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The military budget has been increasing year by year, and the growth potential of military aircraft is huge. In recent years, China's military expenditure has been growing continuously, with a compound annual growth rate of 7.2% from 2017 to 2021. With the increasing of China's comprehensive national strength, national defense construction has achieved "compensatory" development. It is expected that the compound growth rate in the next five years is expected to reach 7.5%, and there is a huge demand for military aircraft installation in the future. The military budget has been increasing year by year, and the growth potential of military aircraft is huge. In recent years, China's military expenditure has been growing continuously, with a compound annual growth rate of 7.2% from 2017 to 2021. With the increasing of China's comprehensive national strength, national defense construction has achieved "compensatory" development. It is expected that the compound growth rate in the next five years is expected to reach 7.5%, and there is a huge demand for military aircraft installation in the future. It is expected that in the next 5 years, the domestic military + civil aerospace titanium material demand accumulated 110,000 tons, a compound growth rate of 16%. Since 2016, under the guidance of supply-side reform, backward production capacity has been gradually closed down and industrial concentration has continued to increase. Considering that the proportion of aerospace titanium materials in the domestic market is much lower than 50% of the total demand of titanium materials in the world, it is estimated that the total market demand of domestic aerospace titanium materials in the next 5 years is 110 thousand tons, and the compound growth rate of the industry is 16%.

Titanium alloy has the characteristics of low density, high strength and corrosion resistance. Titanium alloy pipe, as a new kind of material, is widely used in the field of aerospace, and the proportion of titanium alloy pipe in aero-engine pipeline is increasing. Other, titanium alloy is a very lively metal at high temperature of oxygen, hydrogen, nitrogen and other gases has a great affinity, absorbed and dissolved gas ability is very strong, especially in the welding process, the ability with welding temperature rises, the performance is especially intense, when welding need to absorb oxygen, hydrogen, nitrogen and other gases and dissolved control, avoid the abandonment of the product, This brings great difficulties to the welding of titanium alloy tube. 1. Weldability of titanium alloy catheter (1) embrittlement of welded joints At room temperature, titanium reacts with oxygen to form a dense oxide film, which makes it have better chemical stability and corrosion resistance. Under high temperature, especially in the welding process, titanium and oxygen, hydrogen, nitrogen reaction speed, when the molten pool in the invasion of oxygen, hydrogen, nitrogen and other harmful gases, welding joint of the plasticity, toughness and surface color has the obvious change, especially in the more than 882 ℃, sub grain growth tendency is serious, martensite structure are formed when cooling, The joint strength, hardness, plasticity, toughness decreased, overheating tendency serious, serious embrittlement of the joint. Therefore, in titanium alloy welding, the molten pool, molten drop and high temperature zone, whether positive or negative, should be comprehensive and reliable gas protection. (2) Stoma Porosity is the most common defect in titanium and titanium alloys welding, which mainly occurs near the fusion line. Hydrogen is the main cause of stomata. During welding, TITANIUM has a strong ability to absorb hydrogen (even stronger at high temperature), but its solubility decreases significantly with the decrease of temperature, so the hydrogen dissolved in the liquid metal often has no time to escape and accumulates near the fusion line to form pores. (3) Delay crack near the seam area Titanium alloy in a period of time after welding. Cracks tend to appear in the near seam area (delay cracks). The reason is that hydrogen diffused from the high temperature molten pool to the low temperature heat affected zone. With the increase of hydrogen content, the amount of TiH2 precipitated increased, which increased the brittleness of the heat affected zone. In addition, the microstructure stress generated when the volume of precipitated hydride expanded eventually led to cracks. 2. Welding requirements and matters needing attention for titanium alloy conduit (1) Try to set up a special welding workshop, no smoking indoors, the environment should be kept clean and dry, and the air convection should be strictly controlled. (2) Welders should wear clean work clothes and non-fat gloves when welding. It is strictly forbidden to touch parts with bare hands. (3) The welding area and the surface of the wire should be degreased with acetone. (4) Argon is protected with high purity, purity not less than 99.99%. During welding, the gas supply flow shall be protected on the front and back of the welding pass according to the value specified in the technological procedure. (5) In the welding process, the flow rate of argon in the tube and the nozzle of the welding tool should be kept constant to prevent the convexity and concave phenomenon of the weld pool forming in the tube. (6) When welding, short arc welding should be adopted as far as possible, and small welding line energy should be adopted. (7) The gap is less than 30% of the wall thickness when the pipe is spot welded. Each weld should be welded at one time as far as possible. (8) During welding, the welding tool should not swing from side to side, and the melting end of the welding wire should not be moved out of the gas protection zone. When starting the arc, air supply should be advanced for 10-15s. When resting the arc, the welding torch can not be lifted immediately. The air supply should be delayed for 15-30s until the temperature drops below 250℃. 3. Welding process 1) Clean up before welding. The occurrence of welding defects is closely related to the surface cleanliness of weldment and wire. Before welding, grease, water, oxide film and other dirt within 15 ~ 20mm of the edge of the pipe joint and the surface of the welding wire should be cleaned. Cleaning methods can be chemical (pickling) or mechanical means (stainless steel brush) to remove the surface oxide skin. Acetone or alcohol should also be used to scrub before welding. After cleaning, the weldment must be welded within 24 hours, otherwise it needs to be cleaned again. Wire pickling after the best vacuum dehydrogenation treatment, degreasing with acetone before welding. 2) Gas protection. When welding titanium pipe joint, in order to prevent the welding joint from being polluted by harmful gases and elements at high temperature, necessary argon gas protection must be carried out on the weld with purity not less than 99.99%. Argon gas flow is shown in Table 2-1. 3) Selection of welding process parameters. (1) Selection of welding wire. The grade of the filler wire should be selected according to the base metal, generally using the principle of homogeneity with the base metal, sometimes in order to improve the plasticity of the joint, you can choose a slightly lower degree of alloying than the base metal welding wire. The diameter of the welding wire should be selected according to the thickness of the base metal, as shown in Table 2-1. (2) Power supply and polarity selection. Titanium and titanium alloys are generally welded by DC manual tungsten electrode argon arc power supply, and the polarity connection method is direct DC connection. (3) Selection of tungsten pole. The diameter of tungsten pole is selected according to the thickness of titanium alloy tube wall, which is generally between 1.0-3.Omm. The tungsten extreme part should be ground into a cone of 25° ~ 45°. (4) Selection of welding current and other parameters.

The industrial production of titanium and titanium alloys, whether remelted consumable electrodes, forging blanks, or deformed castings, is mostly obtained by vacuum arc melting of consumable electrodes. With the development and progress of modern technology, titanium and titanium alloy smelting, including vacuum consumable electrode arc smelting, has developed some new advanced technologies. Representative technologies in recent years are as follows: 1. Preparation method of electrode for vacuum self-consumption melting of titanium alloy with high melting point metal directly added In vacuum since the electricity arc smelting with titanium alloy electrode, on the basis of conventional preparation by the direct suppression of certain grooves of the electrode block and is suitable for the high melting point metal rod electrode block groove shape of welding electrode method, by choosing appropriate vacuum since the electricity arc melting process, can achieve melting the matching calculation requirement, composition of even no segregation of high quality ingot. 2, titanium and titanium alloy vacuum self-consumption melting process after the interruption of the arc process Titanium and titanium alloy vacuum self-consumption melting process after the interruption of the arc process, including the following steps: when the interruption of the arc, the melting current quickly raised to 75-80% of the normal melting current, maintain the melting current at this time; When the edge of the molten pool reaches the wall of the crucible, keep it for 2-3min, and then quickly raise the smelting current to the normal smelting current. The technology advantage, make the total arc starting time shortened significantly, reduce the cooling of the ingot after the volume shrinkage and the crucible wall between the gap and avoid the formation of ingot solidification cooling internal shrinkage: when melting current reaches 75 to 80% of normal melting current, keep the melting current for a period of time, so that we can more accurately control electrode and has solidified melt velocity of molten pool, Avoid instantaneous large amount of molten liquid flowing into the gap between the ingot and the crucible wall, or cause cold separation defects. 3. Smelting and recovery method of pure titanium bulk waste In the smelting and recovery method of pure titanium bulk waste, the electron beam cold bed furnace with six electron guns is used to load the raw materials of selected components into the feeder of the electron beam cold bed furnace for melting, and then the obtained ingot is cooled and baked, and the finished product can be obtained. In this method, TA1 recycled material is directly used for melting, which avoids crushing of scrap electrode block and welding of electrode. For single ingot smelting, a single device can melt 9 bars per day with a total weight of about 6.5 tons. For double ingot smelting, a single device can melt 18 bars per day with a total weight of about 13 tons, which greatly improves the recovery efficiency and speed 4. Electron beam cold bed melting recovery method for titanium and titanium alloy scrap The electron beam cold bed melting recovery method of titanium and titanium alloy scrap is as follows: according to the melted titanium and titanium alloy composition, the pure titanium scrap, or one or two of the pure titanium scrap and titanium alloy scrap mixed with titanium sponge and pure alloy added elements and/or intermediate alloy, The addition amount of pure titanium and titanium alloy scrap in the mixture is 10%~90% according to the mass percentage; The electrode block is then pressed into an electrode block, and the electrode block is subjected to a single electron beam cold bed melting in an electron beam cold bed melting furnace to obtain titanium or titanium alloy ingots. This method can produce qualified pure titanium ingot from up to 100% pure titanium scrap, or up to 90% titanium and titanium alloy scrap, and produce qualified titanium alloy ingot. Only the electron beam cold bed is needed for primary melting, not secondary or tertiary melting. 5. Smelting method of clean titanium and titanium alloy ingot Pure titanium and titanium alloy ingot melting method, the method is: according to take titanium sponge or take pure alloy elements added, intermediate alloy and titanium sponge and titanium sponge or pure alloy mixture to add elements, intermediate alloy and titanium sponge pressed into the electrode block, will be pressed into the electrode piece of welding electrode, using electron beam cooling bed furnace electrode on a cooling bed of the electron beam melting, To obtain clean, homogeneous chemical composition of titanium or titanium alloy ingots; The vacuum degree of electron beam cold bed melting is less than 6×10-2Pa, the melting speed is 70~150kg/h, the melting power is 100~ 300kW; Pure alloy addition elements and intermediate alloys are 0%~20% of the total weight of titanium alloy ingot. The chemical composition of titanium and titanium alloy ingot is uniform, and the macro structure of ingot is better than that of vacuum arc melting ingot without high melting point inclusions such as TiN and WC. 6. Smelting method of titanium alloy containing high melting point alloying elements Industrial preparation of titanium alloy ingot containing high melting point alloying elements. By SELECTING THE RAW MATERIAL OF THE ALLOY, USING THE electrode block SPECIALLY assembled, using the conventional vacuum consumable arc melting technology, adjusting the current and voltage of three times melting, the titanium alloy ingot with uniform chemical composition and no inclusion and containing high melting point alloy elements was prepared. High melting point metal distributed evenly in the consumable electrode, consumable electrode convenient preparation, low cost, reasonable smelting as current, voltage parameters, on the basis of traditional craft route, using a low-cost pure metal plate according to the specific consumable electrode spellers way, instead of adding the middle of the high cost of alloy and pure metal to join other titanium alloy, Titanium alloy ingot with uniform composition and high melting point alloy elements was obtained by using vacuum arc melting furnace for many times, which is suitable for industrial application. 7. Preparation of TC4 titanium alloy ingot by electron beam cold bed furnace melting The method of preparing TC4 titanium alloy ingot by electron beam cold bed furnace melting is as follows: the titanium sponge and aluminum-bean are mixed evenly and pressed into electrode block, then the electrode is welded into a vacuum consumable arc furnace, and the Ti-AI intermediate alloy is obtained by one smelting. The Ti-Al intermediate alloy is broken into Ti-Al intermediate alloy particles. The titanium sponge, Al-V intermediate alloy and Ti-Al intermediate alloy particles were mixed evenly and pressed into electrode blocks, which were spliced into electrodes and placed in an electron beam cold bed furnace, and TC4 titanium alloy ingot was obtained by primary melting. Among the Ti - Al alloy instead of aluminum beans, reduced the Al elements volatilize quantity, improve the utilization rate of raw materials and the use of electron beam cooling bed furnace efficiency, the use of an electron beam cooling bed furnace smelting in titanium processing cost and improve production efficiency with the advantages of stronger, and can improve the cleanliness of the titanium alloy ingot casting, access to quality of ingot casting.

The People's Liberation Army (PLA) has launched a large-scale military drill across the Taiwan Strait to deter pro-independence forces and boost national confidence, as US House of Representatives Speaker Nancy Pelosi ignored China's warning to visit the region. Since 2016, titanium is finding wider and wider application in the field of international military, known as the aviation and aerospace applications have spread to the kettle, tableware, such as ordinary individual instruments, the proportion of titanium used in military industry increase from 6% to more than 18%, the large-scale military exercises and on the future of the Taiwan strait and titanium for the next five years of war industry growth has laid a solid foundation. The application of titanium in military industry is mainly reflected in the following aspects: one is in aviation, aerospace in the application of aircraft and missiles; The second is the application on ships; The third is the application in light vehicles; The fourth is the application on individual weapon and weapon. With the development of Chinese titanium industry and the significant update of equipment level, it can be predicted that the application amount of titanium in the military industry will be 20% of the total domestic titanium production this year. More and more titanium materials will replace traditional metal and play a more important role in national defense industry. In the next five years, the prospect of titanium industry is still in a period of rapid rise, and the application of titanium materials is infinitely bright.

At present, steel, titanium and other metal materials are the main components of Marine equipment structure, and steel is the earliest application. Take the pressure hull of the manned deep submersible as an example. In the 1960s, the manned hull of the Sea Cliff and Alvin submersibles developed by the United States were built with steel. With the increase of seawater pressure due to the increase of submersible diving depth, and the increase of cumulative seawater corrosion damage due to long-term service, the specific strength (strength/density ratio) and corrosion resistance of steel gradually fail to meet the requirements of structural design. Titanium and titanium alloys have high specific strength and excellent corrosion resistance, which are called "ocean metals" and are ideal structural materials in the field of ocean engineering manufacturing. The crew capsules of the Sea Cliff and Alvin submersibles were gradually replaced with titanium alloys at a later stage. At present, TI-6AL-4V titanium alloy of 800 MPa strength level is basically adopted in the mainstream manned submersible in the world, including "Jiaolong" and "deep-sea Warrior" manned submersible developed during the "Eleventh Five-Year plan" and "Twelfth Five-Year Plan" Consistent with the requirements of aviation and aerospace on structural weight reduction, the structural weight reduction benefits of deep-sea equipment are obvious. After weight reduction, the navigation agility of Marine exploration equipment can be increased, the amount of buoyant materials can be reduced, energy consumption can be reduced, and the operation cycle of equipment can be improved. Titanium alloy structure weight reduction design require the use of higher strength, but structure strength - the material toughness "upside down" phenomenon, enhance strength after often results in the decrease of toughness, lead to brittle fracture and reduce the reliability and service life of structure, therefore, both high strength and high toughness titanium alloy is often the bottleneck problem of equipment development.

From June 29 to 30, the "2022 (third) Titanium Industry Information Titanium Tube Innovation and Development Forum" was held in Baoji High-tech Zone. Liu Jianjun, deputy director of the High-tech Zone Management Committee, was invited to attend and made a speech to promote the industry chain of titanium and new materials. More than 260 corporate guests, including Aviation Materials Research Institute of China Aviation Development Group, China Heavy Machinery Research Institute Co., LTD., Wuxi China Lottery Group, Changzhou Jinxi Titanium Technology Co., LTD., attended the event. Activities mainly around the titanium alloy tube performance anisotropic control technology, the titanium and titanium alloy tubes in the future market development has carried on the discussion topics, activities during round-table conference convened titanium entrepreneurs, and titanium in high-tech zone science and technology new town and new material industrial park, baoji special steel titanium industry co., LTD., new material technology co., LTD. Baoji nuclear force and so on enterprises in the area of the visit, The director of investment cooperation Bureau of High-tech Zone introduced the development of titanium industry and the planning and construction of industrial park in Baoji High-tech Zone to the participants.

The improvement of aero-engine performance is closely related to the collaborative application of new high-temperature titanium alloy and advanced structural design. Since the 1990s, China has accelerated the research process of new high-temperature titanium alloy materials, and carried out the development of 550 ℃ high-temperature titanium alloy, 600 ℃ high-temperature titanium alloy, flame retardant titanium alloy and Ti-Al series intermetallic compound alloy.

On June 18, the ethylene glycol device fire in Shanghai Petrochemical And Chemical Industry Department once again pushed chemical safety to the forefront of social attention. Chemical equipment in the operation of "running, risk, drip, dew" and other safety hazards in the safety of production are the top priority to eliminate. As we all know, titanium corrosion resistance equipment has played an increasingly important role in the chemical industry in the past 30 years. From salt chemical industry to chlor-alkali chemical industry and then to PTA project, the application amount of titanium material has accounted for more than 50% of the production of titanium material. The development of this accident will promote the application of titanium materials in the field of chemical corrosion resistance equipment, and the market demand will also be significantly increased. This week, the order of baoji mainly titanium material enterprises is sufficient, with busy production. Also material prices have risen. Sponge titanium supply is still tight, but the overall price of materials fluctuates little.

Baoji market quotation range for pure titanium wire: Grade: GR1/GR2 Standard: ASTM B863 Size: ф 1 ~ 5mm Price: 180 ~ 240 RMB/Kg Baoji market quotation range for titanium alloy wire : Grade: GR5 Standard: ASTM B863 Size: ф 1 ~ 5mm Price: 280 ~ 300 RMB/Kg

The application of titanium alloy in warship improves the service life and equipment performance in Marine environment. For this reason, titanium and titanium alloys are known as "future metal," "third metal," and "ocean metal." Russia, the United States, China, France, Japan and other countries attach great importance to the research and development of titanium alloy because of its excellent properties and important applications in Marine engineering and military fields. Titanium and titanium alloy materials are widely used in ships. and titanium may be used in all large equipment and parts except ship equipment and cabin facilities, such as electronic information system, power system, auxiliary system, hull structure parts, propulsion system, etc. Foreign titanium alloy materials are mainly used in ship structure materials, ship pumps, valves, pipes and other accessories, power drives, heat exchangers, condensers, coolers, evaporators, acoustic devices, etc. Domestic titanium alloy materials are mainly used in deep submarine, power drive device, shipborne radar, electronic equipment, fasteners and so on.

This Weeks, over 10 tons of pure titanium plates shall be delivered from Baoji Jintaoyue Metals. Before packaging, JTY invited the international well-known third-party testing company Burea Vferitas to witness the product quality certification process. Surface inspection of titanium plates PMI for titanium sheets Lab inspection for titanium plates All data are sactory and JTY has gained a evaluation from BV for quality and service.

Pure titanium sheet (cold rolled sheet) Brand: GR1/GR2 Standard: ASTM B265 Thickness: 1 ~ 3mm Price: $20 ~ $21.3 /Kg Thickness: 3 ~ 5mm Price:: $18.5~ $19.6 /Kg Pure titanium plate (hot rolled plate) market price range: Brand: GR1/GR2 Standard: ASTM B265 Thickness: 5 ~ 12mm Price: $17/kg-$18.11/Kg

This week, the titanium market is booming. All titanium material production enterprises in Baoji are in full load production. Due to the impact of transportation, the delivery of some raw materials and finished products is blocked, and the delivery time is affected to a certain extent. Due to the strict restrictions on personnel circulation in Baoji city, quarantine measures still need to be taken to enter and return treasures from other provinces, which has certain impact on order procurement and equipment upgrading.

The development of traditional metal building materials, especially roofing materials, follows the sequence of copper, surface treated steel, aluminum, stainless steel and titanium. With the advance of The Times, people's requirements on urban buildings, especially the aesthetic requirements of buildings are getting higher and higher. With the development of the building industry, architects have been pursuing the use of higher building materials than traditional ones in recent years. A series of excellent characteristics of titanium can fully meet many performance requirements of building materials, so it is favored by architects and construction industry. Titanium is suitable for the characteristics of the building: 1. Meeting the requirements of lightweight building materials 2. Good corrosion resistance 3.Low coefficient of thermal expansion 4.Good machinability and welding performance 5.No environmental pollution 6.long service life Application examples of titanium in construction field At present, the United States, Spain, the Netherlands, Canada, The United Kingdom, Belgium, Switzerland, France have buildings using titanium roof and curtain wall. Several new titanium buildings are also under construction in countries such as Sweden, Singapore and Egypt. ABU Dhabi airport was also the first to use titanium, using nearly 100 tons. The airport is the world's first application of titanium as a structural material.

Demand for titanium materials in China declined from year of 2011 to 2016, and then rose sharply. Since 2008, the demand for titanium has generally been on the rise. In 2011, the titanium market reached a stage high, and then the domestic demand for titanium materials began to decline. China's titanium industry has structural overcapacity, with high-end titanium materials in short supply for aviation and low-end titanium materials in serious overcapacity for civil use. Driven by the demand of high-end chemical, aerospace, shipbuilding and power industries, the demand for titanium processing materials in China continues to hit new highs. 1. Batch stability control technology of titanium alloy material quality The batch stability of titanium alloy material quality directly affects the performance and safety of high-end assembly, and the development of its control technology is an eternal topic. Mass production quality stability by technology into the first batch, equipment status, on-site normative and other factors, and with the increase type titanium alloy ingot ingot, bar specifications, must vigorously on research and development to improve the quality of technological rationality, the identification process control key elements, thus improve the quality of the titanium alloy material batch stability control technology, To meet the requirements of the high-end field. 2. Preparation technology of large titanium alloy ingot, bar and forging billet In order to improve the equipment performance and structural efficiency, reduce the weight of the structure, shorten the production cycle and control the cost, the consumption of titanium alloy parts of new military aircraft, civil large passenger aircraft and various aircraft engines is increasing, and the integral proportion of titanium alloy parts is increasing. For example, blades and bladed discs are replaced by integral bladed discs, multiple frame beams are replaced by integral frames, and the diameter of engine casing and drum is becoming larger and larger. In recent years, a number of large die forging forming equipment has been put into production in China, and large tonnage forming technology has developed rapidly. A large number of parts of more new military aircraft and large aircraft in China have clearly adopted the integrated manufacturing process route from the beginning of design, and the specifications of titanium alloy bars and forging billets for related parts and components are becoming larger and larger. The preparation technology of large titanium alloy ingot, bars and forging billets is still one of the important directions of industrial technology development. 3. Research and development of ultra-high strength and high toughness titanium alloy and high temperature titanium alloy As the structural efficiency of new aviation equipment becomes higher and higher, the demand for ultra-high strength and high toughness titanium alloy becomes more and more urgent. Domestic units have also carried out the development of ultra-high strength titanium alloy of more than 1,350MPa. Domestic development of 1300MPa+60MPa• M1/2 grade of ultra-high strength and high toughness titanium alloy and a single weight of 5 tons, the section thickness of nearly 400mm super-large specification forging billet, but at present there is no such large specification forgings for ultra-high strength and high toughness titanium alloy materials. The technical maturity of ultra-high strength and high toughness titanium alloy needs to be further improved. High-temperature titanium alloy is the key material of aero-engine. The service temperature can cover 300℃~600℃. It can replace part of high-temperature alloy and stainless steel and be used to manufacture engine and gas turbine blade, disk, casing, drum and other engine parts. IMI834 titanium alloy is the most widely used titanium alloy with the highest technical maturity at 600℃. It has been used in Trent series of Rolls-Royce, EJ200 and PW350 of Pratt & Whitney. The technical maturity of high-temperature titanium alloys used at 600℃ and above in China cannot meet the development requirements of new aero-engines for the time being, and relevant development work needs to be accelerated. 4.Development and preparation technology of special titanium alloy for weapons With high specific strength and good corrosion resistance, titanium alloy has unique advantages in weapons, ocean engineering, nuclear power and other fields. For example, using titanium alloy as the material of missile warhead can not only improve cruise speed by reducing weight, but also improve the precision strike capability of warhead with good damage tolerance. The development of new special titanium alloy is of great significance to its application in high performance weapons, ocean engineering, nuclear power and other fields.

Baoji Jintaoyue invested 28 million yuan in February 2022 to produce and process titanium Foil, So far, it has stored about 1200 tons of spot foil, which are mostly for precise instrument, aerospace, chemical indurstry and subsea oil equipment.

Due to the conflict between Russia and Ukraine, exports from both countries have been severely hampered. Actually Russia and Ukraine are the main suppliers of titanium raw materials in the world, and their export ratio of titanium sponge and titanium processing materials is very high.The conflict has increased the possibility of titanium raw material supply shortage in the international market, and it is expected that international buyers will shift and lock the procurement target to China. Since last week, titanium demand has surged and exports have also increased in Baoji, China. At the same time, due to the growth of raw materials, it is expected that the price of titanium materials will rise, please titanium manufacturers timely purchase and stock titanium sponge, in order to prevent the price rising and out of stock.

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Titanium alloy has low hardness and poor wear resistance. When it is used as propeller blades, turbine blades, turbines, tail pipes, pumps, valves and other flow components, it is easy to cause cavitation erosion in the components due to the pressure change area in the fluid. When the cavitation bubble collapses near the solid boundary, the surface of the solid material will peel off, which will reduce the equipment performance, shorten the service life, and even lead to the failure of titanium alloy members. Over the years, new research progress has been made on the protection measures of titanium alloy cavitation damage at home and abroad. The following will be discussed in detail from three aspects: heat treatment of the whole material, surface treatment and adding corrosion inhibitor to fluid medium. 1,Heat treatment The results show that heat treatment can improve the cavitation resistance of titanium alloy by changing its microstructure. Li Haibin heat treated Ti6Al4V alloy at different temperatures (1020 ℃, 950 ℃, 850 ℃) to obtain the weidler microstructure, two-state microstructure and equiaxed microstructure. After 8 h cavitation test in deionized water, the author found that the cumulative weight loss of all the heat treated samples was less than that of the original Ti6Al4V. Among them, the weidler sample treated by 1020 ℃+ water quenching has the lowest cavitation erosion weight loss (77.9% of the original sample) and the highest cavitation erosion resistance coefficient (1.83 times of the original sample). The results show that the cavitation resistance of Ti6Al4V alloy with different microstructure is also different. The fracture toughness and tensile strength of Ti6Al4V are enhanced by the martensite α 'phase or flake α phase in the weisenberg structure, and the energy of absorbing cavitation collapse is enhanced. The primary α phase in the two-state structure has a strong work hardening ability, while the β transformation structure (secondary α phase) can improve the strength and hardness of the material, and also enhance the energy of Ti6Al4V to absorb the collapse of cavitation. The equiaxed structure also contains secondary α phase, but its content is less, so the improvement of cavitation erosion resistance is not as obvious as that of the two-state structure. In this experiment, the cavitation erosion resistance of the weidler structure is the best, followed by the two-state structure, and the equiaxed structure is the lowest. 2,Surface treatment As cavitation erosion starts from the surface of the material, surface treatment of titanium alloy naturally becomes an effective measure to improve its cavitation erosion resistance. So far, the surface treatment techniques used to improve the cavitation resistance of titanium alloys at home and abroad include laser texturing, laser gas nitriding, chemical heat treatment, ion implantation, hot dip plating and so on, and some achievements have been achieved. 3,Add corrosion inhibitor Cavitation damage of titanium alloys in corrosive environment usually involves the synergistic effect of corrosion damage. Therefore, adding corrosion inhibitor can be regarded as an effective way to improve the cavitation resistance of titanium alloys. The cavitation damage behavior of Ti6Al4V alloy in 55% (mass fraction) LiBr solution +1% anodic corrosion inhibitor NaNO2 was investigated. The results show that after hollowing for 1 h in LiBr solution containing corrosion inhibitor, the surface voids are significantly reduced compared with the surface without corrosion inhibitor. After 8 h, the cumulative weight loss was 90.5% without corrosion inhibitor. The NO2- generated by the addition of this corrosion inhibitor will be adsorbed into the voids with strong activity on the surface of passivated film, which makes the passivated film more easily generated and inhibits the electrochemical corrosion of Ti6Al4V, thus reducing the cavitation damage caused by the joint action of mechanical and electrochemical corrosion. However, the electrochemical corrosion of the sample was not completely inhibited after adding corrosion inhibitor.