Titanium material

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, namely to titanium materials with high strength and processibility. Titanium material contains iron 0.60 wt % or less and oxygen 0.15 wt % or less, titanium and inevitable impurities are the rest. Material has a non-recrystallised structure formed by processing accompanied by plastic deformation and a recrystallised structure formed by annealing after the above treatment; average size of recrystallised α-grains is 1 mcm or more and 5 mcm or less, and surface area of the non-recrystallised part in a cross section of titanium material is more than 0 to 30%.

EFFECT: material is characterised by high strength and processibility.

2 dwg, 2 tbl, 45 ex

 

AREA of TECHNOLOGY

The present invention relates to a titanium material, and more particularly to a titanium material excellent in its strength, and machinability.

DESCRIPTION of the PRIOR art

Usually the items in the form of plates or in the form of bars, formed from materials such as titanium alloys and pure titanium, was used widely. For example, a titanium material in the form of plates (also referred to hereinafter in the present description "titanium plate") was widely used for industrial products in which titanium plate subjected to various treatments, accompanied by plastic deformation, such as bending, bending and drawing, to form different products. From the titanium plate that is subjected to this treatment, you must have excellent machinability. Further, recently required a reduction in the thickness of the titanium plate in terms of lower cost of raw materials, reduction of product weight and the like. As a result, more was required increasing the strength of the titanium plate. Usually, however, the workability and strength of titanium plates are a compromise ratio, and is time-consuming to simultaneously satisfy these properties. That is the usual titanium plates present a problem in that izgotavlivaeyutsya time-consuming (weak machinability) with increasing yield strength.

In relation to the above subject in the following patent document 1 shows the results of evaluation of the workability of a thin titanium plates having different components and grain size of the crystal in the test hood, and describes that the smaller the crystal grain, the better is the machinability (page 103, line 5). Further, the following patent document 1 discloses a method of manufacturing a thin plate of pure titanium and describes the fabrication of a thin plate of pure titanium having a reduced surface gloss, including the implementation of the final annealing (600 to 800)°C×(2-5) minutes, then the implementation of the etching processing and selection of average grain size of the crystal (referred to in this description is called the particle size of the product to 3-60 microns.

Further, the following patent document 2 discloses pure titanium for building materials, plate of pure titanium and its method of manufacture and describes a titanium material for building materials, which contains 900 part per million or less of oxygen and 100 parts/million or more and 600 part per million or less of Fe, where the content of Ni and Cr is limited. Moreover, in patent document 2 describes a titanium material for building materials, having an average grain size of the crystal is 70 μm or less, which was subjected to treatment�e by etching with an aqueous solution of nitric and hydrofluoric acid after cold rolling and annealing.

However, in these patent documents 1 and 2 is not provided virtually no data that provide an assessment of a titanium material having a small grain size of the crystal is 5 μm or less, and in patent document 2 shows an example in which the grain size of the crystal is 3 μm, but at the same time, in the paragraph [0026] described that "in real production lower limit of approximately 5 microns", which is a negative description of the grain size of the crystal is 5 μm or less.

This is most likely due to the fact that in these documents, the objective is to obtain superior titanium construction material having low gloss and workability in bending, deep drawing and others like them have been studied insufficiently.

Further, the following patent document 4 discloses a titanium plate, excellent machinability, which has a low strength (yield strength) despite having excellent workability and may not simultaneously satisfy and workability, and strength.

The LIST of REFERENCES

PATENT DOCUMENT

Patent document 1: Japanese Laid patent application No. 63-103056

Patent document 2: Japanese Laid patent application No. 9-3573

Patent document 3: Japanese Laid patent application No. 2006-316323

Patent document 4: Vylozhennaya patent application No. 63-60247

Non-PATENT DOCUMENT

Non-patent document 1: "Titanium", Vol. 57, No. 2 (published Japanese Titanium Society, April 2009)

BRIEF DESCRIPTION of the INVENTION

TECHNICAL PROBLEM

The object of the present invention is to provide a titanium plate having high strength and excellent machinability.

The solution to the PROBLEM

Although the strength (yield strength) of titanium material can be increased by adding, mainly oxygen (O) and iron (Fe), but when they are added, will decrease the ductility, thereby reducing the workability. For example, as titanium material designated by JIS class 1, has a low content of oxygen and iron, a titanium plate with use of a material according to JIS class 1 in General has low strength (yield strength), but is excellent in moldability and excellent in workability. When using a titanium material of JIS class 2, which has a higher content of oxygen and iron than the titanium material according to JIS class 1, the resulting titanium material will have a higher strength (yield strength) than the titanium material in which use titanium material according to JIS class 1, while it will have a tendency to have reduced ductility with decreasing workability. Titanium materials of class 3 � class 4 according to JIS, having a much higher content of oxygen and iron, have a much greater strength (yield strength), but have a much more reduced plasticity with a strong decrease in workability. That is, the strength (yield strength) and the machinability have a certain relationship (hereinafter in the present description also called equilibrium "strength (yield strength) - workability").

In particular, the plate material and the wire material produced through the use of titanium materials, formed by exposure of materials processing, accompanied by plastic deformation, such as rolling and wire drawing. These plate materials and wire materials treated, accompanied by plastic deformation, in General, are the inner part, in which the processed structure is formed in the form as it is, and therefore they are subjected to a stage called final annealing, the purpose of recrystallization of the structure before delivering them to the market. For example, a titanium plate is subjected to processing such as cold rolling, for adjusting the thickness to a predetermined value, and then subjected to periodic annealing, continuous annealing or the like to recrystallization of the processed patterns frequent internal� for the formation of equiaxed crystal grains (hereinafter in the present description called "recrystallized grains"). These recrystallized grains grow strongly with time of annealing and the like, and, in particular, in the period immediately after the initiation of recrystallization, where the particle size of recrystallized grains is small, the rate of growth of recrystallized grains will be high and they will grow to a large size of particles exceeding 5 microns in a relatively short time. When recrystallized grains grow to this size, precrystallization part (workpiece structure) will not be saved, but only equiaxed structure, based on the recrystallized grains, will in General be formed in the inner part of the titanium material.

As a result of intensive and extensive studies to achieve the above objective, the authors of the present invention found that an increase in strength (yield strength) of titanium material can be achieved by selecting patterns (the grain refinement of the crystal by maintaining precrystallization parts), which as a means of increasing the strength of the attention was not sought. Specifically, the authors present invention have completed the present invention by exposure available on the market plate of pure titanium, which was cold-rolled to a predetermined thickness, the final annealing in vacuum with the use�m electric furnace; making different titanium plates having different patterns on an experimental basis, by changing its temperature and time; and estimating its strength (yield strength) and workability (plasticity) using residual elongation and samples Eriksen.

The evaluation it was found that, although the strength (yield strength) tends to increase, and the workability (Ericksen) tends to decrease with decreasing grain size of the crystal, the Ericksen number is not reduced significantly, provided that the average particle size of recrystallized grains is of a predetermined size or less, and the balance of strength (yield strength) - the machinability can be improved with conventional titanium materials.

Further, there was a case where, even if the average grain size of the recrystallized crystal grains is a predetermined size or less, the machinability (Ericksen) is reduced and therefore, the balance of strength (yield strength) - machinability can not be improved compared to conventional titanium materials. As a result of a detailed study of the microstructure of this titanium plate was precrystallization parts in addition to the grains recrystallized final annealing. "The balance of strength (predictament) - the machinability was studied based on the number precrystallization parts, and it was found that the machinability is highly reduced, if the area ratio precrystallization parts in cross section of the titanium plate exceeds 30%. It should be noted that in the present description precrystallization portion means a portion in which the processed structure is subjected to plastic processing, is stored.

Specifically, the present invention relates to a titanium material to achieve the above objective, is characterized in that the titanium material has an iron content of 0.60% by mass or less and the oxygen content of 0.15% by mass or less, while the rest consists of a titanium and inevitable impurities, wherein the titanium material has a machined structure formed by processing, accompanied by plastic deformation, and recrystallized structure formed by annealing after treatment, where the titanium material is formed the average particle size of the crystal grains recrystallized structure is 1 μm or more and 5 μm or less and the area precrystallization parts in cross section of the titanium material is more than 0% and 30% or less.

The USEFUL EFFECT of the INVENTION

In the present invention it is possible to create Titus�new material, having high strength and excellent machinability.

BRIEF description of the DRAWINGS

Fig.1 is a micrograph showing the microstructure of the titanium plate from the sample observed using a transmission electron microscope (precrystallization part can be observed in between recrystallized grains).

Fig.2 is a graph showing the relationship between the yield stress and the Ericksen number.

DESCRIPTION of embodiments of the

Further in the present description of the preferred embodiment of the titanium material according to the present invention will be described while taking as an example a titanium plate. Titanium plate in the present embodiment, the implement is formed of a titanium material having a content of iron (Fe) to 0.60% by mass or less and the content of oxygen (O) of 0.15% by mass or less, while the rest consists of a titanium (Ti) and inevitable impurities. Titanium plate is formed by processing involving plastic deformation followed by annealing, and it has in the inner part of the processed structure, accompanied by treatment, and recrystallized structure, accompanied by annealing, where a titanium plate is formed so that the average particle size of the crystal grains recrystallize�structure is 1 μm or more and 5 μm or less and the area precrystallization parts in cross section of the titanium material is more than 0% and 30% or less.

As described above, iron (Fe) contained with the percentage of 0.60% by mass or less. It should be noted that the upper limit of Fe is to 0.60% by weight, since Fe is a stabilizing β-phase element in the titanium material, and if the Fe content exceeds 0.60 percent by mass, structure, component, titanium plate, in addition to α-phase can be formed much of β-phases. That is, because depending on the size of the formed β-phase is strongly reduced plasticity or greatly reduced corrosion resistance is important to keep the content of Fe contained in the titanium material, which forms a titanium plate according to the present embodiment of the at 0.60 percent by mass or less in the sense of forming a titanium plate having high strength and excellent machinability.

It should be noted that although the lower limit of the content of Fe is not necessarily required in the sense of forming a titanium plate having high strength and excellent machinability, as a raw material it is necessary to use an expensive and high-purity sponge titanium, if you have a purpose, the use of titanium plates having the Fe content is less than 0.01% by weight, which may increase material costs on a titanium plate. Therefore, the Fe content is preferably 0.01% by mass or bol�e and 0.60 percent by mass or less in terms of cost titanium plates and the like.

For example, in the process of Crolla titanium material having an Fe content of 0.60% by mass or more, usually formed only in a small area near capacity. Therefore, it is possible to use a larger portion of titanium sponge obtained in the process of Crolla as a titanium plate in the present embodiment, the implementation has a content of iron as a component in the range of 0.01 to 0.60% by mass. That is to say that a titanium plate according to the present embodiment of the is suitable as the consumer of the material, as virtually no restrictions on the use of titanium sponge is not imposed.

Oxygen (O) contained in the titanium material with a content of 0.15% by mass or less. The content Of titanium material, forming a titanium plate according to the present embodiment of the, is 0.15% by mass or less, since if the content exceeds About 0.15 percent by mass, the strength of titanium plates may be excessively increased, preventing proper giving it the properties of workability, even if you have a goal to improve the balance of strength - workability" by reducing the grain size of the crystal, thus making difficult the formation of a titanium plate, suitable for processing, such as bending or deep drawing.

It should be noted that although the lower limit of the content of O is not specifically defined, you may need to produce titanium plate using as raw material expensive and high-purity titanium sponge, if there is to prescribe the content Of titanium material constituting the titanium plate, less than 0,015% by weight. Therefore, the content Of, preferably, 0.015% by mass or more and 0.15% by mass or less.

Further, it is important that inevitable impurities such as carbon (C), nitrogen (N) and hydrogen (H), each contained in an amount corresponding to the class 2 JIH or less to ensure good workability in production. More specifically, it is important that the content of C, N and H were less than 0.02 mass% for each. Further, the content is preferably 0.01% by mass or less, the N content is preferably 0.01% by mass or less, the content of N is preferably 0.01% by mass or less. Although the lower limit is not defined for the above-mentioned content of C, N and H, from the viewpoint of machinability of titanium plates, the manufacturing cost of the titanium plate can increase substantially if there is a purpose to completely remove this content. From the point of view of preventing such cost increase, the content of C is preferably of 0.0005% by mass or more, the soda�the gether N is, preferably, to 0.0005% by mass or more, the content of N is preferably of 0.0005% by mass or more.

As described above, a titanium plate of the present invention has a machined structure and recrystallized structure in the inner part thereof and is formed so that the average particle size of the crystal grains recrystallized structure is 1 μm or more and 5 μm or less, and the surface area precrystallization patterns in the cross section of the titanium plate is greater than 0% and 30% or less.

The upper limit of the average particle size of recrystallized structure is 5 μm or less, since if the average size of the crystal grain equiaxed α grains obtained by recrystallization exceeds 5 μm, the effect of grain refinement of the crystal will be small, making it difficult to achieve the "balance strength-workability". Further, the lower limit is 1 μm, as if a titanium plate is subjected to processing (rolling, forging and the like) in the actual production (industrial suitable way) followed by annealing to obtain the average grain size of the crystal is less than 1 μm, the area ratio precrystallization parts (machined structure), which will be described below, will increase, which extremely increases strength�St', but significantly reduces the workability, making difficult the achievement of a superior "balance strength - workability".

Precrystallization part is formed from the treated structure in which a titanium plate is plastically deformed by processing (cold rolling, forging and the like) to compress the crystal grains, and the strength of the titanium plate can be increased by providing a processed structure stored in a titanium plate. Titanium plate, containing the processed structure formed by cold rolling or the like, has a high strength, while its ductility is very low. Consequently, the processed structure of the conventional way recrystallization by annealing for the formation of equiaxed structure and provided sufficient annealing time to such an extent that the treated structure is not preserved in a titanium plate. On the other hand, relative to the titanium plate in the present embodiment of the treated structure is allowed to remain in the titanium plate by using the annealing conditions, which will be described below, and furthermore, the particle size of recrystallized grains is controlled so as specified above.

In the sense of producing excellent "balance strength - processed�you" is important, to precrystallization part (processed structure) would be created so that the proportion of its area in the cross section of the titanium plate was 30% or less. If the area ratio precrystallization part is more than 30%, the strength of the titanium plates will be greater, but the ductility will be reduced, making time-consuming to deliver superior machinability of titanium plates. As a result it may be impossible to achieve a perfect "balance strength - workability". The area ratio precrystallization parts, preferably 10% or less in the sense of give more reliable titanium plate superior "balance strength - workability". It should be noted that although the lower limit is not specifically limited, the particle size of recrystallized grains will increase dramatically if precrystallization part is lost (the area ratio is 0%). Consequently, the proportion of the area precrystallization part is preferably 0.1% or more, in which the particle size of recrystallized grains can more reliably be adjusted within the range as described above.

Method of controlling the particle size of recrystallized grains and the formation of precrystallization parts, as described above, the method includes, in�Orom titanium plate is adjusted to the desired thickness in a conventional rolling process and others like him, and then subjected to final annealing in a predetermined state.

Welcome annealing, which can be used in the final annealing, can be roughly divided into continuous type and periodical. Among them, the final continuous annealing is a method of annealing by expanding cold rolled coil and transmission of titanium plates with constant speed through the annealing furnace and method can control the time of maintaining the temperature of heating using the passing speed of the plate. In the final annealing conventional titanium plates, in the case of a continuous type, the heating temperature is 700 to 800°C and heating time ranges from several tens of seconds to about 2 minutes. On the other hand, periodic type final annealing is the heating coil titanium plates in a furnace for annealing in a state of the roll itself, where a titanium plate slowly heated to reduce the difference in the application of heat between the outer part and the inner part of the roll, and the heating rate is also very slow. In the final annealing conventional titanium plates, in the case of periodic type, the temperature of the heating is 550-650°C and heating time is from about 3 hours to 30 hours.

On the other hand, the final annealing is carried out in the manufacture of titanium plates truly�the approaches of implementation, preferably, carried out, for example, in a continuous system under conditions of heating at a temperature of 580°C or more and less than 600°C, for 1 minute or more and 10 minutes or less or under conditions of heating at a temperature of 600°C or more and 650°C or less, within 10 seconds or more and 2 minutes or less. The time period of 10 seconds or more chosen as the preferred heating conditions, because if the temperature is less than 10 seconds, the correct range of operating conditions, such as the rate of passage of the plate and the temperature of the heating for the implementation of the predetermined annealing the titanium plates will be extremely narrow, which requires high-precision regulating device or its operation. On the other hand, the condition of 10 minutes or more is preferable as the heating time, because if the exposure time exceeds 10 minutes, the rate of passage of the plate must be reduced, thus reducing the productivity.

Further, the temperature of 580°C or more chosen as the preferred conditions of temperature of heating, because if the heating temperature is less than 580°C will be difficult to cause a predetermined recrystallization in a titanium plate during incubation, 10 minutely less and the area ratio precrystallization parts will in many cases be more than 30%. Moreover, the temperature of 650°C or less choose because if the temperature is more than 650°C, recrystallization titanium plates may fail even for 10 seconds and recrystallized grains can grow to an average particle size of 5 μm or more.

Further, the final annealing is carried out in the manufacture of titanium plate according to the present embodiment of the preferably carried out under conditions of heating at a temperature of 420°C or more and less than 550°C for 3 hours or more and 50 hours or less when it is a periodic type. Condition 3 hours or more is preferred as the heating time, because if the heating time is less than 3 hours, the temperature of the inner part of the roll may not reach the preset temperature depending on the size of the roll. On the other hand, the condition is 50 hours or less is preferable as the heating time, because if the heating time exceeds 50 hours, the time required for annealing, will be excessively long, reducing, thus, the productivity of the titanium plate.

Further, the heating temperature of 420°C is preferred, because if the temperature� heating is less than 420°C, will be difficult to cause a predetermined recrystallization in a titanium plate during incubation, 50 hours or less, and the area ratio precrystallization parts will in many cases be more than 30%. Or it is because you want to have multiple furnaces for annealing (equipment for heating) to ensure a predetermined volume manufacture, which increases the cost of equipment and requires a large space for the installation of furnaces for annealing. It should be noted that in the periodic type, since a titanium plate is heated in a state of roll, the temperature increase speed differs between the outer part and inner part of the roll and the time before the temperature reaches the target temperature is the other. Depending on the size of the roll, the heating temperature and the heating capacity of the furnace for the annealing time before the temperature reaches the target temperature, in General, is different for tens of minutes to several hours. Consequently, it is important to heat the coil to a temperature range where the size of recrystallized grains is not much different, even if the heating time is in some degree different, that is important to the temperature range where the rate of growth of recrystallized grains is low.

Yes�her, the heating temperature preferably is less than 550°C, because due to the fact that the rate of growth of recrystallized grains of the crystal is high at a temperature of 550°C or more, when the heating time is reduced in accordance with the outside of the roll, the target temperature in the inner part of the roll may not be reached, resulting in a state where precrystallization part, which is not recrystallized, may be present in amounts exceeding 30%; on the contrary, when the heating time increases in accordance with the inner part of the roll, recrystallized grains can excessively increase in the outer part of the roll, the resulting average size of crystal grains of 5 μm or more.

It should be noted that the final annealing or continuous type or batch-type, preferably carried out under vacuum or in an inert gas atmosphere. Titanium plate having excellent balance of strength - workability", can be obtained by adjusting the average particle size of recrystallization and the residual percentage precrystallization parts (machined patterns) with annealing conditions as described above.

It should be noted that, although not described in detail in the present description, a well-known approach to conventional titanium plate and method izgotovleniyu plate can also be used in the present invention is in the range which does not weaken the effect of the present invention significantly. Further, although the titanium plate indicate as an example titanium material according to the present embodiment of the titanium material of various forms, such as wire material, bar material, the tubular material is the same as that of a titanium plate, as manifested by an excellent balance of strength - workability, and titanium materials are also subject to volume, implied by the present invention.

EXAMPLES

Hereinafter the present invention will be described in more detail with reference to examples, but the present invention is not limited by them.

Evaluation 1

Samples No. 1-45

Manufacture of test fragments

Ingot (140 mm diameter) were made using a small vacuum arc welding and the ingot was heated to 1050°C and then forged for the manufacture of a workpiece, having a thickness of 50 mm, the Workpiece was subjected to hot rolling at 850°C to a thickness of 5 mm and then annealed at 750°C and burrs on the surface of the annealed billet was removed by shot-blasting cleaning and etching for the preparation of the plate material. The material of the plate was further subjected to cold rolling to obtain a sample in the form of a plate (titanium plate) having a thickness� 0.5 mm. Titanium plate having a thickness of 0.5 mm, was subjected to a final annealing at a temperature of 400-800°C for 48 hours or less in an atmosphere of gaseous argon for receiving the test fragment in which the crystal grain was adjusted.

The measurement of the component

The amount of iron and oxygen contained in the titanium plate was measured using the plate material after hot rolling, which cut surface burrs. The iron content was measured in accordance with JIS H1614 and the oxygen content was measured in accordance with JIS H1620.

Measurement of tensile strength

Further, the tensile strength of the test fragment (titanium plate), in which the grain size of the crystal was adjusted as described above was measured in accordance with JIS Z2241.

Evaluation of machinability

Next, the machinability was evaluated test fragment (titanium plate), in which the grain size of the crystal was adjusted as described above. The evaluation was performed by measuring the number Eriksen using graphite lubricant as lubricants in accordance with JIS Z2247.

The study of the structure

Watched the microstructure of the titanium plate to obtain structural images of grains of the crystal (recrystallized α-granules) and precrystallization parts are treated structure). It should be noted that for the observations used an optical microscope or transmission electron microscope. An example of structural photographs, observed using a transmission electron microscope shown in Fig.1 (microstructure of sample No. 28). This structural photographs are observed recrystallized α-granules and precrystallization part (In the photo shown in Fig.1, the place labeled "A" represents precrystallization part). This photo was researching the area, other than precrystallization part, using software for image analysis to determine the average size of recrystallized α-grains; and the diameter of a circle having the same area as that of the middle size, was determined by calculation to establish the average particle size of recrystallized grains. Further, the share of the area precrystallization parts installed from the square precrystallization parts. The results above are shown in table 1.

Table 1
Sample No.The content (mass. %)The Fe content (mass. %)Conditions OTG�ha The average grain size of the recrystallized crystal grains (μm)The area ratio precrystallization parts (%)Yield strength (MPa)The number of Erichsen (mm)
TemperatureTime
10,0210,0174508 hour2,32519013,9
20,0210,0176001 minthe 3.9216214,5
30,0240,253600110 h2,21635210,9
40,0240,253630 110 h2,81130511,7
50,0240,2536501 min3,4526812,1
60,0300,0224508 hour2,023240the 12.9
70,0300,02245048 hour2,6222913,1
80,0300,0224808 hour2,31023613,0
90,0300,022 48024 hour2,8523013,2
100,0300,02248032 hour2,9322413,3
110,0300,02248048 hour3,1122513,3
120,0300,0225008 hour3,33217the 13.4
130,0300,0225204 hour4,50,521013,6
140,030 0,0226001 min3,52205the 13.4
150,0350,02760010 sec3,61526112,3
160,0350,02760030 sec4,1325512,5
170,0350,0276001 min4,2126212,4
180,0350,02763010 sec4,4226412,4
19 0,0350,02763030 secthe 4.7125013,3
200,0530,2176501 min4,2331011,5
210,0660,3776501 min3,4433611,0
220,0660,37765010 secof 4.9130111,7
230,0680,0594508 hour1,8214289,4
240,0680,0595008 hour3,22356of 10.7
250,0680,0596001 min3,3234510,8
260,0680,05965010 secof 4.90,231312,1
270,0420,02442524 hour1,826360the 10.4
280,0420,02445024 hour2,613304 to 12.0
290,0420,02448024 hour3,34264to 12.0
300,0420,02450024 houra 4.61,524012,5
310,0210,0176004 hour26010714,0
320,0300,0226001 hour120172a 12.7
330,0300,0226004 hour230 15913,0
340,0300,0227501 min46014813,2
350,0350,0278001 min820146the 13.4
360,0530,2178005 min17,204308,0
370,0660,37780015 hour2102669,2
380,0680,0597501 min42 019911,7
390,0680,0598001 min50018912,2
400,0680,05980015 min75019211,5
410,160of 0.06575010 min2803468,2
420,2090,10475010 min220411a 7.6
430,0300,0224501 hour 1,8432638,6
440,0660,3775001 hour2,335238the 10.4
450,0420,02440024 hour1,5454146,9

Each of the above samples Nos. 1-30 is the average size of recrystallized grains of 5 μm or less, and in each of these samples shows precrystallization part, with the share of area less than 30% in the cross section of the titanium plate; and samples Nos. 31-42 are in a state where precrystallization part is not stored as conventional titanium plates. Further, samples No. 43-45 obtained by adjusting the annealing conditions such that precrystallization part was deliberately allowed to remain where precrystallization part allowed to remain in a state where the area ratio exceeds 30%. The above samples Nos. 1-30 and # 31-42 obtained by R�regulation of grain size of the crystal (the equivalent circle average grain size of the α-phase) and the number precrystallization part with the difference between the annealing conditions, regardless of the use of titanium materials, in which the content of oxygen and iron content are almost the same. As shown in table 1, the average particle size can be suppressed to small and high yield strength is manifested by maintaining precrystallization parts. In the above evaluation of machinability (Ericksen) in General tends to decrease as increases, the yield strength, but when samples having comparable workability (Ericksen), are compared among themselves, it is found that the yield strength of these samples is increased, and these samples have high strength due to the presence of precrystallization parts (for example, see the comparison of sample No. 1 with No. 31, No. 9, No. 34 and No. 15 to No. 39). We have found that, when the crystal grain size of 5 μm or less and precrystallization part is present in an amount of 30% or less, the balance of tensile strength - workability is good. On the other hand, when the area precrystallization part is over 30% after final annealing, the machinability (Ericksen) is strongly reduced, as shown in samples Nos. 43-45. These results also showed that the present invention can provide a titanium plate having high strength and excellent machinability.

Assessment 2

The image�s No. A-N

Actual machine test

Manufacture of test roll

Ingot (750 mm diameter) were made using vacuum arc welding, and the ingot was heated to 850-1000°C and then forged for the manufacture of a workpiece, having a thickness of 170 mm, the Workpiece was heated to 850°C and then subjected to hot rolling to a thickness of 3.5 mm, and hot-rolled plate was annealed at a temperature of 750°C followed by removal of burrs on the surface of the annealed workpiece by shot blasting or etching to prepare hot-rolled coil. Hot rolled coil was subjected to cold rolling to obtain a cold-rolled coil having a thickness of 0.4-0.8 mm. Oil and fat such as oil for cold rolling, removed with cold rolled coil by cleaning, and the resulting cold-rolled coils are introduced into a vacuum furnace for annealing. The inner part of the vacuum furnace for annealing, which is cold rolled coil, evacuated, and then filled with gaseous argon, and in the furnace cold rolled coil was subjected to batch-type annealing, in which it is heated to 450-650°C, and kept within 4-36 hours to adjust the size of recrystallized grains. For the purpose of assessing "the measurement of components, measurement of tensile strength", "evaluation of machinability and research patterns" in the same way as in the previous�Noah assessment 1, samples of the required size were selected from the obtained titanium plates and subjected to the evaluations described above. The results are shown in table 2.

Table 2
Sample No.The content (mass. %)The Fe content (mass. %)Annealing conditionsThe average grain size of the recrystallized crystal grains (μm)The area ratio precrystallization parts (%)Yield strength (MPa)The number of Erichsen (mm)
TemperatureTime
A0,0280,017950024 hour3,6121313,5
B0,0320,02448024 hour2,65 23213,1
C0,0350,02248024 hour2,4424812,8
D0,0580023445036 hour2,33385the 10.1
E0,0680,03345036 hour2,444019,9
F0,0220,0146004 hour25011014,0
G0,0300,01863024 hour45 014913,2
H0,0410,0286504 hour55016612,8

Each of the above samples Nos. And E is the average size of recrystallized grains of 5 μm or less, and in each of these samples shows precrystallization part, with the share of area less than 30% in the cross section of the titanium plate; and samples Nos. F-H are in a state where precrystallization part is not stored as conventional titanium plates. In the above samples Nos. A, b and C received a titanium plate having a yield strength of 200 MPa or more and having excellent machinability, in which the number Eriksen is approximately 13 mm. Further, in the samples Nos. D and E received titanium plates, which not only has high strength, in which the yield strength is about 400 MPa, but also having a good workability, in which the number Eriksen is approximately 10 mm. on the other hand, samples Nos. F-H are excellent in workability, but have insufficient strength, in which the yield strength is less Cham MPa. These results also showed that the present invention can provide a titanium plate having high strength and excellent machinability.

Titanium material, characterized by the fact that it contains iron to 0.60 wt.% or less and the oxygen of 0.15 wt.% or less, titanium and inevitable impurities - and the rest is precrystallization structure formed by processing, accompanied by plastic deformation, and recrystallized structure after annealing by the specified handling, while the average size of recrystallized α-grains is 1 μm or more and 5 μm or less, and the area precrystallization parts in cross section of the titanium material is from more than 0% to 30%.



 

Same patents:

FIELD: metallurgy.

SUBSTANCE: manufacturing method cold-deformed pipes from α- and pseudo-α-alloys based on titanium involves melting of an ingot, forging of an ingot in β- and α+β-region with ending of forging in α+β-region into an intermediate shell with forging reduction of 2 to 3; piercing is performed at the temperature that is by 30-50°C higher than Tpp, by multiple-cone rolls and a mandrel with the specified geometry with water supply to a deformation zone, rolling of the shell is performed at the temperature that is by 10-90°C lower than Tpp; straightening of the pipe shell is performed at the temperature of 350-400°C, cold rolling is performed with drawing coefficient of 1.5-4.5 at several stages by alternation with intermediate annealing processes at the temperature equal to 600-750°C, and further heat treatment with the ready dimension at the temperature of 580÷650°C.

EFFECT: high mechanical properties of manufactured pipes, as well as high quality of pipe surface.

4 dwg, 3 tbl

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, namely to a method for obtaining technically pure nano-twinned titanium material. The method for obtaining technically pure nano-twinned titanium material involves casting of technically pure titanium material containing not more than 0.05 wt % N, not more than 0.08 wt % C, not more than 0.015 wt % H, not more than 0.50 wt % Fe, not more than 0.40 wt % O and the rest is not more than 0.40 wt %; cast material is brought to the temperature on the level of or below 0°C and plastic deformation is performed at this temperature in such a degree that nano-twins are formed in the material.

EFFECT: material is characterised by high strength and ductility characteristics.

15 cl, 6 dwg, 4 tbl, 4 ex

FIELD: process engineering.

SUBSTANCE: invention relates to production of long articles from titanium or its alloy or blanks of such articles. Proposed method consists in preparation of titanium or titanium alloy mix (10), melting said mix by electric arc at scull melting (20), casting of one or several ingots, primarily cylindrical in shape, in diameter smaller than 300 mm from said fused mix (30). Then, said ingots are drawn at 800-1200°C at draw bench (40) for application in, for example, aircraft engineering.

EFFECT: higher quality, simplified production.

13 cl, 3 dwg

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, namely to methods of straightening of high-tensile titanium alloys. The method of straightening of the metal stock material, subjected to precipitation strengthening, selected from titanium based, nickel based, aluminium based or iron based alloys, includes heating to the temperature of straightening from 0.3 Tm up to temperature 25°F below the ageing temperatures of alloy, the stretching with the applying of pulling stress at least 20% of yield stress and neither equal nor more than the alloy yield stress. Meanwhile the stock material deviates from a straight line no more than by 0.125 inches (3.175 mm) per any 5 ft of length (152.4 cm) or per shorter length. Then the stock material is cooled with the simultaneous application of pulling stress.

EFFECT: after straightening the stock material conserves high durability characteristics.

21 cl, 9 dwg, 2 tbl, 6 ex

FIELD: process engineering.

SUBSTANCE: set of invention relates to production of thin bars and wires with shape memory effect and superplasticity from alloys of nickel-titanium system to be used in aircraft engineering, radio electronics, medicine, etc. Proposed method consists on production of the alloy with shape memory effect. Bar-like blank is made from said alloy by compaction or helical rolling and heated to make the bar by rotary swaging in several steps to required size with intermediate heating between swaging steps. Blank is heated before rotary swaging to 300-500°C. Method of alloy production for further making of the bar consists in facing the high-strength graphite crucible walls and bottom by nickel plates. The rest mix is placed inside the crucible to fuse in vacuum induction furnace. The melt is held, teemed in vacuum into chill mould and cooled down to get the ingots. Thereafter, electrode is made from obtained ingots or from bard produced from said ingots. Electrode material is subjected to electron beam smelting in vacuum of at least 5x10-3 Hg mm to form the ingot in copper casting mould.

EFFECT: wire production from bar by hot or cold drawing.

9 cl, 2 tbl

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming and can be used for production of articles from three-component titanium-based alloy containing 2-6 wt % of aluminium and not over 4 wt % of vanadium or zirconium. Billets are subjected to equal-channel angular pressing at 400-470°C at the rate of 0.1-1.0 mm/s. Note here that nano- and sub microcrystalline structures are formed in the billet with grain size not over 0.5 mcm. Deformed billets are subjected to isothermal annealing at 450-550°C for 0.5-1.0 h. Then, the billet is subjected to upsetting or rotary forging at the temperature not higher than that of isothermal annealing.

EFFECT: higher strength and operating performances.

3 cl, 1 dwg

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming and is intended for straightening of rolled sheet in annealing at constant load, primarily, large-size sheets and boards from titanium alloys. Proposed creep annealing comprises setting of batch composed of one or several sheets onto steel heated plate of vacuum straightening plant. Plant inner space is evacuated at simultaneous loading of the batch outer side, heating to annealing temperature is performed as well as holding and cooling. Cooling is executed with intermediate stage at temperature of 220±20°C with holding of 1 to 5 hours.

EFFECT: stable sheet surface shape.

2 cl

FIELD: metallurgy.

SUBSTANCE: equichannel angular pressing of a cylindrical workpiece is performed. Ultra-fine structure with the grain size of 200-300 mcm is formed in the workpiece metal. Then the workpiece is cut into disks with each of them being subject to intensive plastic deformation by torsion with the help of two rotating strikers. Deformation of torsion is carried out under the room temperature and the pressure of 4-6 GPa with the number of strikers' revolutions n≤2. Therewith the homogeneous nanocrystalline structure with the grain size of ≤100 mcm is formed.

EFFECT: improved physical and mechanical properties of the material being processed.

2 cl, 1 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: method to produce titanium blanks involves placement of titanium sponge particles in a press chamber, compaction of the sponge particles to produce a blank, its pressing, removal of dirt from the pressed blank surface, its covering with grease and following rolling. Prior to placing the titanium sponge particles in the press chamber they are heated in a vacuum heating furnace up to the temperature of 700-800°C, alloyed by hydrogen up to the concentration of 0.1-0.9 wt %, then the temperature in the furnace is reduced to the temperature not lower than 300°C, compaction is carried out under the temperature of 300-700°C, compacted blanks are pressed by semicontinuous method via a matrix under the temperature of not more than 700°C with reduction ratio of maximum two and then under the temperature of not more than 700°C and the reduction ratio of maximum three, the blanks are rolled under the temperature of not more than 700°C, with following annealing in vacuum under the temperature of not less than 700°C.

EFFECT: possibility to process hardly deformable titanium under lower temperatures, improved mechanical properties of produced blanks.

1 ex

FIELD: medicine.

SUBSTANCE: titanium aluminide alloy Ti3Al contains, wt %: Al 13-15, Nb 3-6, V 2-4, Zr 0.5-1.0, Mo 1-3, Sn 0.5-3, Si 0.1-0.3, Ti - the rest. A titanium aluminide alloy Ti3Al blank is subject to thermal hydrogen processing by hydrogen saturation followed by vacuum annealing. The hydrogen saturation of the blank is carried out to the concentration of 0.4-0.6 wt % at two stages, and then the blank is rolled. Vacuum annealing is two-staged at residual pressure no more than 5·10-5 mmHg.

EFFECT: heat-resistant titanium aluminide alloy Ti3Al is characterised by high plasticity and heat-resistance.

2 cl, 1 tbl

FIELD: process engineering.

SUBSTANCE: invention relates to production of long articles from titanium or its alloy or blanks of such articles. Proposed method consists in preparation of titanium or titanium alloy mix (10), melting said mix by electric arc at scull melting (20), casting of one or several ingots, primarily cylindrical in shape, in diameter smaller than 300 mm from said fused mix (30). Then, said ingots are drawn at 800-1200°C at draw bench (40) for application in, for example, aircraft engineering.

EFFECT: higher quality, simplified production.

13 cl, 3 dwg

FIELD: metallurgy.

SUBSTANCE: alloy contains the following, wt %: titanium 46.3-48.8; aluminium 0.14-2.87, calcium 0.06-1.24; magnesium 0.08-1.61; and iron is the rest.

EFFECT: reducing activation time and increasing alloy sorption capacity.

1 tbl

FIELD: metallurgy.

SUBSTANCE: method to produce titanium blanks involves placement of titanium sponge particles in a press chamber, compaction of the sponge particles to produce a blank, its pressing, removal of dirt from the pressed blank surface, its covering with grease and following rolling. Prior to placing the titanium sponge particles in the press chamber they are heated in a vacuum heating furnace up to the temperature of 700-800°C, alloyed by hydrogen up to the concentration of 0.1-0.9 wt %, then the temperature in the furnace is reduced to the temperature not lower than 300°C, compaction is carried out under the temperature of 300-700°C, compacted blanks are pressed by semicontinuous method via a matrix under the temperature of not more than 700°C with reduction ratio of maximum two and then under the temperature of not more than 700°C and the reduction ratio of maximum three, the blanks are rolled under the temperature of not more than 700°C, with following annealing in vacuum under the temperature of not less than 700°C.

EFFECT: possibility to process hardly deformable titanium under lower temperatures, improved mechanical properties of produced blanks.

1 ex

FIELD: medicine.

SUBSTANCE: titanium aluminide alloy Ti3Al contains, wt %: Al 13-15, Nb 3-6, V 2-4, Zr 0.5-1.0, Mo 1-3, Sn 0.5-3, Si 0.1-0.3, Ti - the rest. A titanium aluminide alloy Ti3Al blank is subject to thermal hydrogen processing by hydrogen saturation followed by vacuum annealing. The hydrogen saturation of the blank is carried out to the concentration of 0.4-0.6 wt % at two stages, and then the blank is rolled. Vacuum annealing is two-staged at residual pressure no more than 5·10-5 mmHg.

EFFECT: heat-resistant titanium aluminide alloy Ti3Al is characterised by high plasticity and heat-resistance.

2 cl, 1 tbl

FIELD: metallurgy.

SUBSTANCE: proposed process comprises production of the mix of powders, forming the pellet therefrom and execution of self-propagating high-temperature synthesis. Obtained the mix of pure metals containing titanium, aluminium, niobium and molybdenum in the following amount, it wt %: aluminium - 40-44, niobium - 3-5, molybdenum - 0.6-1.4, titanium making the rest. This pellet is compacted to relative density of 50-85% and subjected to thermal vacuum processing at 550-560°C for 10-40 min, heating rate of 5-40°C/ min and pressure of 10-1-10-3 Pa while SPS is performed at initial temperature of 560-650°C.

EFFECT: preset shape of casts, high mechanical properties.

2 dwg, 2 tbl, 2 ex

FIELD: metallurgy.

SUBSTANCE: proposed alloy features density at a room temperature of not over 4.2 g/cm3, solidus temperature of at least 1450°C, the number of phases α2 and γ at 600-800°C making at least 20 wt % and at least 69 wt %, respectively. Total quantity of said phase makes at least 95 wt % while niobium content in γ-phase makes at least 3 wt %. Proposed method consists in that said γ-TiAl alloy containing niobium in amount of 1.3 or 1.5 at. % and transition metals selected from chromium in amount of 1.3 or 1.7 at. % and zirconium in amount of 1.0 at. % is subjected to hot isostatic forming. Said forming is combined with annealing at 800°C and holding for 100 hours.

EFFECT: low density, stable phase composition at operating temperatures.

2 cl, 2 dwg, 4 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: proposed alloy comprises the following elements, in wt %: carbon - 0.03-0.10; iron - 0.15-0.25; silicon - 0.05-0.12; nitrogen - 0.01-0.04; aluminium - 1.8-2.5; zirconium - 2.0-3.0; samarium - 0.5-5.0, titanium and impurities making the rest.

EFFECT: higher efficiency of absorption, better working and bonding properties.

3 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: solder contains components at the following ratio in wt %: zirconium - 45-50, beryllium - 2.5-4.5, aluminium - 0.5-1.5, titanium making the rest. Solder represents a flexible band and is produced by super-rapid tempering of the alloy by casting the melt of revolving disc.

EFFECT: higher operating performances, decreased intermetallide interlayers in the weld.

3 cl, 11 dwg, 1 ex

FIELD: metallurgy.

SUBSTANCE: production of titanium-based allot with content of boron of 0.002-0.008 wt % comprises smelting in vacuum arc skull furnace with consumable electrode without extra vacuum port for addition of modifying additives. Preform of modifier B4C wrapped in aluminium foil is fitted in consumable electrode bore drilled from alloyable end to distance defined by electrode fusing interval.

EFFECT: titanium-based alloy of equiaxed structure and grain size smaller than 15 mcm.

1 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: titanium-based alloy contains the following, wt %: Al 5.0-6.6, Mo 1.5-2.5, Zr 1.0-2.8, V 0.4-1.4, Fe 0.08-0.40, Si 0.08-0.28, Sn 1.5-3.8, Nb 0.4-1.2, O 0.02-0.18, C 0.008-0.080, Ti is the rest.

EFFECT: alloy has high strength characteristics at high temperatures, increased processibility level at hot deformation.

2 cl, 3 tbl, 3 ex

FIELD: mechanical engineering; piston internal combustion engines.

SUBSTANCE: invention relates to valve of internal combustion engine, method of its manufacture and heat-resistant titanium alloy used for manufacture of valve consisting of following components, mass %: aluminum 7.5-12.5; molybdenum 1.6-2.6; zirconium 1.4-2.4; silicon 0.1-0.2' yttrium 0.005-0.1; titanium - the rest. It has α+α2+β phase composition with intermetallide α2 phase on Ti3Al base dispersed in α phase. Proposed method includes forming of valve from cylindrical blank by deformation machining with preliminary heating and subsequent heat treatment. Preliminary heating of part of blank related to rod done to temperature 5-20oC lower than temperature of complete polymorphic transformation of alloy, and its deformation machining is carrying out by wedge cross rolling. Deformation machining of part of blank related to head is done by forging with preliminary heating to temperature 5-50oC higher than temperature of complete polymorphic transformation of alloy corresponding to beginning of forging, and forging is finished at temperature lower than complete polymorphic transformation of alloy to form plate head of valve and transition section provided smooth changing of head into rod. Invention provides designing of valve, method of its manufacture and heat-resistant alloy used in manufacture of valve making it possible to operate valve within operating temperature range owing to increased long-term strength and creep resistant of valve head material and increased strength, modulus of elasticity and hardness of valve rod material.

EFFECT: improved quality of valve and increased reliability in operation.

16 cl, 3 tbl, 1 ex, 15 dwg

Up!