Grade 7 (Ti-0.12~0.25Pd) Titanium Tube
Grade 7 (Ti-0.12~0.25Pd) Titanium Tube is a titanium alloy tube with a palladium content of 0.12% - 0.25%, with the following properties:
Physical properties:
Low density: The density is about 4.51g/cm³. This low density makes it light in weight, which has advantages in application scenarios with strict weight requirements, such as in the aerospace field, where it can reduce the overall weight of the aircraft, reduce fuel consumption, and improve flight efficiency; in some mechanical structures that are sensitive to weight, the use of this titanium alloy tube can reduce the load of the structure.
Low thermal conductivity: The thermal conductivity is relatively low, about 21.79W/mK, which means that it has good thermal insulation performance. In some occasions that require heat preservation or insulation, such as high-temperature piping systems, heat exchangers, etc., it can reduce heat transfer, improve energy utilization efficiency, and reduce energy loss.
Moderate expansion coefficient: The thermal expansion coefficient is about 9.7µm/m-°C (20°C to 500°C). When the temperature changes, its dimensional change is relatively small, which is very important for maintaining the dimensional stability of the pipeline system, especially in some working environments with large temperature changes, to ensure the tightness of the pipeline connection and the normal operation of the system.
Mechanical properties:
High strength: It has a high tensile strength, generally not less than 345MPa, and can withstand large loads and stresses. It is suitable for engineering structures and mechanical parts with high strength requirements. For example, in the fields of petrochemicals, marine engineering, etc., it can withstand high pressure and high stress working conditions to ensure the safety and reliability of the pipeline system.
Good toughness and plasticity: The elongation is not less than 20%, with good toughness and plasticity, and can withstand certain deformation without breaking, which is very important for the impact and vibration resistance of the pipeline during installation, processing and use. In some complex working conditions, such as earthquake-prone areas and places with large mechanical vibrations, this titanium alloy pipe can maintain good performance.
Higher elastic modulus: The elastic modulus is about 112GPa, with a higher elastic modulus, which can quickly recover to its original state after being stressed, and maintain the shape and dimensional stability of the pipeline, which is of great significance for the long-term use and repeated loading of the pipeline system.
Corrosion resistance:
Oxidation resistance: In an oxidizing environment, a dense oxide film will form on the surface of the titanium alloy tube, which can prevent oxygen from further corroding the internal metal, making it have good oxidation resistance. Therefore, in the air or in a medium containing oxygen, the titanium alloy tube can maintain stable performance and is not easily oxidized and corroded.
Reduction resistance: Due to the addition of 0.12% - 0.25% of palladium, its corrosion resistance has been significantly improved in reducing media, such as certain acid solutions, salt solutions, etc. For example, in the chemical industry, it is often exposed to various corrosive media. This titanium alloy tube can effectively resist the erosion of these media and extend its service life.
Resistance to crevice corrosion: It has good resistance to crevice corrosion. In some structures with crevice or narrow space, it can effectively prevent the occurrence of corrosion and improve the reliability and service life of the pipeline system.
Welding performance: It has good welding performance and can be welded by various welding methods, such as tungsten inert gas shielded welding (TIG), metal inert gas shielded welding (MIG), etc. The weld after welding has high strength and good sealing, which can meet the welding requirements of various pipeline systems.
Biocompatibility (in specific application scenarios): In some biomedical applications, such as medical devices, human implants, etc., the titanium alloy tube has good biocompatibility and will not produce adverse reactions after contact with human tissues and body fluids.
Processing performance: It has good processing performance and can be made into pipes of various shapes and sizes through rolling, stretching, bending and other processing methods to meet the needs of different application scenarios. At the same time, the surface quality after processing is good, which can ensure the sealing and connection accuracy of the pipeline.
What are the application fields of titanium alloy Grade 7 pipes?
Titanium alloy Grade 7 pipes have a wide range of applications, mainly including the following aspects:
Chemical industry:
Since titanium alloy Grade 7 pipes have extremely strong corrosion resistance, especially to acid corrosion, they can be used to transport various corrosive media in chemical production, such as acids, alkalis, and salt solutions. For example, in the production equipment for manufacturing strong acids such as sulfuric acid, hydrochloric acid, and nitric acid, titanium alloy Grade 7 pipes can be used as delivery pipelines to ensure the safety and stability of the production process.
This pipe is also used in heat exchangers of chemical equipment. Because of its relatively low thermal conductivity, it can reduce heat transfer losses, while being able to withstand complex working conditions such as high temperature and high pressure in the chemical production process.
Oil and gas field:
In the process of oil extraction, oil and gas fields containing corrosive gases such as hydrogen sulfide and carbon dioxide are often encountered. Titanium alloy Grade 7 pipes can resist the erosion of these corrosive gases and can be used for oil well casings, oil pipes, delivery pipelines, etc., to extend the service life of oil and gas extraction equipment.
In the process of natural gas transportation and storage, this pipe can also be used to manufacture pipeline and storage tank components to ensure the safe transportation and storage of natural gas.
Aerospace:
The aerospace field has extremely high requirements for materials, requiring materials to have lightweight, high strength, high temperature resistance, corrosion resistance and other characteristics. Titanium alloy Grade 7 pipes have low density and light weight, which can effectively reduce the weight of aircraft and improve the fuel efficiency and flight performance of aircraft. For example, in the hydraulic system, fuel system, cooling system and other parts of the aircraft, the pipe can be used as a delivery pipeline.
In the manufacture of spacecraft, titanium alloy Grade 7 pipes can also be used to manufacture various structural parts and piping systems, such as propulsion systems and life support systems of spacecraft.
Medical field:
In terms of medical devices, titanium alloy Grade 7 pipes can be used to manufacture implants such as artificial joints, bone nails, bone plates, as well as surgical instruments, medical equipment pipes and components due to their good biocompatibility and corrosion resistance.
In the manufacture of medical equipment, such as dialysis machines, infusion pumps, etc., the pipe can be used to manufacture pipelines for transporting liquids and gases to ensure the normal operation of medical equipment.
Marine engineering field:
The marine environment is highly corrosive. Titanium alloy Grade 7 pipes can resist the erosion of seawater, sea breeze, sea fog, etc., and can be used to manufacture marine platform structural parts, piping systems, seawater desalination equipment, etc. For example, in the seawater cooling system of the marine platform, the pipe can be used as a cooling water pipe to ensure the normal operation of the cooling system.
In shipbuilding, titanium alloy Grade 7 pipes can be used to manufacture ship exhaust pipes, seawater pipes, ventilation pipes, etc., to improve the service life and safety of the ship.
Electronic field:
In the manufacture of electronic equipment, titanium alloy Grade 7 pipes can be used to manufacture parts of semiconductor equipment, such as reaction chambers, pipes, valves, etc. Because the pipe has good corrosion resistance and high temperature strength, it can meet the high purity, high temperature, high pressure and other requirements in the semiconductor manufacturing process.
In electronic communication equipment, the pipe can be used to manufacture antennas, filters and other components, using its good conductivity and mechanical properties to improve the performance and reliability of electronic communication equipment.
Processing technology of titanium alloy Grade 7 tube
The processing technology of titanium alloy Grade 7 tube mainly includes the following:
Tube preparation:
Drilling extrusion method: This is a commonly used tube preparation method. This method has a large deformation, can refine the grains, and the wall thickness uniformity of the tube is good, and thinner tubes can be prepared. In the extrusion process, glass lubrication or sheath lubrication is usually required. However, the glass lubrication extrusion titanium tube process is not yet mature in my country, and the selection of a suitable glass lubricant is the key; although sheath lubrication can obtain a better tube surface, the sheath material consumption is large, and the acid consumption is high when removing the sheath, which is easy to cause environmental pollution, and there are many auxiliary processes and a large workload.
Plate (strip) welding method: The plate or strip is made into a tube by welding. This production method is not suitable for the production of products with many specifications and small batches. The weld is a relatively weak link, and the weld cleaning is difficult. However, it has the advantages of high production efficiency, low cost, relatively uniform wall thickness, good inner surface quality, the ability to produce large-diameter pipes, and simple equipment.
Oblique rolling piercing method: This method is also used in the production of titanium alloy tube billets. It has low metal consumption, low equipment investment, no need for cladding and lubrication, no environmental pollution, low mold consumption, high yield rate, and low processing cost. However, this production method is not flexible enough, the product is relatively single, and thin-walled tube billets cannot be prepared, and the length of the obtained tube billets is limited. Oblique rolling piercing is divided into two-roll oblique rolling piercing method and three-roll oblique rolling piercing method. The three-roll oblique rolling piercing method can produce tube billets with high dimensional accuracy and good internal and external surface quality. It can also produce thin-walled tube billets with a diameter and wall thickness ratio greater than 10, and has high production efficiency.
Rolling process:
Hot rolling: The tube billet is heated to a higher temperature (generally higher than the recrystallization temperature) and then rolled. Hot rolling can improve the processing properties of the material, reduce work hardening, and improve the plasticity and toughness of the tube. For titanium alloy Grade 7 tubes, hot rolling can achieve better forming effects and dimensional accuracy, but it is necessary to strictly control parameters such as heating temperature and rolling speed to avoid problems such as surface oxidation and overheating of the tube.
Cold rolling: Rolling the tube blank at room temperature. Cold rolling can improve the strength and hardness of the tube, improve the surface quality and dimensional accuracy. However, the deformation resistance of cold rolling is large, and the requirements for equipment and molds are high. During the cold rolling process, multiple intermediate annealings are required to eliminate work hardening and ensure the subsequent processing performance of the tube.
Heat treatment: Heat treatment is an important process to improve the performance of titanium alloy Grade 7 tubes. Common heat treatment methods include annealing, quenching and aging.
Annealing: The main purpose is to eliminate processing stress, reduce hardness, improve plasticity and toughness, and provide good performance for subsequent processing and use. The annealing temperature and time need to be determined according to the specific composition, size and processing technology of the tube.
Quenching and aging: The strength and hardness of the tube can be further improved, but the operation process is relatively complicated, and parameters such as heating and cooling speed need to be precisely controlled to obtain ideal performance.
Surface treatment:
Polishing: Remove the oxide scale, oil stains and impurities on the surface of the tube through mechanical polishing or chemical polishing, improve the surface finish and improve the appearance quality.
Pickling: Use acid solution to clean the surface of the pipe, remove surface oxides and rust, etc., to improve the corrosion resistance and surface quality of the pipe.
Sandblasting: Use high-speed sprayed sand to treat the surface of the pipe to remove surface impurities and oil stains, increase surface roughness, and improve the adhesion of the coating or plating.
Welding: If the titanium alloy Grade 7 pipe needs to be connected into a longer pipe or a complex structure, welding is required. The main welding methods are tungsten inert gas shielded welding (TIG welding), melt inert gas shielded welding (MIG welding), etc. When welding, it is necessary to select appropriate welding materials and welding parameters to ensure the quality and performance of the welded joint.
Quality inspection: During the processing, the dimensional accuracy, surface quality, mechanical properties, chemical composition, etc. of the titanium alloy Grade 7 pipe need to be strictly inspected and controlled. Commonly used inspection methods include ultrasonic inspection, X-ray inspection, eddy current inspection, water pressure test, etc.
What are the specific application cases of titanium alloy Grade 7 pipes in the chemical industry?
Titanium alloy Grade 7 pipes have the following specific application cases in the chemical industry:
Corrosive media transportation pipelines:
In chemical production environments with high sulfur and salt content, titanium alloy Grade 7 pipes can be used to transport various corrosive media generated during crude oil refining, such as sulfur-containing sewage, salt-containing wastewater, etc. Due to its strong tolerance to sulfur and salt, it can ensure the long-term stable operation of the pipeline system and reduce the risk of leakage and maintenance costs caused by pipeline corrosion.
In the chemical process of producing chlorinated hydrocarbons, ordinary stainless steel equipment is difficult to handle due to the chlorination reaction involved. Titanium alloy Grade 7 pipes can be used as transportation pipelines in the production of chlorinated hydrocarbons such as dichloromethane, trichloroethane, trichloroethylene, and perchloroethylene. They can resist the corrosion of chlorides and ensure the safety and efficiency of the production process.
Heat exchanger components: Heat exchange is often required in chemical production. Titanium alloy Grade 7 pipes can be used to manufacture heat exchanger pipes or heat exchange elements due to their good thermal conductivity and corrosion resistance. For example, in some processes that require heat exchange under high temperature, high pressure and corrosive media conditions, such as the waste heat recovery system of some chemical reactions, the pipe can effectively transfer heat while ensuring the long-term reliable operation of the equipment.
Lining or pipe accessories of reaction vessels:
In the process of phenol production, the new process of obtaining phenol and acetone from isopropylbenzene and isopropylbenzene peroxide is still in the development stage in my country, but titanium equipment has long been used abroad. When the old process used benzene sulfonated alkaline solution to produce phenol, titanium materials similar to titanium alloy Grade 7 were used to make the lining of the neutralization reactor, coil cooler and agitator sleeve, etc. Titanium alloy Grade 7 pipes can also be used as linings or pipe accessories in similar reaction vessels, which can resist the corrosion of the medium in the phenol production process.
In the devices of acetaldehyde oxidation to acetic acid, ethylene oxidation to acetaldehyde, propylene oxidation to acetone, etc., in addition to the raw materials and products being corrosive to a certain extent, the main corrosive medium is the catalyst, in which ordinary stainless steel corrodes very quickly, while titanium alloy Grade 7 tubes have good corrosion resistance and can be used for the manufacture of various equipment such as high-boiling material reboilers, first-grade acetic acid tower reboilers, condenser coolers, etc. in these devices.
Storage equipment components: During the storage of chemical products, some chemical products are corrosive, and corrosion-resistant materials are required to manufacture storage equipment components. Titanium alloy Grade 7 tubes can be used to manufacture pipes, joints, valves and other components of storage tanks to ensure the sealing and corrosion resistance of storage equipment and ensure the safe storage of chemical products. For example, in storage tanks for highly corrosive chemical products such as strong acids and alkalis, components made of this pipe can effectively prevent leakage and corrosion.
Internal components of towers: In tower equipment such as distillation towers, fractionation towers, and distillation towers in chemical production, titanium alloy Grade 7 tubes can be used as internal components such as tower plate support frames and gas distributors. During the operation of the tower, these components need to withstand the erosion of corrosive media and complex working conditions such as high temperature and high pressure. The excellent performance of this pipe can meet these requirements and ensure the normal operation and separation effect of the tower.
