JP2012525497A - Manufacturing method of titanium extension parts - Google Patents

Abstract

A method for producing an elongated part made of a titanium material or a titanium alloy, or an unfinished product of the part, comprising the step (10) of preparing a titanium material or a titanium alloy mass, and using an electric arc and a skull melting method Melting the mass (20), casting one or more ingots from the molten mass (30) that are substantially cylindrical and having a diameter of less than about 300 mm, and then one of the ingots Extruding one or more at a temperature between 800 ° C. and 1200 ° C. by means of an extrusion press. For example, it is used in the aviation field.
[Selection]
FIG.

Description

  The present invention relates to a method for producing an elongated part made of a titanium material or a titanium alloy, or an unfinished part of the part.

  The term “elongated part” is used here to refer to a metal component having a cross-sectional dimension that is substantially smaller or much smaller than its length.

  The elongated part is composed of metal components, and its manufacturing process generally includes at least one extrusion process. However, the term “elongated part” is not limited to such components.

  More specifically, the elongated part is composed of a metal component obtained by an extrusion process, and is composed of a deformed component composed of a hollow member and a tube.

  The term “incomplete product” is to be understood here in a very broad sense. The term is used to refer to an elongated part that is not completed, but whose overall shape substantially corresponds to the appearance of the finished elongated part. This means that the unfinished elongated part is an elongated metal component.

  This does not preclude, for example, shaping the unfinished product into a more adapted shape by machining, or improving the overall appearance by, for example, bending, bending, or any other plastic deformation.

  Rather, an “unfinished product” of an elongated part should be understood as an elongated element that is subjected to different molding, machining or surface treatment steps to yield a finished product.

  Elongated parts made of titanium material or titanium alloy are used in many fields. These areas include in particular aviation and space related structures.

  There are standards for managing the metallic quality of these parts. The quality was required according to the intended use.

  For example, specific examples of aviation-related structures require a high level of quality due to dramatic consequences caused by component failures.

  Satisfying a certain level of quality is not limited to the aviation sector. In fact, the majority of fields of use, regardless of whether they are subject to standards, require a minimum level of metallic quality, and obtaining high quality parts is not limited to the aerospace and space fields.

  Today, in addition to quality requirements, there are requirements that include cost and availability that are almost as important. In other words, it is no longer sufficient to know how to manufacture parts that meet quality requirements, and it is also necessary to be able to do so with a sufficient cost and an amount sufficient to satisfy the market.

  For that reason, there is a constant search for cheaper manufacturing methods that can produce parts having at least a quality level equivalent to that to be manufactured.

  In the conventional method, first, a titanium material mass comprising sponge titanium, titanium pieces, titanium scrap (sometimes called “titanium scrap iron” in France incorrectly) and / or more generally recycled titanium material is prepared. .

  Subsequently, the titanium material mass is melted and cast to form a single ingot having a large diameter.

  In these conventional methods, various techniques are used to melt / cast titanium ingots.

  The electron impact melting method, which also uses the term “electron beam furnace”, is suitable for melting a mixture of titanium sponge as a raw material and recycled material (waste). Since the recycled material is less expensive than sponge titanium, the economic advantages of the method will be understood.

  The plasma torch melting method and the electron impact melting method in the cooling crucible are relatively recent techniques, and have the possibility of more continuous casting and melting a higher proportion of titanium scrap. For this reason, these techniques are more economical than conventional electron impact melting methods.

  With conventional melting methods, casting of the molten material proceeds gradually and is very slow. In general, as the material melts, the melt tank fills up so that the molten material gradually flows into the ingot mold. The slow casting speed and progressive nature, mainly due to the limitations of the melting technology, result in poor casting in the ingot.

  For example, to meet the high metallic requirements for obtaining safety parts in the aviation field, it is necessary to remelt the ingot obtained after the first melting / casting and cast a new ingot. The continuous melting process improves the metallic quality of the ingot.

  Remelting / casting is conventionally performed by techniques including vacuum arc remelting (VAR). The ingot obtained after the first melting is gradually melted and cast at the same time to form a welding rod, continuously forming an ingot having a similar diameter. Indeed, the diameter of the newly obtained ingot is about 10-20% larger than the diameter of the consumed welding rod, i.e. the first ingot.

  Note that some standards, such as the United States standard AMS 4945 for use in aviation-related structures, require a VAR remelting process.

  This “double melting” proves expensive. Therefore, it has become a conventional method for casting ingots having a large diameter, in practice a diameter of 500 to 1000 mm, for the caster. As the diameter of the cast ingot increases, the cost per volume decreases. In other words, for a material with a predetermined volume, an ingot having a large diameter is less expensive.

  “Skull melting” in English, with an electric arc melting method under vacuum, to overcome the shortcomings of the traditional (first) melting technique, which is primarily slow melting / casting and progressive In recent years, techniques have been developed that use the “self crucible” method, also referred to as “fusion en carriage” in French. The term “skull melting” is used to refer to a melting method in which a furnace crucible is cooled to form a molten material shell, in this case a titanium shell, or melted. A crucible is further formed thereon to isolate the remainder of the material from the furnace crucible.

  A portion of the titanium mass to be melted is placed in a crucible and the other portion of the mass is in the form of a molten rod that is consumed. The entire titanium mass is melted by means of an electric arc generated between the melting bar and the crucible, and then left at the temperature of the melting tank. Subsequently, by tilting the crucible, the molten mass is cast in one or more ingot molds in one step.

  “Skull melting” enables rapid casting of the entire mass of molten material in a single process in a batch process (gradient). This prevents casting defects due to slow casting and sequential progression of the old melting technology.

  For economic reasons, a single large ingot is conventionally cast.

  By melting the skull, the sponge titanium and the recycled material are sufficiently melted to the same extent.

  As a further advantage, the metal gangue material formed to contact the crucible can be easily or directly reused as a new welding rod.

  For the majority of the desired stretched parts, the ingot diameter is excessively large, so the current press capabilities cannot directly extrude the ingot obtained after VAR remelting or skull melting.

  In order to transform a large diameter ingot into one or more rods with a diameter adapted to the extrusion press and the desired elongated part, one or more steps of reducing the diameter by forging are required.

  As an example, an ingot obtained from a VAR remelting or skull melting process has a diameter of about 600 mm and is transformed into a rod having a diameter of about 120 mm by a continuous forging process. That is, the reduction rate of the diameter (cross section) by forging is about 1/25 (2500%) reduction.

  It should be noted that the metallic quality of the rod is substantially improved by forging so that it can be used systematically after melting (VAR or skull melting, etc.).

  Also, for example, additional steps such as machining (removing the fine surface layer from the forged bar or “descaling” (scale layer removal)) or finishing treatment, if necessary, should be performed before extrusion. Can do.

In summary, a conventional manufacturing program for manufacturing high quality elongated parts made of titanium or titanium alloys from titanium ingots consists of the following steps.
-Melting a titanium or titanium alloy mass to cast a single ingot having a large diameter.
-VAR remelting this single ingot to form a single ingot with a large diameter. If the previous melting step was not performed by skull melting, this step is essentially essential and this remelting is required by aviation standards.
-Manufacturing one or more bars by extrusion from an ingot having a large diameter, including one or more forging steps.
-Extruding the bars in an extrusion press to obtain a practical final shaped elongated part.

  Subsequently, one or more steps of surface treatment of the elongated part and / or overall appearance improvement are performed to obtain a finished elongated part.

  This manufacturing program is only partially satisfactory, especially in terms of cost, production time of elongated parts and part availability.

  The applicant tried to improve the situation.

  The proposed method relates to a method for producing elongated parts or unfinished parts of titanium parts or titanium alloys, preparing a titanium material or titanium alloy mass and melting the mass by electric arc and skull melting. One or more ingots having a substantially cylindrical shape and having a diameter of less than about 300 mm are cast from the molten mass, and then one or more of the ingots are heated to 800 ° C. to 1200 ° C. by extrusion press means. It relates to a method comprising extruding at temperature.

  The method yields a stable stretched part, i.e. a stretched part that is practically free from casting defects and in particular has a mechanical strength measured by a tensile test that is at least equivalent to parts obtained by conventional or currently known methods. It is done. By way of example, this method results in an elongated part having a quality equivalent to a part that complies with currently enforced aeronautical standards, for example, the US AMS 4935 or AMS 4945 standards, at least in terms of mechanical strength properties.

  In addition, this method results in potentially lower part manufacturing costs than the manufacturing costs of conventional or currently known methods, and also reduces manufacturing time in connection with the lack of a forging process, and more Generally, the diameter of the cast ingot before the extrusion process is substantially reduced, and a plurality of ingots are cast at the same time.

  The proposed method improves the availability of the resulting elongated parts, in particular due to the simplification of the manufacturing program and the possibility of using a high proportion of recycled material in the prepared titanium or titanium alloy mass.

Other features and advantages of the present invention will be understood upon review of the following detailed description and accompanying drawings.
4 is a process chart illustrating a method according to the present invention. It is a process chart which shows another form of the method of FIG. FIG. 3 is a process chart showing an auxiliary method that can be implemented in addition to the methods of FIGS. 1 and 2. FIG.

  The accompanying drawings not only supplement the invention, but also serve to contribute to its definition where applicable.

  FIG. 1 shows a method for producing elongated parts, or unfinished parts of this kind, from titanium or a titanium alloy.

  The method of FIG. 1 includes a step 10 of preparing a titanium material or titanium alloy mass, a step 20 of melting the mass by electric arc and skull melting, and one substantially cylindrical or a diameter having a diameter of less than about 300 mm. Casting a plurality of ingots from the molten mass 30 and then extruding one or more of the ingots at a temperature of 800-1200 ° C. by extrusion press means. Optionally, the elongated part resulting from this extrusion process is subjected to one or more finishing or semi-finishing steps 50.

  The method of FIG. 1 begins at step 10 where a titanium or titanium alloy mass is prepared. The chemical composition of the mass is based on the grade desired for the elongated part. For example, the mass composition may be used to obtain alloy TA6V4, or the equivalent described in United States Standard AMS4935, or TA3V2.5, or the equivalent described in United States Standard AMS4945. Good.

  These alloys are used in particular in the aviation field, which has stringent standards that require a high level of metallic quality of the parts. However, their applications are in no way limited to their field of activity, and the method embodiment of FIG. 1 is not limited to those particular alloys, in particular a variety of different titanium compositions depending on the envisaged application, such as The application is expanded to T40 or T60.

  This mass includes sponge titanium, titanium scrap or titanium alloy scrap, titanium pieces or titanium alloy pieces, which are produced in whole or in part by skull melting from a casting die, ladle or gangue, or more commonly Includes any form of recycled titanium material. The composition of the recycled material is controlled with respect to its quality and chemical composition.

  The recycled material component is a waste recycled material or a processed recycled material obtained by remelting or machining a residue of a titanium or titanium alloy part used in the titanium industry.

  These recycled materials are not necessarily essential, but have a variety of different chemical compositions based on, for example, the grade desired for the elongated part. These materials correspond to the alloys designed above.

  The recycled material component has availability, and the cost per mass, that is, the cost per kilogram of the material is less than that of sponge titanium, and the promotion of its use is an advantage.

  The titanium or titanium alloy mass of the preparation step 10 is composed of grade adjustment components and / or alloy ratios depending on the procedure desired, the intended use, and / or the grade desired for the elongated member.

  The method of FIG. 1 continues with step 20 in which the titanium material or titanium alloy ingot prepared in step 10 is subjected to electric arc melting and melting using a self-crucible method.

  That is, this melting is performed in the form of “skull melting”.

  Skull melting is performed by means of a furnace consisting of a decompressor and a suitably shaped crucible housed inside the decompressor.

  A welding rod to be consumed is provided in the container, and the crucible is filled with titanium material. A large potential difference is formed between the welding rod and the crucible. When this potential difference reaches a predetermined threshold, an electric arc with a high level of energy is generated between the titanium material in the crucible at the lower end of the welding rod.

  In practice, the welding rod is mounted on a vertical part that moves downward in the vessel.

  When the welding rod is completely melted, the molten titanium mass present in the crucible can be cast, which in one step has a selected shape, in this case a circular cross section and a diameter of less than 300 mm. This is done by one or more ingot molds placed inside the container in the shape they have. This casting process is therefore very rapid. For example, it can be implemented by tilting the crucible. Thus, skull melting is a melting / casting technique involving batch processing.

  During this melting / casting process, a portion of the molten titanium mass solidifies at the interface with the crucible, forming a titanium gangue that protects the titanium during melting from any contamination by the other components in the crucible or by the crucible itself. . In other words, this gangue forms an additional crucible in a crucible physically provided in the furnace (self-crucible melting method). After cooling, the gangue is used as a consumed welding rod in a new melting process, which is advantageous from a cost standpoint. The furnace crucible is formed such that the gangue has a shape adapted for subsequent operation as a consumed welding rod.

  The titanium mass prepared in step 10 advantageously includes a gangue or a casting die resulting from the melting and casting of the titanium mass that has been performed by skull melting.

  Also advantageously, the titanium mass prepared in step 10 comprises a high proportion of recycled titanium material.

  Preferably, the titanium mass of step 10 exclusively includes one or more skull melting dies, recycled materials and required alloy components, or components that adjust the grades to the appropriate proportions.

  In other words, in this case, in the step 10 of preparing a titanium or titanium alloy lump, a titanium material or a mixture of titanium alloys, in which most or all of the mass per mass is composed of a recycled material, is mainly produced. Only the addition of grade-adjusting ingredients is necessary.

  Therefore, in the method of FIG. 1, since the recycled material can be used almost entirely by utilizing the electric arc melting and the skull melting method, a high-quality part can be obtained at a lower cost than the conventional method. Has very specific advantages.

  The temperature referred to as the supermelting temperature used in this melting step depends on the mass composition of the preparation step 10. In the majority of possible compositions, this mass is melted with a supermelting temperature in excess of 1600 ° C.

  In the method of FIG. 1, the process continues with casting an ingot having a generally circular cross-section and a diameter of less than about 300 mm. The diameter of these ingots is preferably less than 250 mm. The casting process relates to rapidly casting the entire molten mass in a single step (“batch processing”), for example by tilting a crucible containing the molten titanium mass.

  There is no lower limit to the diameter of the ingot cast through step 30. However, for economic reasons, it is preferable to cast an ingot having a diameter exceeding 100 mm.

  There is no theoretical limit on the length of the ingot cast in step 30.

  In practice, an ingot is cast whose length is a ratio to the length of the ingot extruded through process 40. For example, to avoid material loss, the length of the ingot cast through step 30 can be selected to be a multiple of the length of the ingot extruded through step 40. More generally, the length of the ingot cast in step 30 can also be selected to be equal to the total length of the ingot extruded through the extrusion step 40.

  Preferably, as much cylindrical ingot as the titanium mass that is melted in step 30 allows is cast through casting step 30. Thus, skull melting provides the greatest advantage of enabling batch processing casting. The titanium or titanium alloy mass cast through step 20, ie, the titanium or titanium alloy mass prepared through step 10, is selected, which is the number of ingots to be extruded, and hence the number of ingots to be pre-cast. And from the viewpoint of the amount corresponding to the dimensions.

  The diameter of each ingot cast in step 30 is less than 300 mm. Each of those ingots can be extruded at step 40 without significantly reducing the diameter prior to the extrusion step.

  However, there may be a descaling step between the casting of step 30 and the extrusion of step 40. The descaling process inevitably results in a reduction in diameter, but the reduction is small (on the order of a few millimeters well) and is not expected to result in a significant reduction in the diameter of the ingot. Further, since descaling is performed in order to remove the surface layer of the cast ingot, by definition, this does not indicate a diameter reduction process that is intended to significantly reduce the diameter of the ingot.

  The cylindrical ingots cast in step 30 can have dimensions that are similar to each other with respect to their diameter and length. The ingots can also have different lengths and / or diameters, for example to produce different elongated parts. The diameter and length of each ingot cast in step 30 can be selected depending on the diameter and length of the ingot extruded through step 40. The length and diameter of the extruded ingot can be determined according to the elongated part to be obtained at the end of the extrusion process 40. In other words, the method of FIG. 1 provides an ingot that, at the end of the casting process 30, can adapt its dimensions to the extrusion process and further calculate the dimensions according to the dimensions of the desired elongated part.

  In this respect, the method of FIG. 1 differs from the conventional method, and in particular includes a single ingot casting process for reducing the cost per mass of the casting ingot and a forging process for reducing the diameter of the ingot. In other words, in the conventional method, the diameter of the casting ingot is forced (on the order of 400 to 600 mm), but in this case, this diameter can be selected.

  It will be appreciated that for the forced dimensions of the elongate part, in practice there is a range of diameters and lengths that are feasible for the extruded ingot 40. If elongated parts having different dimensions have to be produced according to the method of FIG. 1, it is advantageous to choose the values of the diameters of the extruded ingots to accommodate all of the parts, if possible. It becomes. Thereby, a separable ingot can be cast to produce an ingot adapted to extrusion of different elongated parts. This optimizes stock management of the extruded ingot.

  It will also be appreciated that the method of FIG. 1 allows parts with larger diameters and parts with smaller diameters to be manufactured simply and at similar costs (excluding raw material costs). Conversely, in conventional methods that require a forging process to reduce the diameter, it is more complex and expensive to produce parts with small diameters, often forging for those parts Cause a larger reduction rate.

  Currently used presses cannot extrude ingots having a length exceeding 1500 mm. In other words, the length of the ingot cast in step 30 is only less than 1500 mm, but if a more effective press is developed, it can be made longer.

  The method of FIG. 1 ends in a hot extrusion process 40 of a cylindrical ingot by an extrusion press to obtain an elongated part or an unfinished product of the part. The extrusion process 40 can be adapted to obtain a solid part or a hollow part.

  The extrusion temperature is higher than the so-called “beta transus” temperature, which depends on the composition of the ingot.

  The extrusion process 40 is generally performed at a high temperature of 800 ° C to 1200 ° C. The extrusion process is preferably performed at a temperature above 900 ° C. to ensure good plasticity of the material and at a temperature below 1150 ° C. to obtain a suitable metallic structure while preventing inefficient energy consumption. To be implemented.

  The extrusion process is performed by conventional extrusion press means equipped with an extrusion die and a header die. If it is necessary to produce a hollow elongated part, a rod, also referred to as a “needle”, is additionally used (in this case the extruded ingot may be previously penetrated).

  This extrusion process is carried out at a high temperature in the presence of a lubricant. This lubricant typically contains glass, a conventional lubricant for conventional hot extrusion processes at temperatures in excess of 900 ° C.

  In the method of FIG. 1, it is not necessary to reduce the diameter of the ingot cast in step 30 before the extrusion step 40.

  However, for the ingot cast in step 30 to form the ingot that is extruded in step 40, all of one or more unique steps such as descaling, different surface treatment steps or splitting steps are prevented. It should be understood that this is not the case.

  Surprisingly, the metallic quality of the stretched part resulting from the extrusion process 40 is at least as high as that of the part produced by the conventional method, at least in terms of mechanical strength, in particular mechanical strength as measured by the low temperature tensile test. Have.

  The same level of quality obtained without the forging process before the extrusion process 40 is largely related to the fact that the extrusion process has a beneficial and sufficient effect on the metallic structure of the ingot cast to a small diameter. ing.

  The absence of the ingot diameter reduction process, particularly the absence of the forging process, that occurs in the casting process 30 prior to the extrusion process 40 also leads to a reduction in the manufacturing cost of the elongated parts. Therefore, the absence of such a process also shortens the manufacturing time of the part.

  Due to the absence of a forging process or other forming process to the ingot prior to the extrusion process, and the quality of the elongated parts produced during the extrusion process, the method of FIG. Rather, it is more economical than prior art methods in terms of the final cost of the elongated part. Manufacturing time and availability are also improved compared to the prior art.

  All the ingots cast in step 30 or only a part of them can optionally be extruded in parallel on a plurality of different presses after the dividing step, which substantially improves the productivity of the method. The cost of the resulting elongated part is further reduced.

  In the method of FIG. 1, unlike the conventional method, the ingot cast in step 30 is not remelted. Nevertheless, the quality of the stretched part obtained at the end of the extrusion process 40 is surprisingly obtained after VAR remelting without casting defects, even if there is no forging process known as this quality improvement. It is sufficient with regard to the mechanical strength of the parts.

  Although some standards require vacuum remelting, such as VAR remelting, for high quality (or high performance) elongated parts, the parts obtained by the method of FIG. In spite of the absence, the inventor believes it is equally suitable for the applications envisaged by those standards.

  FIG. 2 shows another embodiment of the method of FIG.

  In this example, the step 30 of extruding the ingots includes a step 300 for casting first ingots having a diameter of less than 300 mm, and then a VAR remelting step 302 for the first ingots. In other words, each first ingot obtained after “skull melting” melting / casting, or at least some of them, is individually VAR melted. The first ingot functions as a consumed welding rod for this melting process.

  Finally, the step 30 of casting the ingot includes casting an ingot that is extruded from the second mass of molten material, ie, a cylindrical ingot having a diameter of less than 300 mm.

  Through the VAR remelting process, casting is carried out gradually as the consumed welding rod melts. The diameter of the obtained ingot or the second ingot is generally larger on the order of 10 to 20% than the diameter of the welding rod. Therefore, an increase in the diameter of the ingot cast through process 300 must be considered, in particular to ensure that the ingot extruded through process 40 has a diameter of less than 300 mm without the need for a diameter reduction process. Must be considered.

  FIG. 3 shows a finishing or semi-finishing method 50 performed on an elongated part manufactured according to either of the methods of FIGS.

One or more of the following steps are applied to the elongated part resulting from the extrusion step 40.
One or more heat treatment steps (in the furnace) and one or more chemical surface treatment steps (eg etching) or physical surface treatment step 51;
A straightening and untwisting step 52 that straightens the elongated part with respect to its cross-section and its overall appearance;
A heat treatment step 53;
A length adjusting step 54 by means of cutting or splitting;
A sand peening process 55, also called sandblasting.
-Forming step 56;
A control step 57 by one or more known non-destructive control techniques such as ultrasound, radiography or Foucault current.
-Machining.

  Here, the order of these steps is merely displayed, and the different orders are very well implemented.

  With the proposed method, a satisfactory quality stretched part in line with the enforced standards can be obtained even in the absence of the forging process, so that the conventional VAR remelting process can be selected selectively and substantially recycled material Can be used.

  The proposed method does not include a forging process. The inventor realizes that the extrusion process alone can achieve the same or at least sufficient mechanical properties in the stretched part, thereby countering any expectation and countering the concept prevalent in the art. The beneficial effects of the process could be eliminated.

  The proposed method reduces manufacturing costs, shortens manufacturing time, and increases part availability.

  The present invention is not limited to the above method, and is described by way of example only, in particular as follows.

-Melting step 20 and casting step 30 were described as performing "skull melting". The melting technique, unlike the sequential melting / casting method, enables melting / casting in a batch process. At present, only this technique enables such a casting method. Nevertheless, the methods of FIGS. 1 and 2 can be implemented with different melting techniques, providing similar properties to skull melting. That is, by these methods, preferably a large amount of recycled material can be utilized and cast in a batch process to produce an ingot optimal for extrusion having a diameter of less than 300 mm at a reasonable cost.

  -The remelting steps of steps 302 and 304 can be carried out by different melting methods, improving the metallic quality of the resulting ingot and having an optimum size for the extrusion step 40 at an acceptable cost, i.e. a diameter of less than 300 mm An ingot having

  -At the end of the extrusion step 40 or, if applicable, in the finishing step 50, one or more forming steps, in particular a forging step, including a step of further reducing its cross-section is applied to the resulting elongated part.

  The first melting / casting process, envisaged to extrude an ingot having a diameter of less than 300 mm as a whole immediately after VAR remelting on the ingot without reducing the diameter by a prior forging process Is carried out according to any method, and by this method, an ingot having an optimum diameter can be cast at a reasonable cost.

  -A subsequent molding process, for example a bending process, is applied to the resulting elongated part.

  The invention has been described with respect to the aviation field, in particular with respect to standards in force in this field. This is because this is a wide range of applications for elongated titanium parts and requires high-level quality of these parts. This does not limit the scope of the described method to this particular field of activity. Also, in the field where titanium or titanium alloy parts are used and in other fields where high quality parts are required, it is possible to refer to standards established by the aviation field, not within the scope of the field. Therefore, the present invention can also be applied to these fields. More generally, the present invention serves to apply to all areas where high level quality stretched titanium parts are required in non-aviation applications in addition to the aviation field. In this regard, the method of the present invention provides flexibility and cost savings to provide new applications for elongated titanium parts in fields other than aviation and / or the general public.

  -Strictly speaking, an elongated part manufactured according to the method of Figure 1 conforms to U.S. standard AMS 4935 for use in aviation structures in that it has not undergone multiple melting steps including a melting step under vacuum. Not. However, they constitute parts having equivalent quality, especially in terms of mechanical strength. The inventor believes that these parts can be used in place of the parts specified in this standard, or that this standard should be developed to include parts obtained by the method of FIG. ing. In any case, the quality of these parts is such that they are advantageously used in many fields that refer to this standard without restriction.

  The present invention includes all forms that those skilled in the art can envision in light of this specification.

Claims (14)

A method for producing an elongated part made of a titanium material or a titanium alloy, or an unfinished part of the part,
a) preparing a titanium material or a titanium alloy mass (10);
b) melting the mass (20) using an electric arc and skull melting method;
c) casting one or more substantially cylindrical ingots having a diameter of less than about 300 mm from the molten mass (30), and then d) one or more of those ingots by an extrusion press means 800 And (40) extruding at a temperature of from 1O <0> C to 1200 <0> C. The method of claim 1, wherein
Said step c)
c1) casting (300) one or more first ingots from the molten mass;
c2) melting each of the first ingots to form a second mass of titanium material or titanium alloy (302);
c3) casting (304) one or more ingots extruded from each of the second masses of titanium material or titanium alloy to be substantially cylindrical and having a diameter of less than about 300 mm. A method characterized by that. The method of claim 2, wherein
The step c1)
c11) A method comprising casting (300) one or more substantially cylindrical ingots having a diameter of less than about 300 mm from a molten mass. The method according to claim 2 or claim 3, wherein
The step c3)
c31) casting an ingot extruded from each of the second masses of titanium material or titanium alloy to be substantially cylindrical and having a diameter of less than about 300 mm. The method according to any one of claims 2 to 4, wherein
The step c2)
c21) A method comprising melting at least a first ingot by a vacuum electric arc. In the method according to any one of the preceding claims,
A method wherein the diameter of the extruded ingot is less than 250 mm. In the method according to any one of the preceding claims,
A method wherein the diameter of the extruded ingot is greater than 100 mm. In the method according to any one of the preceding claims,
The method characterized in that step d) is carried out in the presence of a lubricant. The method of claim 8, wherein
The method wherein the lubricant comprises glass. In the method according to any one of the preceding claims,
The extrusion temperature is 900 ° C. to 1150 ° C. In the method according to any one of the preceding claims,
Said step c)
cI) A method characterized in that it comprises the step of practically casting the entire mass melted in step b) to form an ingot that is substantially cylindrical and extruded to have a diameter of less than 300 mm.   A method according to any one of the preceding claims, which does not comprise a step of reducing the diameter of the ingot cast in step c) prior to step d).   A method according to any one of the preceding claims, comprising a descaling step between step c) and step d). In the method according to any one of the preceding claims,
A method characterized in that the diameter of the ingot cast in step c) is selected according to the desired diameter of an elongated part made of titanium material or a titanium alloy, or an unfinished part of the part.

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