CN110983104A

CN110983104A - High-strength high-plasticity heat-strength titanium alloy wire and processing and manufacturing method and application thereof

Info

Publication number: CN110983104A
Application number: CN201911279777.5A
Authority: CN
Inventors: 朱绍祥; 王清江; 刘建荣; 陈志勇; 王磊; 赵子博; 李文渊
Original assignee: Institute of Metal Research of CAS
Current assignee: Institute of Metal Research of CAS
Priority date: 2019-12-13
Filing date: 2019-12-13
Publication date: 2020-04-10

Abstract

The invention belongs to the field of titanium-based alloy, and particularly relates to a high-strength high-plasticity high-strength titanium alloy wire, and a processing and manufacturing method and application thereof. The alloy comprises the following components in percentage by weight: 4.8% -7.0%; 0.3 to 2.5 percent of Sn; zr: 0.3% -4.5%, Si: 0.08 to 0.25 percent of the total weight of Mo or Mo + W, less than or equal to 0.10 percent of C, less than or equal to 0.3 percent of Fe, less than or equal to 0.15 percent of O, less than or equal to 0.05 percent of N, less than or equal to 0.015 percent of H, and the balance of Ti and inevitable impurity elements. The alloy can obtain different matching of tensile strength and plasticity by combining different hot working and heat treatment processes, can be used for manufacturing advanced fasteners such as rivets, bolts, nuts and the like for aerospace, and can be used for a long time within the temperature range of 450-550 ℃.

Description

High-strength high-plasticity heat-strength titanium alloy wire and processing and manufacturing method and application thereof

Technical Field

The invention belongs to the field of titanium-based alloys, and particularly relates to a high-strength high-plasticity hot-strength titanium alloy wire used at 450-550 ℃ for a long time (more than or equal to 100 hours), and a processing and manufacturing method and application thereof.

Background

At present, the aviation titanium alloy fastener is widely used, and common raw materials comprise TC4 titanium alloy, TC16 titanium alloy and the like. Most of domestic work has carried out some researches on the structure and the performance of the wire for the titanium alloy fastener such as alloying, heat treatment, hot working and the like, but almost all the researches are reported on the wire for the aviation fastener in a room temperature environment, and the researches on the high-strength high-plasticity hot-strength titanium alloy wire for the aerospace fastener are not reported. With the increase of Mach numbers of supersonic aircrafts and cruise missiles, the demand on heat-resistant titanium alloy fasteners is gradually increased, and particularly the demand on high-strength and high-plasticity wire materials for fasteners used in the temperature range of 450-550 ℃ is increased.

For the preparation of titanium alloy wire materials such as TC4, TC16 and the like, large-deformation rolling is usually adopted, a disc wire drawing machine is used for cold drawing or hot drawing, and a hyperbolic or slide block straightening machine is used for cold straightening to obtain the wire materials, so that the low strength and the excellent plasticity of the alloy are achieved. The heat-resistant titanium alloy has excellent high-temperature creep and durability, but has poor room-temperature or medium-low-temperature shaping, and cannot be prepared by using the traditional processing technology. The invention discloses a preparation process of a heat-resistant titanium alloy wire with the use temperature of 450-550 ℃, and the titanium alloy wire with the performance and the surface quality meeting the requirements is prepared.

At present, a few heat-resistant titanium alloy wires which can be used for fasteners of supersonic aircrafts and cruise missiles at home and abroad are available, and the heat-resistant titanium alloy wires are not reported at home and abroad at present. Patent publication No. 105018793a of xinshawei et Al discloses a heat-resistant titanium alloy containing an alloy component of Al: 10.0% -12.0%; nb: 5.0% -6.0%; zr: 3.0% -4.0%; mo: 1.5% -2.5%; sn: 1.5% -2.5%; ta: 0.5 to 1 percent; si: 0.2% -0.4%; c: 0.04-0.08 wt%, and the balance Ti and inevitable impurities. The Al content selected by the patent is between the Al content in the traditional heat-resistant titanium alloy and the Ti-Al intermediate compound alloy, the service temperature of the titanium alloy is improved by properly sacrificing the plasticity of the traditional heat-resistant titanium alloy, and the heat-resistant titanium alloy has good comprehensive performance and can meet the requirement of long-term use at 650 ℃. However, the material is mainly a forged bar, the tensile elongation at room temperature is only about 6.5%, and the toughness matching of the material is poor.

Xiaoqiang (patent publication No. 106868340A) developed a heat-resistant titanium alloy and its preparation method, wherein the alloy comprises, by weight, Ti-3.0% -8.0% Al-1.0% -6.0% Sn-0.5% -20% Mo-0.5% -1% Nb-0.1% -0.8% Si-0.3% -1.0% La-0.25% -0.8% W-0.1% -0.5% In-0.05% -0.5% Y. This patent is also used for 650 ℃, and contains an expensive rare element La or the like, and cannot be applied to fasteners.

Qian light congealing, etc. (patent publication No. 109536776A) provide a heat-resistant titanium alloy and a preparation method thereof, wherein the alloy comprises, by weight, 5.5% -6.5% of Al; 3.0 to 4.0 percent of Sn; 3.5 to 5.5 percent of Zr; 0.3 to 0.7 percent of Mo; 0.25 to 0.55 percent of Si; 0.4 to 1.0 percent of Nb; 1.0 to 3.0 percent of Ta; 0.05 to 0.2 percent of Er; 0.03 to 0.09 percent of C; the balance being Ti and unavoidable impurity elements. The alloy is also used at 650 ℃, and the product specification is mainly a bar obtained after smelting, forging and heat treatment.

Li Gury (patent publication No. 105039781A) developed a composite heat-resistant titanium alloy, which comprises the following alloy elements by weight percent: 4.2% -8.5%; sn: 1.5% -4.8%; zr: 2.5% -6.8%; w: 0.8% -2.8%; si: 0.1 to 0.4 percent; nb: 0.5 to 2.0 percent; v: 2.0% -4.0%; b: 4.2% -8.5%; la: 0.2 to 0.8 percent; ta: 1.5% -2.5%; y: 0.5 to 1.5 percent; the balance being Ti. The rod is prepared by smelting, sintering, isothermal forging and heat treatment processes.

The patent indicates that the addition of Hf and Ta can obviously improve the high-temperature tensile strength, creep strength and oxidation resistance of the material, the Hf content in the patent is required to be controlled to be between 0.2 and 3.0 percent (atomic percent), and the Ta content is required to be controlled to be between 0.0 and 1.5 percent (atomic percent), however, the room-temperature tensile elongation of the material is only about 3.5 percent, and the toughness matching of the material is poor.

The research on exploratory properties of 650 ℃ titanium alloy (Rapidly solid titanium alloy) is carried out by Gigliotti M F X and the like by adopting a rapid solidification powder metallurgy method, wherein the adopted alloy system is Ti-Al-Sn-Zr-Nb-Mo-Er-Si, the 650 ℃ tensile strength of the two preferable components can reach 700MPa, but even if the 650 ℃ tensile elongation is only between 4.1 and 6.3 percent, the section shrinkage is between 8.6 and 12.1 percent, and the matching between the material strength and the plasticity is poor.

SUZUKI AKIHIRO et Al (US 6284071B 1/European EP0851036A 1/US 5922274A/Japanese JPH10195563A) developed a heat-resistant titanium alloy and a method for preparing the same, wherein the alloy components are Ti-5.0% -7.0% Al-3.0% -5.0% Sn-2.5% -6.0% Zr-2.0% -4.0% Mo-0.05% -0.8% Si-0.001% -0.2% C-0.05% -0.2% O by weight, Nb and Ta are added in a total amount of 0.3% -2.0% and the balance Ti and inevitable impurity elements.

Chinese patent (patent publication No. 101104898A) discloses a hot working and heat treatment method of high-temperature titanium alloy with high heat resistance and high thermal stability, wherein the alloy comprises 5.3-6.1% by weight of Al; 3.0 to 5.0 percent of Sn; 2.5 to 7.0 percent of Zr; 0.2 to 1.0 percent of Mo; 0.25 to 0.55 percent of Si; 0.2 to 0.8 percent of Nb; 0.2 to 3.0 percent of Ta; 0.01 to 0.09 percent of C; the balance being Ti and unavoidable impurity elements. Creep experimental research under the condition of 600 ℃ finds that Ta has limited influence on alloy creep in a wider range, but the content of Ta is increased, the high-temperature oxidation resistance of the alloy is obviously improved, and the composition range of the Ta is determined to be between 0.2 and 3.0 percent, so that the oxidation resistance of the alloy is improved on the premise of not reducing the creep resistance of the alloy.

Chuaijianming et Al (patent publication No. 1772932A) developed a high temperature titanium alloy suitable for use in an aircraft engine at 600 deg.C, the alloy system being Ti-Al-Sn-Zr-Si-Nb-Ta-C, using a combination of Ta and Nb elements to stabilize the β phase, the ranges of the alloy elements being, by weight, 5.2% -6.0% Al, 3.5% -4.5% Sn, 3.0% -4.0% Zr, 0.3% -1.0% Nb, 0.5% -2.5% Ta, 0.2% -0.5% Si, and 0.03% -0.08% C, which states that the addition of Ta element improves the creep and fatigue properties of the material, but does not give out the relation between the addition of Ta and creep and fatigue properties, and lacks relevant examples and other evidences.

U.S. Pat. No. 4,87292 discloses a titanium alloy with Ti-5-6% Al-2.5-4.5% Sn-2-4% Zr-0.1-0.6% Mo-0.2-0.4 Si (weight percent) and recommends heat treatment above the transformation point of α + β/β. the patent studies have found that the highest creep resistance is obtained when about 0.25% Mo is added to the alloy, while above or below this value the creep resistance is worse.

US4738822 is an invention patent of Ti1100 high temperature titanium alloy applied by the American TIMET company, the alloy components are Ti-5.5% -6.5% Al-2.0% -4.0% Sn-3.5% -4.5% Zr-0.3% -0.5% Mo-0.35% -0.55% Si according to the weight percentage, the alloy is characterized in that the alloy components are strictly controlled, for example, the impurity element Fe is controlled to be less than or equal to 0.03%, and the O is controlled to be less than or equal to 0.13%; mo and Si are limited to a very narrow range to obtain a good match of static strength, creep strength and plasticity after creep.

Sunfishen et al, in "a research on strengthening mechanism of Nd-containing heat-resistant titanium alloy", introduced the influence and mechanism of the structure, room-temperature tensile property and thermal stability of Nd-containing heat-resistant titanium alloy. The alloy is Ti55 titanium alloy which has long been studied in China, is mainly used for engine rotating parts and the like, and has the national standard number TA12 at present.

In summary, the above patents and others mainly refer to titanium alloys with a temperature of 550 ℃ or higher, which have high strength, but poor toughness matching, particularly room temperature plasticity, and affect the applications thereof. The product is mainly bar, forging, etc., and has no application of aviation and aerospace fasteners.

The invention discloses a high-strength high-toughness titanium alloy (patent publication No. 101372729A) by Wangweiqi and the like, and relates to a high-strength high-toughness titanium alloy which is mainly used for manufacturing forged parts in structural members of airframes, wings and landing gears of airplanes. The alloy comprises the following components in percentage by weight: 3.5 to 5.5% of Al, 4.0 to 8.0% of V, 5.0 to 7.0% of Cr, 3.0 to 7.0% of Mo, and the balance of Ti and unavoidable impurities. The high-strength high-toughness titanium alloy provided by the invention has the nominal chemical component of Ti-4Al-6V-6Cr-5Mo, and compared with Ti-1023 and BT22 titanium alloys, the alloy adopts a Ti-Al-Mo-V-Cr alloy system, the content of alloy elements is increased, the proportion of aluminum equivalent to molybdenum equivalent is reasonably adjusted, so that the strength and toughness indexes are obviously improved, and the performance is more excellent. The alloy has high room temperature performance, but poor heat resistance.

The Lewenjun et al (patent publication No. CN104711452A) invented a high-strength high-toughness near Beta type titanium alloy material and its preparation and bar processing method. The titanium alloy is Ti-Al-Fe-V-Mo alloy, the tensile strength is not lower than 1200MPa, and the elongation is not lower than 10%. The titanium alloy material is prepared into a bar through vacuum consumable melting, single-phase region cogging forging and two-phase region upsetting and drawing, belongs to Beta type titanium alloy, and can not be applied to heat-resistant parts.

A fan Yaarmy introduces a research on a preparation process of a high-strength Ti-6Al-4V titanium alloy wire (thermal processing technology, 10 th 2011), adopts a temperature-controlled hot drawing test on Ti-6Al-4V titanium alloys with different oxygen contents to prepare wires with three different specifications of 1.0mm, 2.0mm and 2.5mm, and researches the influence of the oxygen content in the Ti-6Al-4V titanium alloy and the influence of the temperature-controlled hot drawing preparation method on the material structure and the mechanical property. The process aims at the thin wires with small specification, and the alloy is medium-strength alloy.

The Wangqingrui et al invented a preparation method of high-strength titanium alloy wire (patent publication No. CN108570577A), and the titanium alloy used in the method comprises the following components by mass percent: al: 6.3-7; mo: 3.5 to 4.5; v: 5.5 to 6.5; nb: 1.5-2.5; fe: 0.5 to 1.5; c is less than or equal to 0.05; o is less than or equal to 0.13; n is less than or equal to 0.05; h is less than or equal to 0.015; ti-the rest. The invention adopts the alloy which keeps higher plasticity and toughness at higher strength, and alternately uses the temperature above and below the phase transition point in the ingot cogging and rolling processes, thereby ensuring that the original crystal grains are fully crushed, the structure is more uniform and fine, and the invention is more beneficial to obtaining high-performance wire materials. The whole processing process does not need a special annealing process, and continuous rolling or furnace returning and rolling can be adopted below the phase change point, so that the process is simplified, the period is shortened, and the cost is reduced. In addition, the wire processed by the patent can obtain excellent comprehensive properties of tensile strength of more than 1500MPa, elongation of more than 8 percent and shearing property of more than 950MPa through specified heat treatment. The titanium alloy designed in this patent is a rolled wire and contains a large amount of V element and Fe element, and cannot be applied to heat-resistant parts, and it cannot be proved that it can be applied to heat-resistant fasteners.

Disclosure of Invention

The invention aims to provide a high-strength high-plasticity high-strength titanium alloy wire, a processing and manufacturing method and application thereof.

The technical scheme of the invention is as follows:

a high-strength high-plasticity heat-strength titanium alloy wire is characterized in that: the alloy comprises the following components in percentage by weight: 4.8% -7.0%; 0.3 to 2.5 percent of Sn; zr: 0.3% -4.5%, Si: 0.08-0.25%, Mo or Mo + W: 4.0-6.5%, less than or equal to 0.10% of C, less than or equal to 0.3% of Fe, less than or equal to 0.15% of O, less than or equal to 0.05% of N, less than or equal to 0.015% of H, and the balance of Ti and inevitable impurity elements.

The high-strength high-plasticity heat-strength titanium alloy wire is characterized in that: preferably, the alloy comprises the following components in percentage by weight: 4.8% -6.0%; 0.3 to 1.5 percent of Sn; zr: 0.3% -1.5%, Si: 0.08-0.25%, Mo: 4.0 to 5.0 percent of C, less than or equal to 0.10 percent of Fe, less than or equal to 0.3 percent of Fe, less than or equal to 0.15 percent of O, less than or equal to 0.05 percent of N, less than or equal to 0.015 percent of H, and the balance of Ti and inevitable impurity elements.

The high-strength high-plasticity heat-strength titanium alloy wire is characterized in that: preferably, the alloy comprises the following components in percentage by weight: 6.0% -7.0%; 1.0 to 2.5 percent of Sn; zr: 3.0% -4.5%, Si: 0.08-0.25%, Mo: 4.0% -5.0%, W: 0.4 to 1.5 percent of Ti, less than or equal to 0.10 percent of C, less than or equal to 0.15 percent of Fe, less than or equal to 0.15 percent of O, less than or equal to 0.04 percent of N, less than or equal to 0.010 percent of H, and the balance of Ti and inevitable impurity elements.

The invention relates to a preparation method of a high-strength high-plasticity heat-strength titanium alloy wire, which is characterized in that a titanium alloy ingot is smelted by adopting a vacuum consumable smelting process; forging the smelted titanium alloy ingot into a bar by adopting a free forging process; precisely forging the titanium alloy bar into a rough bar blank by adopting a precision forging process; rolling the titanium alloy rough bar blank into a straight bar or a wire rod blank by adopting a hot rolling process; carrying out surface treatment on the titanium alloy annealing wire blank, removing the defects on the surface of the wire blank, and then carrying out pre-oxidation film-hanging treatment; carrying out continuous high-temperature drawing deformation on the titanium alloy wire blank subjected to surface treatment by using a wire drawing machine; adopting electric heating tension to correct the drawn wire; and carrying out annealing heat treatment on the straightened wire material, and finally carrying out centerless grinding.

The rolling process comprises the following steps:

heating the bar material to 990-1050 ℃, preserving heat for 1-2 hours, and rolling the bar material from phi 55 mm-phi 65mm into a straight bar material or a wire rod with phi 10 mm-phi 12mm by adopting a hot rolling process.

The wire drawing pretreatment process comprises the following steps:

turning off the diameter of the rolled straight bar by 0.8-1.2 mm by using a centerless lathe; or after drawing and rounding by adopting a drawing die, peeling the wire rod with the diameter of 0.5-0.8 mm by using a peeling die; and removing defects such as surface oxide scale and cracks. And then heating the mixture for 30-120 minutes at 740-840 ℃ by adopting a trolley furnace to perform surface pre-oxidation.

The wire drawing process comprises the following steps:

heating to 740-840 ℃, lubricating by using graphite emulsion and molybdenum disulfide, and hot-drawing a rolled bar into a wire material by using a direct drawing or disc drawing process, wherein the drawing speed is 1-2 m/min, the pass deformation is 6-10%, and the accumulated deformation is 40-80%.

The straightening process comprises the following steps:

heating the drawn wire to 750-820 ℃, and straightening the wire by adopting an electric heating tension straightening process.

The heat treatment process comprises the following steps:

heating at 650-750 ℃, preserving heat for 1-3 hours, furnace cooling or air cooling, and carrying out annealing heat treatment;

preserving heat for 1-3 hours at 920-980 ℃, air cooling and preserving heat for 3-6 hours at 550-650 ℃, air cooling, and carrying out solid solution aging treatment.

The centerless grinding process comprises the following steps:

and (3) adopting centerless grinding, grinding off 0.4-0.8 mm of the diameter of the wire, and removing the defects of surface oxide skin, cracks and the like.

The invention combines different hot working and heat treatment processes to obtain different matching of tensile strength and plasticity; the obtained titanium alloy wire is used for manufacturing fasteners for advanced hypersonic aircraft structures and can be used for a long time within the temperature range of 450-550 ℃.

The selection of the alloy element types and the component ranges in the high-strength high-plasticity heat-strength titanium alloy wire material is obtained through years of deep research and repeated experiments, wherein the most characteristic component design specifications are as follows:

mo (Mo) + W (W) 4.0-6.5 wt%, Mo is the most common strong β stabilizing element in titanium alloy and is also effective strengthening element, Mo is added into the heat-strength titanium alloy to make it have α + β titanium alloy high strength and simultaneously improve the hot working process performance of the material, besides, a certain amount of Mo is added into the titanium alloy containing Si element to improve the creep property by adjusting the solid solution Si content and the precipitation of Si compounds, in order to ensure that the wire has higher strength, the Mo element content is controlled between 4.0-5.0 wt%, below 4.0 wt% can not obtain the expected strengthening effect, above 5.0 wt% can reduce the creep and endurance of the alloy, W is a well known β stabilizing element which is weaker than Mo element, has certain strengthening effect on α and β phases, and W plays a dragging effect on dislocation as heavy atom to improve the creep and endurance, the room temperature density of W element reaches 19.25g/cm³Density of 10.2g/cm at room temperature close to that of Mo element³Twice of the Ti element, and the room temperature density of the Ti element is 4.51g/cm³More than 4 times, therefore, in order to ensure the most key low-density characteristic of the titanium alloy, the W element should be strictly controlled between 0.4 wt% and 1.5 wt%, the expected strengthening effect cannot be obtained below 0.4 wt%, and the density of the titanium alloy is obviously increased above 1.5 wt%.

When the titanium alloy disclosed by the invention contains Mo element alone, the obtained wire has high room temperature and high temperature strength and high plasticity. The room temperature strength of the annealed wire can reach 1090MPa, the room temperature strength of the solid solution aging wire can reach 1275MPa, and the high-strength characteristic is obvious; the reduction of area at 450 ℃ is up to more than 60%, which can ensure the large deformation upsetting of the nail head of the fastener and has obvious high plasticity. The strength and plasticity of the alloy wire can meet the requirement of long-term use at 450 ℃. With the addition of the W element, the strength of the wire is further obviously improved. When the W content is 1%, the annealing room temperature strength of the wire is 1250MPa, the solution aging room temperature strength is up to 1440MPa or more, the high strength characteristic is very obvious, and the reduction of area can still be maintained to 30% or more. The optimal ratio of Mo to W is preferably 4: 1 (weight ratio), which not only allows the wire to achieve very high strength, but also maintains excellent plasticity to ensure the processing and use of the fastener. In the current content range, the strength cannot reach the optimum when the proportion is too high, and the plasticity of the wire is damaged when the proportion is too low, so that the processing of a fastener cannot be ensured.

The invention has the advantages and beneficial effects that:

1. the titanium alloy does not contain particularly precious rare metals (Nb, Ta, La and Hf), does not need to select high-price raw materials with particularly low impurity content, can ensure low-cost industrial application of the alloy, ensures the high strength and heat resistance of the alloy and also ensures the high plasticity of the alloy by comprehensive matching of alloy elements, namely the addition of Al, Sn, Zr and Si elements strengthens α phase of the alloy to ensure the heat resistance and the high strength, the addition of β isomorphous Mo and W elements with weaker strengthening effect not only improves the strength but also ensures the high plasticity of the alloy, Mo and W have great influence on the strength of a temperature range of 450-550 ℃, the plasticity effect and the content between the strength and the plasticity effect, the titanium alloy is discovered and effectively adopted for the first time, and the total amount of the synergistic effect of Mo and W is controlled to be 4.0-6.5 wt%, and the application is more a main innovation point of the titanium alloy.

2. According to the invention, through optimizing the alloy elements and contents, the qualified wire materials with various specifications for the fastener can be firstly ensured to be manufactured; and secondly, the preferable alloy elements and contents can ensure that the fastener can be used for a long time within the temperature range of 450-550 ℃ through subsequent processing and heat treatment. The alloy elements and the content in other disclosed materials mainly ensure the heat resistance of the alloy at higher temperature (more than 550 ℃), the specifications of products are almost all large-specification bars, forgings, castings and the like, and no wire for fasteners is applied.

3. The rolling process of the invention is more critical, different from other titanium alloy rolling processes, cracking is easily caused by overlarge rolling deformation of the heat-resistant titanium alloy, and thick tissues are not crushed fully due to undersize rolling deformation, so the rolling is carried out at the temperature above the transformation point of β, and the deformation is controlled at 94-96%.

4. Research also finds that the heat-resistant titanium alloy has more microcracks on the rolling surface due to the high-temperature resistance, and if the traditional mode of rounding first and then peeling off a die is adopted, the cracks can be expanded to the inside of the bar. The method adopts a centerless lathe to peel the rolled straight bar and lathe off the defects of surface oxide skin, microcracks and the like; and then heating the wire material for 30-120 minutes at 740-840 ℃ by adopting a tube furnace, and hanging an oxide film on the surface of the wire material to increase the adhesive force of the lubricant on the surface of the wire material.

5. The titanium alloy wire cannot be straightened by a traditional hyperbolic wire or a traditional slide block cold straightening method, and is straightened by electric heating tension, the temperature and the tension are controlled, and the straightness and the microstructure of the wire are ensured.

6. The titanium alloy wire has excellent plasticity, and the reduction of area of the alloy wire containing Mo element alone at high temperature of 450 ℃ is up to more than 60 percent, and the performance can even ensure that the wire is cold deformed at room temperature, and large deformation upsetting processing of a fastener nail head is carried out to process a fastener; under the condition of low-temperature heating, qualified fasteners are very easy to process, so that the energy consumption is reduced, and the cost is reduced. For the alloy containing Mo and W elements, the strength of the obtained wire is greatly improved by the steps of rolling, pretreatment, wire drawing, straightening, heat treatment and the like, the strength is improved by more than 100MPa compared with that of a forged piece, a bar material and the like, and the plasticity is also improved. The microstructure is refined through subsequent hot working, and the comprehensive performance is adjusted through heat treatment, so that the room-temperature strength of the wire reaches up to 1440MPa, excellent plasticity is still maintained, and the processing requirement of a fastener is met.

Drawings

FIG. 1 shows the effect of Sn, Zr, Mo, W contents on the room temperature strength;

FIG. 2 shows the effect of Sn, Zr and Mo contents on 450 ℃ strength;

FIG. 3 shows the effect of Sn, Zr, Mo, W contents on 500 ℃ strength;

FIG. 4 is a graph showing the effect of Sn, Zr, Mo, W contents on 550 ℃ strength;

FIG. 5 shows the difference between the high-strength and high-plasticity microstructure of the processed and heat-treated wire and the forged bar structure (left: wire structure, right: forged bar structure);

FIG. 6 is a microstructure of the wire after different heat treatments in example 1 and comparative example 2 (left: 940 ℃ C. solid solution structure, right: 1020 ℃ C. solid solution structure).

Detailed Description

The present invention will be further described with reference to the following examples.

Unless otherwise specified, the smelting process and the free forging process of the titanium alloy in the examples and comparative examples of the present invention are as follows:

the smelting process comprises the following steps: the raw material adopts 0-1 grade sponge titanium, and alloy elements Sn, Mo, Si and W are added in the form of intermediate alloy; the Sn-containing intermediate alloy is Ti-Sn, the Mo-containing intermediate alloy is Al-Mo, the Si-containing intermediate alloy is Al-Si, and the W-containing intermediate alloy is Al-W. Al is added except the intermediate alloy carrying part, and the rest is added by pure Al beans; zr was added as sponge Zr. The intermediate alloy and the sponge titanium are mixed and pressed into the electrode by a press machine. Welding a plurality of support electrodes together, and smelting for 3 times in a vacuum consumable arc furnace to prepare an alloy ingot. And (4) after the cap opening of the cast ingot is cut off and the surface defects are removed, carrying out a hot working procedure.

The free forging process comprises the following steps: keeping the temperature of a titanium alloy ingot with the diameter of 365mm at 1150 ℃ for 3 hours, and forging the titanium alloy ingot into a square billet with the diameter of 220 mm; after sawing and grinding, preserving heat for 2 hours at 1150 ℃ and forging into a phi 170mm rod; after sawing and grinding, the temperature is kept for 2 hours at 1100 ℃, and the bar with the diameter of 120mm is forged.

Example 1

And (3) precision forging process: sawing and grinding a bar with the diameter of phi 120mm, preserving heat at 1050 ℃ for 70 minutes, and forging the bar into a bar with the diameter of phi 80 mm; after sawing and grinding, preserving heat for 45 minutes at 1050 ℃ and forging into a phi 55mm rod; after sawing and grinding, the temperature is kept for 30 minutes at 1000 ℃ and the bar with the diameter of 55mm is forged.

The rolling process comprises the following steps: grinding and sawing a titanium alloy rough bar blank with the diameter of 55mm, keeping the temperature for 1 hour at 1000 ℃, and rolling to the diameter of 12 mm.

The wire drawing process comprises the following steps: peeling a bar with the diameter of 12mm to the diameter of 11mm by a centerless vehicle; heating for 30 minutes at 820 ℃ by adopting a tube furnace, and hanging an oxide film on the surface; heating at 820 ℃, lubricating by adopting graphite emulsion and molybdenum disulfide, and hot-drawing a rolled bar into a wire by utilizing a straight drawing process, wherein the wire drawing speed is 1.5m/min, the pass deformation is about 8 percent, and the accumulated deformation is 60 percent, so that the wire with the diameter of phi 6.9mm is obtained; heating at 780 ℃, and straightening the wire by adopting an electric heating tension straightening process.

The heat treatment process comprises the following steps: the wires are put in high-temperature resistant cast iron with a straight inner wall one by one, heated at 700 ℃, kept warm for 2 hours, and annealed by furnace cooling; grinding and polishing the wire material by using a centerless grinder to obtain a finished wire material with the diameter of phi 6.1 mm; keeping the temperature at 940 ℃ for 2 hours, air cooling and 550 ℃ for 5 hours, air cooling, and carrying out solid solution aging treatment. The specific chemical components are shown in Table 1, and the mechanical properties are shown in Table 2.

Table 1: example 1 alloy composition (mass%; wt%)

Table 2: example 1 Heat treatment System and Properties

Example 2

And (3) precision forging process: sawing and grinding a bar with the diameter of phi 120mm, preserving heat at 1050 ℃ for 70 minutes, and forging the bar into a bar with the diameter of phi 80 mm; after sawing and grinding, preserving heat for 45 minutes at 1050 ℃ and forging into a phi 55mm rod; after sawing and grinding, the temperature is kept for 30 minutes at 1000 ℃ and the bar with the diameter of 60mm is forged.

The rolling process comprises the following steps: grinding and sawing a titanium alloy rough bar blank with the diameter of 60mm, preserving heat for 1 hour at the temperature of 1005 ℃, and rolling to the diameter of 12 mm.

The heat treatment process comprises the following steps: the wires are put in high-temperature resistant cast iron with a straight inner wall one by one, heated at 650 ℃, kept warm for 2 hours, and annealed by furnace cooling; grinding and polishing the wire material by using a centerless grinder to obtain a finished wire material with the diameter of phi 6.1 mm; keeping the temperature at 940 ℃ for 2 hours, air cooling and 550 ℃ for 5 hours, air cooling, and carrying out solid solution aging treatment. The specific chemical components are shown in Table 3, and the mechanical properties are shown in Table 4.

Table 3: example 2 alloy composition (mass%; wt%)

Table 4: example 2 Heat treatment System and Properties

Example 3

And (3) precision forging process: sawing and grinding a bar with the diameter of phi 120mm, preserving heat at 1050 ℃ for 70 minutes, and forging the bar into a bar with the diameter of phi 80 mm; after sawing and grinding, preserving heat for 45 minutes at 1050 ℃ and forging into a phi 55mm rod; after sawing and grinding, the temperature is kept for 30 minutes at 1000 ℃ and the bar with the diameter of 65mm is forged.

The rolling process comprises the following steps: grinding and sawing a titanium alloy rough bar blank with the diameter of 65mm, preserving heat for 1 hour at 1020 ℃, and rolling to the diameter of 12 mm.

The wire drawing process comprises the following steps: peeling a bar with the diameter of 12mm to the diameter of 11mm by a centerless vehicle; heating for 45 minutes at 820 ℃ by adopting a tube furnace, and hanging an oxide film on the surface; heating at 780 ℃, lubricating by using graphite emulsion and molybdenum disulfide, and hot-drawing a rolled bar into a wire by using a straight drawing process, wherein the wire drawing speed is 1.5m/min, the pass deformation is about 8 percent, and the accumulated deformation is 60 percent, so that the wire with the diameter of phi 6.9mm is obtained; heating at 780 ℃, and straightening the wire by adopting an electric heating tension straightening process;

the heat treatment process comprises the following steps: the wires are put in high-temperature resistant cast iron with a straight inner wall one by one, heated at 650 ℃, kept warm for 2 hours, and annealed by furnace cooling; grinding and polishing the wire material by using a centerless grinding process to obtain a finished wire material with the diameter of phi 6.1 mm; keeping the temperature at 960 ℃ for 2 hours, air cooling and keeping the temperature at 600 ℃ for 5 hours, air cooling, and carrying out solid solution aging treatment. The specific chemical components are shown in Table 5, and the mechanical properties are shown in Table 6.

Table 5: example 3 alloy composition (mass%; wt%)

Table 6: example 3 Heat treatment protocol and Properties

Example 4

The rolling process comprises the following steps: grinding and sawing a titanium alloy rough bar blank with the diameter of 55mm, preserving heat for 1 hour at 1050 ℃, and rolling to the diameter of 12 mm.

The wire drawing process comprises the following steps: peeling a bar with the diameter of 12mm to the diameter of 11mm by a centerless vehicle; heating at 840 ℃ for 120 minutes by adopting a trolley furnace, and hanging an oxide film on the surface; heating at 820 ℃, lubricating by adopting graphite emulsion and molybdenum disulfide, and hot-drawing a rolled bar into a wire by utilizing a straight drawing process, wherein the wire drawing speed is 1.5m/min, the pass deformation is about 8 percent, and the accumulated deformation is 60 percent, so that the wire with the diameter of phi 6.9mm is obtained; heating at 780 ℃, and straightening the wire by adopting an electric heating tension straightening process;

the heat treatment process comprises the following steps: the wires are put in high-temperature resistant cast iron with a straight inner wall one by one, heated at 750 ℃, kept warm for 2 hours, and annealed by furnace cooling; grinding and polishing the wire material by using a centerless grinder to obtain a finished wire material with the diameter of phi 6.1 mm; keeping the temperature at 960 ℃ for 2 hours, air cooling and keeping the temperature at 600 ℃ for 5 hours, air cooling, and carrying out solid solution aging treatment. The specific chemical components are shown in Table 7, and the mechanical properties are shown in Table 8.

Table 7: example 4 alloy composition (mass%; wt%)

Table 8: example 4 Heat treatment System and Properties

Comparative example 1

The difference from the example 1 is that the alloy composition and the annealing heat treatment temperature are different, the specific chemical composition is shown in Table 9, and the mechanical property is shown in Table 10.

Table 9: alloy composition of comparative example 1 (mass%; wt%)

Table 10: comparative example 1 Heat treatment System and Properties

Comparative example 2

The difference from the example 4 lies in the alloy composition and the solution aging treatment process, the specific chemical composition is shown in Table 11, and the mechanical property is shown in Table 12.

Table 11: comparative example 2 alloy composition (mass%; wt%)

Table 12: comparative example 2 Heat treatment System and Properties

The above embodiments are merely illustrative of the technical ideas and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. A high-strength high-plasticity heat-strength titanium alloy wire is characterized in that: the alloy comprises the following components in percentage by weight: 4.8% -7.0%; 0.3 to 2.5 percent of Sn; zr: 0.3% -4.5%, Si: 0.08-0.25%, Mo or Mo + W: 4.0-6.5%, less than or equal to 0.10% of C, less than or equal to 0.3% of Fe, less than or equal to 0.15% of O, less than or equal to 0.05% of N, less than or equal to 0.015% of H, and the balance of Ti and inevitable impurity elements.

2. The high-strength high-plasticity hot-strength titanium alloy wire according to claim 1, wherein: the alloy comprises the following components in percentage by weight: 4.8% -6.0%; 0.3 to 1.5 percent of Sn; zr: 0.3% -1.5%, Si: 0.08-0.25%, Mo: 4.0 to 5.0 percent of C, less than or equal to 0.10 percent of Fe, less than or equal to 0.3 percent of Fe, less than or equal to 0.15 percent of O, less than or equal to 0.05 percent of N, less than or equal to 0.015 percent of H, and the balance of Ti and inevitable impurity elements.

3. The high-strength high-plasticity hot-strength titanium alloy wire according to claim 1, wherein: the alloy comprises the following components in percentage by weight: 6.0% -7.0%; 1.0 to 2.5 percent of Sn; zr: 3.0% -4.5%, Si: 0.08-0.25%, Mo: 4.0% -5.0%, W: 0.4 to 1.5 percent of Ti, less than or equal to 0.10 percent of C, less than or equal to 0.15 percent of Fe, less than or equal to 0.15 percent of O, less than or equal to 0.04 percent of N, less than or equal to 0.010 percent of H, and the balance of Ti and inevitable impurity elements.

4. A method for preparing the high-strength high-plasticity high-strength titanium alloy wire material as claimed in claim 1, 2 or 3, wherein the rolling process comprises the following steps: heating the bar material to 990-1050 ℃, preserving heat for 1-2 hours, and rolling the bar material from phi 55 mm-phi 65mm into a straight bar material or a wire rod with phi 10 mm-phi 12mm by adopting a hot rolling process.

5. The method for preparing the high-strength high-plasticity hot-strength titanium alloy wire according to claim 4, wherein the wire drawing pretreatment process is as follows:

turning off the diameter of the rolled straight bar by 0.8-1.2 mm by using a centerless lathe; or after drawing and rounding by adopting a drawing die, peeling the wire rod with the diameter of 0.5-0.8 mm by using a peeling die; removing surface defects; and then heating the mixture for 30-120 minutes at 740-840 ℃ by adopting a trolley furnace to perform surface pre-oxidation.

6. The method for preparing the high-strength high-plasticity hot-strength titanium alloy wire according to claim 4 or 5, wherein the wire drawing process comprises the following steps: heating to 740-840 ℃, lubricating by using graphite emulsion and molybdenum disulfide, and hot-drawing a rolled bar into a wire material by using a direct drawing or disc drawing process, wherein the drawing speed is 1-2 m/min, the pass deformation is 6-10%, and the accumulated deformation is 40-80%.

7. The method for preparing the high-strength high-plasticity hot-strength titanium alloy wire according to claim 6, wherein the straightening process comprises the following steps: heating the drawn wire to 750-820 ℃, and straightening the wire by adopting an electric heating tension straightening process.

8. The method for preparing the high-strength high-plasticity heat-strength titanium alloy wire according to claim 4, wherein the heat treatment process comprises the following steps: keeping the temperature at 650-750 ℃ for 1-3 hours, furnace cooling or air cooling, and annealing heat treatment.

9. Use of a titanium alloy wire according to claim 1, 2 or 3 in the manufacture of a heat resistant titanium alloy wire for use at a temperature in the range 450 ℃ to 550 ℃.

10. Use according to claim 9, characterized in that: the titanium alloy is used for preparing fasteners for hypersonic aircraft structures.