In the process of cutting titanium, the precautions are

In the process of cutting titanium, the precautions are:
(1) Due to the small elastic modulus of titanium investment casting, the deformation of the workpiece clamped in the processing of large deformation and stress, will reduce the machining accuracy of the workpiece; workpiece clamping force installation should not be too large, increase aid support when necessary.
(2) If using liquid hydrogen cutting, the cutting process will decompose at high temperatures to release hydrogen embrittlement caused by absorption of titanium; it may cause high temperature titanium stress corrosion cracking.
(3) the use of cutting fluid chlorides are also likely to break down or volatile toxic gases, the use of security measures should be taken, otherwise it should not be used; after cutting should be timely and chlorine-free cleaning agent thoroughly cleaned parts, remove residual chlorine thereof.
(4) prohibits the use of lead or zinc-based alloy production workers, fixture and titanium contact, copper, tin, cadmium and its alloys are also prohibited.
(5) All workers, fixtures or other devices must be in contact with the titanium tubing clean; titanium parts cleaned off, to prevent contamination of grease or fingerprints, or after the salt may cause stress corrosion.

With regard to the titanium cutting

With regard to the titanium cutting
HB350 hardness greater than titanium bolts machining particularly difficult, less than HB300 is prone to stick a knife phenomenon, but also difficult to cut. However, only one aspect of the hardness of titanium machining difficult, the key is the combined effect of its machinability of chemical, physical and mechanical properties of titanium itself between. Cutting Titanium has the following characteristics:
(1) deformation coefficient is small: This is a significant feature of titanium machining, deformation coefficient is less than or close to one. Chip away the knife sliding friction surface greatly increases the previous accelerated tool wear.
((3) cutting force per unit area on the big: the main cutting force of about 20% smaller than when cutting steel, due to the length of the chip and the rake face contact is extremely short, the contact area on the cutting forces unit greatly increased, likely to cause chipping Meanwhile, because of the small elastic modulus of the titanium alloy, the processing in the radial force prone to bending deformation, causing vibration, increased tool wear and affects the accuracy of parts.
(4) Chilled serious: Because the chemical activity of titanium plates is large, at high cutting temperature, is easy to absorb oxygen in the air and nitrogen to form a hard and brittle skin; while plastic deformation during the cutting process can also cause surface hardening . Chilled phenomenon will not only reduce the fatigue strength of the parts, but also increased tool wear, is a very important feature when cutting titanium.

Application of titanium in the car

Application of titanium in the car：
Titanium has a light weight, high strength, good corrosion resistance, etc., it is widely used in the automotive industry, the most widely used titanium alloy automotive engine systems. The use of titanium alloys engine parts has many advantages.
Low density titanium alloy, can reduce the inertial mass of the moving parts, while a titanium valve spring can increase the free vibration, reduced body vibrations, increase engine speed and output power.
Reducing the inertial mass of the moving parts, so that the friction is also reduced, improving engine fuel efficiency. Select titanium can reduce the load of stress-related components, reduce the size of the parts, so that the quality of the engine and the vehicle is reduced. Reduce inertia mass parts, so that the vibration and noise reduction, improved engine performance. Titanium applied to other member may improve comfort and the aesthetics of personnel cars and the like. Applications in the automotive industry, titanium alloys in terms of energy consumption plays an invaluable role.
Although titanium alloy parts has such superior performance, but from titanium and its alloys widely used in the automotive industry there is a great distance, causes include expensive, good formability and weldability and poor.
The most widely used titanium bar hinder the automotive industry is still the main reason for the high cost.

Titanium uses editor

Titanium uses editor：
Titanium has a high strength and density and small, good mechanical properties, good toughness and corrosion resistance. In addition, poor process performance. Titanium tubing, machining difficulties in thermal processing, and very easy to absorb carbon hydrogen nitrogen and other impurities. There are poor abrasion resistance, complex production process. Titanium industrial production was started in 1948. Require the development of the aviation industry, the titanium industry with an average annual growth rate of about 8% of the development. World titanium alloy production reached 40,000 tons, nearly 30 kinds of titanium alloys. The most widely used titanium alloy is Ti-6Al-4V, Ti-5Al-2.5Sn and commercially pure titanium.
Titanium is mainly used for the production of aircraft engine compressor components, followed by structure rockets, missiles and high-speed aircraft. The mid-1960s, titanium and its alloys have been in general industrial applications, electrodes for electrolysis industry production, power plant condensers, oil refining and desalination heater and environmental pollution control devices. Titanium wire mesh  have become a corrosion resistant structural materials. In addition, for the production of hydrogen storage materials and shape memory alloys.

Performance Titanium

Performance Titanium：
Titanium plate  at low and ultra-low temperature, retains its mechanical properties. Low temperature performance, low interstitial elements of titanium, as TA7, at -253 ℃ still maintain a certain plasticity. Thus, low-temperature titanium alloy is also an important structural materials.
1. The chemical activity of large
Chemical activity of titanium is large, a strong chemical reaction with atmospheric O, N, H, CO, CO2, water vapor, ammonia and the like. Carbon content greater than 0.2%, it will form a hard TiC in the titanium alloy; at higher temperatures, and also the role of N forms TiN hard surface; at above 600 ℃, the high hardness of hardened layer is formed of titanium absorbs oxygen ; hydrogen content increased, brittle layer will form. Absorbing gas produced brittle surface to a depth of 0.1 ~ 0.15 mm, the degree of hardening of 20% to 30%. Chemical affinity of titanium is also large, easy and sticking friction surface.
2. The thermal conductivity of small elastic
Thermal conductivity of titanium λ = 15.24W / (mK) approximately 1/4 of nickel, iron 1/5, 1/14 aluminum, while the thermal conductivity of various titanium electrodes for chlorinator cell decreased by 50% than the thermal conductivity of titanium. Elastic modulus was about 1/2 of the titanium alloy for steel, so the poor rigidity, deformation, and should not be made thin-walled elongated rod member, the machined surface when cutting a large amount of spring back, the stainless steel is about 2 to 3 times, causing severe tool flank friction, adhesion, adhesive wear.

The structure and application of titanium

The structure and application of titanium：

Titanium is an important structural metal in the 1950s developed, titanium because of its high strength, corrosion resistance, and high heat resistance and are widely used in various fields. Many countries recognize the importance of titanium wire alloy materials, have their research and development, and has been applied.
Titanium is the first practical American successfully developed in 1954, because of its heat resistance, strength, ductility, toughness, formability, weldability, corrosion resistance and biocompatibility are good, and become titanium ace alloy alloy industry, which accounts for the use of an alloy of 75% to 85% of all titanium alloys. Many others can be seen as a modification of titanium alloy Ti-6Al-4V alloy.
1950s and 1960s, mainly in the developing high temperature titanium and titanium alloy airframe aviation engine, the 1970s developed a number of corrosion resistant alloys, since the 1980s, corrosion resistant and high-strength titanium alloy has been further development of. Temperature resistant titanium alloys 400 ℃ from the 1950s up to the 1990s 600 ~ 650 ℃.
Appears based alloy, the titanium tube being propelled by the cold end to the hot end of the engine in the direction of the engine using the engine parts. Titanium alloy development to high-strength, high plastic, high strength and high toughness, high modulus and high damage tolerance direction.
In addition, since the 1970s, there was memory alloys, and get increasingly widely used in engineering.

 

 

Titanium has the following advantages

Titanium has the following advantages:
① high specific strength (tensile strength / density), a tensile strength of up to 100 ~ 140kgf / mm2, and the density of only 60% of steel.
② temperature strength, operating temperature of several hundred degrees higher than aluminum, at moderate temperatures can still maintain the desired strength, long-term work at a temperature of 450 ~ 500 ℃.
③ good corrosion resistance, Titanium heat exchanger surface immediately in the atmosphere to form a layer of uniform dense oxide film, the ability to resist the erosion of a variety of media.
④ low temperature performance, low interstitial elements of titanium, at -253 ℃ still maintain a certain plasticity.
⑤ low elastic modulus, low thermal conductivity, no ferromagnetism.

Titanium rod has good physical and chemical properties, low density, light weight, non-magnetic, high strength, good corrosion resistance, which has good mechanical properties and weldability, Baoji Titanium rods are widely used in chemical equipment, water desalination, ship parts, electroplating industries, titanium is 10 times the general corrosion resistance of stainless steel, and titanium is the body's rejection of relatively low metal, so the medical titanium rod machining parts, widely used in human implants and medical devices with.
Technical requirements: 1, the chemical composition of titanium and titanium alloy bars shall comply with GB / T 3620.1, provisions, when the demand side reinspection, the chemical composition of the tolerances shall comply with the provisions of GB / T 3620.2 of.
2, thermal processing bar diameter or side length and tolerances shall comply with the provisions of one of the table.
3, after thermal processing by car (mill) light bar and cold-rolled, cold drawn rod diameter tolerances shall comply with the provisions of Table II.
4, after thermal processing by car (grinding) roundness light bars should be no greater than half the size of tolerance. 5, the processing state bar is not definite length of 300-6000mm, not length annealed state bar length 300-2000mm, length or double length should not length over the length of the

Medical titanium alloy.

Titanium non-toxic, high light, strength and has excellent biocompatibility, is ideal for medical metal materials, can be used as implanted human implants and the like. Currently, in the medical field is still widely used Ti-6Al-4v ELI alloys. But the latter will precipitate a very small amount of vanadium and aluminum ions, reducing their cell adaptation and possibly cause harm to humans, this issue has already caused widespread concern in the medical profession. Qiang States early in the 20th century the mid-1980s began to develop non-aluminum, non-vanadium, biocompatible titanium alloy, which is used in orthopedic surgery. Japan, the United Kingdom also has done a lot of the research work, and made some new progress. For example, the Japanese have developed a range of α + β titanium alloy having excellent biocompatibility, including Ti-15Zr-4Nb_4ta-0.2Pd, Ti-15Zr-4Nb-aTa-0.2Pd-0.20 ~ 0.05N, Ti-15Sn -4Nb-2Ta-0.2Pd and Ti-15Sn-4nb-2Ta-0.2Pd-0.20, corrosion strength of these alloys, fatigue strength and corrosion resistance are better than Ti-6Al-4v ELI. Compared with the α + β titanium alloy, β titanium alloy having a higher strength almost water, and better performance and notch toughness is more suitable as an implant implanted in the human body. In the US, there are five kinds of β titanium alloys are recommended to the medical field, namely TMZFTM (TI-12Mo- ^ Zr-2Fe), Ti-13Nb-13Zr, Timetal 21SRx (TI-15Mo-2.5Nb-0.2Si), Tiadyne 1610 (Ti-16Nb-9.5Hf) and Ti-15Mo. Estimated that in the near future, such a high strength, low modulus of elasticity and excellent formability and corrosion resistance of titanium House is likely to replace the current widely used in the medical field Ti-6Al-4V ELI alloy [28'32 ].

Density of titanium metal is small as 4.5g / cm3, only 60% of iron, usually aluminum, magnesium, light metals and the like are known, the corresponding titanium, aluminum, magnesium alloy is known as a light alloy. Many countries recognize the importance of titanium alloy, titanium alloy materials have been research and development, and has been applied. Titanium is an important structural metal in the 1950s developed, titanium because of its high specific strength, good corrosion resistance, heat resistance, easy to weld other characteristics have been widely used in various fields, especially high strength, easy welding performance in favor of the golf club head manufacture.

Titanium is a new structural material, it has excellent performance, such as low density (~ 4.5gcm-3), strength and fracture toughness than the ratio, strength and resistance to fatigue crack propagation ability, good low-temperature toughness, corrosion excellent performance, maximum operating temperature titanium alloy for some 550ºC, is expected to reach 700ºC. So it gets increasingly widely used in aviation, aerospace, chemical, shipbuilding and other industrial sectors, is developing rapidly. Light alloy, steel, etc. (σ0.2 / density) versus temperature stronger than titanium than other light metals, steel and nickel alloys, and this advantage can be kept to about 500ºC, so some titanium alloys suitable for manufacture of gas turbine components. Approximately 80% of titanium production for the aviation and aerospace industries. Airframe structural materials such as the US B-1 bomber, the titanium or about 21 percent, mainly for the manufacture of the fuselage, wings, skin and bearing components. Airframe structural materials F-15 fighter, the titanium alloy with a capacity of 7000kg, accounting for about 34% weight of the structure. Boeing 757 aircraft structural parts, titanium or about 5%, with a capacity of 3640 kg. McDonnell Douglas (Mc-Donnell-Dounlas) produced the DC10 aircraft, titanium with a capacity of 5500kg, accounting for more than 10% of the weight of the structure. The amount of titanium in the chemical and general engineering areas: US accounts for about 15% of its production in Europe accounts for about 40%. Due to the excellent corrosion resistance of titanium and its alloys, good mechanical properties, as well as qualified histocompatibility make it for the production of biological materials prosthetic devices.

titanium-based titanium aluminum compound.

Compared with the general titanium alloys, titanium, aluminum, sodium-based compound Ti3Al (α2) and TiAl (γ) intermetallic compounds biggest advantage is a good temperature performance (maximum operating temperatures of 816 and 982 ℃), a strong antioxidant capacity, anti-good creep resistance and light weight (density of only nickel-based superalloy 1/2), these advantages make it the aero engine and aircraft structural parts most competitive materials in the future.
Currently, there are two Ti3Al-based titanium alloy Ti-21Nb-14Al and Ti-24Al-14Nb- # v-0.5Mo start mass production in the United States. Other Ti3Al-based titanium recent development has Ti-24Al-11Nb, Ti25Al-17Nb-1Mo and Ti-25Al-10Nb-3V-1Mo like. TiAl (γ) is in the range of interest of the titanium-based composition of Ti- (46-52) Al- (1-10) M (at.%), Where M is v, Cr, Mn, Nb, Mn, Mo and W, at least one element. Recently, TiAl3 titanium based begun to attract attention, such as Ti-65Al-10Ni alloys

High temperature titanium alloy.

Successfully developed the world's first high-temperature titanium alloy is Ti-6Al-4V, use temperature of 300-350 ℃. Was subsequently developed using a temperature of 400 ℃ IMI550, BT3-1 and other alloys, and the use of a temperature of 450 ~ 500 ℃ of IMI679, IMI685, Ti-6246, Ti-6242 alloy. Has been successfully applied in military and civil aircraft engines in the new high-temperature titanium alloy has a British IMI829, IMI834 alloys; United States of Ti-1100 alloy; Russia BT18Y, BT36 alloy. Table 7 as part of a new national high temperature titanium maximum use temperature [26].
In recent years, the use of foreign fast solidification / powder metallurgy technology, fiber or particle reinforced composite materials developed high temperature titanium alloy titanium alloy as the development direction, so that the use of temperature titanium alloy can be increased to above 650 ℃ [1'27'29'31 ]. American McDonnell Douglas using rapid solidification / powder metallurgy technology Qi successfully developed a high-purity, high density of titanium, its strength at 760 ℃ equivalent strength titanium alloys used in the current room temperature

The physical properties of titanium heat exchanger

Titanium heat exchanger made of high quality titanium tubing. On the physical properties of titanium tube with a light quality, superior mechanical properties, and other advantages. The big strength of titanium, titanium tensile strength of up to 180kg / mm2. Some higher strength steel alloy, but the specific strength of titanium alloy (tensile strength and density ratio) is more than high-quality steel. In addition, titanium has good heat intensity, low-temperature toughness and fracture toughness.

Explosively Formed way titanium steel composite panels and application characteristics

America in the 1960s began to produce titanium steel composite blasting materials, seminars 1980s success with titanium steel sandwich composite dairy law. Blow molding is the use of explosives, blasting high voltage pulse generator load direct role in the cover plate, cover plate so that within a few microseconds are accelerated to speeds of several hundred meters per second, the cover plate from the detonation end sequentially beginning with the substrate skew bump , the two pressure plates occurs bump greatly exceeds the dynamic limits of the metal bow, the occurrence of severe plastic deformation of the speed bump in the data area, accompanied by vigorous heat effect, the two metal plates similar to the bump surface layer of the fluid at the moment have the same action constitute two share movement in the opposite direction of the metal jet. Free bump point located in front of the jet ejection speed is not welded to the space, which washed away the two metals to be linked to form the mask, revealing a clean active surface metallurgy contact form under high pressure.

Advantages of a combination of blasting method is that a wide range of adaptability of information, such as different melting points, a large linear expansion coefficient and hardness of the molded material can be selected to produce a composite data burst. Greatly different linear expansion coefficients, such as titanium and stainless steel can be used to produce a composite sheet forming blasting. Blow-molded composite material selection can be made of two or more layers. Its drawback is the high production safety requirements can not be continuously produced only apply to certain materials.

Titanium steel composite board now has a variety of production methods, such as direct rolling, casting dairy France, blasting rolling method and blasting method. These approaches have been able to use a variety of thickness and width of the output specifications of the composite sheet. Titanium clad steel sheet substrate is generally carbon steel, structural steel or pressure vessel steel, titanium or titanium alloy cladding material, both with high strength, but also has excellent corrosion resistance of titanium, the use of the characteristics of each monomer materials, use a wide scale. Titanium steel composite panels can be made by a variety of hot and cold processing of industrial products, such as tube sheet heat exchanger, head, reactor, the reactor cylinder and containers. Titanium steel composite panels used in demand particularly suitable corrosion resistant equipment, which has been widely used in the manufacture of various metallurgical, chemical and marine industrial equipment.

Titanium in the course of development of China's aviation sector

In the field of aviation, the current consumption of titanium is only 10%, but with the start-up and implementation of China's large aircraft program, the Chinese titanium industry ushered in a dual high-end development of favorable policies and markets. Titanium application in the aviation field will usher in major development. During the "Eleventh Five-Year", China launched a large trunk aircraft project, who tied for civil aircraft industry in 2020 China's long-term plan, one hundred million yuan invested 50 billion -600 major projects development of large aircraft, large aircraft major projects set up by the State Council Leading Group has been completed, "large aircraft demonstration program report", with 13 years to develop its own mainline aircraft, and the establishment of a large trunk aircraft manufacturing company. China now has the ability to develop large trunk aircraft. In addition to the design capacity, in the course of cooperation with McDonnell Douglas MD90 in production, has already started to master the production and management capacity trunk aircraft. From the ARJ-21 start from, to do an exercise for the development of large aircraft.