RU2541251C2 - Production of long articles from titanium - Google Patents

Abstract

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

Description

The invention relates to a method for the production of elongated products from titanium, or a titanium alloy, or preforms of such products.

The term "elongated product" here means a metal part whose cross-sectional dimensions are much smaller, or even many times less than its length.

Elongated products include metal parts, the production of which usually involves at least one drawing operation. However, the definition of an elongated product is not limited solely to such details.

Under elongated products, most often they mean metal parts obtained during the drawing operation, and profile parts, including hollow sections and pipes.

The term "procurement" should be understood here in a fairly broad sense. It means an elongated product, not a final product, but one whose general shape mainly has the general appearance of a final elongated product. This means that the preform of the elongated product is an elongated metal part.

This does not exclude the subsequent molding of this preform, for example, by machining, or the modification of this general shape, for example, by bending, folding or any other plastic deformation.

It should be understood that the "blank" of the elongated product is an elongated part that can be subjected to various types of processing, such as molding, machining or also surface treatment to obtain the final product.

The applications for elongated titanium or titanium alloy products are numerous. In particular, they include aviation and aerospace construction.

There are certain rules governing the metallurgical quality of products. The required quality depends on the intended application.

For example, aviation construction requires high quality due to the serious consequences that result in inadequate product quality.

Compliance with established quality standards is not limited to the field of aviation: in practice, most applications require compliance with minimum metallurgical quality in order to determine whether they comply with the norm or not. And obtaining a high-quality product is not limited to the aviation and aerospace fields.

Today's requirements for quality are supplemented by requirements for cost and availability, which are almost equally important. In other words, it is no longer enough to obtain a product that meets the quality requirements, it is also necessary to achieve a satisfactory price and sufficient quantity to satisfy the market.

Therefore, they are constantly looking for the least expensive method of production, which will allow to obtain products of at least equivalent quality.

Conventional methods begin with preparing a mass of titanium, which may contain titanium sponge, titanium chips, titanium waste (which is sometimes mistakenly called “titanium scrap”) and / or most often secondary titanium.

This mass of titanium is then melted and fused into a single ingot of significant diameter.

In these traditional methods, various techniques can be applied to effect the smelting / casting of a mass of titanium.

Electron bombardment smelting, also defined by the English term "Electron beam furnance", is used to melt a mixture of sponge titanium and secondary material (waste) as a primary material. Recycled materials are less expensive than titanium sponge, which implies the economic interest that can be obtained by this method.

Plasma melting and electron-bombardment melting in a cold crucible are more recent technologies that allow for more continuous casting and make it possible to melt more titanium waste. These technologies are also more economical than smelting through traditional electron bombardment.

With traditional smelting methods, casting molten material is stepwise and rather slow. Typically, the molten material is gradually poured into the casting crucible due to the overflow of the melting boiler as the material melts. Duration and phasing of castings, mainly due to limitations of smelting technology, lead to casting defects in the ingot.

In order to meet the high requirements for metallurgical quality, for example, critical parts from the aviation field, it is necessary to re-melt the ingot obtained after primary melting / casting and pour it again. Subsequent melts ultimately improve the metallurgical quality of the ingot.

Traditionally, melting / casting is carried out according to the technology of remelting by means of a vacuum electric arc, also called "VAR" (from the English "vacuum arc remelting" ("vacuum-arc remelting")). The ingot obtained after the first melting is an electrode that must be gradually melted and simultaneously cast into an ingot of a similar diameter in a continuous manner. In practice, the diameter of a new ingot is on average 10-20% greater than the diameter of the electrode used, that is, the primary ingot.

It should be noted that certain standards, such as US standard AMS 4945, used in the field of aircraft construction, require the use of remelting "VAR".

This double smelting is expensive. It is also customary for casters to cast large-diameter ingots, approximately between 500 and 1000 mm, since the cost per unit mass decreases with increasing diameter of the cast ingot. In other words, larger diameter ingots are less expensive for a given volume of material used.

To get rid of the disadvantages of traditional (primary) melting technologies, which are mainly the slowness and phasing of the melting / casting, later the melting technology was applied by means of a vacuum electric arc using the skull melting method, also defined by the English term "skull melting" (literally translated from French - "melting on the crust"). By means of skull melting, a melting method is achieved in which the furnace crucible cools so that a layer of molten material, in this case titanium, or an additional crucible isolating the rest of the molten material from the crucible of the furnace is formed over it.

Part of the mass of titanium to be melted is placed in a crucible, while another part of this mass performs the function of the electrode used. The entire mass of titanium is melted due to the electric arc formed between the electrode and the crucible, and then subjected to heat treatment in a casting bath. The molten mass is then cast into one or more molds at a time by tilting the crucible.

Skull melting allows you to quickly pour at a time, in one batch (tilt) the entire mass of molten material. This can avoid casting defects associated with the slowness and phasing of older smelting technologies.

For economic reasons, it is usually customary to pour one large ingot.

Skull melting equally allows melting of both titanium blanks and secondary material.

An additional advantage is that the gangue that forms in contact with the crucible can be easily, i.e. directly, reused as a new electrode.

For most of the elongated products required, the capabilities of modern mills do not allow dragging directly the ingots obtained after remelting "VAR" or skull melting due to the too large diameter of the ingot.

One or more operations to reduce the diameter by forging is necessary to transform a large diameter ingot into one or more ingots of suitable diameter for the drawing mill and for the desired elongated product.

As an example, an ingot obtained by VAR technology or skull melting can have a diameter of about 600 millimeters and can be transformed by subsequent forging operations into blanks with a diameter of about 120 millimeters, that is, the reduction in diameter by forging is about 25 times (2500%) .

It should be noted that forging definitely improves the metallurgical quality of the ingots, thus, it is systematically used after melting (VAR, skull melting, etc.).

Additional operations, such as machining (to remove a thin surface layer of a forged blank or “stripping”) or finishing, can also be performed before drawing, if necessary.

As a result, the usual set of stages for the production of elongated high-quality products from titanium or a titanium alloy, starting with the mass of titanium, includes the following operations, in which:

- the mass of titanium or a titanium alloy is melted and a single ingot of large diameter is poured;

- remelted using the "VAR" technology, this single ingot into a single ingot of also large diameter; this stage is practically mandatory if the previous melting was not carried out by means of skull melting; this smelting may be required by aviation standards.

- from the ingot of a large diameter, one or more blanks are drawn for drawing, performing one or more forging operations;

- carry out the drawing of blanks by means of a drawing mill to obtain elongated products of almost final shape;

Then, one or more surface treatment and / or changes in the general appearance of the elongated product can be performed to obtain the final elongated product.

This set of production steps is not entirely satisfactory, in particular with respect to the cost, duration of production of an elongated product, and also regarding the availability of finished products.

The applicants have found a way to improve the situation.

The proposed method is a method of manufacturing elongated products from titanium or a titanium alloy, or preforms of such products, including preparing a mass of titanium or a titanium alloy, melting this mass by means of an electric arc and method of skull melting, pouring into one or more ingots of predominantly cylindrical shape and a diameter of approximately less 300 mm from the molten mass, then drawing one or more of such ingots at a temperature between 800 ° C and 1200 ° C by means of a drawing mill.

This method allows to obtain intact elongated products, i.e. practically devoid of all casting defects, and in their mechanical strength, in particular as measured by a tensile test, at least equivalent to products obtained by traditional or currently known methods. For example, this method allows you to get elongated products that are comparable in quality to products that meet current aviation standards, at least with regard to mechanical strength, for example, US standards AMS 4935 or AMS 4945.

In addition, this method offers a potentially lower cost of production of the product compared to traditional or currently known methods, as well as a shortened production time, partly due to the absence of any forging operations, and, in general, a significant reduction in the diameter of the ingots cast before the operation drawing, which allows for the simultaneous casting of several ingots.

The proposed method increases the availability of the obtained elongated products, in particular, due to the simplification of the set of stages of production and the possibility of using a large proportion of the secondary material in the prepared mass of titanium or titanium alloy.

Other differences and advantages of the invention are revealed when studying the following detailed description and the attached graphic materials, on which:

- Figure 1 shows a block diagram illustrating the method according to the invention,

- FIG. 2 is a flowchart illustrating one embodiment of the method of FIG. 1,

- FIG. 3 is a flowchart illustrating an additional method that can be implemented in addition to the methods of FIGS. 1 and 2.

The attached graphic materials can not only complement the invention, but also, if necessary, contribute to its definition.

In FIG. 1 shows a method for manufacturing elongated articles from titanium or a titanium alloy, or blanks of articles of this type.

The method of FIG. 1 includes a step of preparing 10 masses of titanium or a titanium alloy, a melting operation 20 of this mass by means of an electric arc and a skull melting method, a casting operation 30 of a molten mass of one or more ingots of predominantly cylindrical shape and a diameter of less than about 300 mm, then a drawing operation 40 of one or several ingots at a temperature between 800 ° C and 1200 ° C by means of a drawing mill. Optionally, the elongate product obtained at this stage of drawing can be subjected to one or more of the final or intermediate processing steps 50.

The method of FIG. 1 begins with the operation of preparing a mass of titanium or titanium alloy 10. The chemical composition of this mass corresponds to the desired grade of elongated product. For example, the chemical composition of this mass may be intended to produce a TA6V4 alloy, or equivalent, such as that specified in US Standard AMS 4935, or TA3V2.5, or equivalent, such as that described in US Standard AMS 4945.

These alloys are particularly used in the field of aviation, in which strict standards require high metallurgical quality of products. Their use is in no way limited to this industry. And the implementation of the method of FIG. 1 is also not limited specifically to these alloys, but rather extends to many different titanium compounds according to the intended use, for example T40, T60 or others.

This mass may include sponge titanium, titanium waste or titanium alloy, referred to in English as “scrap”, scrap of titanium or titanium alloy, all or part of the crust, shell or gangue resulting from skull melting, or most often secondary titanium in any form. The composition of the secondary material is controlled with respect to its quality and chemical composition.

Secondary elements can come from the raw materials being laid, processed secondary materials intended for the production of titanium by smelting, machining of residual parts from titanium or titanium alloys, etc.

These secondary materials may have a different chemical composition, for example, according to the desired grade of elongated product, but not necessarily. These materials may correspond to the above alloys.

The availability and cost of secondary elements depends on their mass, that is, the cost of a kilogram of material is less than the cost of a kilogram of sponge titanium, so its use has a greater advantage.

The mass of titanium or titanium alloy in the preparation step 10 may also include alloying and / or alloy elements in proportions that depend on the subsequent stage of the method, on the intended use, and / or the desired grade of elongated product.

According to the method of FIG. 1, a melting operation follows by means of an electric arc and a skull melting method 20 of a mass of titanium or a titanium alloy prepared in step 10.

Thus, the melting is carried out in the form of skull melting.

Skull melting is carried out by means of a furnace containing a vacuum tank and a correspondingly made crucible placed inside the tank.

The consumable electrode is installed inside the tank, while titanium is loaded into the crucible. A large potential difference between the electrode and the crucible is generated. When this potential difference reaches a certain threshold, an electric arc is formed with a high energy level between the lower end of the electrode and the titanium in the crucible.

In practice, the electrode can be mounted on a vertical part extending from top to bottom in the tank.

When the electrode is completely melted, the molten mass of titanium in the crucible can be poured at one time into one or more molds of the selected type, in this case with a circular cross-section and a diameter of less than 300 mm, placed inside the tank. Thus, casting is carried out very quickly: it can, for example, be carried out by tilting the crucible. Skull melting is also a batch melting / casting technology.

During such melting / casting, part of the molten mass of titanium solidifies at the border with the crucible and forms a titanium waste rock that protects the titanium during melting from any contamination from other elements present in the crucible or from the crucible itself. In other words, this waste rock forms an additional crucible located in the crucible, which is provided in the furnace (skull melting). After cooling, this waste rock can be used as a consumable electrode for new smelting, which is of economic interest. The furnace crucible can be arranged in such a way that the waste rock has a shape adapted to its further function as a consumable electrode.

The prepared mass of titanium in step 10 includes predominantly gangue or crust formed as a result of melting and casting using the skull melting method of the initial mass of titanium.

Also, mainly, prepared for operation 10, the mass of titanium contains a significant proportion of secondary titanium.

Preferably, the titanium mass for operation 10 includes only one or more crusts of recycled material and the necessary alloy or alloy elements in an appropriate proportion.

In other words, the operation of preparing the mass of titanium or titanium alloy 10 in this case consists mainly in obtaining a mixture of titanium or titanium alloy, in which most or all of the mass consists of recycled materials. It may only be necessary to add alloying elements.

The method of FIG. 1, therefore, has the advantage, mainly, that the method allows to obtain high-quality products at a lower cost than with traditional methods, due to the use of almost exclusively secondary materials using melting by means of an electric arc or skull melting .

The temperature used for this smelting operation, called the subcooling temperature, may depend on the composition of the mass during the preparation operation 10. The subcooling temperature above 1600 ° C allows this mass to be melted in most possible compositions.

According to the method of FIG. 1, an operation is followed for casting ingots with a predominantly round cross section and a diameter of about less than 300 mm. Preferably, the diameter of these ingots should be less than 250 mm. Casting is carried out using the entire molten mass at a time (in one “batch”) and quickly, for example, by tilting the crucible containing the molten mass of titanium.

There is no lower limit on the diameter of the 30 ingots cast during the operation. However, for economic reasons, it may be preferable to pour ingots with a diameter of more than 100 mm.

Theoretically, there are no restrictions on the length of the ingots poured in step 30.

In practice, ingots whose length is related to the length of the ingots for drawing during operation 40 are poured. For example, the length of the ingot poured during operation 30 can be selected as a multiple of the length of the ingot for drawing during operation 40 to avoid loss of material. Most often, the length of the ingot cast during operation 30 can also be chosen equal to the sum of the lengths of the ingots for drawing during the drawing operation 40.

Preferably, during the casting operation 30, as many cylindrical ingots are poured as the titanium mass melted during operation 30 allows. Thus, they fully benefit from the fact that skull melting allows casting in batches. The mass of titanium or titanium alloy poured during step 20, and therefore the mass of titanium or titanium alloy prepared in step 10, can be selected in an amount based on the number of ingots to be drawn and, therefore, preliminarily poured , as well as based on their size.

The diameter of each of the 30 ingots cast during the operation is less than 300 mm. Each of these ingots can then be drawn during operation 40 without substantially reducing its diameter before the drawing operation.

However, between casting during operation 30 and drawing during operation 40, a peeling operation may be performed. Despite the fact that during the peeling operation a decrease in diameter certainly occurs, this decrease is so small (of the order of several tenths of a millimeter) that it cannot be considered as a significant decrease in the diameter of the ingot. In addition, the peeling is aimed at removing the surface layer of the cast ingots, and thus, it cannot be considered an operation to reduce the diameter, the purpose of which is to significantly reduce the diameter of the ingot.

Cylindrical ingots poured during operation 30 may have similar dimensions both in length and in diameter. These ingots may also have different lengths and / or diameters, for example, for the manufacture of various elongated products. The diameter and length of each of the ingots cast during operation 30 can be selected depending on the diameter and length of one or more ingots intended to be drawn during operation 40. You can set the length and diameter of the ingot for drawing, depending on the elongated product you want to obtain the result of the drawing operation 40. In other words, the method of FIG. 1 allows to obtain 30 ingots as a result of the casting operation, the dimensions of which are adapted to the drawing, and the sizes of which can be calculated depending on the sizes required elongated product.

In this regard, the method of FIG. 1 differs from traditional methods involving casting a single ingot, in particular, to reduce the cost per unit mass of the ingot being poured, and forging operations to reduce the diameter of the ingot. In other words, the diameter of the cast ingot in the traditional methods is limited (about 400-600 mm), while in this case the diameter can be selected.

It should be noted that, for the limited dimensions of the elongated product, in practice there is a range of possible diameters and lengths of the ingot for drawing 40. When elongated products of various sizes are to be obtained by the method of FIG. 1, it may be better, if possible, to choose the appropriate size of the diameter of the ingot for drawing, which could be adapted to the totality of such products: thus, one ingot can be poured, which can be cut to obtain ingots adapted to the drawing of various lengths GOVERNMENTAL products. Thus, the management of the presence of ingots for drawing is optimized.

It should also be noted that the method of FIG. 1 allows with equal ease and at a similar cost (in addition to the cost of the primary material) to obtain products of larger and smaller diameters. In the classical method, which requires forging operations to reduce the diameter, on the contrary, it is more difficult and expensive to produce products with a small diameter, which require additional costs for reducing the diameter, which is most often done by forging.

Currently used mills do not allow drawing of ingots with a length of more than 1500 millimeters. In other words, the ingots cast in step 30 are less than 1,500 millimeters in length, but can be longer if mills with greater capabilities appear.

The method of FIG. 1 ends with a hot drawing operation of 40 cylindrical ingots under the drawing mill to obtain an elongated product or blank of this product. The drawing operation 40 can be adapted to obtain a solid or hollow product.

The drawing temperature exceeds the temperature of the so-called "beta transus", which depends on the composition of the ingot.

The drawing operation 40 is carried out in a hot manner at a temperature typically of 800 ° C-1200 ° C. Preferably, the drawing is performed at a temperature above 900 ° C to ensure good ductility of the material, and below 1150 ° C to avoid excessive energy consumption, while still obtaining an adapted metallographic structure.

Drawing is carried out by means of a traditional drawing mill equipped with a drawing and a punch. If it is necessary to make a hollow elongated product, a rod, also called a “needle”, is also used (in this case, a hole must be made in the ingot for drawing beforehand).

Drawing is carried out hot in the presence of a lubricating component. This lubricating component typically contains glass, i.e. conventional lubricant component for traditional hot drawing operations at temperatures above 900 ° C.

The method of FIG. 1 does not require a reduction in the diameter of the ingot cast during operation 30 before the drawing operation 40.

However, it should be understood that this does not exclude the possibility that one or more specific operations, such as grinding, various types of surface treatment or cutting, can be performed with the ingot poured in step 30 to prepare the ingot for drawing to step 40.

The metallurgical quality of the elongated product obtained during the drawing operation 40 is surprisingly comparable to the metallurgical quality of the products obtained in the traditional way, at least in terms of mechanical strength, in particular as measured by the cold tensile test.

This comparable quality, obtained in the absence of the forging operation preceding the drawing operation 40, is largely due to the fact that the drawing has a beneficial and sufficient effect on the metallographic structure of the small-diameter ingots that were cast.

The absence of any operation to reduce the diameter of the ingot obtained during the casting operation 30, in particular, the absence of forging preceding the drawing operation 40, also reduces the cost of the elongated product. The absence of this operation, respectively, reduces the duration of the manufacture of such a product.

The absence of a forging operation, or any other operation for forming an ingot before a drawing operation; and the quality of the elongated product resulting from the drawing is such that, despite the rather small diameter of the ingots cast during operation 30, the method of FIG. 1 is more economical with respect to the final cost of the elongated product than the methods known in the art. Duration of manufacture and availability are also improved compared to those known in the art.

The whole set of 30 ingots poured during the operation or only some of them can be drawn in parallel on several different mills, if necessary after cutting, which especially increases the productivity of the method. The cost of an elongated product is reduced to the same extent.

Unlike traditional methods, the ingot cast during operation 30 is not remelted according to the method of FIG. 1. However, the quality of the elongated product obtained as a result of the drawing operation 40 is entirely sufficient, as regards the absence of casting defects and mechanical strength, compared to products obtained after the "VAR" smelting, and without the forging operation known for that it improves quality.

Although vacuum melting, such as "VAR" melting, is regulated by certain standards for elongated products of high quality (or high strength), the applicant has determined that the products obtained by the method of Figure 1 are also suitable for the applications provided by these standards, despite the absence of such a remelting.

Figure 2 shows an embodiment of the method of Figure 1.

The casting operation of the ingots 30 in this case includes the operation of casting the first ingots with a diameter of less than 300 millimeters 300, then the operation "remelting VAR" 302 of these first ingots. In other words, each of the first ingots obtained after melting / casting using the “skull melting” method, or at least some of them, are separately subjected to “VAR” melting. These first ingots serve as consumable electrodes for such melting.

The ingot casting operation 30 then includes ingot casting operations for drawing from the second mass of molten material, i.e. ingots of cylindrical shape and diameter less than 300 mm.

When remelting "VAR", casting is performed in stages, as the consumable electrode is melted. The diameter of the resulting ingot or second ingot is usually about 10-20% larger than the diameter of the electrode. Consequently, the diameter of 300 ingots cast during the operation should be obtained taking into account this increase, in particular because the ingots for drawing during operation 40, as a rule, have a diameter of less than 300 mm without any need to carry out the operation to reduce the diameter.

Figure 3 shows a method of final processing 50 or intermediate processing, which can be subjected to elongated products obtained in accordance with one of the methods shown in figures 1 and 2.

An elongated product obtained during a drawing operation 40 may be subjected to one or more of the following operations:

- one or more heat treatments (in the oven) and one or more chemical treatments (eg, cleaning) or physical surface treatments 51;

- operations of straightening and untwisting 52, designed to straighten elongated products, in relation to their cross section and General view;

- heat treatment operation 53;

- the operation of giving the desired length 54 by sawing or cutting,

- sandblasting operation 55, also called sandblasting;

- molding operation 56,

- control operation 57 by one or more known control technologies without destruction of the product, such as ultrasound, fluoroscopy, eddy currents, etc.,

- mechanical restoration.

These operations are presented solely in illustrative order and can equally be performed in a different order.

The proposed method allows to obtain elongated products of satisfactory quality, relative to current standards, without forging operations, which makes the traditional VAR remelting operation optional and gives a significant opportunity to use recycled material.

The proposed method eliminates the forging operation. As a result, the applicants proved, against any expectation and against ideas widespread in the art, that comparable or at least sufficient mechanical properties of elongated products can only be obtained by drawing, making the beneficial effect of the forging operation unnecessary.

The presented method has a lower cost of production, reduced production time and greater availability of products.

The present invention is not limited to the methods described above, given solely as examples. In particular:

- The operation of melting 20 and casting 30 is described as performing skull melting. This melting technique allows melting / casting in batches, in contrast to stepwise melting / casting methods. To date, only this technology allows for such a casting method. However, the methods of FIGS. 1 and 2 can be performed using a different melting technology, if only it has characteristics similar to skull melting, that is, the methods allow the manufacture of ingots suitable for drawing, with a diameter of less than 300 mm, with a reasonable cost, preferably using a large amount of recycled material and batch casting.

- Smelting at stages 302 and 304 can be carried out by various smelting methods, if only they would improve the metallographic quality of the obtained ingots and allow, at an acceptable cost, to obtain ingots adapted for size 40 drawing operation, i.e. with a diameter of less than 300 mm.

Upon completion of the drawing operation 40 or, if necessary, the final processing operation 50, the obtained elongated product may undergo one or more molding operations, in particular forging, including those intended to further reduce its cross section.

- It is possible to consider more broadly the drawing of ingots with a diameter of less than 300 mm immediately after they have passed the VAR remelting, without reducing the diameter by preliminary forging, despite the fact that the first melting / casting was performed according to any method that would allow the ingots to be poured adapted diameter at a reasonable price.

- Received elongated products can be subjected to subsequent molding, for example, bending.

The present invention has been described with reference to the field of aviation, in particular with regard to the standards applicable in this field. This is due to the fact that this industry is an extensive field of application for elongated titanium products and requires high quality of these products. This does not in any way limit the application of the described method to this particular manufacturing industry. However, other industries that use elongated titanium or titanium alloy products and require high-quality products may refer to the standards set for the aviation industry, while not being part of this industry. The present invention also applies in such industries. In general, the invention is intended for use in all sectors, except aviation, which require elongated high-quality titanium products in a non-aviation field. In this regard, the method according to the invention offers such flexibility and such a reduction in cost that elongated titanium products can be introduced in areas not related to aviation and / or for widespread use.

Strictly speaking, elongated products made according to the method of FIG. 1 do not comply with US standard AMS 4935 for use in the aircraft industry, since several melts, including in vacuum, do not pass. But, nevertheless, they are products of comparable quality, in particular in terms of their mechanical strength. The applicant believes that these products can be used instead of products defined by this standard, or the standard should be changed so as to include products obtained by the method of Figure 1. In any case, the quality of these products is such that in many industries where this standard is applied, but it is not strictly limiting, you can safely use them.

The present invention encompasses all options that can be foreseen by a person skilled in the art in light of the present description.

Claims (13)

1. A method of manufacturing elongated products and preforms of titanium or titanium alloy, comprising the steps of:
a) preparing a mass of titanium or titanium alloy (10) for melting,
b) skull molding of said mass by means of an electric arc (20),
c) casting from the molten mass of one or more ingots of predominantly cylindrical shape with a diameter of approximately less than 300 mm (30), then
d) drawing one or more of said ingots at a temperature between 800 ° C-1200 ° C by means of a drawing mill (40). 2. The method according to claim 1, characterized in that step c) comprises the following steps:
C1) casting one or more first molten ingots from a molten mass (300),
c2) smelting each of these first ingots to obtain a second corresponding mass of titanium or titanium alloy (302),
c3) casting one or more ingots for drawing, preferably of a cylindrical shape, with a diameter of about less than 300 mm from each of said second corresponding masses of titanium or titanium alloy (304). 3. The method according to claim 2, characterized in that step c) includes a step:
c11) casting one or more ingots of a predominantly cylindrical shape with a diameter of about less than 300 mm from the molten mass (300). 4. The method according to claim 3, characterized in that step c3) comprises the step of:
c31) casting an ingot for drawing a predominantly cylindrical shape with a diameter of about less than 300 mm from each of said second corresponding masses of titanium or titanium alloy. 5. The method according to claim 4, characterized in that step c2) includes a step:
c21) smelting at least the first ingot by means of a vacuum electric arc. 6. The method according to claim 1, characterized in that the ingot is cast for drawing with a diameter of less than 250 mm 7. The method according to claim 1, characterized in that the ingot is cast for drawing with a diameter of more than 100 mm 8. The method according to claim 1, characterized in that in step d) the drawing is carried out by means of a drawing mill using a lubricating component. 9. The method according to claim 8, characterized in that the drawing is carried out using a lubricating component containing glass. 10. The method according to claim 1, characterized in that the drawing is carried out at a temperature of 900 ° C-1150 ° C. 11. The method according to claim 1, characterized in that step c) comprises:
C1) casting almost the entire mass of titanium or a titanium alloy, melted by skull melting by means of an electric arc in step b) into ingots for drawing mainly cylindrical shapes with a diameter of less than 300 mm. 12. The method according to claim 1, characterized in that before drawing carry out peeling of the ingot. 13. The method according to any one of claims 1 to 12, characterized in that the ingot is cast in the step c) with a diameter before drawing, depending on the specified diameter of the elongated product.

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