JPH02129330A - High wear-resistant titanium alloy material - Google Patents

Abstract

PURPOSE:To obtain the title material exhibiting excellent wear resistance as it is or as subjected to cladding by welding without requiring particularly troublesome surface treatment by crystallizing out or precipitating and dispersing titanium carbide into a beta phase titanium matrix. CONSTITUTION:The Ti alloy material has a constitution having a cold micro structure of which TiC or TiC and alpha phase Ti are crystallized out or precipitated and dispersed in a beta phase matrix; or the Ti alloy material has a constitution having a cold micro structure of which TiC crystalloids and/or precipitates and hard ceramics or TiC crystalloids and/or precipitates and an alpha Ti precipitated phase and hard ceramics are dispersed in a beta phase Ti matrix; where the betaphase Ti matrix denotes the one contg. large amounts of Cr, Mo, etc., as betaphase stabilizing elements and showing a Ti beta phase of a body-centered cubic structure at an ordinary temp. To obtain the Ti alloy material, e.g., about 0.2 to 5wt.% C is incorporated into the components of the raw material to form a beta phase Ti alloy, which is melted and solidified.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention is particularly applicable to wear-resistant members that require high resistance to sliding wear and high-speed droplet erosion, such as automobile valve train parts (engine pulp, springs, etc.). , retainer
The present invention relates to a highly wear-resistant titanium alloy material that is lightweight, can be hot-rolled, and has excellent bondability to titanium members, and is suitable for use as steam turbine blade members.

<Conventional technology and its issues> Titanium alloys, which have become relatively easy to mass-produce on an industrial scale due to significant advances in manufacturing technology in recent years, are used in various mechanical parts due to their high specific strength and excellent corrosion resistance and heat resistance. However, it also has the problem that it does not have sufficient wear resistance in a dry environment, making it difficult to use it as is for sliding parts of mechanical parts. Ta. Therefore, when applied to members that require wear resistance (for example, automobile valve train parts such as engine valves), it is essential to perform wear-resistant treatment on the surface.

By the way, “
Stellite (trade name) is known to exist and is widely used as a build-up material and bonding material on the surfaces of parts that require wear resistance. However, although this stellite can be overlaid or bonded to iron-based materials, it is impossible to apply the same treatment to titanium alloy members, so the application of stellite was considered effective. Measures to improve wear resistance were not suitable for titanium alloy members.

Therefore, in order to improve the wear resistance of the surface of titanium alloy members, conventional methods include nitriding, plating (Ni plating, Cr plating, etc.), vapor deposition (PVD or CVD), or carburizing. ``A method was adopted in which a wear-resistant coating film was formed on the surface of the alloy member.

Recently, metal oxides such as TiO□, metal carbides, metal nitrides, or hardening substances such as oxygen are attached to the surface of titanium products, and then the attached portion is irradiated with a high-energy beam to remove the surface layer. (Japanese Patent Application Laid-Open No. 61-231151), in which the surface layer of a titanium product is melted by high-energy beam irradiation, and in the molten pool there is a method of fusion and solid solution strengthening of hardened materials (TiN, etc.). Method of injecting and mixing materials (oxygen gas, etc.) (Japanese Patent Application Laid-open No. 62-56561)
A method for improving the wear resistance of titanium product surfaces by a type of hardfacing has also been proposed.

However, when applying conventional nitriding or carburizing treatments, there is a problem in that the treated material is exposed to high temperatures, which tends to cause thermal distortion. It has been pointed out that the coating film is disadvantageous in that it tends to peel off.

Although the hard overlay method for titanium alloys described above increases the hardness of the overlay part, it does not necessarily have good matte-lag properties with the mating material (for example, iron-based materials), and wear is observed on the overlay material and the mating material. Something happened.

On the other hand, in a wet environment, the wear resistance of titanium alloys is less of an issue than in a dry environment, but it is still subject to severe wear conditions (e.g. droplet erosion conditions at high flow rates such as in power generation steam turbines). ), it was not possible to maintain sufficient resistance, and appropriate measures against wear were still essential.

By the way, in the case of turbine blades made of iron-based materials used under such conditions, countermeasures have been taken to build up or bond stellite members as erosion shield materials, but as mentioned above, stellite is made of titanium alloy. Therefore, for example, Ti-6Aj!
As erosion shielding materials for steam turbine blades made of -4V alloy, β-type titanium alloys (Ti-15Mo-5Zr alloy and Ti-15Mo-5Zr alloy and Ti-
15Mo-5Zr-3A1 alloy, etc.) was used.

However, aging materials made of β-type titanium alloy cannot be expected to have the same high erosion resistance as stellite against droplet erosion in a wet environment. There was a strong demand for the development of a means that could provide excellent wear resistance.

In light of these circumstances, the purpose of the present invention is to develop titanium that exhibits excellent wear resistance in both dry and wet environments without the need for particularly troublesome surface treatments. Our goal is to provide alloy materials.

<Means for Solving the Problems> In order to achieve the above object, the present inventors have conducted research from various viewpoints, particularly reconsidering the characteristics of various titanium alloys, and have found the following. We have obtained some knowledge. That is, (al) Conventionally, titanium alloys that exhibit three types of phase structures at room temperature: “α phase single phase,” 1α + β2 phase,” and “β phase single phase” have been put into practical use. "β-phase titanium" has sliding wear resistance and erosion resistance as it is or in the aged state, compared to "α-phase titanium" and "α+".
Compared to 'β2 phase titanium', 'C-C' is higher.

(However, the wear resistance and erosion resistance of β-phase titanium are still lower than that of stellite.
As it was, it was doubtful that it could be used as a wear-resistant component in mechanical equipment, etc., but when TiC hard particles are uniformly precipitated and dispersed in the β-phase titanium, its wear resistance and erosion resistance performance are greatly improved. However, excellent properties comparable to those of Stellite can be obtained.

(A titanium alloy material in which titanium carbide hard particles are uniformly precipitated and dispersed in C1 β-phase titanium is produced by containing 0.2% by weight or more of carbon in the component that becomes the β-phase titanium alloy. The amount of carbon is approximately 0.01% by weight) and can be easily and stably produced by melting and solidifying.

(d) In addition, if the upper limit of the amount of carbon added is suppressed to 5% by weight, it is possible to suppress deterioration of the hot ductility, toughness, ductility, etc. of the titanium alloy material obtained, which would cause special disadvantages as a practical alloy. not to be

Furthermore, when a titanium alloy material in which titanium carbide hard particles are precipitated and dispersed in β-phase titanium is aged at a temperature of 350 to 550°C, fine α-phase titanium is precipitated in the β-phase and age-hardened. Further improvement in wear resistance.

(f) W2C may occur during melting of the titanium alloy.

If hard ceramics such as NbC and TiN (preferably 150 tan or less) are mixed or formed to create a titanium alloy material in which titanium carbide precipitates and hard ceramic fine particles are dispersed in β-phase titanium, its wear resistance will be further improved. What can be done.

(gl) In addition, if a titanium alloy material in which titanium carbide precipitates and hard ceramics are dispersed in β-phase titanium is aged at a temperature of 350 to 550°C in the same manner as above, fine α-phase titanium will be present in β-phase. Precipitates and age hardens, further improving its wear resistance.

(h) Titanium alloy materials such as those mentioned above have low density and are lightweight, and can be easily welded to other titanium alloys, so they can also be used as joining materials to improve wear resistance by joining to titanium alloy surfaces. Must be fully applicable.

The present invention has been made based on the above knowledge, and [the titanium alloy material has a room-temperature microstructure formed by precipitating and dispersing titanium carbide on a β-phase titanium base] and ``a microstructure consisting of titanium carbide and α-phase titanium base on a β-phase titanium base. ``room-temperature microstructure consisting of precipitated and dispersed titanium phase'', ``room-temperature microstructure consisting of titanium carbide precipitates and hard ceramics dispersed in β-phase titanium substrate'', or ``room-temperature microstructure consisting of titanium carbide precipitates and α-phase titanium substrate dispersing It is characterized by its excellent wear resistance and erosion resistance due to its structure having a room-temperature microstructure consisting of a dispersed titanium precipitate phase and hard ceramics. be.

Note that the "β-phase titanium base material" referred to here refers to β-phase stabilizing elements such as Cr, Mo, W, Nb, Ta,
V, Fe.

A material that contains a large amount of Mn etc. and exhibits a titanium β phase with a body-centered cubic structure at room temperature, and examples of practical alloys with a single β phase titanium include, for example, Ti-3A1Ti-3A1-
8V-6Cr-4, Ti-15V-3A1-3Sn −
3Cr, Ti-10V-2Fe-3Aj, etc. However, W and Cr, which are eutectoid β-stabilizing elements, seem to be particularly effective as β-phase stabilizing elements for titanium alloys. Therefore, [α+β]-based titanium titanium alloy Ti6Al
For example, by adding 25% by weight of W or 10% by weight of Cr to -4V, a titanium alloy having a β-phase titanium matrix can be obtained.
Even if a large amount of r is contained, a β-phase titanium matrix can be obtained.

In order to obtain a titanium alloy in which hard titanium carbide particles are uniformly precipitated in a β-phase titanium matrix, as mentioned above, 0.2 to 5% by weight of carbon is included in the raw material component for the β-phase titanium alloy and dissolved.・Just let it solidify.

Alternatively, the titanium alloy surface can be formed by overlaying a mixed powder obtained by mixing titanium alloy powder with carbide (for example, W2 C, Cr3 Cz) powder that melts and agglomerates to form a β-titanium phase. In this case, the reason why the carbon content is set to 0.2% by weight or more is that if the carbon content is less than this value, carbon will dissolve in the β-phase titanium and will not precipitate as titanium carbide. The reason why the upper limit of the amount is set to 5% by weight is that if the content exceeds this value, cracks will occur during solidification of the alloy, and the hot ductility, ductility, and toughness will be extremely deteriorated.

In addition, as a means of mixing carbon into the alloy, a method is adopted in which alloying is performed by adding carbide powder or burr, which is less stable as a carbide than Tic such as WzC, Cr3C2, NbC, etc., during melting. This is desirable.

Now, FIG. 1 (al is a schematic diagram schematically showing the microstructure of a titanium alloy material according to the first invention of the present proposal, in which titanium carbide (TiC) is contained in the matrix of β-phase titanium.
This shows a structure in which precipitated particles are uniformly dispersed. The shape of titanium carbide precipitates is usually one elliptical spherical particle, one spherical particle, or a mesh particle, but the size is about 0.5 to 5 nodes from the viewpoint of uniformity of structure and uniformity of wear resistance. It is desirable that the particles be fine particles.

In order to obtain a titanium alloy in which titanium carbide and α-phase titanium are uniformly precipitated in a β-phase titanium base, the titanium alloy material in which titanium carbide is precipitated in a β-phase titanium base must be aged at a temperature of 350 to 550°C. good.

By this treatment, the titanium alloy material in which titanium carbide is precipitated in the β-phase titanium matrix precipitates fine α-phase titanium and is age-hardened, further improving the wear resistance. In this case, if the aging treatment temperature is lower than 350℃, aging may take a long time or age hardening may not occur.On the other hand, if the aging treatment temperature is higher than 550℃, overaging will occur and the hardness will increase due to age hardening. There are concerns that this may not be possible.

FIG. 1(b) is a schematic diagram showing the microstructure of the titanium alloy material according to the first invention shown in FIG. 1(a) aged in the range of 350 to 550°C. , a very fine α phase (about 0.1 μm) was uniformly precipitated and dispersed in a β phase titanium matrix in which titanium carbide precipitates were dispersed.

In order to obtain a titanium alloy material in which titanium carbide is precipitated and dispersed in the β-phase titanium matrix and hard ceramics are also dispersed, it is necessary to
．． A β-phase titanium alloy material containing 2 to 5% by weight of carbon may be melted at a temperature below the melting temperature of the hard ceramic, and the hard ceramic may be introduced into the molten pool and solidified. In this case, the hard ceramic charging process may be carried out by melting the entire β-phase titanium alloy material, or may be carried out by melting only the necessary surface layer portion. In addition, the hard ceramics to be introduced include W C, W 2 C, T i N,
Cr 3 CzN b C+ S iC+ T iN
+ Fine particles of 150 or less grains such as Al z Os are preferred. This is because the size of the hard ceramic particles is 150
If the titanium alloy material is larger than 1, when the titanium alloy material is applied to a sliding member, hard ceramic particles may fall off during sliding, leading to concerns about deterioration of wear resistance.

Figure 1 (C1) schematically shows a micro-Mi weave of a titanium alloy material made by further dispersing hard ceramics of 1501 or less in the titanium alloy material according to the first invention of the present proposal shown in Figure 1 (al). This schematic diagram shows that titanium carbide precipitates are uniformly dispersed in the β-phase titanium matrix, and hard ceramic particles are further uniformly dispersed.

In order to obtain a titanium alloy material in which titanium carbide and α-phase titanium are precipitated and dispersed in a β-phase titanium matrix and hard ceramics are also dispersed, an alloy in which titanium carbide precipitates and hard ceramics are dispersed in β-phase titanium is required. The material may be aged at a temperature of 350 to 550°C.

FIG. 1(d) is a schematic view schematically showing the micro-U weave of the titanium alloy material according to the third invention of the present proposal shown in FIG. 1 (C1) aged in the range of 350 to 550°C. , β with titanium carbide precipitates and hard ceramic particles dispersed
The extremely fine α phase (approximately 0.1q) is uniformly precipitated and dispersed in the phase titanium matrix.

Effects> The titanium alloy material according to the present invention has t
It has a finely dispersed structure of titanium carbide and hard ceramics that have a hardness of more than lvloooo, and furthermore, fine α-phase titanium is uniformly dispersed and age-hardened, so the effects of these are synergistic, and the titanium alloy Despite this, it exhibits wear resistance equal to or higher than that of Stellite in dry or wet environments.

Further, since the titanium alloy material is titanium-based, unlike stellite, welding to the titanium alloy can be stably performed without defects by TIG welding or the like. Moreover, the titanium alloy material of the present invention can be easily hot rolled by heating the ingot material to around 1000°C.

Furthermore, the density of the titanium alloy material of the present invention can be made 5 or less by adjusting the contained elements, without impairing the lightweight properties expected of the titanium alloy material.

Next, the effects of the present invention will be specifically explained using examples.

<Example> First, a titanium alloy having the composition shown in Table 1 was melted by button melting to form an ingot with a thickness of 201 m, a width of 50 mm, and a length of 100 nm. The alloy raw materials used were sponge Ti,
Sponge Zr, electrolytic Sn, Aj! -V master alloy, ^l-M
o Master alloy, pure^f, W, C powder, CrzCz powder, Nb
They were C powder and TiN powder.

Next, these ingots were heated to 1050°C and then
The plate was hot rolled in three passes to a thickness of 0+*m, and the occurrence of defects such as cracks due to hot rolling was investigated.

Furthermore, alloy 6. 7. 8.11.12.14.16.
Regarding Nos. 17 and 18, aging was performed after hot rolling to precipitate the α phase.

Next, the hardness (Vickers hardness) at room temperature of the rolled plate (10 mm thick) obtained as described above was measured, and the
0 dragon φ x length 40 dragon specimen for sliding wear test and 10
Erosion test pieces of 11 thickness x 10 nm width x 15 length were taken and used for each test. Also, from the same material
A specimen for linear diffraction was also collected, and the "phase" was identified using a diffractometer.

In addition, similar tests were also conducted on Stellite No. 6 (trade name), which is used as an abrasion-resistant material.

The "wear test" was conducted using the bin-on-disk method shown in Figure 2, and the test conditions were: Pressure load of the test piece:
2kg.

Sliding speed between test piece and mating material (disk) = 62.8m
/min.

Sliding distance: 2.5X 10’m.

Mating material (disc): 60 kg class high tensile strength steel.

Friction surface lubrication: None, and the weight M? Abrasion resistance was evaluated using a small amount of J&.

For the "erosion test," a water jet method as shown in Figure 3 was adopted, and a water jet nozzle diameter: 1.2 mmφ was sprayed onto the surface of the test piece, which had been mirror-polished by puff polishing in advance.

Injection water flow rate: 370 m/sec.

Nozzle-test piece path M: 65 μl.

After spraying high-speed water under the following conditions: spray angle: 90° spray time: 600 seconds, the depth of the traces produced by the high-speed water spray was measured to evaluate erosion resistance.

These results are also shown in Table 1.

The results shown in Table 1 also show that the titanium alloy material according to the present invention not only has excellent hot rollability, but also has sufficiently small sliding wear amount and erosion depth, which is the same as Stellite No. 6, which is a comparative example. It is clear that it exhibits excellent abrasion resistance in both dry and wet environments.

<Summary of Effects> As shown above, the present invention exhibits excellent wear resistance in both dry and wet environments, has good hot workability, and is lightweight. We can provide titanium alloy materials for sliding parts such as automobile valve train parts and artificial bones.

Alternatively, it can be applied to steam turbine blades, etc. to maintain excellent performance, and it can also be welded to other titanium and titanium alloy materials, so it can also be used as a wear-resistant shielding material. Above all, very useful effects are brought about.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram schematically showing the microstructure of a titanium alloy material according to the present invention, and FIG. FIG. 1(b), FIG. 1fc) and FIG. 1(d) each show different examples. FIG. 2 is a conceptual diagram illustrating the sliding wear test method. FIG. 3 is a conceptual diagram explaining the erosion test method. Figure 1: Procedure (Authentic seal) Figure 2: 1. Display of the case 1988 Patent Application No. 282435 2. Name of the invention: High wear-resistant titanium alloy material 3. Person making the amendment. Relationship with the case. Patent application. Figure 3, Figure 4, "Claims" in the attorney's specification and [Details of the invention (contents of amendment) 1) Amend the claims as shown in the attached sheet. 2) In the specification, page 6, line 19 and page 7, lines 3-4, “
The phrase "uniformly precipitated and dispersed" should be corrected to "uniformly crystallized and/or precipitated and dispersed." 3) In the description, page 7, line 14, the phrase "precipitated and dispersed" should be corrected to "crystallized and/or precipitated and dispersed." 4) In the specification, page 8, lines 1 and 4, the words "titanium carbide precipitates" are corrected to "titanium carbide crystals and/or precipitates." 5) In the specification, page 8, line 18 and lines 19-20, “
The phrase "by precipitation and dispersion" should be corrected to "by crystallization and/or precipitation and dispersion." 6) In the specification, page 9, lines 1 and 3, the words "titanium carbide precipitates" are corrected to "titanium carbide crystals and/or precipitates." 7) In the specification, page 10, line 7, "melt blooming" is corrected to "melting dispersion." 8) In the specification, page 10, lines 12-13, the phrase "does not precipitate as titanium carbide" is corrected to "does not crystallize and/or precipitate as titanium carbide." 9) Specification, page 11, lines 5-6: “Titanium carbide (T
iC) "Precipitated particles" is corrected to "Titanium carbide (TiC) crystallized particles and/or precipitated particles." 10) In the specification, page 11, line 7, the phrase "titanium carbide precipitates" should be corrected to "titanium carbide crystals and/or precipitates." 11) In the specification, page 11, line 13, the phrase "uniformly precipitated" should be corrected to "uniformly crystallized and/or precipitated." 12) Specification, page 11, line 14 and lines 16-1
In line 7, the statement "Titanium carbide was precipitated" is corrected to "Titanium carbide was crystallized and/or precipitated." 13) In the specification, page 12, line 7, the phrase "titanium carbide precipitates" is corrected to "titanium carbide crystals and/or precipitates." 14) In the specification, page 12, line 10, the phrase "titanium carbide is precipitated and dispersed" is corrected to "titanium carbide is crystallized and/or precipitated and dispersed." 15) Specification, page 13, line 10 and lines 15-1
In line 6, the words "titanium carbide precipitates" should be corrected to "titanium carbide crystals and/or precipitates." 16) “Precipitated and dispersed” in the specification, page 13, line 14
The statement has been corrected to "crystallization and/or precipitation/dispersion." 17) In the specification, page 14, line 2, the phrase "titanium carbide precipitates" is corrected to "titanium carbide crystals and/or precipitates." 2. Claims (1) A highly wear-resistant titanium alloy material characterized by titanium carbide precipitated and dispersed in a β-phase titanium matrix. (2) β-phase A highly wear-resistant titanium alloy material characterized by titanium carbide and α-phase titanium precipitated and dispersed on a titanium base. (3) Titanium carbide-8 grade u/or on a β-phase titanium base. A highly wear-resistant titanium alloy material characterized by a dispersion of di-precipitates and hard ceramics. (4) Titanium carbide, silicon precipitates, and α-titanium precipitates on a β-phase titanium matrix. A highly wear-resistant titanium alloy material characterized by a dispersion of hard ceramics and hard ceramics.j

Claims (4)

[Claims] (1) A highly wear-resistant titanium alloy material characterized by titanium carbide precipitated and dispersed in a β-phase titanium matrix. (2) A highly wear-resistant titanium alloy material characterized by titanium carbide and α-phase titanium precipitated and dispersed in a β-phase titanium base. (3) A highly wear-resistant titanium alloy material characterized by having titanium carbide precipitates and hard ceramics dispersed in a β-phase titanium matrix. (4) A highly wear-resistant titanium alloy material, characterized in that titanium carbide precipitates, α titanium precipitates, and hard ceramics are dispersed in a β-phase titanium matrix.