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.

Application and status quo of lightweight automotive titanium alloy materials

Studies have shown that for every 0.1t reduction of a car, it can save up to 0.6L/100km of fuel and reduce carbon dioxide emissions by 11g/100km. A large number of studies have proved that lightweighting of cars is important for reducing fuel consumption of fuel vehicles and meeting energy-saving and environmental protection requirements. effect. At the same time, for new energy vehicles, lightweight vehicles can not only save energy, but also increase the vehicle's cruising range and extend battery life under the same battery capacity. It can be seen that the lightweight of electric vehicles also plays an important role in improving the performance of electric vehicles. In addition, reducing the mass of the car can also reduce the burden of the suspension system, reduce the inertia of the car, and protect the car.

The all-titanium car was first developed by the American General Company in 1956 as the "Firebird II" type car. However, due to the high price of titanium and titanium alloys, the application in the automotive field has been limited. In the 1950s, Japan began to develop titanium and titanium alloy auto parts. In the 1960s, titanium was used in racing engines. It was not until the end of the 20th century that titanium and titanium alloys were widely used with the development of luxury cars. With the emergence and development of titanium alloys, titanium alloy tube have begun to be widely used in the manufacture of ordinary automobiles.

Studies have confirmed that 20kg steel automotive power valve parts have the same effect as 0.8kg titanium alloy parts, but their quality is reduced by 96%. Using titanium alloys to make automobile engine valves can reduce weight by 30% to 40% and increase the maximum speed. For the shock absorption system, studies have shown that it is feasible in many aspects to completely replace the original steel spring with a titanium alloy spring, which can reduce the weight by 43.3%.

Titanium and titanium alloys are commonly used in exhaust systems. Using titanium mufflers to replace stainless steel mufflers can reduce weight by about 40%. Chevrolet Corvette Z06 successfully realized this replacement, ensuring that the quality of the system is unchanged. Lighter, faster and save fuel. Studies have also shown that if all the traditional parts in a 1500kg mid-size car are replaced with titanium alloy parts, the weight of the vehicle will be reduced by about 500kg, which can also greatly reduce fuel consumption.

At present, my country has the ability to produce titanium and Titanium Capillary Tube, but due to the high price of titanium alloys and sensitivity to process parameters, the application of titanium alloys in auto parts has been restricted. Titanium alloys have poor fluidity and casting defects are easy to form in castings. Therefore, the equipment and conditions required for titanium alloy casting and processing are relatively high. This is one of the important reasons why titanium alloy parts are not favored by automobile manufacturers. With the rapid improvement of my country's scientific and technological level, the research and development of titanium and titanium alloys has attracted much attention, which will inevitably make titanium alloys develop towards low cost and high quality.

Pipe cutting and groove processing of titanium pipes!

As the application fields of titanium tubes continue to expand, so does the amount used. Our titanium pipes have been applied in construction, in order to make the construction more scientific to provide users with high-performance titanium pipes.

The research on refractory materials for casting molds has always been linked to the crucible materials for smelting titanium tubes and titanium alloy tubes. Based on dynamics, the crucible material has to be in contact with the titanium liquid for a long time during smelting, and the titanium liquid is in contact with the titanium liquid for a long time. The contact time of the holding material is much shorter, so the usable crucible material can be used as the casting material of the Grade 9 Ti3Al2.5V Titanium Tube

The materials that have been studied include carbides, nitrides, borides, sulfides, oxides, rare earth oxides, fluorides, oxyfluorides, sulfur oxides, and refractory metals such as W and Mo. Only a few materials have high chemical stability to titanium liquid, including ThO2, some rare earth oxides, TaB2, Npc, some rare earth sulfides and some rare earth oxyfluorides.

Pipe cutting and bevel processing of titanium pipes; pipe cutting and bevel processing should be carried out by mechanical processing methods in a special workplace. Use clean water with non-polluting media for cooling during processing to prevent oxidation. Processing tools should be dedicated and kept clean to prevent iron pollution. The processed nozzle should ensure that the surface is smooth and free of defects such as cracks and heavy leather. The maximum inclination of the incision plane does not exceed 1% of the pipe diameter.

Surface cleaning: Use a steel wire brush made of austenitic stainless steel to remove scale, paint, dirt, dust, and debris that can react with titanium welded tube on all welding surfaces of the titanium pipe and within 100mm near the groove. Use a grinding wheel to trim the machined surface to remove flashes, burrs, convexities and other defects.

Align and clamp the titanium pipe and fittings. The axis should not be offset, the gap should be uniform, and the titanium pipe should be prevented from being damaged and contaminated during assembly. Avoid forced pairing. Tack welding adopts the same welding process as formal welding.

Titanium tube degreasing treatment: Use celluloid sponge dipped in sulfur-free ethanol or sulfur-free acetone to degrease all the welding surfaces and the vicinity of the groove within 50mm, and there should be no residue on the surface after treatment. Welding: It should be carried out under the conditions specified in the relevant standards.

Causes of black bar defects in the rolling process of TC4 titanium rods!

TC4 (Ti-6Al-4V) is a Martens a/3-type two-phase titanium alloy with good comprehensive properties, and its service temperature can reach 450. It is widely used in important structural parts of the aviation industry, such as wing blades, aero engine discs, etc. Because the TC4 titanium rod is a two-phase titanium alloy, if the composition of the microscopic area is not uniform, it will inevitably lead to abnormal macrostructure and microstructure, resulting in a significant difference between the hardness of the abnormal area and the normal area, and the overall performance of the material is uneven. Causes fatigue crack sources, brings great hidden dangers to the safety of parts, and reduces the service life of the alloy. Aiming at the black streak defect found in the low-power inspection of a TC4 titanium alloy bar product, in order to accurately determine the defect type, a metallographic microscope was used to observe the metallographic structure and determine the abnormal area of ​​the metallographic structure. Then, a scanning electron microscope was used to analyze the chemical segregation defects of molybdenum-rich and aluminum-poor areas in the black stripe area. Through the microhardness test, it is determined that the component segregation in the black stripe region is non-brittle segregation.

The experimental results show that the composition segregation and type of TC4 titanium alloy can be effectively determined according to the above method. And it is determined that this type of defect will not affect the use and can be delivered after removal. Such defects can be reduced or eliminated by controlling the selection of raw materials for titanium alloy ingots, material mixing, electrode preparation and voltage and current during smelting. The segregation of Grade 1 Titanium Bar can be divided into hard segregation (hardness higher than normal zone, also called brittle segregation) and soft segregation (hardness lower than normal zone, also called non-brittle segregation) according to the difference between the hardness of segregation site and normal zone. If there is only non-brittle segregation in the product, and all properties meet the requirements of the product standard, the product can still be delivered for use after the segregation is eliminated. Fragile segregation is not allowed to be delivered after removal, and should be discarded in batches.

A. For the black streak defects of titanium rectangular rod found by visual inspection, the structure is observed through a metallographic microscope, the defect area is not much different from the normal area, and the defect type cannot be judged; in addition, the chemical composition of the defect area of ​​the titanium rod is analyzed by scanning electron microscope. It is found that the defect area is the segregation of chemical elements rich in heavy and poor in aluminum. Finally, combined with the microhardness test, it is determined that the segregation type of TC4 titanium rod is the non-brittle segregation of rich aluminum and poor aluminum. Through microstructure observation, micro-area composition analysis and microhardness test, the composition segregation and type of TC4 titanium alloy can be effectively determined.

B. The segregation in the TC4 titanium alloy bar is a non-brittle segregation of rich and poor aluminum, which does not affect the use and can be continuously transported after cutting; by controlling the selection of raw materials, mixing and electrode preparation parameters, as well as the voltage and current during the smelting process, it can be Reduce or eliminate such defects.

How to deal with surface problems with titanium wire mesh

Titanium wire mesh is difficult to be corroded due to its special metallographic arrangement and surface passivation film, making it difficult to chemically react with the medium under normal conditions, but it is not impossible to be corroded under any conditions. Titanium wire processing is in the presence of corrosive media and inducements (such as scratches, splashes, cutting slag, etc.). Titanium mesh can also be corroded by slow chemical and electrochemical reactions with corrosive media.

And under certain conditions, the corrosion rate is appropriately fast and rust phenomenon occurs, especially pitting corrosion and crevice corrosion. Therefore, during the processing operation of the titanium wire mesh, all useful methods should be adopted to prevent the corrosion conditions and inducements. happened. In fact, many rust conditions and inducements (such as scratches, splashes, cutting slag, etc.) also have obvious adverse effects on the appearance quality of titanium wire mesh, and should and must be overcome.

How to deal with the appearance of titanium wire mesh? Commonly used titanium wire mesh surface treatment skills have the following treatment methods: Titanium wire mesh surface natural whitening treatment: during the processing of titanium mesh, black oxidation occurs through coiling, binding, welding, or artificial surface fire heating. Skin. However, this method is expensive, pollutes the environment, harmful to the human body, and highly corrosive, and is gradually being screened.

Titanium wire mesh surface mirror bright treatment method: according to the messiness of titanium mesh products and user requirements, mechanical polishing, chemical polishing, electrochemical polishing and other methods can be selected to achieve the mirror luster. Gr5 Ti-6Al-4V Titanium Wire surface color treatment: titanium mesh The color not only imparts various colors to the titanium mesh products, but also adds the variety of colors to the products, and improves the wear resistance and corrosion resistance of the products.

How many methods are commonly used for cutting?

Before the titanium plate is processed into shape, the material must be cut first. Titanium plate blanking also adopts conventional sawing, milling, punching and shearing methods. Due to the high strength of Ultra-Thin Titanium Alloy Sheet, it is different from aluminum alloy blanking.

Band saw. Band saw processing efficiency is high, production preparation is convenient, but it is not suitable for processing too thin materials. It is often used for cutting titanium plates with a thickness of more than 3 mm. This method does not produce edge cracks. The disadvantage is that there are burrs, which must be polished after cutting. At present, it is mostly used for trimming, trimming and end trimming processes.

Band saw cutting can be divided into three categories: friction type, semi-friction type and ordinary band saw. When the friction band saw is working, due to the high linear speed, severe friction occurs between the saw blade and the workpiece, and the temperature in the cutting zone is very high, thus reducing the cutting resistance of the material, improving the machinability and high efficiency.

The belt used for sawing titanium should have a rigid structure and have enough power to maintain a constant speed during sawing; it should be able to feed automatically, tension the band saw and provide sufficient coolant. With ordinary high-speed steel band saws, the edge can be maintained and stable results can be obtained. Saw blades with tungsten carbide blades are used for cutting particularly thick materials, which can reduce the height of burrs and the depth affected by heat.

Milling. Use a milling cutter to mill a stack of Grade 5 Ti-6Al-4V Titanium Sheets to the desired shape, and the milling head moves along the milling template, or use a large CNC sheet metal milling machine for automatic milling. For stretched edges such as concave curves or flanging, the waist is polished before forming to prevent cracks.

Cut. Manufacturing straight-line shape wool or parts can be cut on the gantry shearing machine. If an ordinary shearing machine is used, carefully check whether the equipment can shear the titanium plate. Titanium alloy plates with a thickness of less than 35 mm can already be cut to the required size under production conditions. If necessary measures are taken to avoid slipping during cutting, thicker plates can also be cut. In order to prevent slippage, a higher clamping pressure is required. On the edge of the sheared titanium plate, especially for thicker titanium plates, the linear deviation is 0.25-0.50 mm. This deviation is usually caused by insufficient shear blade rigidity. Switching to a thicker blade can sometimes overcome this defect. If you modify the stopper device, and use digital display, fine-tuning and other technologies, the cutting accuracy can also be improved. The crack depth on the edge of the titanium plate does not exceed 0.4 mm, which can be removed by grinding wheel grinding and filing. If the shearing will cause cracks in the key parts of the part, a cutting method such as a band saw should be considered. When cutting materials with gantry shears, the minimum gap between the single sides of the scissors is 2-3% of the material thickness, the cutting angle is 75°-85°, the relief angle is 2°-3°, and the inclination angle of the blade on the oblique blade shearing bed is 2 degrees-5 degrees.

Ordinary rolling shear equipment can also be used for cutting. Circular shears can cut contour lines with a large radius of curvature (the minimum radius is about 250 mm). This method is used for titanium plates with a thickness of less than 2.5 mm. The current vibrating shears are only suitable for cutting titanium plates with a thickness of about 2 mm, and the edges of the cut wool must be filed or ground, leaving a file repair margin of more than 0.25 mm. For thin materials (thickness <0.8 mm), when the quantity is not large, you can also use lever type manual shears or hand-cut materials.

Die cut. Generally, the wool material of the required shape is punched out on the punching machine at one time. Generally, for wool with a simple shape, the maximum blanking thickness is about 3 mm. The titanium plate blanking die should have sufficient rigidity, and the upper and lower die should be kept in an accurate relative position with guide posts. When manufacturing various flat parts or various shapes of wool, the minimum size of the punching hole of the titanium plate and the minimum radius of the connecting edge of the punching parts should meet the requirements.

In addition, you can also use a punching and shearing machine to cut the material. When processing pure titanium plates, use a small die to punch out crescent-shaped incisions according to the template and connect them, so as to cut out the burrs of the parts, and then repair the key edges. The edge quality and accuracy are not as good as the die. Blanking is not efficient. The advantage of punching and shearing processing is that the production preparation cycle is short, and it is often used for small batch production.