Processing characteristics of titanium

In addition to pure titanium, nearly 30 types of titanium alloys have been produced in the world. The most widely used titanium alloys are Ti-6Al-4V, Ti-5Al-2.5Sn, and so on. The industrial method for the production of titanium metal is the Kraul method, and the product is a titanium sponge. The traditional process of making titanium is to melt and cast sponge titanium into ingots, and then process them into titanium. According to this, the main steps of the technological process from mining to making titanium are:

Titanium Ore->Mining->Ore Dressing->Too Concentrated Ore->Enrichment->Titanium-rich Material->Chlorination->Crude TiCl4->Refined->Pure TiCl4->Magnesium Reduction->Sponge Titanium->Melt Casting-> Titanium Ingot -> Processing -> Titanium Material or Titanium Parts In the above steps, if the rutile is obtained by mining, it does not need to be enriched and can be directly chlorinated to obtain crude TiCI4. In addition, the casting operation should be a metallurgical process, but sometimes it is also classified as a processing process.

The processing in the above process refers to plastic processing and casting. Plastic processing methods include forging, extrusion, rolling, stretching and so on. It can process titanium ingots into various sizes of cakes, rings, plates (titanium plates), pipes, bars, profiles and other products, and can also be cast into various shapes of parts and components.

The plastic processing of titanium and titanium alloys has the characteristics of large deformation resistance; normal temperature plasticity difference, high yield limit and strength limit ratio, large rebound, sensitivity to notches, easy to bond with the mold during deformation, and easy to absorb harmful gases when heated, etc. Plastic processing is more difficult than steel and copper.

Therefore, the processing technology of titanium and Titanium Alloy Rectangular Tube must consider these characteristics.

Titanium adopts plastic processing, the size of adding soil is not limited, and it can be mass-produced, but the yield rate is low, and a large amount of scraps and residues are generated during the processing.

Aiming at the above shortcomings of titanium plastic processing, powder metallurgy technology has been developed in recent years. The powder metallurgy process of titanium is the same as ordinary powder metallurgy, except that the sintering must be carried out under a vacuum. It is suitable for the production of large-volume, small-sized parts, and is especially suitable for the production of complex parts. This method requires almost no processing and has a high yield rate. It can not only make full use of titanium waste as raw materials, but also reduce production costs, but it cannot produce large-size grade 5 titanium round rod parts. The powder metallurgy process of titanium is: titanium powder (or titanium alloy powder) -> sieving -> mixing -> press forming -> sintering -> auxiliary processing -> titanium products.

Titanium alloys for large aviation forgings

Titanium alloy has been widely used in the aviation industry due to its high specific strength, specific rigidity, corrosion resistance, and other excellent properties, and it has significant effects on the weight reduction of aircraft structures and the improvement of the service life of parts. Especially for military aircraft, some important structural components such as wing spars, bulkheads, landing gears, etc. are widely processed by titanium alloy forgings, which have high weight, large size, and cross-sectional area.

At present, the main grades of titanium alloys for aviation are TC4, TC18, TC21, TA15, TB6 (Ti 1023 Titanium Thick Plate in the United States), and so on. Among them, TC18 is suitable for manufacturing large forgings due to the highest hardenability and is currently the most widely used in China. Russia developed Ti-55531 titanium alloy on the basis of TC18 alloy based on the demand of civil aircrafts such as Boeing and Airbus by reducing the content of easily segregated element Fe. Ti-55531 has higher strength, superior hardenability, and a wider processing window. It has been used in parts such as A380 aircraft suspension joints and landing gear struts.

The domestic C919 aircraft has also carried out the research and development of domestic materials, and the domestic heavy-duty helicopters are also using this material to develop the central part of the large helicopter hub. The data collected so far show that: Compared with TC21 and TC18, Ti-55531 has higher tensile strength, lower plasticity and fracture toughness, higher fatigue limit, and is suitable for long-life design.

Development and application of titanium alloy materials in bicycle manufacturing

With the change in people's understanding of bicycle functions, especially the increasingly fierce international bicycle competition, bicycle manufacturers continue to seek new materials with lightweight and high strength, so titanium seamless pipe has become their target of attention.

According to the functions of each part of the bicycle, the bicycle can be divided into 13 parts, namely, the body part, the control part, the drive part, the walking part, and the transmission part. Braking part, seat part, loading part, parking part, alarm part, lighting part, accessories and connecting parts. The car body includes the frame, the front car, the front, the suspension, the valve seat and the mudguard. This part accounts for about 27% of the car's weight by its weight. The driving part includes a sprocket, a crankshaft, a pedal, a chain, a flywheel, and a chain box. This part accounts for about 22% of the car's weight. The walking part includes tires, inner Grade 3 Pure Titanium Tube, rims, spokes, and wheels, which account for about 24% of the total weight of the bicycle. It can be seen that the weight of the three parts of the body, the driving part and the walking part account for more than 70% of the total weight of the bicycle.

Therefore, the issue of titanium materialization to reduce the weight of bicycles first started here, and after more than 10 years of development and research, some of the human parts have been made of titanium material.

Surface treatment method of titanium tube

The alloying of the surface of the titanium tube can also be called a kind of coating. Compared with the oxide coating of palladium on titanium, it has the advantages of strong bonding force, wears resistance, and corrosion resistance. Compared with the titanium-palladium alloy, the surface content of palladium is high, which saves the precious metal palladium, reduces the cost, and also has excellent performance.

Aluminizing the surface of the Grade 5 Titanium Tube can reduce the hydrogen absorption tendency of titanium. Mixing 88% alumina, 4% aluminum fluoride, and 8% aluminum powder to coat the titanium workpiece is a good aluminizing condition, the temperature is 810℃. The thickness and structure of the aluminized layer depend on the holding time. Aluminizing by the permeation method, a thin coating about 2 mm thick can be obtained by diffusion in a short time, and the bonding force is good, and the mechanical properties of the substrate are not affected. The coating is mainly composed of titanium oxide phase, which forms a barrier layer that prevents hydrogen penetration very effectively.

After palladium is plated on the titanium tube, it can be heated by different methods to diffuse the palladium-plated layer to the surface area of ​​the titanium tube to form a titanium-palladium alloyed layer on the surface, thereby improving the corrosion resistance. Heating diffusion or laser surface remelting are both feasible in principle. Use a laser to irradiate the titanium surface to quickly melt and condense, which can quickly melt the pre-vacuum-deposited palladium film of 150 microns to form an effective palladium alloy.

The surface treatment of the Titanium Condenser Tubes has many advantages, which can increase the oxidation resistance of the titanium tube and enhance the brightness of the surface of the titanium tube. Different titanium tube surface treatment methods will meet the different performance requirements of titanium tube, which is an important manifestation of the production capacity of titanium tube manufacturers at this stage.

Why hardness requirements are required for titanium screws

The density of titanium alloy is generally about 4.51g/cm3, which is only 60% of steel. Some high-strength titanium alloys exceed the strength of many alloy structural sheets of steel. Therefore, the specific strength (strength/density) of titanium alloy is much greater than that of other metal structural materials.

 It can produce parts with high unit strength, good rigidity and light weight. The aircraft's engine components, skeletons, skins, fasteners and landing gear all use titanium alloys. So when we customize titanium metric screws, how do we choose the material of the screws? In fact, titanium alloys are produced to meet the different needs of the industry.

Because all the screws in the world are used in different environments, the positions used on machine parts are also different, and the hardness, flexibility, thermal conductivity, and wear resistance of the screws required by the machine are also different. Therefore, when customizing the production of screw fasteners for customers, they will always ask where the user’s screws are used and what kind of performance is required?

If hardness is required, then it is recommended to use titanium-cobalt alloy. Titanium-cobalt alloy is generally used to make cutting tools. When selecting the screw material, it must be understood that when the hardness of the screw is high, the titanium screw is easy to break.

The main application of surgical implants and medical titanium plates in orthopedic surgery

The disabled in the world are close to one-twelfth of the world’s population, according to incomplete statistics. There are 60 million physically disabled people and nearly 2 billion dental patients. At present, there are only 35 million surgical implants. The annual joint replacement volume is about 1.5 million, which is far from the actual number of replacements. Therefore, the potential market demand for biomedical materials is huge. As the first choice for Ultra-Thin Titanium Alloy Sheet the demand for medical titanium and titanium alloys will also greatly increase, so it is imperative to increase the research and development of medical titanium plates.

There is no scar on the face. Compared with traditional treatment methods such as small steel plate, steel wire internal fixation, single jaw ligation, and intermaxillary traction, the titanium plate in the treatment of maxillofacial fracture internal fixation has the advantages of simple operation, less damage, and Accurate and reliable anatomical fixation. Except for condyle and zygomatic arch fractures, extraoral incisions are required. For other mandibular fractures, intraoral incisions are often used. It can also avoid damaging the facial nerve.

The problem of intermaxillary traction during Grade 2 Pure Titanium Sheet internal fixation is that intraoperative intermaxillary traction can provide the correct reduction of the fracture end and a good bite-jaw relationship, and can also prevent drilling. Disturbance of the bite-jaw relationship is caused. Except for the cases of combined mandibular fractures, which need to be assisted for 1 week after internal fixation, traction and fixation are generally not required after other fracture fixation operations. Because of the short traction time, it is difficult for the patient to The mandibular joint function has little impact, easy to maintain oral hygiene, can eat, is conducive to nutrition and wound healing of patients, and at the same time greatly reduces the pain of patients compared with the past.

The choice of the fixed position of the titanium plate, and the choice of the appropriate placement position of the titanium splint are considered to be one of the conditions to ensure the success of the titanium plate internal fixation. All mandibular fractures other than condyle fractures were fixed according to Champi ideal line, that is, the mandibular body fracture titanium plate was fixed on the inner flat bone surface of the outer oblique line, that is, between the root of the tooth and the inferior alveolar nerve tube, midline and next to the midline The fracture needs to be fixed with 2 parallel titanium plates. The best place to place the mini-titanium plate for midface fractures should be the orbital rim, the zygomatic alveolar ridge, and the edge of the pear-shaped hole. The screws are placed on the thick bones of the vertical pillars.

Hot workability and industry application of titanium alloy

TC4 titanium alloy is also called Ti-6Al-4V, this type of alloy contains 6% Al and 4% V. TC4 is widely used in titanium alloys. Al is an element that improves the stability of the phase, and V is an element that improves the stability of the β phase. After adding aluminum to pure titanium, aluminum has sufficient solubility in a-Ti. Aluminum is widely distributed in nature, easy to prepare, and relatively cheap. Aluminum is much lighter than titanium. Adding aluminum to titanium reduces the density and increases the specific strength. More importantly, aluminum can effectively solid solutions strengthen while the alloy maintains sufficient plasticity. Aluminum can effectively strengthen the a-phase not only at room temperature but also at high temperatures, improving the thermal strength and working temperature of the titanium alloy. 6al4v titanium round bar with 6% aluminum can work for a long time at 400℃ and maintain high strength. However, only aluminum-containing titanium aluminum alloy (Ti-4Al) will become brittle after long-term heating at 550°C. Therefore, adding an appropriate amount of β-type stabilizing element X to the titanium aluminum alloy will hinder the formation of brittleness, and contains a certain amount of β phase, which improves the hot workability of the alloy and the plasticity of the alloy, and it can also be heat treated ( Such as solid-solution + aging to further improve the strength). The structure of TC4 deformed and annealed is a+β coexistence. The content of the β phase in TC4 is relatively small, accounting for about 10%. TC4 alloy has good overall mechanical properties after being air-cooled (recrystallization annealing) after being kept at 750~800℃ for 1-2h. The structure of the alloy at this time is equiaxed a+β phase.

6al4v titanium bar can usually be solid-solution + aging strengthening heat treatment, such as heating at 913~940℃ for 1h, water quenching +523~550℃ for 3~4h, after air cooling, the strength can be increased by 20%~25%, but the plasticity is slightly declined. However, the current domestic TC4 is mainly used in the annealed state, and it is rarely used in the strengthened heat treatment state. The high-temperature strength of TC4 is greatly improved due to the addition of aluminum.

TC4 titanium alloy is suitable for manufacturing various jet engine compressor blades, impellers, etc. Petroleum machinery parts, ultrasonic molds, ultrasonic welding heads, etc.