TW201812039A - Titanium composite material and method for manufacturing same, and package - Google Patents

Abstract

A titanium composite material 1 has an inner layer part 4 and outer layer parts 2, 3, the outer layer parts 2, 3 comprise titanium alloy or commercially pure titanium having a chemical composition belonging to any of JIS types 1 through 4, and the inner layer 4 is provided with a portion in which one or more types of titanium compounds selected from a carbide, a nitride, and an oxide are dispersed in titanium, carbon being diffused on the periphery of the carbide, nitrogen being diffused on the periphery of the nitride, and oxygen being diffused on the periphery of the oxide, and has voids in an area ratio of more than 0% to no more than 30%. The titanium composite material 1 has excellent mechanical characteristics and can be manufactured at low cost.

Description

   Titanium composite material, manufacturing method thereof and packing body   

The invention relates to a titanium composite material, a manufacturing method thereof, and a packing body.

Titanium is a metal material with excellent corrosion resistance, so it has been used in heat exchangers using seawater or various chemical plants. In addition, since its density is smaller than that of carbon steel and its specific strength (strength per unit weight) is excellent, it is also used in a large amount in aircraft bodies. In addition, since a titanium material is used in land transportation equipment such as automobiles, the land transportation equipment itself becomes lightweight, and a reduction in fuel cost can be expected.

However, compared with steel, titanium is produced through complicated and very many steps. The representative manufacturing steps are as exemplified below: (1) Chain-making step: chlorinating titanium oxide as a raw material to form titanium tetrachloride, and then reducing it with magnesium or sodium to produce a sponge-like (lumpy) Steps of metal titanium (hereinafter referred to as "sponge titanium"); (2) melting step: a step of pressing titanium sponge to form an electrode and melting it in a vacuum arc melting furnace to produce an ingot; (3) forging Steps: Steps of making ingots as hot forging to produce flat embryos (hot-rolled materials) or small embryos (materials such as hot extrusion or hot rolling); (4) Hot processing steps: heating the flat embryos or small embryos It is also used for the steps of hot rolling or extrusion to manufacture plates or round bars, etc .; (5) Cold working step: the step of cold rolling or pressing the plates or round bars to manufacture thin plates or round bars, wires, etc.

Titanium is very expensive because it is manufactured in so many steps. Therefore, titanium materials can hardly be applied to land transportation equipment such as automobiles. Therefore, in order to promote the use of titanium, it is necessary to improve the productivity of its manufacturing steps. In order to cope with this problem, there is a matching mechanism that simplifies the manufacturing steps of titanium

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

Patent Document 2 discloses a method for manufacturing a titanium alloy round rod by adding copper powder, chromium powder, or iron powder to a titanium alloy powder, encapsulating the same in a carbon steel envelope, and heating and extruding it. According to this method, since the melting step and the forging step described above can be omitted, the manufacturing cost can be reduced.

Patent Document 3 discloses a method for manufacturing a round rod by filling sponge titanium powder in a copper package and preheating it at 700 ° C. or lower and performing warm extrusion processing. According to this method, since the melting step and the forging step described above can be omitted, the manufacturing cost can be reduced.

In addition, the previously known laminated sheet rolling method is a method of coating a core material such as a titanium alloy with poor workability with a coating material such as carbon steel with good processability and then hot rolling. For example, after applying a release agent to the surface of the core material, at least two sides of the core material are covered with a covering material, or four peripheral surfaces are covered with a covering material in addition to the upper and lower surfaces, and the seam is welded to make a closed covering box. Then, the inside was evacuated and sealed, and then hot rolled.

Regarding lamination rolling, Patent Document 4 discloses a method for assembling a closed coating box; Patent Document 5 discloses a method of setting a vacuum degree of 10 ^-3 torr (about 0.133Pa) and sealing (packaging) the coating material. And a method for manufacturing a closed coating box; Furthermore, Patent Document 6 discloses a method of coating with carbon steel (coating material) and sealing by high energy density welding under a vacuum of 10 ^-2 torr (approximately 1.33Pa). (Packaging), a method for manufacturing a closed covered box.

According to these laminated rolls, since the core material of the rolled material is covered with a covering material and hot-rolled, the surface of the core material does not directly contact the cold medium (air or roller), and the core material can be suppressed. The temperature is reduced, so that even a core material with poor workability can produce a thin plate.

As the covering material, an inexpensive carbon steel or the like is used which is a material different from the core material and has good workability. Since the covering material becomes unnecessary after hot rolling, in order to make it easy to separate from the core material, the surface of the core material is coated with a release agent.

    [Previous technical literature]         [Patent Literature]    

[Patent Document 1] Japanese Patent Laid-Open No. 2011-042828

[Patent Document 2] Japanese Patent Laid-Open No. 2014-019945

[Patent Document 3] Japanese Patent Laid-Open No. 2001-131609

[Patent Document 4] Japanese Patent Laid-Open No. 63-207401

[Patent Document 5] Japanese Patent Laid-Open No. 09-136102

[Patent Document 6] Japanese Patent Laid-Open No. 11-057810

According to the method disclosed in Patent Document 1, high-priced titanium powder (average particle diameter of 4 to 200 μm) is used as a raw material, and many steps such as sintering or compacting are required. Therefore, the obtained titanium sheet is very expensive and cannot be obtained. Promote the use of titanium.

According to the method disclosed in Patent Document 2, because a titanium powder alloy with a high price is used as a raw material, the obtained titanium alloy round rod is expensive and fails to promote the use of a titanium material. In addition, since the sponge titanium powder is oxidized during heating, the surface layer and the inside of the obtained round rod contain titanium oxide. Compared with the round rod produced in the general process, there are problems such as appearance discoloration and deterioration in tensile properties.

According to the method disclosed in Patent Document 3, since the sponge titanium powder is oxidized during heating, the surface layer and the inside of the obtained round rod contain titanium oxide. Compared with the round rod manufactured by ordinary steps, the round rod has discoloration and tensile properties. Problems such as deterioration.

In addition, according to the methods disclosed in Patent Documents 4 to 6, since the covering material is peeled off and discarded after being rolled, such as lamination rolling, the manufacturing cost becomes higher than ordinary steps, and the obtained titanium material The fact that it is high cost has not changed.

Therefore, the titanium material has not reached the point where it can be applied to land transportation equipment such as automobiles.

The present invention was developed based on such facts, and its purpose is to provide titanium materials such as titanium plates or titanium rods at a low cost.

In order to solve the above-mentioned problems, the present inventors devotedly studied the means for manufacturing titanium materials without omitting the melting step and the forging step, and obtained the narrative general knowledge and opinions (A) ~ (F) listed below, and finally completed this invention.

(A) It is not a high-priced titanium powder or a sponge-like titanium powder, but an irregular and sponge-like (lumpy) sponge titanium is used as a raw material. Sponge-like sponge titanium has been manufactured since earlier and can be obtained at a lower cost. In addition, the main impurities such as iron and chlorine of the sponge titanium are removed in the chain-making step, so even if the titanium material is directly produced from the sponge titanium, there is no problem in chemical composition. In addition, a titanium material (hereinafter, referred to as a "titanium scrap") which cannot be used as an undercut of a product can be obtained relatively inexpensively. However, the titanium scrap is irregular, so it cannot be processed and manufactured directly.

(B) If the container is made of a pure titanium material or titanium alloy material for industrial use (hereinafter referred to as a "packaging material"), and it is a titanium packaging body that contains a filling material such as sponge titanium and is hermetically sealed, During hot working, it is possible to suppress the occurrence of surface cracks such as surface cracks and scale-like defects. In particular, by setting the chemical composition of the filler material to be the same as that of the pure titanium material, there is no need to peel and discard the coating material after rolling, as in the previous laminated sheet rolling. After processing, it can be effectively used as a part of the titanium composite material (product).

(C) In order to prevent the filling materials such as sponge titanium from being oxidized when heating before hot working, and to easily reduce the gap between the filling materials or between the filling material and the packing material during hot processing, it is important to pack The internal pressure of the material should be reduced as much as possible in advance.

(D) As a packing material contained in a packing material, titanium compound such as sponge titanium is filled with one or more powders selected from carbon, carbide, nitride, and oxide to improve titanium compounding. Tensile strength of wood.

(E) That is, because the tough material (stretch material) of industrial pure titanium, that is, the titanium packing material, is filled and sealed with sponge titanium, and it is selected from carbon and carbide to improve the tensile strength of the titanium composite material. Powder of at least one of nitride, oxide, and oxide, and the internal pressure is reduced to form a titanium bundle body. This titanium bundle body is hot-processed and further cold-processed as necessary to form a titanium composite material. The result is that the assembly of titanium blocks before thermal processing, that is, the titanium packing body, becomes a titanium composite material (three-layer clad material) that is integrally compressed and integrated after thermal processing.

(F) The titanium composite material is a compression-molded body in which only the inner layer portion contains titanium containing one or more titanium compounds selected from carbides, nitrides, and oxides, which can improve the tensile strength of the titanium composite material, and the surface layer portion is Industrial pure titanium or a tough material of titanium alloy material has excellent workability and high tensile strength, and can be manufactured without the previous melting step and forging step, so the manufacturing cost can be greatly reduced.

The invention is described as listed below.

(1) A titanium composite material is a titanium composite material having an inner layer portion and a surface layer portion covering the inner layer portion, and the surface layer portion includes an industrial pure titanium material having a chemical composition of any one of JIS 1 to 4 or Titanium alloy material, the inner layer part is a titanium compound in which one or more titanium compounds selected from carbides, nitrides, and oxides are dispersed, and the periphery of the carbides is carbon, and the periphery of the nitrides is nitrogen. The portions surrounding the above oxides are oxygen and diffuse separately, and have an area ratio of greater than 0% and less than 30%.

(2) The titanium composite material according to the above (1), wherein the total of the average content of carbon, nitrogen, and oxygen in the inner layer portion is 0.05 to 2.0% by mass, and the titanium compound is a strip arranged along the rolling direction The compound-like aggregate is dispersed in a titanium material.

(3) The titanium composite material as described in (1) or (2) above, wherein the chemical composition of the above-mentioned industrial pure titanium material is expressed as mass%: C: 0.08% or less, H: 0.013% or less, O: 0.4% Below, N: 0.05% or less, Fe: 0.5% or less, and the rest: Ti and impurities.

(4) A method for manufacturing a titanium composite material, which is filled with a material selected from the group consisting of sponge titanium and titanium blocks by using a titanium packing material including industrial pure titanium material or titanium alloy material belonging to any of JIS1 to 4 And titanium scraps, and at least one powder selected from carbon, carbides, nitrides, and oxides are sealed, and the internal pressure is reduced to 10 Pa or less to form a titanium bundle. The titanium package is hot-worked.

(5) The method for producing a titanium composite material according to the above (4), wherein the hot working is performed before the cold working.

(6) A packaging body for thermal processing, comprising: a titanium packaging material including industrial pure titanium materials or titanium alloy materials belonging to any one of JIS1 to 4; and a titanium packaging material filled inside the titanium packaging material. Packing body of filling material; The filling material includes: one or more powders selected from sponge titanium, titanium block and titanium scrap, and one or more powders selected from carbon, carbide, nitride, and oxide; The pressure is 10 Pa or less.

The titanium composite material of the present invention is excellent in mechanical properties such as tensile strength and Young's modulus, and can be manufactured without a melting step and a forging step, so the manufacturing cost can be greatly reduced. In addition, the titanium composite material of the present invention can be removed without cutting and removing a large number of defective portions on the surface layer and the bottom surface of the ingot, and the front and rear end portions (cutting heads) of the surface after cracking or poor shape after forging. Manufacturing is not performed by cutting or removing a large amount of titanium material, so the manufacturing yield can be greatly improved, and the manufacturing cost can be greatly reduced at this point.

1‧‧‧ titanium composite

2‧‧‧ Surface Department

3‧‧‧ Surface Department

4‧‧‧ Inner Department

41‧‧‧ Titanium

42‧‧‧ titanium compounds

42a‧‧‧ Strip Compound

43‧‧‧Gap

5‧‧‧ titanium package

6‧‧‧Titanium packing material

7‧‧‧ titanium sponge

8‧‧‧ titanium powder

9‧‧‧ gap

10‧‧‧ block

11‧‧‧ Welding Department

12‧‧‧ titanium package

Fig. 1 is an explanatory diagram showing an example of the constitution of the titanium composite material of the present invention.

Fig. 2 is a view schematically showing a strip-shaped compound aggregate 42a.

FIG. 3 is a diagram showing the concept of the distance between the thickness direction of one particle and the element concentration distribution around the titanium composite material 1 in a section (thickness section) parallel to the longitudinal direction (rolling direction) and the thickness direction.

FIG. 4 is an explanatory diagram showing an example of the structure of a titanium bundle which is a material for thermal processing of a titanium composite material according to the present invention.

Fig. 5 is an explanatory diagram showing an example of the structure of a titanium block.

Fig. 6 is an explanatory diagram showing another example of the structure of the titanium packing body of the present invention.

Figure 7 is a photograph of the cross-section microstructure of a Ti-0.1% N plate.

The titanium composite material and the titanium packing body of the present invention will be described with reference to the drawings. In addition, the "%" in the chemical composition means "mass%" without special objection.

    1. Composition of the titanium composite material 1 of the present invention    

FIG. 1 is an explanatory diagram showing an example of the configuration of the titanium composite material 1 of 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 parts 2, 3         (a-1) Chemical composition of surface layer parts 2 and 3    

As the industrial pure titanium material forming the surface layer portions 2 and 3, an industrial pure titanium material having a chemical composition of any one 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 chemical composition of the remaining portions of Ti and impurities.

In addition, the above-mentioned JIS types 1 to 4 are those specified in JISH4600: 2012. JIS1 refers to the composition of: 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, the rest of Ti and impurities. JIS2 refers to the composition of: 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, the rest of Ti and impurities. JIS3 refers to the composition of: 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, the rest of Ti and impurities. JIS4 refers to the composition of: 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, the rest of Ti and impurities.

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 (here, Mm refers to a mixed rare earth metal), Ti-0.5Ni-0.05Ru, and 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-0.4Mo-0.45Si, etc.

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, and Ti- 6Al-2Sn-4Zr-6Mo, Ti-1Fe-0.35O, Ti-1.5Fe-0.5O, Ti-5Al-1Fe, Ti-5Al-1Fe-0.3Si, Ti-5Al-2Fe, Ti-5Al-2Fe- 0.3Si, Ti-5Al-2Fe-3Mo, Ti-4.5Al-2Fe-2V-3Mo, etc.

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

    (a-2) Thickness of surface layer parts 2 and 3    

If the thickness of the surface layer portions 2 and 3 of the titanium composite material 1 is too thick, the thickness of the inner layer portion 4 becomes thin, so that the effect of improving mechanical properties cannot be sufficiently obtained. Therefore, the thickness of the surface layer portions 2 and 3 is preferably 40% or less per one side, and more preferably 25% or less per one side relative to the full 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 thicker, so that the effect of improving mechanical properties is increased. 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 broken and the inner layer portion 4 appears on the surface, so that the titanium compound located in the inner layer portion 4 falls off, or the Titanium compounds appearing on the surface are the starting point and surface cracks or end cracks occur. In addition, if a liquid such as water comes into contact with it, the problem that the liquid invades the inner layer portion 4 occurs. Therefore, the thickness of the surface layer portions 2 and 3 should preferably be 0.1 mm or more.

    (b) Inner layer part 4    

The inner layer portion 4 is a titanium compound 42 dispersed in titanium 41 and has respective constituent elements around the titanium compound (that is, the periphery of the carbide is carbon, the periphery of the nitride is nitrogen, or an oxide). The surrounding area is oxygen) diffused (not shown), and has an area 43 in an area ratio of greater than 0% to 30%.

    (b-1) Chemical composition of inner layer part 4    

As titanium constituting the inner layer portion 4 of the titanium composite material 1, industrial pure titanium of JIS1 to JIS4 can be used, for example. That is, the titanium system as a general impurity contains 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 rest is Ti for industrial use. titanium.

In particular, if JIS1 ~ 3 kinds of industrial pure titanium are used, they will have sufficient processability without cracking, etc., and they can be integrated with the industrial pure titanium forming the surface layer parts 2 and 3 after hot working. Of titanium composite material 1.

The rest other than the above are impurities. As an impurity, it can be contained in the range which does not reduce processability and the improvement effect of a mechanical characteristic. Impurities other than the above are mainly impurity elements mixed from scrap materials, including Al, V, Cr, Nb, Si, Sn, Mo, Cu, etc., and general impurity elements (C, N, Fe, O, H ) Total, the total is allowable below 5%.

Since the inner layer portion 4 can provide the titanium composite material 1 with good mechanical properties, it is used in which one or more titanium compounds selected from carbides, nitrides, and oxides are dispersed in titanium. In order to obtain the above-mentioned effects in the inner layer portion 4, the total of the average contents of carbon, nitrogen, and oxygen is preferably 0.05 to 2.0% by mass. The preferable range of the average content of each element and the reason for limitation are described below.

    [C: 0.001 ~ 0.1%]    

If the average concentration of C is less than 0.001%, the effect of increasing the strength of the inner layer portion 4 more than the surface layer portions 2 and 3 can hardly be confirmed, and the mechanical properties of the titanium composite material 1 cannot be improved. On the other hand, if the average concentration of C is more than 0.1%, the toughness of the inner layer portion 4 will be deteriorated, resulting in frequent cracking during hot working or cold working, and the thickness and thickness of the inner layer portion 4 will be cut off and peeled off. Possibility to maintain the shape of the titanium composite material 1. Therefore, the average concentration of C in the inner layer portion 4 should be set to 0.001 to 0.1%.

    [N: 0.001 ~ 0.5%]    

If the average concentration of N is less than 0.001%, the effect of increasing the strength of the inner layer portion 4 more than the surface layer portions 2 and 3 can hardly be confirmed, and the characteristics of the titanium composite material 1 cannot be improved. On the other hand, if the average concentration of N is more than 0.5%, the toughness of the inner layer portion 4 will be deteriorated, resulting in frequent cracking during hot working or cold working, and the thickness and thickness of the inner layer portion 4 will be cut off and peeled off. Possibility to maintain the shape of the titanium composite material 1. Therefore, the average concentration of N in the inner layer portion 4 is preferably set to 0.001 to 0.5%.

    〔O: 0.01 ~ 1.0%〕    

If the average concentration of O is less than 0.01%, the effect of increasing the strength of the inner layer portion 4 more than the surface layer portions 2 and 3 can hardly be confirmed, and the characteristics of the titanium composite material 1 cannot be improved. On the other hand, if the average concentration of O is more than 1.0%, the toughness of the inner layer portion 4 will be deteriorated, resulting in frequent cracking during hot working or cold working, and the thickness and thickness of the inner layer portion 4 will be cut off and peeled off. Possibility to maintain the shape of the titanium composite material 1. Therefore, the average concentration of O in the inner layer portion 4 is preferably set to 0.01 to 1.0%.

The composition analysis of the surface layer portion and the inner layer portion can be performed by a known method (for example, JIS H 1612 (1993), JIS H 1614 (1995), JIS H 1615 (1997), JIS H 1617 (1995), JIS H 1619 (2012 ), JIS H 1620 (1995)). At this time, the measurement was performed after cutting out the surface layer portion and the inner layer portion from the titanium composite material. The surface layer is used to analyze the cutting powder obtained by processing such as cutting, and the inner layer is used to analyze the residual material after the surface layer is removed. The analysis sample was taken from the central portion of the surface layer portion and the inner layer portion in the thickness direction of 0.5 g or more. If the thickness of the surface layer part or the inner layer part is thin and a sufficient amount of cut powder cannot be obtained, the entire component analysis of the titanium composite material can be performed, and the analysis value, surface layer part or inner layer part can be analyzed. Values and their respective plate thicknesses, and calculate (inversely calculate) the components of the surface layer or the inner layer portion.

    (b-2) Void ratio of inner layer portion 4    

If the porosity of the voids 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, although the number of voids 43 is preferably as small as possible, in order to completely press the voids, it is necessary to perform pressing under a large pressure. As a result, the shape (thickness) of the manufactured titanium composite material 1 is limited, and the manufacturing cost also increases.

On the other hand, in order to maintain the structure as the titanium composite material 1 and contain the voids 43 to such an extent that it has sufficient mechanical characteristics (strength, ductility, etc.), the density of the inner layer portion 4 becomes low, and the titanium composite material can be obtained. Lightweight.

As described above, when the mechanical properties of the bulk metal are important, the porosity is reduced. On the other hand, when the weight reduction of the titanium composite 1 is given priority, the porosity is increased. If so, the porosity can be selected according to the application. The range of the porosity at this time is preferably greater than 0% and 30%, and more preferably greater than 0% and 10%. Moreover, by setting the porosity to 10% or less, it can have mechanical properties not inferior to those of general industrial pure titanium.

The ratio (void ratio) of the voids 43 remaining in the inner layer portion 4 of the titanium composite material 1 can be calculated as follows. After the titanium composite material 1 is embedded in the resin so that the thickness cross section parallel to the longitudinal direction (rolling direction) can be observed, the observation surface is ground (mirror-finished) using diamond diamond or alumina suspension, and finally processed for observation Sample.

The observation sample subjected to the mirror surface processing was photographed with an optical microscope at the center of the thickness of 20 locations at different locations. Here, the center portion in the case where the titanium composite material 1 is a plate means the center of the plate thickness, and in the case where it is a round rod, it means the center of a circular cross section. The area ratio of the voids 43 observed in the optical microscope photograph was measured, and the average value of the void fraction values of the 20 photographs was calculated as the void fraction.

Moreover, when taking a photograph of a tissue with an optical microscope, an appropriate magnification is selected in accordance with the size or void ratio of the titanium composite material 1. For example, when the void ratio is 1% or less, since there are few voids, it is advisable to observe at a high magnification of about 500 times and take a photograph. When the porosity is 10% or more, large voids increase, so it is appropriate to observe at a low magnification of about 20 times and take photos for photography. When the void ratio is 1% or less as the voids become smaller, a differential interference microscope capable of polarized observation can be used to observe more clearly than a general optical microscope.

    (b-3) Organization of inner layer 4    

As shown in FIG. 1, a large amount of the titanium compound 42 is contained in the inner layer portion 4 in the titanium composite material 1. This titanium compound 42 is composed of respective constituent elements around the titanium compound 42 (that is, the periphery of the carbide is carbon, the periphery of the nitride is nitrogen, or oxidation) according to thermal processing or the like in the manufacturing process of the titanium composite material 1. The periphery of the object is oxygen) will diffuse into the titanium 41, and each of the constituent elements that cannot be dissolved in the titanium 41 remains in a state where the titanium compound 42 is dispersed in the titanium material 41. At this time, the titanium compounds 42 are aligned in the processing (rolling) direction to form a strip-shaped compound aggregate 42a. In addition, the titanium compound 42 includes a compound in which carbon is present in addition to a compound completely formed. For example, when carbon is used as a material of a titanium compound, although carbon reacts with titanium to form a titanium compound during the manufacturing process such as hot rolling, there may be cases where carbon that has not reacted with titanium remains in the titanium compound.

    (b-3-1) Shape of titanium compound    

Fig. 2 is a view schematically showing a strip-shaped compound aggregate 42a. As shown in FIG. 2, the strip-shaped compound aggregate 42 a means that the distance D between the centers of the particles of the titanium compound 42 projected in the rolling direction (hereinafter, referred to as “inter-particle distance”) is a plural number of 20 μm or less. An assembly of titanium compound 42. In addition, in this specification, when the distance between particles exceeds 20 micrometers, this is considered as another strip compound compound.

The thickness of the strip-shaped compound assembly 42a (that is, the size in the compression processing direction) is preferably 100 μm or less. This is because if the thickness exceeds 100 μm, the possibility of cracking from the titanium compound 42 as a starting point increases when the titanium composite material is processed. On the other hand, regarding the strip-shaped compound assembly 42a, the length L (that is, the size in the processing direction) should be 2.0 times or more the thickness (thickness) t in the thickness direction (that is, L / t ≧ 2.0), and more It is preferably 3.0 times or more (that is, L / t ≧ 3.0). This is because if the length L is small, the inner layer portion is easily broken when the titanium compound is used as a starting point when subjected to tensile stress. In addition, L / t ≦ 100 is preferable, and L / t ≦ 40 is more preferable.

The size (length L and thickness t) of the strip-shaped compound aggregate 42a is calculated in the following manner. The titanium composite material 1 is embedded in the resin so that its cross-section (thickness cross-section) parallel to the length direction (rolling direction) and thickness direction is set as the observation surface, and the observation surface is polished with diamond or alumina suspension for final processing. Observation sample.

Photographs were taken of 20 locations at different locations in the center of the thickness of the observation surface using an optical microscope. Here, the thickness center portion refers to the thickness center portion of the plate in the case where the titanium composite material 1 is a plate, and refers to the center of a circular section in the case of a round bar. From the obtained 20 photos, the length L and the thickness t of the strip-shaped compound aggregate 42a were measured, and the average value of each value was taken as the length L and the thickness t to calculate L / t.

    (b-3-2) Existence of diffusion layer    

Around each particle of the titanium compound 42, there is a diffusion layer of each constituent element (that is, carbon in the case of carbide, nitrogen in the case of nitride, and oxygen in the case of nitride). The diffusion layer refers to a titanium compound 42 dispersed in the titanium 41 of the inner layer portion 4. The constituent element (carbon, nitrogen, or oxygen) diffuses to the surrounding titanium 41 with the titanium compound 42 as the center, and forms a layer having a concentration gradient. .

FIG. 3 is a diagram showing the concept of the distance between the thickness direction of one particle and the concentration distribution of its constituent elements in a section (thickness section) of the titanium composite material 1 parallel to the length direction (rolling direction) and thickness direction. . The diffusion layer is diffused from the particles of the titanium compound 42 to the surroundings when the titanium composite 1 is heated and held (heating before hot rolling, heat treatment during hot rolling, heat treatment after hot rolling, etc.). A layer formed of titanium 41. As shown in FIG. 3, each of the constituent elements in the diffusion layer is contained more than the value of each constituent element contained in the titanium 41 of the inner layer portion 4. By this existence of a diffusion layer, the particles of the titanium compound 42 of the inner layer portion 4 and the titanium 41 are strongly bonded. Therefore, when the titanium composite material 1 is processed, cracking does not occur from the titanium compound 42 as a starting point.

This diffusion layer can be understood as follows. After the titanium composite material 1 is embedded in the resin with a section (thickness section) parallel to the longitudinal direction (rolling direction) and the thickness direction as the observation surface, the observation surface is ground using diamond diamond or alumina suspension for final processing Observation sample. Using EPMA, line analysis was performed in the thickness direction with the particles of the titanium compound 42 observed in the observation sample as the center. The analysis target is each constituent element (that is, the case of carbide is carbon, the case of nitride is nitrogen, and the case of oxygen is oxygen). Based on the value of titanium 41 in the inner layer portion 4, a region having a higher concentration and containing no particles is a diffusion layer.

The thickness of the above-mentioned diffusion layer may vary due to various factors. For example, when a titanium compound is added, it is formed by (1) decomposition of the titanium compound and (2) diffusion of each constituent element toward the periphery. Therefore, the thickness is due to the decomposition rate of the titanium compound and the constituent elements in titanium. The diffusion speed in the material varies. In addition, it may change due to the thermal history at the time of manufacture. Furthermore, the degree of contact with a titanium compound such as sponge titanium when the package body as a hot-rolled material is heated may vary. Therefore, the thickness of the diffusion layer has various thicknesses of the diffusion layer even in the same composite material, which is difficult to determine uniformly, but it is formed in a large amount around the titanium compound and each constituent element to be present or existing.

    (b-4) Thickness of inner layer part 4    

The thicker the thickness of the inner layer portion 4 relative to the full thickness of the titanium composite 1 is, the more the mechanical properties are improved. Therefore, it is preferable that the total thickness of the titanium composite 1 is greater than 20%, and more preferably greater than 50%. On the other hand, as the thickness becomes thicker, the workability deteriorates. Therefore, the thickness of the inner layer portion 4 is preferably set to 95% or less with respect to the total thickness of the titanium composite material 1.

    2. Structure of the packing body 5 of the present invention    

The titanium packing body 5 includes a titanium packing material 6 and fillers 7 and 8. The shape of the titanium bundle 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 manufacturing the titanium composite material 1 of a plate material, the titanium bundle body 5 of a rectangular parallelepiped shape is used. Moreover, in the case of manufacturing the titanium composite material 1 of a round rod, a wire, or even an extruded material, a titanium packing body 5 having a polygonal column shape such as a cylindrical shape or an octagonal column is used. The size of the titanium package 5 is determined by the size (thickness, width, and length) of the product and the manufacturing quantity (quality).

    (a) Titanium packing material 6         (a-1) Chemical composition of titanium packing material 6    

The titanium packing material 6 is the same as the surface layer portions 2 and 3 of the titanium composite material 1, and industrial pure titanium or titanium alloy materials belonging to JIS1 to JIS4 are used.

    (a-2) Titanium packing material 6 shape    

The shape of the titanium packaging material 6 depends on the shape of the titanium packaging body 5 used as a material for thermal processing. Therefore, there is no particular shape, and a plate material, a pipe material, or the like can be used.

In order for the titanium composite material 1 produced through manufacturing steps such as hot working, cold working, and annealing to have excellent surface properties, a retained state of the inner layer portion 4, and workability, the thickness of the titanium packaging material 6 is important.

When the thickness of the titanium packaging material 6 is thinner than 1 mm, the titanium packaging material 6 may be broken during thermal processing along with plastic deformation, so that a part of the inside of the titanium packaging body 5 may fall off. In this case, the vacuum breaks at the same time, so that the titanium material 7 filled in the titanium packing body 5 is oxidized. In addition, the undulations of the titanium material 7 filled in the titanium packing body 5 are transferred to the surface of the titanium packing body 5 so that there is a possibility that large surface undulations are generated during thermal processing.

As a result of these events, mechanical properties such as surface properties and ductility of the manufactured titanium composite material 1 are deteriorated. Furthermore, if the titanium packing material 6 becomes too thin, there is a possibility that the weight of the titanium material 7 which is filled internally cannot be supported. Therefore, the rigidity of the titanium bundle 5 may be insufficient during the maintenance or processing between room temperature and heat, and there is a risk of deformation.

In order to manufacture the titanium composite material 1 having excellent surface properties, the holding state and workability of the inner layer portion 4 without performing such problems, the thickness of the titanium packing material 6 should be 1 mm or more, more It is more than 2mm.

Moreover, the thickness of the titanium packing material 6 is preferably 25% or less of the full thickness of the titanium packing body 5. If the thickness of the titanium packaging material 6 is thicker than 25% of the total thickness of the titanium packaging body 5, although there is no particular problem in manufacturing, the titanium packaging material 6 occupies the entire thickness of the titanium packaging body 5. The ratio increases, and the thickness of the inner or inner layer portion 4 becomes thin. Therefore, the amount of the titanium compound in the titanium packing body 5 is reduced, and the effect of improving the mechanical properties is lowered, which is not satisfactory.

    (b) Fillers 7, 8         (b-1) Titanium 7    

The titanium material 7 as a filler is one or more selected from the group consisting of sponge titanium, titanium blocks, and titanium scraps.

    (b-1-1) Chemical composition of titanium 7    

For the chemical composition of the titanium material 7, industrial pure titanium equivalent to JIS1 to JIS4 can be used. That is, it has 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, and the rest of Ti and impurities.

    (b-1-2) Shape of titanium 7    

As the titanium material 7, a general sponge titanium produced by a chain-forming process such as the Kroll method can be used. Its size should be less than 20mm. If the average particle diameter is larger than 20 mm, it is difficult to uniformly mix the powder 8 with a titanium compound or the like, so that the titanium compound 1 in the inner layer portion 4 of the titanium composite material produced by thermal processing may be uneven. On the other hand, if the average particle diameter is small, there is no problem in terms of characteristics. However, if the average particle diameter of the titanium material 7 is less than 0.5 mm, it will take time to break, and fine dust will be generated and scattered. Inferior efficiency. Therefore, the average particle diameter of the titanium material is preferably 0.5 mm or more.

As the titanium material 7, a titanium scrap can be used. For example, titanium scraps include scraps that cannot be made into products during the manufacturing steps of industrial pure titanium materials, titanium cutting powders that occur during cutting and grinding in order to form industrial pure titanium materials into product shapes, and as Pure titanium material for industrial use which becomes unnecessary after the product is used. If the titanium scrap is too large, there are problems such as difficulty in transportation and difficulty in placing the titanium packing body 5, and therefore, moderate cutting is desired.

Sponge titanium or titanium scraps are block-shaped, so there will be gaps (gap) 9 between the materials. In order to improve the rationality of sponge titanium, etc., or reduce these voids, powders 8 of sponge titanium and titanium compounds and the like can be mixed and compressed in advance to form a block 10 as shown in FIG. 5. Then, a titanium bundle body 5 was placed.

    (b-2) Titanium compound powder 8         (b-2-1) Chemical composition of powder 8 of titanium compound    

Examples of powders 8 of titanium compounds include carbon powders and TiC powders in the case of carbides, and Fe ₃ N powders and Fe ₄ N powders in the case of nitrides in addition to TiN powders. (However, the Fe concentration of titanium in the inner layer portion 4 must not exceed the JIS standard.) In the case of oxides, in addition to TiO powder, TiO ₂ powder, and Ti ₂ O ₃ powder, FeO powder, Fe ₂ O ₃ powder, and Fe ₃ O ₄ powder, etc. (except that the Fe concentration of titanium in the inner layer portion 4 must not exceed the JIS standard). These powders 8 can be used commercially.

    (b-2-2) Shape of powder 8 of titanium compound    

If the average particle diameter of the powder 8 of the titanium compound or the like is larger than 50 μm, it will be difficult to uniformly mix the powder with the titanium material 7. Therefore, the titanium compound cannot be uniformly dispersed in the inner layer portion 4 of the titanium composite material 1. Therefore, the average particle diameter of the powder 8 of the titanium compound or the like is preferably 50 μm or less.

On the other hand, when the average particle diameter of the powder 8 such as a titanium compound is small, there is no problem in terms of characteristics, but if it is too small, it is mixed with the titanium material 7 or filled with the titanium bundle 5 , The scattering of dust will become a problem, and it may cause obstacles to operation. Therefore, the average particle diameter of the powder 8 of the titanium compound or the like is preferably 0.1 μm or more.

    (C) Internal pressure of the packing body 5    

If air remains in the voids 43 in the titanium bundle body 5, the titanium material 7 will be oxidized and nitrided when heated before hot working, so that the ductility of the manufactured titanium composite material 1 is reduced. Therefore, it is effective to reduce the pressure inside the titanium package 5 to a high vacuum.

In order to prevent oxidation and nitridation of the titanium material 7 during hot working, the internal pressure (absolute pressure) of the titanium bundle body 5 is set to 10 Pa or less, preferably 1 Pa or less. If the internal pressure of the titanium package 5 is greater than 10 Pa, the titanium material 7 will be oxidized or nitrided due to the remaining air. If the internal pressure is set to be extremely small, it is necessary to improve the airtightness of the device and enhance the vacuum exhaust device, which are closely related to the increase in manufacturing costs. Therefore, the lower limit of the internal pressure should be set to 1 × 10 ^-3 Pa.

    3. Manufacturing method of titanium composite material 1    

The titanium composite material 1 is produced by hot working or further cold working the titanium package 5.

    (a) Hot working method    

The method of thermal processing can be selected according to the shape of the product. In the case of manufacturing a titanium composite material 1 of a plate material, a titanium package 5 having a rectangular parallelepiped shape (flat embryo) is heated and hot-rolled to form a titanium plate. If necessary, as in the previous step, the surface oxide layer can be removed by pickling or the like after hot rolling, and then cold rolled and further thinned.

In the case of manufacturing the titanium composite material 1 of round rods or wires, the cylindrical or polygonal (small embryo) titanium bundle 5 is heated and hot-rolled or hot-extruded to form a titanium round rod or Wire. In addition, if necessary, as in the previous step, the oxide layer can be removed by pickling or the like after hot working, and then cold rolled, and further refined.

    (a-1) Heating temperature for hot working    

Further, in the case of manufacturing the titanium composite material 1 of extruded profiles, the titanium bundle body 5 having a cylindrical or polygonal shape (small embryo) is heated and hot-extruded to form titanium profiles of various cross-sectional shapes. . As the heating temperature before hot working, the same heating temperature as in the case of general hot processing of titanium flat embryos or small embryos may be adopted. Although the heating temperature varies depending on the size of the titanium bundle body 5 and the degree of heat processing (processing ratio), it is preferable to heat the temperature to 600 ° C or higher and 1200 ° C or lower.

If the heating temperature is too low, the high-temperature strength of the titanium bale body 5 becomes high, and the deformation energy is low. Therefore, cracking easily occurs during hot working. In particular, the welded portion of the titanium package 5 is broken and exposed to the inside so that part of it is detached or internally oxidized. If this is the case, it is difficult for the titanium composite material 1 to obtain necessary characteristics. Further, the diffusion layer of the constituent elements around the particles of the titanium compound is not formed, and the particles of the titanium compound in the inner layer portion and the titanium cannot be sufficiently bonded. Therefore, when the titanium composite material is processed, cracks may occur starting from the titanium compound. On the other hand, if the heating temperature is too high, the structure of the obtained titanium composite material 1 is coarsened, and sufficient material characteristics cannot be obtained. In addition, the packaging material 6 on the surface is thinned due to oxidation. Therefore, the recommended heating temperature is 600 ° C to 1200 ° C.

    (a-2) Processing rate of hot working    

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

In the case where the processing rate is low, the voids 43 inside the titanium packing body 5 are not sufficiently pressed. Therefore, even after the hot working, the voids 43 remain as they are. Such a titanium composite material 1 containing a large amount of voids will be lightweight to a degree corresponding to the voids contained therein, and it will not pose a problem in improving the mechanical properties. However, because there are many voids 43 in the inner layer portion 4, the mechanical characteristics cannot be sufficiently obtained. On the other hand, if the processing rate is increased, the porosity is reduced and the mechanical characteristics are improved. Therefore, when the mechanical characteristics of the manufactured titanium composite material 1 are valued, the processing rate should be high.

    (b) Thermal processing steps    

After hot rolling, it can be used for annealing and cold rolling. Whether the titanium composite material 1 is a hot-worked material (for example, a hot-rolled sheet) or a cold-worked material (for example, a cold-rolled sheet), the effect of improving mechanical properties is not much different. In addition, the surface state is good regardless of the original state after rolling, after pickling, and after annealing, and the effect of improving mechanical properties remains unchanged.

    4. Manufacturing method of titanium packing body 5         (a) Mixing of fillers 7 and 8    

In the titanium material 7, it is necessary to fill the powder 8 of a titanium compound or the like uniformly and at a high density. To this end, the titanium material 7 and the powder 8 of the titanium compound may be filled in a container to be rotated or vibrated, and the internal titanium material 7 and the powder 8 of the titanium compound may be uniformly dispersed.

The stirring method can be exemplified by rotating the container in an up-down direction, obliquely rotating from a horizontal tilt of 20 to 70 °, vibrating the container in an up-down or horizontal direction, or inserting a stirring member into the container to stir How to rotate the pieces and so on.

The stirring time varies depending on the size of the container or the amount of the titanium material 7 and the powder 8 of the titanium compound to be mixed, and is preferably 1 to 30 minutes. If productivity is taken into consideration, it is preferable to determine the size or processing capacity of the container in such a way that it can be uniformly mixed within a few minutes.

The mixed titanium material 7 and powder 8 of a titanium compound and the like are filled in the titanium packing body 5 as they are. Alternatively, in order to improve the rationality of the titanium material 7 or reduce the above-mentioned voids, it may be compression-molded into a titanium block 10 as shown in FIG. 5 and then incorporated into the titanium bundle body 5.

    (b) Welding    

Examples of the method for welding the titanium packaging material 6 by the welding portion 11 include arc welding such as TIG welding or MIG welding, and electron beam welding or laser welding, which are not particularly limited. Among them, the welding atmosphere is suitable for 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 seam (welding portion 11) of the titanium packing material 6 is finally welded, it is preferable to place the titanium packing body 5 in a container (chamber) in a vacuum atmosphere for welding, so that the titanium packing body 5 Vacuum is maintained inside.

As shown in FIG. 6, a titanium block 10 which is mixed with powder 8 of a titanium compound and the like and is compression-molded may be coated with a titanium tough material (stretch material) as a packing material, and the entire periphery of the titanium tough material may be connected. The seam welding (resistance welding using a rotating electrode) was sealed, and the titanium bundle body 12 was manufactured. At this time, the titanium tube can be depressurized to a specific pressure through a copper tube that has been previously holed at the end and brazed and welded there, and the copper tube can be pressed after decompression to maintain the titanium toughness. Pressure inside the material.

    5. Uses of Titanium Composite 1    

In addition to having high tensile strength and good processability, it can be manufactured at low cost, so it can be used as a structural member of land transportation equipment such as automobiles.

    [Example 1]    

The titanium bundles shown in Table 1 were manufactured, and titanium composite materials 1 (plate materials) were manufactured by the manufacturing steps shown in Table 1 for the titanium bundles.

As the filler, a particle size of 2.5 mm to 6 mm manufactured by the Kroll method is used, and the chemical composition is equivalent to JIS1 (C: 0.002%, H: 0.001%, O: 0.03%, N: 0.001%, Fe: 0.03). %, The rest of Ti and impurities) of sponge titanium. As the filler, commercially available TiO ₂ powder (average particle diameter of 2 μm), TiC powder (average particle diameter of 3 μm), or TiN powder (average particle diameter of 5 μm) was used.

The above-mentioned powders of sponge titanium and titanium compounds are put into a V-type mixer in a specific amount and mixed. The mixed material was put into a mold for compression molding to form a titanium block shown in Fig. 5 with a thickness of 15 mm, a width of 50 mm, and a length of 60 mm. For comparison, in Sample No. 11, a titanium block was prepared by adding only sponge titanium particles 7 without powder raw materials 8.

As the titanium packing material, one type of JIS (TP270C; C: 0.001%, H: 0.005%, O: 0.04%, N: 0.001%, Fe: 0.03%, the rest of Ti and impurities) or JIS (TP340C) is used. ; C: 0.002%, H: 0.004%, O: 0.09%, N: 0.001%, Fe: 0.05%, the rest of Ti and impurities) industrial pure titanium material and a thickness of 1.0mm.

As shown in FIG. 6, the titanium block is coated with industrial pure titanium material as a packing material, and the entire periphery of the industrial pure titanium material is sealed by seam welding (resistance welding using rotating electrodes) and sealed. For this industrial pure titanium material, a hole was opened in advance at the end and the copper pipe was brazed and welded there. After the joints are welded, the inside of the industrial pure titanium material is decompressed to a specific pressure (0.06 ~ 1.2Pa) through the copper tube. After the pressure is reduced, the copper tube is pressed to maintain the internal pressure of the industrial pure titanium material. In Sample No. 12, when the pressure was reduced to 38 Pa, the copper tube was pressed to form a packing body.

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

In order to observe the cross section (thickness cross section) parallel to the length direction (rolling direction) and thickness direction of the titanium composite material, after the resin is embedded, the observation surface is polished with diamond or alumina suspension (mirror surface processing), and It was finally processed into observation samples. The porosity was measured by taking 20 photos of the central part of the thickness of the observation sample with an optical microscope, and the area ratio of the voids was measured for each photo to obtain the average value. The strip-shaped compound aggregate was obtained by observing the thickness center portion of the observation sample with an optical microscope to determine its morphology. In addition, about 20 strip-shaped compound aggregates to be observed, the thickness t and the length L were measured, L / t was calculated, and the average value of these was calculated.

For the thickness of the diffusion layer, with respect to No. 2, No. 4, and No. 6 in which TiO ₂ powder, TiC powder, and TiN powder were added, five strip-shaped compound aggregates were observed at the center portion of the thickness of the above observation sample. The three titanium compounds observed were measured by EPMA. Perform line analysis in the thickness direction with the particles of the titanium compound as the center, and use the value of titanium in the inner layer as a reference to determine the concentration of the constituent elements (carbon, nitrogen, or oxygen) that are higher than those of the titanium compound, without particles The distance between the side regions was averaged to obtain the thickness of the diffusion layer of each of the stripe compound aggregates.

The tensile test was performed on the rolling direction of the titanium composite. The tensile speed was measured at a rate of 0.4% / min until the fall point was exceeded, and 30% / min was exceeded when the fall point was exceeded, and the strength was measured. In addition, the Young's modulus was obtained from the gradient of the stress-strain curve until the drop.

The results are summarized in Table 1.

Fig. 7 is an example of a photograph of a cross-section microstructure of a Ti-0.1% N plate.

As shown in FIG. 7, if the structure of the cross section of the titanium composite plate of the sample No. 8 of the example of the present invention is observed, the black titanium compound can be confirmed everywhere. This black strip compound assembly is an assembly of titanium nitride. As a result of X-ray diffraction measurement, it is TiN.

Sample Nos. 1 to 8 of the present invention examples in which one or more titanium compounds selected from carbides, nitrides, and oxides are dispersed in titanium, compared with sample No. 10 in which no titanium compound is present Material strength and Young's modulus are improved. In the production of the titanium bale body 5, the vacuum degree inside the titanium bale body was set to sample No. 9 larger than 10 Pa. The titanium composite material was partially oxidized and the strength was reduced, but the Young's modulus Maintained above a certain value. After adding No. 2 of TiO ₂ powder, the thickness of the oxygen diffusion layer is 4-6 μm. After TiC powder No. 4 is added, the thickness of the carbon diffusion layer is 25 to 32 μm. After adding TiN powder No. 6, the thickness of the nitrogen diffusion layer is 1 to 2 μm.

Sample No. 11 in which a large amount of oxide powder was added, internal cracking occurred during hot rolling, and a solid titanium composite material could not be obtained. In the sample No. 12 in which the rolling reduction of the titanium packing body 5 was small and the porosity of the inner layer portion was large, both the oxide and the voids were distributed in a point shape without directionality, and cracked when the tensile test piece was produced.

    [Example 2]    

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

The sponge titanium used as a filler is a chemical composition equivalent to JIS1 (C: 0.001%, H: 0.001%, O: 0.04%, N: 0.001%, Fe: 0.03%, and the remainder) manufactured by the Kroll method. (Ti and impurities) sponge titanium, sponge titanium B is used with a particle size of 6mm to 13mm, sponge titanium C is used with a particle size of 2.5mm and 6mm or less, and sponge titanium D is used with a particle size of 0.8mm to 2.5mm.

In addition, as the titanium scrap, some (samples Nos. 26 and 27) are made of two types of JIS (C: 0.002%, H: 0.006%, O: 0.08%, N: 0.001%, Fe: 0.05%, and the rest of Ti and impurities ) Of the sheet is cut into 10 ~ 20mm square.

In addition, as a powder of a titanium compound or the like used as a filler, commercially available TiO ₂ powder (average particle diameter of 2 μm), TiC powder (average particle diameter of 3 μm), or TiN powder (average particle diameter of 5 μm) is used. These sponge titanium particles and powders of titanium compounds are put into a V-type mixer for mixing in a specific amount.

As the material of the packing material, a pure titanium material for industrial use is JIS1 (TP270H; C: 0.002%, H: 0.006%, O: 0.04%, N: 0.002%, Fe: 0.03%, the rest of Ti and impurities) JIS2 (TP340H; C: 0.001%, H: 0.002%, O: 0.10%, N: 0.002%, Fe: 0.06%, the rest of Ti and impurities), and Ti-0.06% Pd's pickled thickness 10mm thick plate.

As shown in Fig. 4, five pieces of industrial pure titanium materials are temporarily combined, and sponge titanium particles or a mixture of titanium scraps and powders of titanium compounds (filling materials) are filled therein, and the remaining industrial pure titanium materials are filled. Titanium packaging material is used to cover it.

In this state, it is placed in a vacuum chamber, and after the pressure is reduced (vacuum) to a specific pressure, the seams of the packing materials are welded by electron beams around the entire circumference. The pressure in the chamber at this time is 9.5 × 10 ^-3 to 2.1 × 10 ^-1 Pa.

In the above manner, a titanium packing body filled with a sponge titanium or a titanium scrap material and a powder of a titanium compound and the like is prepared, and the atmosphere is a vacuum. The size of the titanium packing body is thickness 80 × width 100 × length 120 mm.

The produced titanium bundle was heated at 850 ° C. for 6 hours in an atmospheric 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 acid-washed to remove scale on the surface layer, and then subjected to a tensile test. The structure observation and tensile test were performed in the same manner as in Example 1, and the porosity of the titanium composite material, the shape and size of the titanium compound L / t, the thickness, strength, and Young's modulus of the diffusion layer were obtained.

The results are summarized in Table 2.

In the case where two types of JIS are used for the packing material, the sample Nos. 13 to 19 of the example of the present invention in which titanium compound powder is added are compared with the sample No. 20 to which no titanium compound is added. Number of improvements.

In addition, in Sample No. 21, in which the rolling reduction of the titanium package was small and the porosity of the inner layer portion became large, both the oxide and the voids were distributed in a point shape without directionality, and cracked when the tensile test piece was produced.

In the case of using JIS1 as the packing material, the sample No. 22 to 24 of the example of the present invention in which titanium compound powder is added has a strength and a Young's modulus of the titanium composite material compared to the sample No. 25 without the titanium compound added Promotion.

In the case of using a sheet scrap with an oxygen content of 0.08% by mass as the filler, the sample No. 26 of the example of the present invention in which titanium compound powder was added was compared with the sample No. 27 in which titanium compound powder was not added. Increase in strength and Young's modulus.

When a JIS 1 type of packaging material is used, a titanium composite material 1 having good processability can be obtained as compared with a JIS 2 type of packaging material. As the packing material 6, a sample No. 23 of Ti-0.06% Pd was used. Compared with the packing material 6 of JIS 2 type, a titanium composite material with good corrosion resistance was obtained. In addition, No. 14 in which TiO ₂ powder was added had a thickness of the oxygen diffusion layer of 2 to 6 μm. After adding TiC powder No. 16, the thickness of the carbon diffusion layer is 12-18 μm. After TiN powder No. 17 is added, the thickness of the nitrogen diffusion layer is 1 to 2 μm.

    [Example 3]    

Samples Nos. 13, 14, 16, and 20 having a thickness of 5 mm shown in Table 2 obtained by hot rolling were annealed at 725 ° C for 15 minutes, and then acid-washed to remove scale deposits. The titanium composite (hot-rolled material) from which the scale was removed was cold-rolled until it reached a thickness of 1.0 mm, and then annealed at 700 ° C for 15 minutes using a vacuum heating furnace for a tensile test. The structure observation and tensile test were performed in the same manner as in Example 1. The porosity of the titanium composite material, the shape and size of the titanium compound L / t, the thickness and strength of the diffusion layer, and the Young's modulus were determined.

The results are summarized in Table 3.

In samples Nos. 28 to 30 of the examples of the present invention, by adding the titanium compound powder, compared with the sample No. 31 without adding the titanium compound powder, the strength and Young's modulus of the titanium composite are improved. In addition, the thickness of the oxygen diffusion layer was 1 to 4 μm by adding TiO ₂ powder No. 29. After adding TiC powder No. 30, the thickness of the carbon diffusion layer is 2-6 μm.

Claims (6)

    A titanium composite material is a titanium composite material having an inner layer portion and a surface layer portion covering the inner layer portion, and the surface layer portion includes an industrial pure titanium material or a titanium alloy material having a chemical composition of any one of JIS 1 to 4 The above-mentioned inner layer is a titanium compound in which one or more titanium compounds selected from carbides, nitrides, and oxides are dispersed, and the periphery of the carbides is carbon, the periphery of the nitrides is nitrogen, and the oxidation The area around the object is a portion that is diffused by oxygen, and has an area ratio of more than 0% to 30%.         For example, the titanium composite material of the first patent application range, wherein the total average content of carbon, nitrogen and oxygen in the inner layer portion is 0.05 to 2.0% by mass, and the titanium compound is in a strip shape arranged along the rolling direction The compound aggregate is dispersed in a titanium material.         For example, the titanium composite material in the scope of patent application No. 1 or 2, in which the chemical composition of the above-mentioned industrial pure titanium material is calculated as 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, and the rest: Ti and impurities.         A method for manufacturing a titanium composite material, which is filled with a material selected from the group consisting of titanium sponge, titanium blocks and titanium scraps because of a titanium packaging material containing industrial pure titanium materials or titanium alloy materials belonging to any one of JIS1 to 4 One or more powders, and one or more powders selected from carbon, carbides, nitrides, and oxides are sealed, and the internal pressure is reduced to 10 Pa or less to form a titanium bundle, and then the titanium is packaged The body is thermally processed.         For example, the method for manufacturing a titanium composite material according to item 4 of the scope of patent application, wherein the above-mentioned hot working is followed by cold working.         A packing body for thermal processing, comprising: a titanium packing material including industrial pure titanium material or titanium alloy material belonging to any one of JIS1 to 4; and a packing material filled inside the titanium packing material. A packing body; the above-mentioned filling material comprises: one or more kinds selected from sponge titanium, titanium block and titanium scrap, and one or more kinds of powder selected from carbon, carbide, nitride, and oxide; the internal pressure is 10Pa or less.