Niobium-tungsten alloy extrusion processing method and product

Abstract

The invention provides an extrusion processing method of a niobium-tungsten alloy cast ingot and a niobium-tungsten alloy extrusion processing product, the extrusion processing method comprises the following steps: carrying out stepped heating on the niobium-tungsten alloy cast ingot with an anti-oxidation coating by using a medium-frequency induction furnace to obtain a blank to be extruded, the lowest holding temperature of the stepped heating is 800 DEG C + / -20 DEG C, the highest holding temperature is 1200 DEG C-1300 DEG C, and the total duration of the stepped heating is 30 min-45 min; and the blank to be extruded is subjected to non-sheath extrusion machining in the extrusion cylinder, and the niobium-tungsten alloy extrusion machining product is obtained. The non-sheath extrusion processing method provided by the invention has the advantages that the production period is shortened, the production loss is reduced, and the surface quality, the straightness and the processing plasticity of an extrusion processing product are improved.

Description

Technical Field

[0001] The present application belongs to the technical field of material processing, and specifically relates to an extrusion processing method and a product of a niobium-tungsten alloy. Background Art

[0002] Niobium tungsten alloy has excellent high temperature resistance and high temperature specific strength. Niobium tungsten alloy represented by NbW5-1 alloy is the preferred material for use in high temperature and high pressure extreme environments. Its typical application scenarios include the thrust chamber of the attitude-orbit control engine of aerospace vehicles, the engine nozzle, and the thrust chamber of the scramjet engine of weapons and equipment. Niobium tungsten alloy belongs to the solid solution strengthening and dispersion strengthening type alloy. The alloying elements W, Mo, Zr and C in NbW5-1 alloy play an important role in strengthening the alloy system and improving high temperature performance, but at the same time may bring about the problems of poor alloy processing plasticity and easy cracking during forging processing.

[0003] In the prior art, extrusion processing is generally used to refine the internal structure of niobium tungsten alloy ingots to improve processing plasticity. In order to reduce surface damage, prevent oxidation and reduce friction, it is often chosen to install a sheath on the surface of the niobium tungsten alloy ingot before extrusion processing. It is inevitable to carry out a series of preparatory work such as sheath production, assembly, and sealing welding. After extrusion processing, in order to remove the steel layer introduced by the sheath on the surface of the extruded rod blank, it must also undergo a long period of pickling, which is a complicated and time-consuming process. In addition, the extrusion processing technology of adding a sheath may also cause the steel layer to be embedded in the rod blank, hydrogen embrittlement during the pickling process, and uneven radial force on the extruded rod blank, resulting in a large curvature. These problems seriously affect the subsequent pressure processing process of the rod blank. Summary of the invention

[0004] The present invention provides an extrusion processing method for a niobium-tungsten alloy ingot, and a niobium-tungsten alloy extrusion processed product. A non-jacketed extrusion method is adopted to avoid the influence of a jacket on the surface of the ingot on the straightness and processing plasticity of the rod blank, thereby greatly shortening the production cycle and improving the direct recovery rate.

[0005] The first aspect of the present application provides an extrusion processing method for a niobium tungsten alloy ingot, which comprises: performing step-wise heating on a niobium tungsten alloy ingot having an antioxidant coating in a medium frequency induction furnace to obtain a billet to be extruded, wherein the step-wise heating comprises 2-5 insulation stages, the minimum insulation temperature of the step-wise heating is 800°C±20°C, the maximum insulation temperature is 1200°C~1300°C, and the total duration of the step-wise heating is 30min~45min; performing unjacketed extrusion processing on the billet to be extruded in an extrusion barrel to obtain a niobium tungsten alloy extruded product.

[0006] In any embodiment of the first aspect, the temperature difference between two consecutive insulation stages in the step heating is 100°C to 200°C. Preferably, the step heating includes 4 insulation stages, and the temperature of each insulation stage is 800°C±20°C, 1000°C±20°C, 1100°C±20°C and 1200°C to 1300°C.

[0007] In any embodiment of the first aspect, the duration of the insulation stage at 1200° C. to 1300° C. in the step-wise heating is 2 min to 10 min.

[0008] In any embodiment of the first aspect, the extrusion processing method further includes a process of providing an anti-oxidation coating, and the process of providing an anti-oxidation coating includes: preheating the niobium tungsten alloy ingot to 80°C to 120°C, and then coating the surface with an anti-oxidation coating to form an anti-oxidation coating, wherein the anti-oxidation coating preferably includes sodium silicate, SiO 2 、Al 2 O 3 , B 2 O 3 , CaO, MgO or more.

[0009] In any embodiment of the first aspect, the thickness of the anti-oxidation coating is 0.3 mm to 0.6 mm.

[0010] In any embodiment of the first aspect, the extrusion processing method further comprises coating graphite emulsion on the surface of the niobium tungsten alloy ingot before preheating.

[0011] In any embodiment of the first aspect, before providing the anti-oxidation coating, the extrusion processing method further comprises heat treating the niobium tungsten alloy ingot for 1 to 2 hours, and the heat treatment temperature is 1350°C to 1450°C.

[0012] In any embodiment of the first aspect, before the unsheathed extrusion process is performed, the extrusion process method further includes a pretreatment process of the extrusion system, and the pretreatment process of the extrusion system includes: preheating the extrusion barrel and the extrusion die in the extrusion system to 350° C. to 650° C.; filling and lubricating the extrusion die with a first extrusion lubricant, the first extrusion lubricant including glass powder and sodium silicate, and the glass powder including SiO 2 、Al 2 O 3 , B 2 O 3 , CaO, MgO or more; the extrusion barrel is sprayed and lubricated with a second extrusion lubricant, the second extrusion lubricant comprising graphite emulsion, molybdenum disulfide and grease.

[0013] In any embodiment of the first aspect, the uncapped extrusion process satisfies one or more of the following conditions: (1) the extrusion speed is 40 mm / s to 120 mm / s, and can be optionally 95 mm / s to 103 mm / s; (2) the extrusion breakthrough pressure is 25 MN to 44 MN; (3) the extrusion temperature is 1200°C to 1350°C, preferably 1200°C to 1280°C, and more preferably 1200°C to 1250°C.

[0014] In any embodiment of the first aspect, the diameter of the niobium tungsten alloy ingot is 200 mm to 290 mm.

[0015] In any embodiment of the first aspect, the niobium tungsten alloy ingot has a chamfer, and preferably the chamfer is a 45° chamfer with a width of 2 mm to 10 mm or a 1 / 4 arc chamfer with a radius of 15 mm to 25 mm.

[0016] In any embodiment of the first aspect, the time t≤50s for transferring the billet to be extruded into the extrusion cylinder.

[0017] In any embodiment of the first aspect, the niobium-tungsten alloy ingot comprises, by mass percentage, 4.5% to 5.5% W, 1.7% to 2.3% Mo, 0.7% to 1.2% Zr, 0.05% to 0.12% C, and the balance being Nb and unavoidable impurities.

[0018] The second aspect of the present application provides a niobium tungsten alloy extruded product obtained by any one of the niobium tungsten alloy extrusion processing methods in the first aspect.

[0019] The third aspect of the present application provides a niobium-tungsten alloy extruded product, the grain size of the niobium-tungsten alloy extruded product is level 4 to 6 and / or the straightness tolerance t is ±(3 to 5) mm / m.

[0020] In any embodiment of the third aspect, the niobium-tungsten alloy extruded product comprises, by mass percentage, 4.5% to 5.5% W, 1.7% to 2.3% Mo, 0.7% to 1.2% Zr, 0.05% to 0.12% C, and the remainder being Nb and unavoidable impurities.

[0021] In any embodiment of the third aspect, the diameter of the niobium tungsten alloy extruded product is 118 mm to 190 mm.

[0022] In any embodiment of the third aspect, the niobium tungsten alloy extruded product meets one or more of the following mechanical performance indicators: yield strength greater than or equal to 270 MPa; tensile strength greater than or equal to 400 MPa; elongation greater than or equal to 20%.

[0023] Compared with extrusion processing after adding a steel sleeve, the sleeve-free extrusion processing method provided in the present application has the following advantages: (1) The sleeve-free extrusion processing also saves the processes of sleeve production, sleeve welding assembly, sleeve pickling and removal, and significantly saves the production cycle; (2) The sleeve-free extrusion processing removes the restriction of the sleeve on the diameter of the ingot to be extruded, and can realize the extrusion processing of ingots with larger diameters; (3) During the sleeve-free extrusion processing, the friction force on the surface of the ingot is greater, and a higher tonnage pressure can be provided. Therefore, the cast coarse-grained structure can be fully broken during extrusion, achieving the excellent effect of refining the internal structure and improving the processing plasticity; (4) The sleeve-free extrusion processing can significantly improve the surface quality and straightness of the niobium tungsten alloy extruded products, shorten the tail length of the extruded products, and increase the direct recovery rate from about 80% to more than 90%, greatly reducing the production loss and cost expenditure. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific embodiments of the present invention, the drawings required for use in the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 The microstructure morphology of the forging after the niobium tungsten alloy ingot was extruded and forged without a jacket in Example 6 is shown;

[0026] Figure 2 A schematic diagram of the structure of an A3 steel (Q235) mild steel jacket is shown. DETAILED DESCRIPTION

[0027] The following embodiments further describe the implementation of the present application in detail. The detailed description of the following embodiments is used to illustrate the principle of the present application, but cannot be used to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0028] If not otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0029] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0030] As analyzed in the background technology of this application, in order to reduce oxidation during extrusion processing, the prior art usually adopts the method of adding a can and then extruding the niobium tungsten alloy ingot. Not only is the process complicated and time-consuming, but it is also easy to cause a series of problems such as large curvature of the extruded product, long tail shrinkage, low effective extrusion force and low material utilization rate, which is not conducive to subsequent forging processing.

[0031] In order to avoid the above-mentioned problems of jacket extrusion and at the same time reduce oxidation during extrusion, in the first embodiment of the present application, an extrusion processing method of a niobium tungsten alloy ingot is provided, the extrusion processing method comprising: step-wise heating the niobium tungsten alloy ingot with an antioxidant coating in a medium frequency induction furnace to obtain a billet to be extruded, the step-wise heating comprising 2-5 insulation stages, the minimum insulation temperature of the step-wise heating being 800°C±20°C, the maximum insulation temperature being 1200°C~1300°C, and the total duration of the step-wise heating being 30min~45min; the billet to be extruded is subjected to unjacketed extrusion processing in an extrusion barrel to obtain a niobium tungsten alloy extruded product.

[0032] Niobium is highly active and can easily react with oxygen to form Nb at temperatures above 500°C. 2 O 5 , when the above oxidation occurs on the surface of niobium tungsten alloy, destructive "powdering" will occur. This application adopts a jacketless extrusion process. In the case of no jacket protection, in order to avoid the surface powdering of the niobium tungsten alloy ingot, on the one hand, it is protected by the anti-oxidation coating on the surface, and on the other hand, a medium-frequency induction furnace is used to replace the traditional box furnace for heating. The medium-frequency induction furnace is used to achieve a higher heating rate, thereby shortening the heating time and effectively controlling the surface oxidation of the ingot. Considering the high heating rate of the medium-frequency induction furnace, there may be uneven heating between the surface and the center, and between the upper end and the lower end of the ingot. This application adopts a step-by-step heating method, by setting 2 to 5 insulation stages, and controlling the total duration of the step-by-step heating to 30 minutes to 45 minutes to make the ingot evenly heated. During the step-by-step heating process, the minimum insulation temperature is 800℃±20℃, and the maximum insulation temperature is 1200℃~1300℃, which can reduce the deformation resistance of the billet to be extruded, which is beneficial to subsequent extrusion processing.

[0033] Compared with extrusion processing after adding a steel sleeve, the sleeve-free extrusion processing method has the following advantages: (1) The sleeve-free extrusion processing also saves the processes of sleeve production, sleeve welding assembly, sleeve pickling and removal, and significantly saves the production cycle; (2) The sleeve-free extrusion processing removes the restriction of the sleeve on the diameter of the ingot to be extruded, and can realize the extrusion processing of ingots with larger diameters; (3) During the sleeve-free extrusion processing, the friction force on the surface of the ingot is greater, which can provide a higher tonnage of pressure, so that the cast coarse-grained structure can be fully broken during extrusion, achieving the excellent effect of refining the internal structure and improving the processing plasticity; (4) The sleeve-free extrusion processing can significantly improve the surface quality and straightness of the niobium tungsten alloy extruded products, shorten the tail length of the extruded products, and increase the direct recovery rate from about 80% to more than 90%, greatly reducing the production loss and cost expenditure.

[0034] In some embodiments, the temperature difference between two consecutive insulation stages in the step heating of the above-mentioned extrusion processing method is 100°C to 200°C. Controlling the temperature difference between two consecutive insulation stages at 100°C to 200°C can make the ingot heated more evenly and improve the heating efficiency. Preferably, the step heating includes 4 insulation stages, and the temperature of each insulation stage is 800°C ± 20°C, 1000°C ± 20°C, 1100°C ± 20°C and 1200°C to 1300°C, which helps to reduce the internal stress formed by heating and better suppress the risk of cracking in the subsequent extrusion process caused by excessive internal stress. Step heating is set with multiple insulation stages, which can effectively reduce the temperature difference at various locations in the cross section and length direction of the ingot, make the structure more uniform, and obtain a more significant plasticity improvement effect, while being more energy-efficient.

[0035] Preferably, in some embodiments, the holding period at 1200°C to 1300°C is 2 minutes to 10 minutes. The temperature range of 1200°C to 1300°C includes the plastic platform in the compression curve of the niobium tungsten alloy ingot. Holding the plastic platform for the above-mentioned period of time can further increase the elongation of the billet to be extruded and improve the processing plasticity.

[0036] The anti-oxidation coating on the above-mentioned niobium tungsten alloy ingot can be provided by conventional methods in the art. In some embodiments, the above-mentioned extrusion processing method also includes the process of providing an anti-oxidation coating, and the process of providing an anti-oxidation coating includes: preheating the niobium tungsten alloy ingot to 80°C to 120°C, and then coating the surface with an anti-oxidation coating to form an anti-oxidation coating. The purpose of preheating is to better combine the coating and the ingot surface. Preferably, a graphite emulsion is coated on the surface of the niobium tungsten alloy ingot before preheating, which can play a protective and lubricating role. The thickness of the above-mentioned graphite emulsion can be selected to be 0.1mm to 0.3mm.

[0037] The thickness of the anti-oxidation coating can also be referenced to the thickness of the anti-oxidation coating in conventional extrusion processing. In some embodiments, the thickness of the anti-oxidation coating is 0.3 mm to 0.6 mm; because the ingot is stretched and deformed during the extrusion process, the thickness of the anti-oxidation coating can meet the needs of the ingot stretching and deformation, and achieve excellent protection effect during the entire extrusion process.

[0038] The above-mentioned anti-oxidation coating can be based on the anti-oxidation coating used in conventional extrusion processing. In some embodiments, the above-mentioned anti-oxidation coating includes sodium silicate, SiO 2 、Al 2 O 3 , B 2 O 3 The above-mentioned anti-oxidation coating has the high temperature resistance and anti-oxidation performance of high temperature glass powder, and can be applied to high temperature environment conditions of 1150℃~1400℃, and plays an anti-oxidation effect when the niobium tungsten alloy ingot is heated in the furnace.

[0039] In some embodiments, before providing the anti-oxidation coating, the extrusion processing method further includes heat treating the tungsten alloy ingot for 1 to 2 hours at a heat treatment temperature of 1350°C to 1450°C. The purpose of the heat treatment is to relieve stress, further homogenize the structure of the ingot, improve the coarse grain structure and secondary precipitation phase in the cast state, and thus improve the plasticity and strength of the material. Within the above temperature range, the increase in the heat treatment temperature can achieve a more significant effect of reducing hardness and eliminating casting stress.

[0040] In some embodiments, before performing the unsheathed extrusion process, the extrusion process method further includes a pretreatment process of the extrusion system, and the pretreatment process of the extrusion system includes:

[0041] Preheat the extrusion barrel and extrusion die in the extrusion system to 350℃~650℃;

[0042] The extrusion die is filled and lubricated with a first extrusion lubricant, wherein the first extrusion lubricant comprises glass powder and sodium silicate (i.e., water glass), and the glass powder comprises SiO 2 、Al 2 O 3 , B 2 O 3 , CaO, MgO or more. For example, the first extrusion lubricant may be a glass mat formed by mixing glass powder and sodium silicate in a mass ratio of 1:1 and pressing;

[0043] The second extrusion lubricant is used to spray lubricate the extrusion barrel, and the second extrusion lubricant includes graphite emulsion, molybdenum disulfide and grease, which is beneficial to reduce the surface roughness of the extrusion barrel. For example, the second extrusion lubricant can be a slurry mixed with graphite emulsion, a small amount of molybdenum disulfide (for example, the mass content is less than 10%) and a small amount of grease (for adjusting the viscosity of the slurry, such as the mass content is less than 10%), wherein the mass fraction of granular graphite in the graphite emulsion is 10% to 40%. The above-mentioned graphite emulsion can be commercial graphite emulsion, which will not be described in detail in this application.

[0044] The above preheating process is conducive to the combination of the barrel wall or the die surface with the lubricant, further improving the surface quality of the extruded product. The first extrusion lubricant is applied to the die entrance in solid form, and is converted into a molten state by high temperature during the extrusion process, playing a lubricating role; the second extrusion lubricant is applied to the inner wall of the extrusion barrel, which can effectively reduce the friction between the billet and the extrusion barrel wall, which is conducive to reducing the extrusion force and improving the extrusion surface quality. Molybdenum disulfide can significantly improve the lubrication effect and effectively improve the surface quality of the extruded product.

[0045] The first extrusion lubricant is mainly extruded at the extrusion die through high-temperature extrusion to cover the surface of the extruded product. The average thickness of the first extrusion lubricant on the surface of the extruded product can be selected to be 0.5mm to 1mm; the coating thickness of the second extrusion lubricant can be selected to be 0.1mm to 0.3mm.

[0046] After the heating is completed to obtain the billet to be extruded, it can be immediately sent to the extrusion step according to conventional operations. In some embodiments, the time t≤50s for transferring the billet to be extruded into the extrusion barrel. The purpose of controlling the transfer time is to keep the temperature of the billet to be extruded as much as possible during the transfer process. If the transfer time is too long, the extrusion may be easily "stuck" (i.e., the billet is difficult to extrude) due to the lowering of the temperature of the billet to be extruded.

[0047] According to metal extrusion theory, based on the deformation and flow characteristics of metal during the extrusion process, the metal extrusion process can be divided into breakthrough extrusion stage, stable extrusion stage and turbulent extrusion stage. In the breakthrough extrusion stage, the billet fills the extrusion barrel and die hole, and the extrusion pressure rises sharply; in the stable extrusion stage, the extrusion pressure will be slightly reduced, the billet undergoes plastic deformation and gradually hardens, and the extrusion breakthrough pressure is the minimum force to achieve plastic deformation of the material; in the turbulent extrusion stage, due to the significant hardening effect of the billet after stable extrusion, the deformation resistance increases, and the extrusion pressure rises again.

[0048] In some embodiments, the uncapped extrusion process satisfies one or more of the following conditions: (1) the extrusion speed is 40 mm / s to 120 mm / s; (2) the extrusion breakthrough pressure is 25 MN to 44 MN; (3) the extrusion temperature is 1200° C. to 1350° C., preferably 1200° C. to 1280° C., and more preferably 1200° C. to 1250° C. With one or more of the above conditions, the friction and deformation resistance of the blank in the die can be more fully overcome, the blank can flow out of the die evenly, the internal structure of the blank can be more effectively refined, and better straightness and processing plasticity can be obtained.

[0049] It is easier to achieve the above-mentioned extrusion breakthrough pressure by using extrusion barrels of corresponding diameters for different niobium tungsten alloy ingot diameters. For example, if the diameter of the niobium tungsten alloy ingot is 285mm, an extrusion barrel with a diameter of φ300mm can be used. Generally, the extrusion breakthrough pressure is relatively high, for example, in the range of 38MN to 44MN. For another example, if the diameter of the niobium tungsten alloy ingot is 205mm, an extrusion barrel with a diameter of φ220mm can be used. Relatively speaking, the extrusion breakthrough pressure is relatively low, for example, in the range of 28MN to 33MN.

[0050] The higher the extrusion breakthrough pressure of the niobium tungsten alloy ingot during the extrusion process, the higher the deformation storage energy accumulated in the niobium tungsten alloy extruded products. In the subsequent heat treatment process, the niobium tungsten alloy extruded products have a greater recrystallization driving force and are more likely to obtain a uniform fine-grained structure through recrystallization, which helps to improve its internal structure and comprehensive mechanical properties.

[0051] In some embodiments, the diameter of the niobium tungsten alloy ingot in the above extrusion processing method is 200 mm to 290 mm.

[0052] In some embodiments, the niobium tungsten alloy ingot in the above extrusion processing method has a chamfer, preferably a 45° chamfer with a width of 2 mm to 10 mm or a 1 / 4 arc chamfer with a radius of 15 mm to 25 mm, which is beneficial to further reduce the extrusion breakthrough pressure and prevent damage to the extrusion die.

[0053] In some embodiments, the niobium tungsten alloy ingot in the above extrusion processing method includes W4.5% to 5.5%, Mo 1.7% to 2.3%, Zr 0.7% to 1.2%, C 0.05% to 0.12%, and the balance is Nb and inevitable impurities. In the above element composition, W and Mo can be well dissolved in the Nb lattice, and the strength can be improved through solid solution strengthening. Zr and C can form Nb-ZrC secondary precipitation strengthening phase, so that the niobium tungsten alloy has excellent high-temperature mechanical properties. Through the non-jacketed extrusion processing method of the present application, the internal structure can be fully refined, the formation of hard and brittle phases caused by W segregation and aggregation can be controlled, and the Nb-ZrC precipitation phase can be suppressed in the form of needles or strips, which reduces the risk of cracking and effectively improves the processing plasticity of the niobium tungsten alloy ingot.

[0054] The second embodiment of the present application provides a niobium-tungsten alloy extruded product, which is obtained according to the extrusion processing method in the first embodiment. The product obtained by the method of the present application has a refined internal structure and good processing plasticity.

[0055] The third embodiment of the present application provides a niobium tungsten alloy extruded product, the grain size of the niobium tungsten alloy extruded product is 4 to 6 and / or the straightness tolerance t is ± (3 to 5) mm / m. Grain size is used to characterize the scale of grain size. The standard grain size is divided into 8 levels, of which 1 to 4 are coarse grains and 5 to 8 are fine grains. The grain size of the niobium tungsten alloy extruded product provided by the present application is 4 to 6, the grain structure is uniform, and it has improved room temperature forging plasticity. The niobium tungsten alloy extruded product has higher straightness, which reduces the impact on subsequent processing technology.

[0056] In some embodiments, the diameter of the niobium tungsten alloy extruded product is 118 mm to 190 mm. During the extrusion process of the niobium tungsten alloy ingot with a steel jacket, the surface deformation of the niobium tungsten alloy billet after extrusion is greater than the core deformation, because the elongation coefficient of steel is greater than that of the niobium tungsten alloy, and a longer extrusion tail is formed at the tail of the billet, resulting in a low yield rate of niobium tungsten alloy extrusion processing. Since it will not be affected by the deformation difference between the surface steel jacket and the niobium tungsten alloy ingot, the length of the compression tail of the extruded product without a jacket is greatly reduced, which improves the material utilization rate.

[0057] In some embodiments, the niobium tungsten alloy extrusion product includes W4.5% to 5.5%, Mo 1.7% to 2.3%, Zr 0.7% to 1.2%, C 0.05% to 0.12%, and the balance is Nb and unavoidable impurities. This niobium tungsten alloy extrusion product, as a solid solution strengthening and dispersion strengthening alloy, has excellent mechanical properties under high temperature conditions of 1500°C.

[0058] In some embodiments, the niobium tungsten alloy extrusion products meet one or more of the following mechanical performance indicators: yield strength greater than or equal to 270MPa; tensile strength greater than or equal to 400MPa; elongation greater than or equal to 20%. The above niobium tungsten alloy extrusion products have a large elongation, strong room temperature processing plasticity, and are not prone to cracking during forging. They can be forged into various types of niobium tungsten alloy plates, alloy tubes, and special-shaped forgings for aviation or weapon equipment.

[0059] The beneficial effects of the present application will be further illustrated below in combination with examples and comparative examples, but the scope of the present invention is not limited to these examples.

[0060] Example 1

[0061] In this embodiment, a niobium-tungsten alloy ingot with a diameter of 205 mm and a length of 500 mm is used. The composition of the niobium-tungsten alloy ingot is W5.22%, Mo 1.96%, Zr 0.92%, C 0.083%, and the rest is Nb and unavoidable impurities. The extrusion process steps are as follows:

[0062] Step 1: Chamfer one end of the niobium tungsten alloy ingot to 45°×4mm, then use a medium frequency induction vacuum annealing furnace for homogenization heat treatment at a temperature of 1350°C for 90 minutes, then take it out and cool it down in the furnace until it is taken out of the furnace at a temperature below 80°C;

[0063] Step 2: Use a box-type resistance furnace to preheat the niobium tungsten alloy ingot coated with graphite emulsion to 100°C, and then spray an anti-oxidation coating on the surface of the niobium tungsten alloy ingot to form a 0.5mm anti-oxidation coating. The anti-oxidation coating is made of Ta1350 protective lubricant from Tianli Chuang Glass Technology, and is fully mixed with a special binder NJ-1 in a mass ratio of 1:1 before use;

[0064] Step 3: Use a box-type resistance furnace to preheat the extrusion barrel (diameter φ is 220 mm) and the extrusion die to 450°C, spray lubrication on the preheated extrusion barrel, the extrusion lubricant consists of graphite emulsion, molybdenum disulfide and hydraulic oil, and fill and lubricate the preheated extrusion die. The extrusion lubricant is a mixture of glass powder and sodium silicate mixed and pressed in a mass ratio of 1:1. The glass powder uses TB1200-16 protective coating from Tianlichuang Glass Technology.

[0065] Step 4: The niobium tungsten alloy ingot treated in steps 1 and 2 is transferred into a medium frequency induction furnace for stepwise heating, with 4 insulation stages of 800°C, 1000°C, 1100°C and 1200°C. The insulation time of each stage is 2 to 3 minutes, and the total duration of the stepwise heating is 32 minutes. After the stepwise heating is completed, the billet to be extruded is obtained, and the billet to be extruded is transferred to an extrusion barrel with a diameter of φ220 mm through an ingot feeder, and the transfer time is 45 seconds.

[0066] Step 5: Under the conditions of 1200°C and atmospheric atmosphere, a 45MN extruder is used to perform unjacketed extrusion processing on the billet to be extruded in the extrusion barrel. The extrusion speed is 100mm / s, and the extrusion breakthrough pressure is 31MN. The niobium tungsten alloy extruded product obtained after extrusion is a rod billet with a diameter of 120mm. After the rod billet is cooled to room temperature, the shrinkage tail of the rod billet is cut off and the test can be carried out.

[0067] Example 2

[0068] In this embodiment, a niobium-tungsten alloy ingot with a diameter of 205.5 mm and a length of 500 mm is used. The composition of the niobium-tungsten alloy ingot is W5.00%, Mo 2.04%, Zr 0.92%, C 0.073%, and the rest is Nb and unavoidable impurities. The extrusion process steps are as follows:

[0069] Step 1: Chamfer one end of the niobium tungsten alloy ingot to 45°×4mm, then use a medium frequency induction vacuum annealing furnace for homogenization heat treatment at a temperature of 1350°C for 90 minutes, then take it out and cool it down in the furnace until it is taken out of the furnace at a temperature below 80°C;

[0070] Step 2: Use a box-type resistance furnace to preheat the niobium tungsten alloy ingot coated with graphite emulsion to 90°C, and then spray an anti-oxidation coating on the surface of the niobium tungsten alloy ingot to form a 0.4mm anti-oxidation coating. The anti-oxidation coating uses Ta1350 protective lubricant from Tianlichuang Glass Technology, and is fully mixed with a special binder NJ-1 in a mass ratio of 1:1 before use;

[0071] Step 3: Use a box-type resistance furnace to preheat the extrusion barrel (diameter φ is 220 mm) and the extrusion die to 450°C, spray lubrication on the preheated extrusion barrel, the extrusion lubricant consists of graphite emulsion, molybdenum disulfide and hydraulic oil, and fill and lubricate the preheated extrusion die. The extrusion lubricant is a mixture of glass powder and sodium silicate mixed and pressed in a mass ratio of 1:1. The glass powder uses TB1200-16 protective coating from Tianlichuang Glass Technology.

[0072] Step 4: The niobium tungsten alloy ingot treated in steps 1 and 2 is transferred into a medium frequency induction furnace for stepwise heating, with three insulation stages of 800°C, 1100°C and 1200°C, and the insulation time of each stage is 2 to 3 minutes. The total duration of the stepwise heating is 31 minutes. After the stepwise heating is completed, the billet to be extruded is obtained, and the billet to be extruded is transferred to an extrusion barrel with a diameter of φ220 mm through an ingot feeder, and the transfer time is 40 seconds.

[0073] Step 5: Under the conditions of 1200°C and atmospheric atmosphere, a 45MN extruder is used to perform unjacketed extrusion processing on the billet to be extruded in the extrusion barrel. The extrusion speed is 98mm / s, and the extrusion breakthrough pressure is 28.5MN. The niobium tungsten alloy extruded product obtained after extrusion is a rod billet with a diameter of 127mm. After the rod billet is cooled to room temperature, the shrinkage tail of the rod billet is cut off and the test can be carried out.

[0074] Example 3

[0075] In this embodiment, a niobium-tungsten alloy ingot with a diameter of 205.5 mm and a length of 500 mm is used. The composition of the niobium-tungsten alloy ingot is W5.00%, Mo 2.04%, Zr 0.92%, C 0.073%, and the rest is Nb and unavoidable impurities. The extrusion process steps are as follows:

[0076] Step 1: Chamfer one end of the niobium tungsten alloy ingot to 45°×4mm, then use a medium frequency induction vacuum annealing furnace for homogenization heat treatment at a temperature of 1350°C for 90 minutes, then take it out and cool it down in the furnace until it is taken out of the furnace at a temperature below 80°C;

[0077] Step 2: Use a box-type resistance furnace to preheat the niobium tungsten alloy ingot coated with graphite emulsion to 90°C, and then spray an anti-oxidation coating on the surface of the niobium tungsten alloy ingot to form a 0.4mm anti-oxidation coating. The anti-oxidation coating uses Ta1350 protective lubricant from Tianlichuang Glass Technology, and is fully mixed with a special binder NJ-1 in a mass ratio of 1:1 before use;

[0078] Step 3: Use a box-type resistance furnace to preheat the extrusion barrel (diameter φ is 220 mm) and the extrusion die to 450°C, spray lubrication on the preheated extrusion barrel, the extrusion lubricant consists of graphite emulsion, molybdenum disulfide and hydraulic oil, and fill and lubricate the preheated extrusion die. The extrusion lubricant is a mixture of glass powder and sodium silicate mixed and pressed in a mass ratio of 1:1. The glass powder uses TB1200-16 protective coating from Tianlichuang Glass Technology.

[0079] Step 4: The niobium tungsten alloy ingot treated in steps 1 and 2 is transferred into a medium frequency induction furnace for stepwise heating, with three insulation stages of 800°C, 1100°C and 1200°C, and the insulation time of each stage is 2 to 3 minutes. The total duration of the stepwise heating is 32 minutes. After the stepwise heating is completed, the billet to be extruded is obtained, and the billet to be extruded is transferred to an extrusion barrel with a diameter of φ220 mm through an ingot feeder, and the transfer time is 40 seconds.

[0080] Step 5: Under the conditions of 1200°C and atmospheric atmosphere, a 45MN extruder is used to perform unjacketed extrusion processing on the billet to be extruded in the extrusion barrel. The extrusion speed is 102mm / s, and the extrusion breakthrough pressure is 32.5MN. The niobium tungsten alloy extruded product obtained after extrusion is a rod billet with a diameter of 128mm. After the rod billet is cooled to room temperature, the shrinkage tail of the rod billet is cut off and the test can be carried out.

[0081] Example 4

[0082] In this embodiment, a niobium-tungsten alloy ingot with a diameter of 207 mm and a length of 503 mm is used. The composition of the niobium-tungsten alloy ingot is W5.02%, Mo 2.03%, Zr 0.98%, C 0.075%, and the rest is Nb and unavoidable impurities. The extrusion process steps are as follows:

[0083] Step 1: Chamfer one end of the niobium tungsten alloy ingot to 45°×4mm, then use a medium frequency induction vacuum annealing furnace for homogenization heat treatment at a temperature of 1350°C for 90 minutes, then take it out and cool it down in the furnace until it is taken out of the furnace at a temperature below 80°C;

[0084] Step 2: Use a box-type resistance furnace to preheat the niobium tungsten alloy ingot coated with graphite emulsion to 100°C, and then spray an anti-oxidation coating on the surface of the niobium tungsten alloy ingot to form a 0.35mm anti-oxidation coating. The anti-oxidation coating uses Ta1350 protective lubricant from Tianlichuang Glass Technology, and is fully mixed with a special binder NJ-1 in a mass ratio of 1:1 before use;

[0085] Step 3: Use a box-type resistance furnace to preheat the extrusion barrel (diameter φ is 220 mm) and the extrusion die to 450°C, spray lubrication on the preheated extrusion barrel, the extrusion lubricant consists of graphite emulsion, molybdenum disulfide and hydraulic oil, and fill and lubricate the preheated extrusion die. The extrusion lubricant is a mixture of glass powder and sodium silicate mixed and pressed in a mass ratio of 1:1. The glass powder uses TB1200-16 protective coating from Tianlichuang Glass Technology.

[0086] Step 4: The niobium tungsten alloy ingot treated in steps 1 and 2 is transferred into a medium frequency induction furnace for stepwise heating, with three insulation stages of 800°C, 1100°C and 1200°C, and the insulation time of each stage is 2 to 3 minutes. The total duration of the stepwise heating is 34 minutes. After the stepwise heating is completed, the billet to be extruded is obtained, and the billet to be extruded is transferred to an extrusion barrel with a diameter of φ220 mm through an ingot feeder, and the transfer time is 46 seconds;

[0087] Step 5: Under the conditions of 1200°C and atmospheric atmosphere, a 45MN extruder is used to perform unjacketed extrusion processing on the billet to be extruded in the extrusion barrel. The extrusion speed is 103mm / s, and the extrusion breakthrough pressure is 30MN. The niobium tungsten alloy extruded product obtained after extrusion is a rod billet with a diameter of 125mm. After the rod billet is cooled to room temperature, the shrinkage tail of the rod billet is cut off and the test can be carried out.

[0088] Example 5

[0089] In this embodiment, a niobium-tungsten alloy ingot with a diameter of 208 mm and a length of 504 mm is used. The composition of the niobium-tungsten alloy ingot is W4.86%, Mo 2.08%, Zr 0.95%, C 0.065%, and the rest is Nb and unavoidable impurities. The extrusion process steps are as follows:

[0090] Step 1: Chamfer one end of the niobium tungsten alloy ingot to 45°×4mm, then use a medium frequency induction vacuum annealing furnace for homogenization heat treatment at a temperature of 1350°C for 90 minutes, then take it out and cool it down in the furnace until it is taken out of the furnace at a temperature below 80°C;

[0091] Step 2: Use a box-type resistance furnace to preheat the niobium-tungsten alloy ingot coated with graphite emulsion to 85°C, and then spray an anti-oxidation coating on the surface of the niobium-tungsten alloy ingot to form a 0.4mm anti-oxidation coating. The anti-oxidation coating is made of Ta1350 protective lubricant from Tianlichuang Glass Technology, and is fully mixed with a special binder NJ-1 in a mass ratio of 1:1 before use;

[0092] Step 3: Use a box-type resistance furnace to preheat the extrusion barrel (diameter φ is 220 mm) and the extrusion die to 450°C, spray lubrication on the preheated extrusion barrel, the extrusion lubricant consists of graphite emulsion, molybdenum disulfide and hydraulic oil, and fill and lubricate the preheated extrusion die. The extrusion lubricant is a mixture of glass powder and sodium silicate mixed and pressed in a mass ratio of 1:1. The glass powder uses TB1200-16 protective coating from Tianlichuang Glass Technology.

[0093] Step 4: The niobium tungsten alloy ingot treated in steps 1 and 2 is transferred into a medium frequency induction furnace for stepwise heating. There are three insulation stages at 800°C, 1100°C and 1200°C. The insulation time of the first three stages is 2 to 3 minutes respectively, and the insulation time of the last stage is 2 minutes. The total duration of the stepwise heating is 33 minutes. After the stepwise heating is completed, the billet to be extruded is obtained, and the billet to be extruded is transferred to an extrusion barrel with a diameter of φ220 mm through an ingot feeder. The transfer time is 48 seconds.

[0094] Step 5: Under the conditions of 1200°C and atmospheric atmosphere, a 45MN extruder is used to perform unjacketed extrusion processing on the billet to be extruded in the extrusion barrel. The extrusion speed is 95mm / s, and the extrusion breakthrough pressure is 29MN. The niobium tungsten alloy extruded product obtained after extrusion is a rod billet with a diameter of 119mm. After the rod billet is cooled to room temperature, the shrinkage tail of the rod billet is cut off and the test can be carried out.

[0095] Example 6

[0096] In this embodiment, a niobium-tungsten alloy ingot with a diameter of 285 mm and a length of 504 mm is used. The composition of the niobium-tungsten alloy ingot is W5.22%, Mo 2.01%, Zr 0.95%, C 0.085%, and the rest is Nb and unavoidable impurities. The extrusion process steps are as follows:

[0097] Step 1: Chamfer one end of the niobium tungsten alloy ingot to 45°×9mm, then use a medium frequency induction vacuum annealing furnace for homogenization heat treatment at a temperature of 1350°C for 90 minutes, then take it out and cool it down in the furnace until it is out of the furnace at a temperature below 80°C;

[0098] Step 2: Use a box-type resistance furnace to preheat the niobium tungsten alloy ingot coated with graphite emulsion to 85°C, and then spray an anti-oxidation coating on the surface of the niobium tungsten alloy ingot to form a 0.35mm anti-oxidation coating. The anti-oxidation coating is made of Ta1350 protective lubricant from Tianlichuang Glass Technology, and is fully mixed with a special binder NJ-1 in a mass ratio of 1:1 before use;

[0099] Step 3: Preheat the extrusion barrel (diameter φ is 300 mm) and the extrusion die to 450°C using a box-type resistance furnace, spray lubricate the preheated extrusion barrel, and fill and lubricate the preheated extrusion die. The extrusion lubricant is a mixture of glass powder and sodium silicate mixed and pressed in a mass ratio of 1:1. The glass powder uses TB1200-16 protective coating from Tianlichuang Glass Technology.

[0100] Step 4: The niobium tungsten alloy ingot treated in steps 1 and 2 is transferred into a medium frequency induction furnace for stepwise heating. There are 4 insulation stages at 800°C, 1100°C, 1200°C and 1280°C. The insulation time of the first 3 stages is 2 minutes respectively, and the insulation time of the last stage is 8-10 minutes. The total duration of the stepwise heating is 40 minutes. After the stepwise heating is completed, the billet to be extruded is obtained, and the billet to be extruded is transferred to an extrusion barrel with a diameter of φ300 mm through an ingot feeder. The transfer time is 38 seconds.

[0101] Step 5: At 1280°C and atmospheric conditions, use a 45MN extruder to perform unjacketed extrusion processing on the billet to be extruded in the extrusion barrel. The extrusion speed is 102mm / s, and the extrusion breakthrough pressure is 38.5MN. The niobium tungsten alloy extruded product obtained after extrusion is a rod billet with a diameter of 180mm. After the rod billet is cooled to room temperature, the shrinkage tail of the rod billet is cut off and the test can be carried out.

[0102] Example 7

[0103] In this embodiment, a niobium-tungsten alloy ingot with a diameter of 288.2 mm and a length of 502 mm is used. The composition of the niobium-tungsten alloy ingot is W5.09%, Mo 1.97%, Zr 0.93%, C 0.091%, and the rest is Nb and unavoidable impurities. The extrusion process steps are as follows:

[0104] Step 1: Chamfer one end of the niobium tungsten alloy ingot to 45°×9mm, then use a medium frequency induction vacuum annealing furnace for homogenization heat treatment at a temperature of 1350°C for 90 minutes, then take it out and cool it down in the furnace until it is out of the furnace at a temperature below 80°C;

[0105] Step 2: Use a box-type resistance furnace to preheat the niobium-tungsten alloy ingot coated with graphite emulsion to 95°C, and then spray an anti-oxidation coating on the surface of the niobium-tungsten alloy ingot to form a 0.3mm anti-oxidation coating. The anti-oxidation coating is made of Ta1350 protective lubricant from Tianlichuang Glass Technology, and is fully mixed with a special binder NJ-1 in a mass ratio of 1:1 before use;

[0106] Step 3: Preheat the extrusion barrel (diameter φ is 300 mm) and the extrusion die to 450°C using a box-type resistance furnace, spray lubricate the preheated extrusion barrel, and fill and lubricate the preheated extrusion die. The extrusion lubricant is a mixture of glass powder and sodium silicate mixed and pressed in a mass ratio of 1:1. The glass powder uses TB1200-16 protective coating from Tianlichuang Glass Technology.

[0107] Step 4: The niobium tungsten alloy ingot treated in steps 1 and 2 is transferred into a medium frequency induction furnace for stepwise heating, with 4 insulation stages of 800°C, 1100°C, 1200°C and 1280°C. The insulation time of the first three stages is 2 minutes respectively, and the insulation time of the last stage is 8-10 minutes. The total duration of the stepwise heating is 43 minutes. After the stepwise heating is completed, the billet to be extruded is obtained, and the billet to be extruded is transferred to an extrusion barrel with a diameter of φ300 mm through an ingot feeder, and the transfer time is 48 seconds.

[0108] Step 5: At 1280°C and atmospheric conditions, use a 45MN extruder to perform unjacketed extrusion processing on the billet to be extruded in the extrusion barrel. The extrusion speed is 98mm / s, and the extrusion breakthrough pressure is 42MN. The niobium tungsten alloy extruded product obtained after extrusion is a rod billet with a diameter of 183mm. After the rod billet is cooled to room temperature, the shrinkage tail of the rod billet is cut off and the test can be carried out.

[0109] Example 8

[0110] In this embodiment, a niobium-tungsten alloy ingot with a diameter of 287.7 mm and a length of 500 mm is used. The composition of the niobium-tungsten alloy ingot is W4.94%, Mo 2.05%, Zr 0.88%, C 0.089%, and the rest is Nb and unavoidable impurities. The extrusion process steps are as follows:

[0111] Step 1: Chamfer one end of the niobium tungsten alloy ingot by setting the tool at 45° on a lathe. The axial length of the chamfer is 9 mm. Then, a medium frequency induction vacuum annealing furnace is used for homogenization heat treatment at a temperature of 1350°C. The heat treatment holding time is 90 minutes. Then, the ingot is taken out and cooled with the furnace. The ingot is taken out of the furnace when the temperature is below 80°C.

[0112] Step 2: Use a box-type resistance furnace to preheat the niobium tungsten alloy ingot coated with graphite emulsion to 100°C, and then spray an anti-oxidation coating on the surface of the niobium tungsten alloy ingot to form a 0.4mm anti-oxidation coating. The anti-oxidation coating is made of Ta1350 protective lubricant from Tianlichuang Glass Technology, and is fully mixed with a special binder NJ-1 in a mass ratio of 1:1 before use;

[0113] Step 3: Preheat the extrusion barrel (diameter φ is 300 mm) and the extrusion die to 450°C using a box-type resistance furnace, spray lubricate the preheated extrusion barrel, and fill and lubricate the preheated extrusion die. The extrusion lubricant is a mixture of glass powder and sodium silicate mixed and pressed in a mass ratio of 1:1. The glass powder uses TB1200-16 protective coating from Tianlichuang Glass Technology.

[0114] Step 4: The niobium tungsten alloy ingot treated in steps 1 and 2 is transferred into a medium frequency induction furnace for stepwise heating, with 4 insulation stages of 800°C, 1100°C, 1200°C and 1280°C. The insulation time of the first three stages is 2 minutes respectively, and the insulation time of the last stage is 9 minutes. The total duration of the stepwise heating is 43 minutes. After the stepwise heating is completed, the billet to be extruded is obtained, and the billet to be extruded is transferred to an extrusion barrel with a diameter of φ300 mm through an ingot feeder, and the transfer time is 48 seconds.

[0115] Step 5: At 1280°C and atmospheric conditions, use a 45MN extruder to perform unjacketed extrusion processing on the billet to be extruded in the extrusion barrel. The extrusion speed is 98mm / s, and the extrusion breakthrough pressure is 42MN. The niobium tungsten alloy extruded product obtained after extrusion is a rod billet with a diameter of 183mm. After the rod billet is cooled to room temperature, the shrinkage tail of the rod billet is cut off and the test can be carried out.

[0116] Example 9

[0117] In this embodiment, a niobium-tungsten alloy ingot with a diameter of 288 mm and a length of 503 mm is used. The composition of the niobium-tungsten alloy ingot is W4.85%, Mo 2.02%, Zr 0.90%, C 0.064%, and the rest is Nb and unavoidable impurities. The extrusion process steps are as follows:

[0118] Step 1: Chamfer one end of the niobium tungsten alloy ingot to 45°×9mm, then use a medium frequency induction vacuum annealing furnace for homogenization heat treatment at a temperature of 1350°C for 90 minutes, then take it out and cool it down in the furnace until it is out of the furnace at a temperature below 80°C;

[0119] Step 2: Use a box-type resistance furnace to preheat the niobium tungsten alloy ingot coated with graphite emulsion to 90°C, and then spray an anti-oxidation coating on the surface of the niobium tungsten alloy ingot to form a 0.35mm anti-oxidation coating. The anti-oxidation coating uses Ta1350 protective lubricant from Tianlichuang Glass Technology, and is fully mixed with a special binder NJ-1 in a mass ratio of 1:1 before use;

[0120] Step 3: Preheat the extrusion barrel (diameter φ is 300 mm) and the extrusion die to 450°C using a box-type resistance furnace, spray lubricate the preheated extrusion barrel, and fill and lubricate the preheated extrusion die. The extrusion lubricant is a mixture of glass powder and sodium silicate mixed and pressed in a mass ratio of 1:1. The glass powder uses TB1200-16 protective coating from Tianlichuang Glass Technology.

[0121] Step 4: The niobium tungsten alloy ingot treated in steps 1 and 2 is transferred into a medium frequency induction furnace for stepwise heating. There are 4 insulation stages at 800°C, 1100°C, 1200°C and 1280°C. The insulation time of the first 3 stages is 2 minutes respectively, and the insulation time of the last stage is 8-10 minutes. The total duration of the stepwise heating is 44 minutes. After the stepwise heating is completed, the billet to be extruded is obtained, and the billet to be extruded is transferred to an extrusion barrel with a diameter of φ300 mm through an ingot feeder. The transfer time is 42 seconds.

[0122] Step 5: At 1280°C and atmospheric conditions, use a 45MN extruder to perform unjacketed extrusion processing on the billet to be extruded in the extrusion barrel. The extrusion speed is 100mm / s, and the extrusion breakthrough pressure is 41.5MN. The niobium tungsten alloy extruded product obtained after extrusion is a rod billet with a diameter of 187mm. After the rod billet is cooled to room temperature, the shrinkage tail of the rod billet is cut off and the test can be carried out.

[0123] Example 10

[0124] In this embodiment, a niobium-tungsten alloy ingot with a diameter of 286.5 mm and a length of 501 mm is used. The composition of the niobium-tungsten alloy ingot is W5.01%, Mo 1.99%, Zr 0.94%, C 0.073%, and the rest is Nb and unavoidable impurities. The extrusion process steps are as follows:

[0125] Step 1: Chamfer one end of the niobium tungsten alloy ingot to 45°×9mm, then use a medium frequency induction vacuum annealing furnace for homogenization heat treatment at a temperature of 1350°C for 90 minutes, then take it out and cool it down in the furnace until it is out of the furnace at a temperature below 80°C;

[0126] Step 2: Use a box-type resistance furnace to preheat the niobium tungsten alloy ingot coated with graphite emulsion to 105°C, and then spray an anti-oxidation coating on the surface of the niobium tungsten alloy ingot to form a 0.3mm anti-oxidation coating. The anti-oxidation coating uses Ta1350 protective lubricant from Tianlichuang Glass Technology, and is fully mixed with a special binder NJ-1 in a mass ratio of 1:1 before use;

[0127] Step 3: Preheat the extrusion barrel (diameter φ is 300 mm) and the extrusion die to 450°C using a box-type resistance furnace, spray lubricate the preheated extrusion barrel, and fill and lubricate the preheated extrusion die. The extrusion lubricant is a mixture of glass powder and sodium silicate mixed and pressed in a mass ratio of 1:1. The glass powder uses TB1200-16 protective coating from Tianlichuang Glass Technology.

[0128] Step 4: The niobium tungsten alloy ingot treated in steps 1 and 2 is transferred into a medium frequency induction furnace for stepwise heating. There are 4 insulation stages at 800°C, 1100°C, 1200°C and 1280°C. The insulation time of the first 3 stages is 2 minutes respectively, and the insulation time of the last stage is 8-10 minutes. The total duration of the stepwise heating is 44 minutes. After the above-mentioned stepwise heating is completed, the billet to be extruded is obtained, and the billet to be extruded is transferred to an extrusion barrel with a diameter of φ300 mm through an ingot feeder. The transfer time is 45 seconds.

[0129] Step 5: At 1280°C and atmospheric conditions, use a 45MN extruder to perform unjacketed extrusion processing on the billet to be extruded in the extrusion barrel. The extrusion speed is 95mm / s, and the extrusion breakthrough pressure is 43.2MN. The niobium tungsten alloy extruded product obtained after extrusion is a rod billet with a diameter of 186mm. After the rod billet is cooled to room temperature, the shrinkage tail of the rod billet is cut off and the test can be carried out.

[0130] Embodiment 11

[0131] In this embodiment, a niobium-tungsten alloy ingot with a diameter of 286.5 mm and a length of 501 mm is used. The composition of the niobium-tungsten alloy ingot is W4.98%, Mo 2.08%, Zr 0.99%, C 0.092%, and the rest is Nb and unavoidable impurities. The extrusion process steps are as follows:

[0132] Step 1: Chamfer one end of the niobium tungsten alloy ingot to 45°×9mm, then use a medium frequency induction vacuum annealing furnace for homogenization heat treatment at a temperature of 1450°C for 90 minutes, then take it out and cool it down in the furnace until it is taken out of the furnace at a temperature below 80°C;

[0133] Step 2: Use a box-type resistance furnace to preheat the niobium tungsten alloy ingot coated with graphite emulsion to 90°C, and then spray an anti-oxidation coating on the surface of the niobium tungsten alloy ingot to form a 0.4mm anti-oxidation coating. The anti-oxidation coating uses Ta1350 protective lubricant from Tianlichuang Glass Technology, and is fully mixed with a special binder NJ-1 in a mass ratio of 1:1 before use;

[0134] Step 3: Preheat the extrusion barrel (diameter φ is 300 mm) and the extrusion die to 450°C using a box-type resistance furnace, spray lubricate the preheated extrusion barrel, and fill and lubricate the preheated extrusion die. The extrusion lubricant is a mixture of glass powder and sodium silicate mixed and pressed in a mass ratio of 1:1. The glass powder uses TB1200-16 protective coating from Tianlichuang Glass Technology.

[0135] Step 4: The niobium tungsten alloy ingot treated in steps 1 and 2 is transferred into a medium frequency induction furnace for stepwise heating, with 4 insulation stages of 800°C, 1100°C, 1200°C and 1280°C. The insulation time of the first three stages is 2 minutes respectively, and the insulation time of the last stage is 9 minutes. The total duration of the stepwise heating is 44 minutes. After the stepwise heating is completed, the billet to be extruded is obtained, and the billet to be extruded is transferred to an extrusion barrel with a diameter of φ300 mm through an ingot feeder, and the transfer time is 49 seconds;

[0136] Step 5: At 1280°C and atmospheric conditions, use a 45MN extruder to perform unjacketed extrusion processing on the billet to be extruded in the extrusion barrel. The extrusion speed is 95mm / s, and the extrusion breakthrough pressure is 43.8MN. The niobium tungsten alloy extruded product obtained after extrusion is a rod billet with a diameter of 186mm. After the rod billet is cooled to room temperature, the shrinkage tail of the rod billet is cut off and the test can be carried out.

[0137] Example 12

[0138] In this embodiment, a niobium-tungsten alloy ingot with a diameter of 287 mm and a length of 505 mm is used. The composition of the niobium-tungsten alloy ingot is W4.98%, Mo 2.01%, Zr 0.92%, C 0.088%, and the rest is Nb and unavoidable impurities. The extrusion process steps are as follows:

[0139] Step 1: Chamfer one end of the niobium tungsten alloy ingot to 45°×9mm, then use a medium frequency induction vacuum annealing furnace for homogenization heat treatment at a temperature of 1350°C for 90 minutes, then take it out and cool it down in the furnace until it is out of the furnace at a temperature below 80°C;

[0140] Step 2: Use a box-type resistance furnace to preheat the niobium tungsten alloy ingot coated with graphite emulsion to 100°C, and then spray an anti-oxidation coating on the surface of the niobium tungsten alloy ingot to form a 0.3mm anti-oxidation coating. The anti-oxidation coating is made of Ta1350 protective lubricant from Tianlichuang Glass Technology, and is fully mixed with a special binder NJ-1 in a mass ratio of 1:1 before use;

[0141] Step 3: Preheat the extrusion barrel (diameter φ is 300 mm) and the extrusion die to 450°C using a box-type resistance furnace, spray lubricate the preheated extrusion barrel, and fill and lubricate the preheated extrusion die. The extrusion lubricant is a mixture of glass powder and sodium silicate mixed and pressed in a mass ratio of 1:1. The glass powder uses TB1200-16 protective coating from Tianlichuang Glass Technology.

[0142] Step 4: The niobium tungsten alloy ingot treated in steps 1 and 2 is transferred into a medium frequency induction furnace for stepwise heating. There are 4 insulation stages at 800°C, 1100°C, 1200°C and 1280°C. The insulation time of the first 3 stages is 2 minutes respectively, and the insulation time of the last stage is 7 minutes. The total duration of the stepwise heating is 42 minutes. After the stepwise heating is completed, the billet to be extruded is obtained, and the billet to be extruded is transferred to the extrusion barrel through the ingot feeder. The transfer time is 40 seconds.

[0143] Step 5: At 1280°C and atmospheric conditions, use a 45MN extruder to perform unjacketed extrusion processing on the billet to be extruded in the extrusion barrel. The extrusion speed is 98mm / s, and the extrusion breakthrough pressure is 40.5MN. The niobium tungsten alloy extruded product obtained after extrusion is a rod billet with a diameter of 185mm. After the rod billet is cooled to room temperature, the shrinkage tail of the rod billet is cut off and the test can be carried out.

[0144] Comparative Example 1

[0145] A3 steel (Q235) soft steel sleeve is used for sleeve extrusion, and the sleeve extrusion process is carried out on a φ230mm extrusion system. Figure 2 It is a schematic diagram of the package structure, specifically:

[0146] 1 is the front pad, made of A3 steel, with dimensions of φ210×30mm and a middle hole diameter of φ6mm; 2 is the niobium-tungsten alloy ingot to be extruded, with dimensions of φ209~210×520~535mm; 3 is the sheath, made of A3 steel, with dimensions of φ217~218×3×545~560mm, i.e., the diameter is 217mm~218mm, the sheath wall thickness is 3mm, and the length is 545mm~560mm; 4 is the rear pad, made of A3 steel, with dimensions of φ209~210×5mm; 5 is a soft steel pad for extrusion, made of A3 steel, with dimensions of φ217~218×80mm and a middle hole diameter of φ30mm.

[0147] A niobium-tungsten alloy ingot with a diameter of 205 mm and a length of 500 mm, which is the same as that in Example 1, is selected. The composition of the niobium-tungsten alloy ingot is W 5.22%, Mo 1.96%, Zr 0.92%, C 0.083%, and the rest is Nb and unavoidable impurities. The extrusion process steps are as follows:

[0148] Step 1: preheat the niobium tungsten alloy ingot encapsulated in an A3 steel sleeve by heating it at 800°C for 4 hours in a ring furnace;

[0149] Step 2: transfer the preheated ingot into a medium frequency induction furnace for heating, raise the temperature to 1200°C to 1250°C and keep it warm for 2 to 5 minutes to obtain a billet to be extruded;

[0150] Step 3: transfer the billet to be extruded into the φ230mm extrusion system, and extrude the billet in the extrusion barrel using a 45MN extruder at 1250°C and atmospheric conditions, with an extrusion speed of 105mm / s and an extrusion breakthrough pressure of 30.5MN. The niobium-tungsten alloy extruded product obtained after extrusion is a rod billet with a diameter of 125mm. After the rod billet is cooled to room temperature, the shrinkage tail of the rod billet is cut off;

[0151] Step 4: Post-process the rod blank. Since A3 steel remains on the surface of the sleeve after extrusion, it is necessary to use a mixed acid composed of nitric acid (concentration of 68%, analytical grade), hydrochloric acid (36%, analytical grade), and hydrofluoric acid (concentration of 42%, analytical grade) with a volume ratio of 3:2:1 to pickle the steel layer on the surface of the niobium tungsten alloy rod blank. Immerse the steel sleeve in the above mixed acid solution to corrode and dissolve it. The pickling time is about 7 days.

[0152] <Test Method>

[0153] The grain size and straightness of the niobium-tungsten alloy rod blanks obtained in the above-mentioned embodiments and comparative examples were evaluated as follows.

[0154] Grain size is used to characterize the scale of grain size. The standard grain size is divided into 8 levels, of which 1 to 4 are coarse grains and 5 to 8 are fine grains. The grain size rating method is as follows: from the shrinkage tail of the niobium tungsten alloy extrusion product, after sawing off 80mm-100mm shrinkage tail, cut a 15mm-20mm diameter φ120mm sample along the plane perpendicular to the processing direction for grain size determination. The grain size determination is carried out by the intercept method. The specific operation refers to the corresponding content in the national standard GB / T 6394-2017 "Method for Determination of Average Grain Size of Metals".

[0155] The evaluation of straightness is expressed by straightness tolerance t, which can be measured by platform feeler gauge. The niobium tungsten alloy billet is placed on the platform and rotated for one circle, and the maximum arc gap height between the niobium tungsten alloy billet and the platform is measured with a feeler gauge.

[0156] Table 1 records the grain size and straightness of the niobium-tungsten alloy rod blanks obtained in each embodiment and comparative example.

[0157] Table 1

[0158]

[0159]

[0160] The straightness tolerance of the niobium-tungsten alloy bar blank prepared in the above embodiment is in the range of 3.5 mm / m to 4.8 mm / m, and the grain size can be controlled within the range of 4.5 to 6.0, and the grain size range is controlled within 1.5 or less.

[0161] The mechanical properties of the niobium-tungsten alloy rods obtained in the embodiments and comparative examples were tested in the following manner. The test results are recorded in Table 2.

[0162] Tensile strength, yield strength and elongation can all be measured by tensile tests. Under axial loading conditions, the load on the sample increases steadily and slowly, and the sample deforms until it breaks. After the sample is broken, the percentage of the residual elongation of the gauge length after breaking to the original gauge length is the elongation after breaking A. The stress corresponding to the maximum force reached during the test is the tensile strength R m The lowest stress in the yielding process of the specimen without considering the initial transient effect is the yield strength (i.e. the lower yield strength R eL ). The room temperature mechanical properties can be tested on a tensile testing machine in accordance with the contents of GB / T 228.1-2021 "Tensile tests on metallic materials - Part 1: Room temperature test methods".

[0163] Table 2

[0164]

[0165]

[0166] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A method for extruding a niobium-tungsten alloy ingot, characterized in that: The extrusion processing method comprises: The niobium-tungsten alloy ingot with an anti-oxidation coating is subjected to step-wise heating in a medium-frequency induction furnace to obtain a billet to be extruded, wherein the step-wise heating includes 2-5 insulation stages, the lowest insulation temperature of the step-wise heating is 800°C±20°C, the highest insulation temperature is 1200°C-1300°C, and the total duration of the step-wise heating is 30min-45min; The blank to be extruded is subjected to unjacketed extrusion processing in an extrusion cylinder to obtain a niobium-tungsten alloy extruded product.

2. The extrusion processing method according to claim 1 or 2, characterized in that: The temperature difference between two consecutive insulation stages in the step heating is 100°C to 200°C. Preferably, the step heating includes 4 insulation stages, and the temperature of each insulation stage is 800°C±20°C, 1000°C±20°C, 1100°C±20°C and 1200°C to 1300°C; preferably, the time used in the insulation stage of 1200°C to 1300°C is 2min to 10min.

3. The extrusion processing method according to any one of claims 1 or 2, characterized in that: The extrusion processing method further includes a process of providing the anti-oxidation coating, and the process of providing the anti-oxidation coating includes: After preheating the niobium-tungsten alloy ingot to 80° C. to 120° C., an anti-oxidation coating is used for surface coating to form the anti-oxidation coating, wherein the thickness of the anti-oxidation coating is preferably 0.3 mm to 0.6 mm; Preferably, before the preheating, graphite emulsion is coated on the surface of the niobium tungsten alloy ingot; Preferably, the anti-oxidation coating includes one or more of sodium silicate, SiO2, Al2O3, B2O3, CaO, and MgO.

4. The extrusion processing method according to any one of claims 1 to 3, characterized in that: Before providing the anti-oxidation coating, the extrusion processing method further comprises heat treating the niobium-tungsten alloy ingot for 1 to 2 hours at a heat treatment temperature of 1350°C to 1450°C.

5. The extrusion processing method according to any one of claims 1 to 4, characterized in that: Before performing the unjacketed extrusion process, the extrusion process method further includes a pretreatment process of the extrusion system, and the pretreatment process of the extrusion system includes: Preheating the extrusion barrel and the extrusion die in the extrusion system to 350° C. to 650° C.; The extrusion die is filled and lubricated with a first extrusion lubricant, wherein the first extrusion lubricant comprises glass powder and sodium silicate, and the glass powder comprises one or more of SiO2, Al2O3, B2O3, CaO, and MgO; The extrusion barrel is spray-lubricated with a second extrusion lubricant, wherein the second extrusion lubricant comprises graphite emulsion, molybdenum disulfide and grease.

6. The extrusion processing method according to any one of claims 1 to 5, characterized in that: The uncapped extrusion process satisfies one or more of the following conditions: (1) The extrusion speed is 40 mm / s to 120 mm / s, and can be selected as 95 mm / s to 103 mm / s; (2) Extrusion breakthrough pressure is 25MN~44MN; (3) The extrusion temperature is 1200°C to 1350°C, preferably 1200°C to 1280°C, and more preferably 1200°C to 1250°C.

7. The extrusion processing method according to any one of claims 1 to 6, characterized in that: The diameter of the niobium-tungsten alloy ingot is 200 mm to 290 mm.

8. The extrusion processing method according to any one of claims 1 to 7, characterized in that: The niobium-tungsten alloy ingot has a chamfer, and preferably the chamfer is a 45° chamfer with a width of 2 mm to 10 mm or a 1 / 4 arc chamfer with a radius of 15 mm to 25 mm.

9. The extrusion processing method according to any one of claims 1 to 8, characterized in that: The time taken to transfer the billet to be extruded into the extrusion barrel is t≤50s.

10. The extrusion processing method according to any one of claims 1 to 9, characterized in that: In terms of mass percentage, the niobium-tungsten alloy ingot comprises W 4.5%-5.5%, Mo 1.7%-2.3%, Zr 0.7%-1.2%, C 0.05%-0.12%, and the remainder is Nb and unavoidable impurities.

11. A niobium-tungsten alloy extruded product obtained by the extrusion method according to any one of claims 1 to 10.

12. A niobium-tungsten alloy extruded product, characterized in that: The grain size of the niobium-tungsten alloy extruded product is 4 to 6 levels and / or the straightness tolerance t is ±(3 to 5) mm / m.

13. The niobium-tungsten alloy extruded product according to claim 11 or 12, characterized in that: Calculated by mass percentage, the niobium-tungsten alloy extruded product comprises W 4.5%-5.5%, Mo 1.7%-2.3%, Zr 0.7%-1.2%, C 0.05%-0.12%, and the remainder is Nb and inevitable impurities.

14. The niobium-tungsten alloy extruded product according to any one of claims 11 to 13, characterized in that: The diameter of the niobium-tungsten alloy extruded product is 118 mm to 190 mm.

15. The niobium-tungsten alloy extruded product according to any one of claims 11 to 14, characterized in that: The niobium tungsten alloy extrusion products meet one or more of the following mechanical performance indicators: Yield strength greater than or equal to 270MPa; Tensile strength greater than or equal to 400MPa; The elongation is greater than or equal to 20%.

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