JP2792319B2 - Titanium alloy crampons and their manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a titanium alloy crampon which is lightweight, has high strength, and has good manufacturability, and a method for producing the crampon.

[0002]

2. Description of the Related Art Conventionally, steel has been used as a material for crampons, and it is required that the rocks and ice have a strength capable of supporting a load several times their weight. However, steel crampons have a high Young's modulus, making it difficult for nails to bite into the rock surface, and the high specific gravity of steel increases their weight and increases the load on climbers, and they are prone to rust. There are problems such as.

In order to solve such a problem in the steel crampon, a crampon made of a titanium alloy containing 3 to 8% by weight of aluminum and 3 to 25% by weight of vanadium has been proposed (Japanese Patent Laid-Open Publication No. Sho. 63-17
7802).

[0004] However, such titanium alloy crampons have the following problems. That is, at the time of manufacturing a crampon, a material having a crampon shape is basically obtained from a thin plate having a thickness of about 3 mm by cold punching, and then the claws of the crimp are formed by cold bending. Manufacture of crampons
In the Ti-6Al-4V alloy used in the embodiment of No. 5, it is impossible to perform such cold stamping and bending. Further, the Ti-6Al-4V alloy is difficult to obtain high strength even by the solution aging treatment, and has a problem in heat treatment properties such as being easily deformed due to thermal strain since the solution treatment is performed by water cooling after forming. Furthermore, the Ti-22V-4Al alloy, which is another example of this publication, has a high specific gravity because of a β-type alloy, a long aging treatment time, and a large amount of expensive metal V. There is a problem that the ingot cost is greatly increased due to the inclusion.

[0005]

As described above, the titanium alloy used in the conventional titanium alloy crampons is inferior in cold workability such as cold punching property and cold bending property and heat treatment property, and has a low specific gravity. However, conventional titanium alloy crampons have poor productivity, are inferior in strength properties, are inefficient in terms of weight reduction, and further increase production costs. There's a problem.

The present invention has been made in view of such circumstances, and provides a titanium alloy crampon which is excellent in cold workability and heat treatment property, is lightweight and high in strength, and has a low cost. With the goal.

[0007]

According to the present invention, in order to solve the above problems, 3 to 7% by weight of Al, 2 to 5% by weight of V, 1 to 3% by weight of Mo, and 1 to 3% by weight of Fe. % By weight, O in the range of 0.06 to 0.20% by weight, with the balance being Ti
And a titanium alloy crampon formed of a titanium alloy comprising unavoidable impurities.

[0008] Further, there is provided a method for producing a titanium alloy crampon, which comprises heat-treating a titanium alloy crucible having the above-mentioned composition at a heating temperature of 750 ° C or more and 850 ° C or less, and thereafter shaping the thin plate into crampons. I do.

Further, after the forming, the solution temperature is 800
℃ or more, less than 900 ℃, aging temperature is 450 ℃ or more, 60
The present invention provides a method for producing a titanium alloy crampon, wherein a solution aging treatment is performed under the conditions of 0 ° C. or less and an aging time of 1 hour to 10 hours.

The present inventors have conducted various studies to develop a titanium alloy crampon that has solved the above-mentioned problems. As a result, the above-mentioned problems were solved by examining the additive components of the titanium alloy constituting the crampon, defining its composition in a specific range, and applying a heat treatment under specific conditions to a material having such a composition range. Found to be. That is, it is possible to satisfy the characteristics required as crampons only by using a titanium alloy having a specific narrow composition range, and by applying a heat treatment under specific conditions to a material having the specific composition, Actually, cold punching and cold bending can be performed, so that crampons having desired characteristics can be manufactured. Hereinafter, the present invention will be described in detail. First, the composition of the alloy constituting the crampon of the present invention will be described.

(1) Al: Al has a great effect on the strength of a titanium alloy, and the higher the content, the higher the strength. However, if the Al content is less than 3% by weight, sufficient strength as a crampon cannot be obtained. On the other hand, if the content exceeds 7% by weight, the strength as a crampon is sufficient, but the cold workability deteriorates. For this reason, the Al content is specified in the range of 3.0 to 7.0% by weight.

(2) V: V is a β-stabilizing element. By adding an appropriate amount, a two-phase microstructure of α + β can be obtained, and the β-phase is stabilized to provide good strength and cold workability. However, if the V amount is less than 2% by weight, sufficient strength as a crampon cannot be obtained. Further, since the addition of V increases the specific gravity, it is not desirable to add more than necessary if the strength and cold workability are sufficiently obtained. Further, V is an expensive metal, and a large amount of V increases the raw material cost. For this reason, the V content is set to 2% by weight or more, and the upper limit is suitably 5% by weight.

(3) Mo: Mo is a β-stabilizing element like V, and has the same effect as V, but also has the effect of refining fine crystal grains. For this reason, by adding together with V, the α + β2 phase microstructure can be refined, and the strength characteristics and the cold workability can be further improved. However, if the Mo amount is less than 1% by weight, the effect is not obtained and the strength characteristics are poor. Further, the addition more than necessary results in an increase in specific gravity, which is not desirable. For this reason, Mo
The amount is defined as 1% by weight or more and 3% by weight or less.

(4) Fe: Fe is β more than V and Mo.
The effect of stabilizing the phase is great, and it has a great effect on improving the strength and cold workability in the α + β2 phase structure. Therefore, Fe is an essential alloying element for the titanium alloy constituting crampons. However, when the Fe content is less than 1% by weight, the effect is small, and when it exceeds 3% by weight, the specific gravity increases,
In addition, a brittle intermetallic compound phase composed of Ti and Fe may be formed. Therefore, the amount of Fe is specified to be 1% by weight or more and 3% by weight or less. In addition, sufficient characteristics can be obtained in this range.

(5) O: O increases the strength of the titanium alloy by increasing its content, but the addition of a large amount deteriorates the cold workability. For this reason, the range of the amount of O is specified to be 0.06% by weight or more in order to secure sufficient strength characteristics as crampons, and to be 0.20% by weight or less in order to obtain sufficiently good cold workability as crampons. Next, a method for producing a titanium alloy crampon of the present invention will be described.

When manufacturing crampons, generally,
First, a thin plate with a thickness of about 3 mm is punched in a cold state,
The claws are formed by cold bending, and finally heat treated to increase strength. However, Ti-6Al-4V alloy used as a crampon in the prior art is inferior in cold workability, so it is necessary to perform punching and bending work hot, and it is very difficult to manufacture and the production cost is low. Was growing.

In the present invention, a heating temperature of 750 ° C. or higher is applied to a titanium alloy sheet having the above-described composition.
By performing a heat treatment at 850 ° C. or less. Ti-6Al
Cold working, which was difficult with a -4V alloy, has been enabled. That is, at such a heat treatment, about 2 to 2
The volume ratio of the stabilized β phase having an average particle size of 3 μm is 20
% Or more of the fine α + β2 phase microstructure can be obtained. However, since the β phase is soft and rich in workability, the cold workability is remarkably improved. Further, by heating in this temperature range, recrystallization and recovery progress, and the strength can be lowered so that cold working is easy.

However, if the heating temperature is lower than 750 ° C., the progress of recrystallization and recovery is delayed, so that the cold workability is hardly improved. On the other hand, when the heating temperature is higher than 850 ° C., the microstructure becomes coarse and acicular α-crystals precipitate in the β-phase, so that the cold workability deteriorates. For this reason, the heat treatment heating temperature before cold working is set to 750 ° C. or more and 85
0 ° C. or less. After such heat treatment, as described above, punching is performed in a cold state, and then the claws are formed into crampons by cold bending.

In order to impart sufficient strength as a crampon after molding, it is preferable to increase the strength by solution aging treatment. At this time, in order to obtain a good strength-ductility balance, it is necessary to optimize the soaking temperature, aging temperature and aging time.

If the solution temperature is lower than 800 ° C., a sufficient increase in strength cannot be obtained after aging, and if it is higher than 900 ° C., the microstructure becomes coarse and the ductility decreases. For this reason, the solution temperature was set to 800 ° C. or more and less than 900 ° C.

When the aging temperature is lower than 450 ° C., the aging time until the strength is sufficiently increased is too long, and the strength cannot be increased with an appropriate aging time. On the other hand, the aging temperature is 600 ° C
If the temperature exceeds the temperature, the temperature is too high and the strength increase due to aging is not sufficient. Therefore, the aging temperature should be 450 ° C or more, 60
0 ° C. or less. In order to obtain a proper balance between the wrought temperature and the ductility in this aging temperature range, the aging time is 1 hour or more and 10 hours or more.
Less than hours is appropriate.

A particularly significant feature of the solution aging treatment is that it is not necessary to perform water cooling after solution treatment, and that a large increase in strength after aging can be obtained by air cooling. Ti-6Al
In the case of forming a crampon with a -4V alloy, it is necessary to perform water cooling after solution treatment in order to obtain high strength, and there is a problem that a molded product is deformed by thermal strain during water cooling.
Since the titanium alloy of the present invention can obtain high strength by air cooling and aging after solution treatment, there is no concern about deformation of a molded product due to heat treatment.
Such a difference is due to the fact that the titanium alloy of the present invention contains β-stabilizing elements such as Fe and Mo.

The solution heat aging time in the solution aging treatment does not need to be long if the titanium alloy is sufficiently solution-heated at the solution heat temperature. Actually, an appropriate time is from 30 minutes to 2 hours.

As described above, according to the present invention, light weight, good corrosion resistance (no rust etc.), low Young's modulus (about 1)
0000kgf / mm ² ) By optimizing the alloy composition and heat treatment conditions as well as the inherent properties of titanium alloys such as), it is possible to manufacture titanium alloy crampons that have excellent properties such as high strength and good manufacturability. Becomes

[0025]

Embodiments of the present invention will be described below.

Example 1 A titanium alloy having an alloy composition shown in Tables 1 and 2 was melted and forged by heating at 1100 ° C.
Hot rolling at a reduction ratio of 4 was performed by heating at 0 ° C, and finishing hot rolling was performed at a reduction ratio of 5 by heating at 800 ° C to produce a thin plate having a thickness of 3.1 mm. Thereafter, a heat treatment of maintaining the temperature at 800 ° C. for 1 hour and air cooling was performed, and an oxide layer on the surface was removed by shot-pickling to obtain a test material. At this time, the plate thickness was 3.0 mm.

From these test materials, bending samples (width 20 m)
m, length 150 mm) and a test piece for density measurement,
It was subjected to a bending test and a density measurement. Bending test is cold 180
° Bending, the radius of the bending jig from 1.6 mm to 5.0 mm
And the minimum bend radius that can be bent without generating cracks was defined as the critical bend radius.

Further, the front body and the rear body of the crampon were actually subjected to cold punching and cold bending of the claws from these test materials. Further, these test materials were heated at 850 ° C. for 1 hour, air-cooled, kept at 510 ° C. for 6 hours, air-cooled, subjected to a solution aging treatment, and subjected to a tensile test.

Tables 1 and 2 show the results of the test. In addition,
In these tables, examples indicate compositions having compositions falling within the scope of the present invention, and comparative examples indicate compositions falling outside the composition range of the present invention.

[0030]

[Table 1]

[0031]

[Table 2]

Nos. 1 to 6 of the test materials are affected by the amount of Al, 7 to 10 are affected by the amount of V, 11 to 14 are affected by the amount of Mo, 15 to 18 are affected by the amount of Fe, and 19 to 19: Numeral 22 is for grasping the influence of O.

From the table, each of the components Nos. 1, 7, 11, 15, and 19 in which each component is smaller than the amount specified in the present invention has a tensile strength of 120 kgf / mm ² suitable for crampons. Lower than that, and it was confirmed that the strength was insufficient.

Further, from these tables, it can be seen that as the content of each component increases, the tensile strength increases, but the bendability decreases accordingly. And, the content of each component exceeds the range of the present invention.
All of No. 22 had poor bendability of 3.0 or more, which was less than 3.0, which is the critical bending radius at which bending of the nail of the crampon could be performed, and could not be punched into crampons.
In other words, it was considered that the actual punching of the crampons and the processing of the claws were possible without causing cracks, etc., but they are considered to be excellent as titanium alloys for crampons, but these are inferior in such processability. It was confirmed that the alloy was unsuitable as a crampon alloy.

No. 23 is a Ti-6Al-4V alloy, but punching was impossible due to poor workability. The number 24 is Ti-22V-4Al, but the workability is good.
Specific gravity although Tsu Der is too large.

On the other hand, in Examples within the composition range of the present invention, the tensile strength was 120 kgf / mm ^2. It was confirmed that the above was satisfied, the workability was also good, and it was suitable for crampons.

(Example 2) Within the composition range of the titanium alloy of the present invention, Ti-4.5Al-3.0V-2.0Mo-
2.0Fe-0.08O alloy and heat treatment conditions of 70
The bending properties and the actual punchability were tested, varying from 0 to 900 ° C at 50 ° C intervals (numbers 25 to 29).
The evaluation was performed in the same manner as in Example 1. Ti-6A for comparison
The same test was performed for the 1-4V alloy (Nos. 30 to 3).
4). Table 3 shows the results.

[0038]

[Table 3]

As is clear from this table, Ti-6Al
The -4V alloy had poor punchability and bendability in all heat treatments. Also, Ti-4.5Al-3.0
In the case of the V-2.0Mo-2.0Fe-0.08O alloy, when the heat treatment temperature was 700 ° C. and 900 ° C. Nos. 25 and 29, the cold workability was reduced, but the 750-850 ° C. Nos. 26-28. It was confirmed that good workability was obtained.

Example 3 The same titanium alloy used in Example 2 was subjected to a solution aging treatment under the conditions shown in Table 4, and the tensile strength and elongation were measured by a tensile test. The solution temperature at this time is Ti-4.5Al-3.0V-
2.0Mo-2.0Fe-0.08O alloy 700 ~
Change at 50 ° C intervals up to 950 ° C (No. 35-4)
1) For the Ti-6Al-4V alloy, the temperature was fixed at 950 ° C. (Nos. 42 to 43). The cooling after solution treatment was water cooling with number 40, but the other was air cooled. Aging temperature is 450
６００600 ° C. and the aging time was 1-10 hours.

[0041]

[Table 4]

As is clear from this table, Ti-6Al
-4V number of 42 to 44, the cooling after the solution because the tensile strength of the air cooling was insufficient strength of less than 120 kgf / mm ^2. Also, Ti-4.5Al-3.0V-2.0Mo
In the case of the −2.0Fe-0.08O alloy, when the solution temperature was 750 ° C. and 900 ° C., Nos. 35 and 41, the tensile strength was 120 kgf / mm ² or less. It was confirmed that a sufficient strength as a crampon could be obtained even with air cooling at a number of 36 to 40 lower than ° C.

[0043]

According to the present invention, there is provided a titanium alloy crampon which is excellent in cold workability and heat treatment property, is lightweight, has high strength, and is inexpensive, and a method for producing the same.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) A43C 15/06 C22C 14/00

Claims (3)

(57) [Claims] 1. A range of 3 to 7% by weight of Al, 2 to 5% by weight of V, 1 to 3% by weight of Mo, 1 to 3% by weight of Fe, and 0.06 to 0.20% by weight of O. And the balance is Ti
And a titanium alloy crampon formed of a titanium alloy comprising unavoidable impurities. 2. A range of 3 to 7% by weight of Al, 2 to 5% by weight of V, 1 to 3% by weight of Mo, 1 to 3% by weight of Fe, and 0.06 to 0.20% by weight of O. And the balance is Ti
A method for producing a titanium alloy crampon, which comprises heat-treating a thin titanium alloy sheet consisting of unavoidable impurities at a heating temperature of 750 ° C. or more and 850 ° C. or less, and then forming the crimp into a crampon. 3. After the forming, the solution temperature is 800 ° C. or more and less than 900 ° C., and the aging temperature is 450 ° C. or more and 600 ° C.
The method for producing a titanium alloy crampon according to claim 2, wherein the solution aging treatment is performed under the condition that the aging time is 1 hour or more and 10 hours or less.