm or less, and sponge titanium D has a particle size. Those having a diameter of 0.8 mm or more and 2.5 mm or less were used.

In addition, as titanium scrap, JIS type 2 (C: 0.002%, H: 0.006%, O: 0.08%, N: 0.001%, Fe: 0.05%, balance Ti and impurities) A thin plate cut into 10 to 20 mm squares was used in a part (Sample Nos. 29 and 33). Further, as the metal powder used as the filler, commercially available Fe powder and Cu powder were used. These titanium sponge particles and metal powder were mixed by putting a predetermined amount into a V-type mixer.

As the material of the packing material, the industrial pure titanium material is JIS type 1 (TP270HC: 0.002%, H: 0.006%, O: 0.04%, N: 0.002%, Fe: 0.03%. , Remaining Ti and impurities), JIS2 type (TP340H; C: 0.001%, H: 0.002%, O: 0.10%, N: 0.002%, Fe: 0.06%, Remaining Ti and An impurity) and a 10 mm thick plate pickled with Ti-0.06% Pd were used.

As shown in FIG. 4, five pieces of industrial pure titanium material are temporarily assembled and filled with sponge titanium grains or a mixture (filler) of titanium scrap and metal powder, and the remaining industrial pure titanium material. The lid was covered with the titanium packing material.

In this state, the mixture was placed in a vacuum chamber, depressurized (vacuum) until a predetermined pressure was reached, and then the seams of the packing material were welded with an electron beam all around. The pressure in the chamber at this time was 8.8 × 10 ^{-3 to} 3.6 × 10 ^-1 Pa.

As described above, a titanium packing body having a vacuum atmosphere was prepared by filling the inside with a mixture of titanium sponge or titanium scrap and metal powder. The size of the titanium package was 80 mm in thickness × 100 mm in width × 120 mm in length.

The produced titanium package was heated at 850 ° C. for 6 hours in an air atmosphere and then hot-rolled to produce a titanium composite plate having a thickness of 5 mm. Then, the titanium composite material was annealed at 725 ° C. for 15 minutes and then pickled to remove the scale of the surface layer and subjected to a tensile test. The structure was observed and the tensile test was carried out in the same manner as in Example 1, and the porosity of the titanium composite material, the morphology and size L / t of the compound and the like, the thickness of the diffusion layer, the strength and the Young's modulus were determined.

The results are summarized in Table 2.

When JIS2 type industrial pure titanium was used as the packing material, the sample No. which is an example of the present invention to which metal powder was added. 27 to 29, 31 to 33, 35 are sample Nos. No. 27 to which no metal powder was added. Compared with 37, the strength of the titanium composite material was improved.

In addition, the sample No. which had a small reduction rate of the titanium package and a large porosity of the inner layer portion. In No. 39, the metal compound (TiFe) was scattered together with the voids in a non-directional manner and cracked when the tensile test piece was manufactured.

When a soft JIS Class 1 industrial pure titanium or Ti-0.06% Pd alloy was used for the packing material 6, the sample No. 1 which is an example of the present invention to which a metal powder was added. Nos. 30 and 34 are sample numbers to which no metal powder is added. Compared with 36, the strength of the titanium composite material 1 was improved.

When a thin sheet scrap having an oxygen content of 0.08% by mass was used as the filler, the sample No. 1 which is an example of the present invention to which a metal powder was added. 29 and 33 are sample Nos. No. 29 and 33 to which no metal powder was added. Compared with 38, the strength of the titanium composite material 1 was improved.

Sample No. to which 0.5 to 2.5% of Fe, which is a β-phase stabilizing element of titanium, was added. Nos. 27 to 31 are sample Nos. No. 27 to which no metal powder was added. Young's modulus was smaller than 37.

Sample No. in which less than 2% of Cu, which is a β-phase stabilizing element of titanium, was added. In Nos. 32 to 34, since the titanium β phase is not stable and the α phase is stable, the sample No. 32 to which no metal powder is added is used. Young's modulus was higher than 37. In addition, sample No. in which 2% or more of Cu was added. In No. 35, the titanium β phase became stable, and sample No. 35 to which no metal powder was added. Young's modulus was smaller than 37.

Sample No. using soft JIS Class 1 industrial pure titanium as the packing material. No. 30 is a sample No. 30 using JIS2 type industrial pure titanium as a packing material. A titanium composite material having better workability can be obtained as compared with 27 to 29, 31 to 33, 35. In addition, Sample No. using Ti-0.06% Pd as the packing material. Reference numeral 34 is a sample No. 34 in which JIS 2 type industrial pure titanium was used as the packing material. A titanium composite material having better corrosion resistance can be obtained as compared with 27 to 29, 31 to 33, 35.

No. to which Fe powder was added. At 27, the thickness of the diffusion layer of Fe was 12 to 18 μm. No. to which Cu powder was added. At 32, the thickness of the diffusion layer of Cu was 10 to 15 μm.

Sample No. 2 which is a titanium composite material having a thickness of 5 mm and shown in Table 2 obtained by hot rolling. 28, 35, 37 were annealed at 725 ° C. for 15 minutes and then pickled to remove surface scale. The titanium composite (hot rolled material) from which the scale had been removed was cold-rolled to a thickness of 1.0 mm, and then annealed at 700 ° C. for 15 minutes using a vacuum heating furnace to be subjected to a tensile test. The structure was observed and a tensile test was carried out in the same manner as in Example 1, and the porosity of the titanium composite material, the form and size L / t of the compound and the like, the thickness, strength and Young's modulus of the diffusion layer were determined.

The results are summarized in Table 3.

Sample No. which is an example of the present invention. Nos. 40 to 45 are sample numbers 40 to 45 in which the metal powder is added and the metal powder is not added. Compared with 46 to 48, the strength of the titanium composite material was improved. In addition, the sample No. which is an example of the present invention. Since the inner layer portion of the titanium composite material of 40 to 45 contains a large amount of Fe and Cu which are β-phase stabilizing elements, the sample No. 4 to which no metal powder is added is added. Young's modulus was smaller than 46-48. No. to which Fe powder was added. At 41, the thickness of the diffusion layer of Fe was 5 to 8 μm. No. to which Cu powder was added. At 44, the thickness of the diffusion layer of Cu was 4 to 8 μm.

1 Titanium composite 2 Surface layer 3 Surface layer 4 Inner layer 41 Titanium 42 Compounds, etc. (metals other than titanium or compounds thereof)
42a Aggregate of streaky compounds, etc. 43 Void 5 Titanium packing body 6 Titanium packing material 7 Sponge titanium 8 Metal powder 9 Void 10 Bricket 11 Welded part 12 Titanium packing body

Claims (5)

A titanium composite material having an inner layer portion and a surface layer portion covering the inner layer portion.
The surface layer portion is made of an industrial pure titanium material or a titanium alloy material having a chemical composition belonging to any of JIS types 1 to 4.
The inner layer portion includes a portion in which a metal other than titanium or a compound thereof is dispersed in titanium and the metal element is diffused around the metal or the compound, and the metal other than titanium or the compound thereof is in a rolling direction. It is dispersed in the titanium as streaky aggregates lined up in a row, and has voids of more than 0% and 30% or less in terms of area ratio.
Titanium composite material. The metal is one or more selected from Sn, Zr, Al, Mo, V, Nb, Fe, Cr, Cu, Co and Ni.
The titanium composite material according to claim 1. The streaky aggregate satisfies the following equation (1) when its length is L (μm) and its thickness is t (μm).
The titanium composite material according to claim 1 or 2.
2.0 ≤ L / t ≤ 100 ... (1) The chemical composition of the industrial pure titanium material is mass%.
C: 0.08% or less,
H: 0.013% or less,
O: 0.4% or less,
N: 0.05% or less,
Fe: 0.5% or less,
Remaining: Ti and impurities,
The titanium composite material according to any one of claims 1 to 3. Titanium packing material made of industrial pure titanium material or a titanium alloy material belongs to one of the JIS1~4 species, a packaging body and a filled filler inside the titanium packing materials,
The filler has one or more selected from titanium sponge, titanium briquette and titanium scrap, and powder of a metal other than titanium or a compound thereof, and the internal pressure is 10 Pa or less.
Packing body for hot processing.

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