Application of titanium alloy materials in petroleum refining

With the development of industrial modernization, titanium is being widely used as a new metal material. In the petrochemical industry, in general, industrial pure titanium is mainly used to manufacture equipment with high corrosion resistance and high strength; titanium targets, grade 5 titanium round rod molybdenum nickel alloys are used to manufacture equipment used in low oxygen, low pH, and high-temperature chloride environments. Application practice has proved that titanium and titanium alloys are irreplaceable metal structural materials in the development of the petrochemical industry.

Since titanium and titanium alloys have good processing performance and welding performance, they can ensure the manufacturing quality of equipment. Therefore, titanium equipment used in the petrochemical industry has a wide range of materials, mainly titanium plates, titanium strips, titanium tubes, titanium Bars, titanium forgings, castings, titanium composites, etc.

Titanium is an active metal with a strong affinity for oxygen. There is a non-porous and dense oxide film on its surface, which protects the titanium matrix from being corroded in many corrosive media. In the air and any other environment containing moisture and oxygen, when the oxide film is damaged, the titanium surface can immediately form a new film and repair itself. It is precise because of the corrosion resistance of titanium and titanium alloys that titanium can be Completely resistant to corrosion by natural freshwater, semi-alkali water, and saltwater. In the exploitation of sour oil fields and sour gas fields, and in the process of petrochemical production, titanium is highly resistant to a variety of corrosive compounds such as hydrogen sulfide, sulfur dioxide, ammonia, hydrides, alkalis, and various hydrocarbons found in refineries. All have excellent corrosion resistance. In many refineries, titanium heat exchangers have also shown excellent resistance to abrasion corrosion and cavitation in sour water strippers.

Titanium is completely resistant to corrosion by distilled water and fresh water above 260°C. Industrial pure titanium has been successfully used in chloride media above 260°C. In high-temperature seawater, salt water, high-temperature wet chlorine gas and other high-temperature chlorides with higher than normal concentration, titanium-titanium phase nickel alloy or titanium alloy is used in occasions where industrial pure titanium is prone to local crevice or sediment corrosion.

The equipment used in oil extraction and refining is mainly subject to strong corrosion by atmospheric chlorides such as magnesium chloride, sodium chloride, calcium chloride, and hydrogen sulfide, especially the hydrogen chloride formed when the hydrolysis of the compound is present. Corrosive. Therefore, the atmospheric distillation units used in oil refineries, especially the tower top and tower top condensers, oil and gas coolers and other equipment, transport sea water pumps, valves and pipes polluted by sulfide and ammonia, etc., have been used in many refineries at home and abroad. Titanium heat exchangers, titanium pumps, valves, titanium piping replace these equipment traditionally made of carbon steel, BIO, B30 copper-nickel alloy, Monel, etc.

The advantages of titanium heat exchangers are: ① Corrosion resistance, and its service life is expected to be more than 10 years; ② It is not easy to produce scaling, and the heat transfer efficiency is high; ③ It is not easy to leak; Stop phenomenon; ⑤ Reduce the consumption of corrosion inhibitors; ⑥ Reduce the pollution to the labor environment; ⑦ Improve the quality and output of products.

Development and application market of low alloy titanium coil

Due to the late start of the development of titanium coil strip products in my country, construction was not started until the national "Eleventh Five-Year Plan" period of this century. So far, the key technologies for the production of low-alloy titanium coils are still in the hands of several large titanium coil manufacturers abroad. A domestic enterprise has only begun to conduct in-depth research in recent years and has made preliminary progress. However, the domestic low-alloy titanium coil still needs to be imported in large quantities every year, and its price and demand are controlled by others, so as to suppress and stifle the production of domestic low-alloy titanium coil, so as to achieve the purpose of exporting titanium processed products to China and monopolizing the market.

Titanium alloy coils are mainly used in high-tech fields such as aircraft, spacecraft, submarines, nuclear power plants, medical care, high-end racing cars, and civil fields such as metallurgy, chemical industry, and decoration.

At present, a number of complete titanium coil production lines have been built in China, and they have begun to take shape. The equipment strength has far exceeded that of similar foreign manufacturers. In November 2008, with the successful trial production of domestic cold-rolled titanium coils, a complete production chain from sponge titanium, smelting, forging, rolling, finishing, and deep processing was formed. The production technology of titanium coils has been perfected day by day, and a lot of data and experience have been accumulated for the production of low-alloy wide-width titanium coils.

Due to its excellent compatibility with the human body, titanium has been the preferred material in the medical industry. With the development of the tape market, the medical industry, which previously relied on sheet production to provide raw materials, began to prefer tape production instead, mainly because of the high precision and high consistency of tape production, which can fully guarantee the environment in which the human body is used. Safety, but at the same time, it also puts forward slightly higher strength index requirements, which also promotes the potential of the low alloy market.

In recent years, due to the promotion of titanium for construction and titanium for kitchen utensils, the use of titanium in the civilian market has gradually been accepted by people. Everyone has begun to take the proportion of titanium in life as strength of corporate publicity. In emerging markets such as mobile phone cases, laptops, business card holders, and even business cards, titanium has gradually become a propaganda tool and a carrier of information transmission.

The titanium powder in the titanium coil has the following properties:

1. Relative density

Among the commonly used white pigments, the relative density of titanium dioxide is small. Among the white pigments of the same quality, titanium dioxide has a large surface area and a high pigment volume.

2. Melting point and boiling point

Since the anatase type transforms into a rutile type at high temperatures, the melting point and boiling point of anatase titanium dioxide do not actually exist. Only rutile titanium dioxide has a melting point and boiling point. The melting point of rutile titanium dioxide is 1850 ° C, the melting point in air is (1830 ± 15) ° C, and the melting point in oxygen-rich is 1879 ° C. The melting point is related to the purity of titanium dioxide. The boiling point of rutile titanium hydrogenate powder is (3200±300)°C, and titanium dioxide is slightly volatile at this high temperature.

3. Dielectric constant

Titanium dioxide has excellent electrical properties due to its high dielectric constant. When determining some physical properties of titanium dioxide, the crystallographic direction of titanium dioxide crystals should be considered. The dielectric constant of anatase titanium dioxide is relatively low, only 48.

4. Conductivity

The titanium powder in the titanium coil has the properties of a semiconductor, its electrical conductivity increases rapidly with the increase of temperature, and it is also quite sensitive to less oxygen. The dielectric constant and semiconductor properties of rutile titanium dioxide are very important to the electronics industry, and these properties can be used to produce electronic components such as ceramic capacitors.

5. Hardness

According to the Mohs hardness scale of 10 points, the rutile type titanium dioxide is 6-6.5, and the anatase type titanium dioxide is 5.5-6.0. Therefore, in the chemical fiber extinction, the anatase type is used to prevent the wear of the spinneret holes.

The titanium coil is mainly used for heating and cooling the container, and its fixing methods are divided into two types: detachable and non-detachable, which depends on the medium of the material and the corrosion of the titanium tube, but in the design, it is mainly detachable. It is mainly based on the type, which is convenient for the maintenance and cleaning of the titanium tube.

Welding requirements for titanium pipe joints:

Welding personnel should wear clean work clothes, and there should be no oil pollution. Welding gloves should be white gauze gloves, and gloves made of cotton thread and other fabrics are strictly prohibited.

The welding platform layout and the wire brushes used for decontamination of the welding area of ​​the welded joint should be made of stainless steel, and other polluting materials such as carbon steel are strictly prohibited.

The welding site should be set indoors or in a dedicated welding workshop as much as possible. Smoking is strictly prohibited in the room. The environment should be kept clean and dry. The room temperature should not be lower than 5℃, and the air convection should be strictly controlled.

In order to obtain better welding quality, the end of the Titanium Condenser Tubes will be processed into a V-shaped groove as much as possible, and the welding area and the surface of the welding wire should be degreased with acetone.

The effect of laser welding on the surface treatment of titanium rods!

The process parameters of laser welding are difficult to grasp because the thermal efficiency fluctuates greatly during the welding process, and the surface condition of the welded titanium rod has a great influence on the thermal efficiency: the brighter the surface, the larger the emitted laser light, and most of the laser energy is reflected on other objects. , transferred to the surrounding material or medium in the form of "heat". But thermal efficiency changes suddenly. Before the titanium rod is melted, only about 10%-20% of the light energy is absorbed by the titanium rod and heats the titanium rod. When the temperature rises to the melting point of the weld metal and begins to melt, the light absorption rate of the Grade 23 Titanium Rod increases sharply. Titanium rod company tells you that at this time, about 60%-80% of the light capacity is absorbed by the metal, and the sudden change of thermal effect can easily cause the weld to burn through.

In order to avoid or reduce this adverse effect, the titanium rod company tells you that you can take corresponding measures, such as welding Grade 7 Titanium Rods; roughening the surface, using a pulsed laser beam; adjusting the input energy; adjusting the spot size; Pulse width and steepness.

A ruby ​​natural crystal containing aluminum oxide and dissolved with a low concentration of chromium atoms is used as the working material of the laser generator, which is called a solid-state laser generator. If CO2 is used as the working substance of the laser generator, it is called a force gas laser generator.

At present, the power of the laser welding machine is only kilowatts, and it is expensive, the welding cost is high, and the application range is not wide. It is only used for the solder joints of some tiny parts in the manufacture of some instruments and meters, especially when some solder joints are hidden and cannot be welded by ordinary welding methods. Multi-station welding is possible using laser beams, optical fibers and deflection prisms.

Problems in CNC titanium machining!

Because the thermal conductivity of titanium exhaust flange processing is small, the heat generated during cutting cannot be dissipated and will be stored in the tool, so the wear on the tool will increase.

Because of the large chemical activity, when the cutting speed increases, cutting heat will occur, and the temperature of the cutting part will increase, so the activity will increase and the wear on the tool will increase.

Because the continuous deformation causes chips to be generated, the cutting resistance of the cutting edge increases, and the tip is prone to chipping and wear.

Because the elastic modulus is small, the machining material is prone to great deformation during cutting, especially when machining thin workpieces, the machining accuracy will be reduced and chattering will occur.

When cutting with a worn tool or when fine chips occur when cutting, the high temperature can sometimes cause the chips to ignite.

Titanium alloy processing parts occupy an important position in the machinery manufacturing industry!

Titanium alloy has the advantages of low density, high specific strength, good corrosion resistance and good process performance, and is an ideal aerospace engineering structural material. Titanium and its alloys are replacing traditional aluminum alloys in many aerospace applications. Today, the aerospace industry consumes about 42% of total global production, and demand for titanium is expected to continue growing at a double-digit rate between now and 2010. Advantages of titanium alloy materials Titanium alloys have high strength, high fracture toughness, and good corrosion resistance and weldability. With the increasing use of composite structures in aircraft fuselage, the proportion of titanium-based materials used in the fuselage will also increase, because the combination of titanium and composite materials is far better than aluminum alloys. For example: Compared to aluminum alloys, Titanium Threaded Rod can increase the life of airframe structures by 60%.

Because titanium alloys are more difficult to machine than ordinary alloy steels, titanium alloys are generally considered to be difficult-to-machine materials. The metal removal rate of a typical titanium alloy is only about 25% of that of most common steel or stainless steel, so machining a titanium alloy workpiece takes about 4 times as long as machining a steel workpiece. To meet the growing demand for titanium machining in the aerospace industry, manufacturers need to increase production capacity and therefore need a better understanding of the effectiveness of titanium machining strategies. The machining of a typical titanium alloy workpiece starts with forging until 80% of the material is removed to obtain the final workpiece shape.