Application of titanium alloy materials such as titanium rod, titanium wire and titanium plate in construction industry

When there is a corrosive medium in the titanium tube heat exchanger, it is suitable to use composite plates and titanium-lined tube plates. Nowadays, large-scale exchangers are mostly made of integral tube sheets with a thickness of 100mm and integral heads of the same thickness. Since the use of titanium is often associated with strong corrosive media, in order to avoid corrosion, in the structural design of titanium equipment, attention should be paid to:

(1) Avoid gaps and stagnant areas. In order to achieve a complete seal and prevent a gap between the tube and the tube sheet, expansion and sealing welding should be adopted. Regardless of whether it is an all-titanium or composite board, many designers support the use of step welding based on the consideration of weld penetration, but some people think that this will cause greater difficulties in repair welding. The fasteners in the tower should be connected by wedges instead of bolts. The sealing surface of the flange should be covered with asbestos gasket with PTFE film. Under the conditions of high temperature, high pressure and strong corrosion, it is recommended to use titanium reinforced polytetrafluoroethylene winding and T0.2Pd metal pad.

(2) In the conductive medium, avoid contact between titanium and other metals as much as possible. In the structure, a third material with a potential between the two can be used as a transition layer (such as by surfacing) or isolated by insulating materials. When the medium is seawater, a heat exchanger made of titanium tubes filled with different metal tube sheets and rolled up can be used. The premise is that the tube sheet material is compatible with titanium.

(3) The expansion coefficient of titanium is smaller than that of steel. Therefore, thermal stress cracking may occur in the heating equipment of the titanium steel composite structure, and the thermal compensation link should be set in the design.

(4) In some corrosive media with high flow rates and sudden changes in flow rate, titanium equipment and components are prone to erosion, so when the flow rate exceeds 6m/s, an anti-scouring baffle should be installed. In the titanium tube heat exchanger, due to vibration, the contact between the titanium tube and the supporting hole is prone to fracture. Therefore, shock absorption measures should be taken and a PTFE ring can be caulked at the contact between the titanium tube and the supporting hole.

(5) The thermal conductivity of the titanium surface depends to a large extent on the design and process parameters. For the heat exchanger using cold water as the coolant, the available value is 425~550W/(m2·℃); for the heat exchanger using steam or hot water to heat the static liquid, the available value is 800~1450W/(m2·℃) . For the condenser cooled by seawater, when the tube wall thickness is 0.5~1.0mm and the flow velocity is lower than 3.9m/s, the measured data is 54006800W/(m2·℃).
machined titanium round bar     3 Inch Titanium Pipe     titanium powder     grade 5 titanium plate

Nuclear submarine made of titanium rod, titanium wire and titanium plate

Among the titanium materials, the most commonly used industrial pure titanium (TA2 is the most widely used), Ti-6Al-4V (when a certain strength is required), and Ti-0.8Ni-0.3Mo (when there are gaps or in a non-oxidizing medium). When hydrogen absorption and hydrogen embrittlement may occur, especially in the case of weld corrosion and hydrogen absorption, low-iron (<0.05%) titanium materials are required. Titanium heat exchangers, condensers, and related auxiliary equipment have been successfully used for more than 20 years in petrochemical enterprises.

There are many products and complicated processes in the petrochemical industry. Here is an example to introduce the application of titanium:

1. Terephthalic acid is the raw material for synthetic polyester, which is prepared by the p-xylene oxidation method in the industry. No matter high-temperature oxidation or low-temperature oxidation, there is high-temperature corrosion of acetic acid and bromide. In the medium with a temperature higher than 135℃, pitting corrosion of 316L stainless steel will occur after dozens of hours. Therefore, the design specification stipulates that titanium must be used above 135°C. Beijing Petrochemical Plant has introduced a complete set of titanium equipment, including 16 oxidation reactors, solvent dehydration towers, heaters, condensers, and reboilers. Nanjing Yangzi Petrochemical Company has introduced an annual output of 450,000 tons of terephthalic acid equipment, 56 sets of titanium equipment, and a large number of titanium pipeline valves. The oxidation reactor introduced by Shanghai Petrochemical Plant is 32m high, with an upper diameter of 4m, a lower diameter of 5.3m, a volume of 505m, and a weight of 175t. The effect of using titanium material is very good, and the prospect of promotion and application is bright.

2. In the device where ethylene is oxidized to acetaldehyde, acetaldehyde is oxidized to acetic acid, and propylene is oxidized to acetone, the main corrosive medium is a catalyst, except that the raw materials and products are corrosive. Stainless steel corrodes quickly, and only titanium has Good corrosion resistance. As early as 1963, the United States successfully applied titanium in the production of acetaldehyde by oxidation of ethylene. my country's first ethylene oxidation to acetaldehyde plant was put into use in 1976, and the titanium plant has been operating well so far. Foreign titanium-lined reactors are as high as 9.6m, with a diameter of 3m, and there are 11 sets of titanium equipment including heat exchangers, catalyst regeneration towers, and acetaldehyde solution coolers. Since the 1980s in my country, Shanghai and Jilin have introduced foreign complete sets of equipment for the production of acetaldehyde by ethylene oxidation. Many of the equipment and pump valves are made of titanium. Compared with stainless steel, it has obvious advantages and the use effect is very satisfactory.

3. Urea is a high-quality fertilizer and a raw material for petrochemicals. Since the first titanium-lined urea synthesis tower was put into production in 1963, there have been nearly 10,000 equipment in operation all over the world, and practice shows that there is no obvious corrosion in the titanium-lined synthesis tower. The converted corrosion rate of 316L stainless steel is 4.1-4.5 mm/a. Therefore, titanium has better economic benefits than stainless steel. In addition to the titanium-lined urea synthesis tower, CO 2 stripping towers, heat exchangers, mixers and pump valves have been used in China since the 1970s.

4. In the refining of crude oil with high sulfur and high salt content, titanium equipment is ideal. In foreign countries, titanium equipment has been successfully used in many processes such as atmospheric distillation equipment, sewage treatment equipment, desulfurization separation tower condenser, and stripping tower radiator for many years. Our country has also used cast titanium seawater pumps, titanium condensers in catalytic cracking fractionation, cryogenic separation titanium condensers, and porous titanium plates in this system, all of which have been in normal operation for more than ten years.

5. Chlorinated hydrocarbon is one of the largest varieties of the petrochemical industry. Due to the chlorination reaction involved, stainless steel equipment has been difficult to handle. In foreign countries, titanium materials have been used to manufacture methylene chloride rectification towers, trichloroethane heat exchangers, condensation towers and fractionation towers, trichloroethylene condensation towers, perchloroethylene heat exchangers, and polychloride coil heaters. In the production of vinyl chloride in my country, the cooling tower, wastewater stripping tower, and wastewater storage tank tray support frame, connection pipe, flange sealing surface, using Ti-0. 2Pd lining has been used for nearly ten years without corrosion. Titanium pipes, joints, and gas distributors have all been made of titanium for many years.

6. Phenol is an important raw material for the petrochemical industry. It is a new process to obtain phenol and acetone from cumene and cumene peroxide using propylene and benzene in oil and gas refining as raw materials. Foreign countries have adopted titanium equipment more than ten years ago, and this technology is still under development in my country. The old process used benzene sulfonated alkali solution to produce phenol. Our country has adopted a titanium neutralization reactor, titanium coil cooler, ion titanium nitride agitator sleeve, and titanium target, and the effect is very good.

7. Oxidation of acetaldehyde to acetic acid is a common technology in our country. Titanium is now used as a high-boiling material reboiler, first-grade acetic acid tower reboiler and condensing cooler and other equipment. Foreign countries have adopted titanium equipment in rectification towers, fractionation towers, and distillation towers. Especially in the oxidation of lower alkane to produce acetic acid, there are many by-products, with a formic acid content of 8%, which is extremely corrosive. At this time, titanium is used to replace stainless steel, and the effect is very ideal.
T40 Titanium Bar     bending titanium tubing     Sputtering Target     Grade 7 Titanium Plate

Mechanical properties of titanium and titanium alloys

The main measure to eliminate cold barriers or flow marks is to use the correct gating system to prevent two or more metal flows from converging, or turbulent and interrupted flow when liquid titanium is filling the mold. In gravity pouring, it is recommended to use bottom pouring system as much as possible, so as to avoid or reduce cold barriers or flow marks on the surface of castings as much as possible.

In order to obtain castings with a smooth surface and a complete filling, centrifugal casting is usually used. At this time, the flow rate of liquid titanium from the bypass into the cavity is very large, which is prone to strong splashing. It is very difficult to completely avoid cold barriers or flow marks. In this case, more attention should be paid to the process design of the castings, reasonable casting process, correct gating system, avoid reverse metal flow in the cavity, try to eliminate metal splash, and try to increase the molten metal if possible. The pouring temperature.

The influence of the wall thickness of titanium castings on the microhardness of the surface layer (the degree of surface contamination). For castings poured in the same mold, the thicker the casting, the more serious the contamination of the surface layer. For castings with wall thickness (greater than 10mm), it is not advisable to preheat the mold to an excessively high temperature before pouring. Some literature pointed out that when the wall thickness of the casting is below 10mm, the influence of the wall thickness of the casting on the surface roughness of the casting is not very obvious. The contamination layer on the surface of the casting is mainly caused by the interaction between titanium and the mold and the adsorption of a gas on the surface of the mold, of which oxygen is the most harmful.
titanium alloy rod     Gr1 Pure Titanium Pipe     Titanium Planar Target     thin titanium sheet

A feasible method for reducing surface contamination of titanium screws and titanium workpieces

Russia is an international leader in the research and manufacturing technology of building titanium alloy nuclear submarines, and is also the first country to build pressure hulls with titanium alloys. During the peak period, the annual output of titanium alloy plates and pipes for submarines was as high as 10,000 tons, accounting for 1/3 to 1/2 of the annual output of titanium alloy processed materials. Titanium plates for submarine heat exchangers require good thermal conductivity. The shell material is required to have good toughness to resist the shock wave caused by the depth charge explosion. The titanium plate (thick plate) for the submarine shell is produced in St. Petersburg, and the ingot is provided by the Upper Salda Metallurgical Production Joint Company. In terms of the development level of the titanium industry and the scale of use of titanium plates and wires in the shipbuilding industry, Russia is far ahead of all other countries in the world. Because Russia is ahead of competitors such as the United States in the field of ship materials research, its scholars have called on the government to formulate a near-term shipbuilding plan to avoid losing the leading position and development potential it has achieved, and at the same time to ensure that the Russian Navy will continue to lead in the 21st century. In other countries.

Since the 1960s, there have been 4 generations of nuclear submarines developed by Russia. The world’s first K162 all-titanium nuclear submarine was launched in December 1968 and has been in operation for more than 30 years. It has been to various oceans and sea areas and has withstood different loads and loads. Environmental assessment, there has never been any accident. Russia built the first "ALFA" class nuclear submarine in 1970, and continued to build 6 ships from the 1970s to the 1980s. Each of them uses titanium rods, titanium wires, and titanium plates about 3000t. The maximum diving depth is 914m, which is light and fast. .

In the 1980s, six "Typhoon" class nuclear submarines with a capacity of 9000t of titanium rods, titanium wires and titanium plates were manufactured. The first "Typhoon" class nuclear submarine was built in 1980 and commissioned in 1984. Its underwater displacement With a speed of 33800t and an underwater speed of about 27 knots, the "Typhoon" class nuclear submarine is the world's largest submarine. It has a double hull structure. The non-pressure hull is made of high-strength and low-magnetic steel, and the pressure hull is made of titanium alloy. It can carry 20 strategic missiles. The launch of the sixth "Typhoon" submarine was at the end of 1989, and the "Typhoon" series of submarines will be decommissioned at the beginning of the 21st century.

The first submarine in the new series of "The God of the North Wind", which was commissioned in 2003, is the "Yuri Dolgoruky". It is a new fourth-generation submarine, and its combat performance should exceed the existing ones of the same level. All submarines. Its underwater displacement is greater than that of the "Detal" class (11740t), but less than the "Typhoon" class (33800t), and the construction cost requires several trillion rubles.

The "Ohio" missile submarine that the United States entered service in 1980 has an underwater speed of 20n mile/h (knots).
titanium alloy bar     Gr1 Pure Titanium Tube     TiN Sputtering Target     thin titanium plate

Chemical properties of titanium materials such as titanium rods and titanium wires

Whether it is the development of the marine economy or the development of the modern navy, it is necessary to develop a series of marine engineering equipment. Practice has shown that advanced offshore equipment, whether it is deep-sea oil and gas exploration equipment, nuclear submarines, deep submersibles and other equipment, are all titanium-related equipment. Lightweight and corrosion-resistant titanium and titanium alloy materials can be used to achieve high-efficiency offshore equipment. , Long life and high reliability make a major contribution.

At present, the time is ripe to accelerate the development of titanium for marine engineering. my country is already a big country in the world's titanium industry. It has a relatively complete titanium R&D-production-application system, large-scale production capacity and many application technology reserves. It is not only necessary but also feasible to accelerate the development of titanium for marine engineering. Compared with commonly used materials such as steel, stainless steel, copper and aluminum, the most prominent features of titanium are low density, high specific strength, and strong corrosion resistance. At the same time, it is also resistant to seawater erosion, non-magnetic, non-cold brittleness, and high sound permeability. The coefficients and other properties are convenient for forming, casting, and welding, making it widely applicable to various marine engineering.

Titanium can be used in ocean engineering, but there are also some shortcomings and problems worth noting. Titanium alloy materials for marine engineering face many challenges, mainly in five aspects:

1. Titanium production

Due to the high melting point of titanium (1668°C), high resistance to high temperature deformation, and narrow thermal processing temperature zone, it is difficult to produce titanium materials, especially large-size, high-performance titanium materials. Not only a large vacuum melting furnace (vacuum electric arc furnace, electron beam cooling bed furnace, etc.) is required, but also heavy pressure processing equipment (forging press, rolling mill, extruder, etc.) is required. Titanium production unit product investment is huge, up to 300,000 ~ 400,000/ton. The equipment capacity of titanium production is equal to or greater than that of steel of the same specification, and its output and equipment utilization are only a few tenths of it, resulting in high production costs.

2. Product design

Titanium has a high flex-strength ratio (above 0.9), a high welding strength coefficient (above 0.9), and a low modulus of elasticity, thermal conductivity and damping coefficient. Under certain conditions, titanium will have crevice corrosion, contact galvanic corrosion and hydrogen embrittlement. Due to these physical, chemical and mechanical characteristics of titanium, the design of titanium equipment is required to adopt new design specifications and technical specifications (such as safety factor, corrosion margin, fire and explosion prevention measures, structural form, weld form, etc.). Titanium materials have a small damping coefficient (except for TiNi shape memory alloys), and they will vibrate during use. Therefore, anti-vibration and vibration reduction measures must be taken. Titanium has only a few decades of history in the industrial field, there is little design experience, and many issues remain to be explored.

3. Product manufacturing　　

Due to the low modulus of elasticity of titanium, large springback during cold working, low thermal conductivity, easy abrasion and scratches on the surface, etc., it brings certain difficulties to the molding, heat treatment, and machining of titanium parts. Mature technology It takes a long time to explore.

4. Titanium material application

Due to the strong corrosion resistance of titanium, many titanium equipment are "permanent" or semi-permanent equipment, and the equipment assessment cycle is very long, so that the first, second, and third generation engineers and technicians of the equipment user can not fully grasp the application history data of a certain equipment , It is impossible to make a comprehensive and objective evaluation of the use effect of titanium equipment.

5. Material selection concept

It is still difficult for most people to break through the inertial thinking that "titanium is too expensive". In the case of limited investment capacity, it is difficult to use titanium, which is 5-10 times more expensive than hull steel, to replace steel or copper to manufacture offshore equipment. Relatively speaking, the one-time investment of titanium equipment is indeed very large, and the technical and economic advantages of titanium equipment are mainly reflected by the "full life cost", that is, mainly by long-term benefits. Titanium should be expanded in marine engineering, and a lot of work must be done in benefit evaluation and publicity.
titanium hexagon rod     Gr12 Ti-0.3Mo-0.8Ni Titanium Plate     titanium metric screw     F3 Pure Titanium Forging

Surface treatment technology for titanium and titanium alloy materials is widely used in energy conservation and environmental protection

There are generally three process methods for the manufacture of titanium equipment such as titanium coils, titanium heat exchangers, and titanium reboilers: forming method, casting method, and powder metallurgy method.

The molding method can prepare large-scale titanium equipment of any degree of complexity and is the most important process method. The casting method and powder metallurgy method are suitable for equipment and parts with small size and not very complicated shape, but they have the characteristics of short process flow and low cost in mass production. Large-scale titanium equipment generally needs to undergo pressure forming, machining, welding, surface treatment, and other processes. Small single equipment such as titanium pumps, titanium valves, and titanium impellers are often produced by casting. For products with special functions such as titanium filters, powder metallurgy is considered.

The first process of material preparation in the manufacture of titanium equipment is scribing. The purpose of scribing is to draw the boundary line of sheet metal cutting and processing, which will have a great impact on the subsequent assembly and welding procedures. Scribing includes marking the material line, processing line, and position line and inspection line, etc., and marked with the necessary signs. The titanium material can be cut by cutting, punching, cutting (gas cutting, water cutting or plasma cutting, etc.), or cutting. For pipes and bars, mechanical methods such as sewing machines, pipe cutting machines, and grinding wheel cutting machines can be used to cut. Iron ion contamination must be prevented in each process, and mechanical cutting must be used for edge processing of titanium materials.
titanium rod grade 5     Gr2 Pure Titanium Sheet     titanium u bolt     Hollow Titanium Ball

Titanium wire classification standard, application, surface performance treatment

In the chemical industry and other application fields, high requirements are placed on semi-finished products and processed parts of titanium or titanium alloys. Therefore, in the fields of aviation and aerospace, the cost of developing inspection instruments and monitoring devices is particularly high. The price of the parts has a big impact. Titanium alloy has the highest tensile plasticity and can be welded in various ways. It can be used for a long time at a temperature of up to 250 degrees Celsius. It is mainly used to manufacture various structural parts of aircraft and engines that are not stressed. Industrial pure titanium has good plasticity, can form various sheet metal stamping parts in cold state, and has relatively high corrosion resistance. Ti5Al2.5Sn titanium alloy has a moderate room temperature tensile strength (800 degrees Celsius 1000MPa and good welding performance. Compared with industrial pure titanium, the new titanium alloy mainly includes various grades of industrial pure titanium and widely used Ti5Al2.5Sn For titanium alloys, the room temperature tensile strength of industrial pure titanium fluctuates in the range of 350 degrees Celsius and 700 MPa. Ti5Al2.5Sn alloy has a slightly lower plasticity and higher thermal strength, and the long-term working temperature can be as high as 450 degrees Celsius.

With the rapid development of cutting-edge science and technology such as aviation, aerospace, nuclear energy, etc., the requirements for materials are becoming more and more stringent. Not only are the materials used for manufacturing these equipment parts to be corrosion-resistant, wear-resistant, and anti-fretting, but also require high-end resistance. temperature. It is necessary to pay attention to the long-term test, in many places, before the large-scale application of titanium to the chemical industry. Under the test conditions, cooperate to test its service life and material structure. If the lack of safety (immaturity) due to the use of conventional structural data is mostly indicated and the economic benefits are not great, then the first step is to gradually develop titanium and titanium alloys, as well as the development of high-level technology in the field of structural data in recent decades. Various other mature new materials. Therefore, the military sector has developed faster in the application field of titanium and its alloys than in the civilian field.

In many industrial media, rare earth metals and precious metals are often mainly used for stability, or materials such as stainless steel can only reach a certain limit in corrosion resistance. Most application fields use titanium to obtain benefits due to its low density, corrosion resistance and high strength. So far. Moreover, the consumption cost is relatively high, so the application of titanium or titanium alloy can obtain relatively high corrosion resistance. The creep characteristics of hard titanium at temperatures exceeding 150T surpass that of aluminum and its alloys. Considering that compared with other materials, titanium alloys have the advantages of unique creep characteristics under low density conditions. It is found that hard titanium is used in aircraft manufacturing and missile manufacturing. The importance of application. The earliest application of titanium and titanium alloys is the aviation industry. Recently, the aviation industry has become increasingly urgent for high-strength and low-density materials, which greatly promotes the development of titanium manufacturing. In the early 1950s, the United States successfully used titanium in aircraft. At that time, although an E aircraft only used 1% of the structural weight of titanium, it opened up a pioneering approach to the use of titanium in the aviation industry. At present, titanium alloys are widely used as structural materials in many high-speed aircrafts in the world.
Titanium Threaded Rod     Gr5 Ti-6Al-4V Titanium Plate     6al4v titanium plate     Titanium Elbow