Dunaharazti60SI2MN alloy round steelWhat is the benefit if you complete the work in one go?

announcer:hp535HP136858825 release time:2024-05-08 09:21:48

The editor of this website of t2 Medical Copper Tube Company said that if there is no table, they can only stand to eat and probably enjoy food in other places. In the catering industry, there are various kinds of tables, and all kinds of tables are available. There are wooden tables and medical copper controlled tables. This table controlled by red copper in Chinese medicine is most common in large canteens such as schools, while wooden tables can often be found in small restaurants as one of the steel products of medical copper tubes. As his name is common medical copper tubes have the ability to prevent rust. In the catering industry, tables made of medical copper tubes have many advantages. Next, the teacher of Medical Copper Tube Consumption Co., Ltd. will introduce you to the master. The medical copper tube table is easy to see in the large canteen. This kind of canteen is extremely large, so it is extremely difficult to settle accounts. If a wooden table is used, it will cost a lot of money, and it will also take a lot of work to settle after eating.

The degreased copper tube is made of oxygen free copper rod, which has good processing characteristics and can be punched, bent and other process design requirements. The surface can be subject to anti-corrosion treatment, such as nickel plating, tin plating, zinc plating, etc. The surface anti-corrosion can reach 72 hours of fog test. The surface tin plating is environment-friendly lead-free tin and the surface tin layer supports soldering. T2 degreased copper tube is mainly used for communication cabinet, transformer, charging pile,DunaharaztiTinned copper bar, box type substation and other electrical facilities. The copper bar is harder than the plastic pipe and has the degree of common metal (the strength of the cold drawn degreased copper pipe is equivalent to that of the steel pipe with the same wall thickness). It is not easy to corrode and is resistant to high temperature and high pressure. It can be used in various applications. The main material of copper bar is copper. The melting point of copper is as high as 1083 ℃, and the temperature of hot water can be ignored for degreased copper pipe, so as long as it is used correctly, there is no need to worry about safety. When choosing to decorate the house, few people ask about the water supply pipe of the house. In fact, the material of water supply pipeline will greatly affect people's health. T2 copper tube has strong capacity. Escherichia coli in the water supply will not continue to breed in the degreased copper tube, and more than 99% of the water will disappear after entering the degreased copper tube for 5 hours. This biological characteristic is that there is a small amount of copper ions dissolved in water in the degreased copper tube, and copper ions have a strong ability. Copper and zinc plating can avoid rusting and show a zinc protective film to metal materials. The conductive metal material repair and color enhancement care agent I can generate the thickness of the metal material epoxy protection layer and the pipeline cathodic protection layer, which can resist extreme weather and is suitable for the long-term surface of metal materials. The actual effect of salt and water corrosion resistance is good. The copper bar tin plating can prevent the air oxidation of the copper bar and the connection surface of the copper bar. In addition, the melting of metal tin and copper will produce aluminum alloy, which will improve the adhesion of copper strip coating. In addition, the conductivity of metal tin is good. The purpose of copper and tin plating: effectively prevent copper from becoming verdant due to moisture, which greatly increases the service life of the copper and plays a considerable role in protecting the copper. The of tinned metal surface treatment on copper bar is to avoid air oxidation. As the air in industrial production air, marine climate or cold air is easy to turn black or produce copper green when oxidized, the copper bar surface shall be tinned for the total area, the resistance and conductivity of the steel bar lap surface.With the continuous development of industry, the demand for plastic coated copper tubes is gradually increasing. Then how to apply wood grain paint on alloy pipes. Wood like paint is a kind of wood like paint. It is used for spraying plastic coated copper pipe and its process flow. Plastic coated copper pipe is mainly used to manufacture high-pressure alloy pipe for heating surface of water tube boiler with high pressure and above. In the morning market, the mainstream spot price quoted by Lianzhong was 7900-7950 yuan/ton, and the tax inclusive base price quoted by Hongwang and Chengde was 8070-8150 yuan/ton. On a month on month basis, part of the producing areas recalled 50 yuan, and the mainstream tax inclusive base price in the market changed from strong to weak in the 7900-8100 plastic coated copper pipe supply and demand relationship. It was difficult for the price of plastic coated copper pipe in the Guangzhou market to fall sharply this week. Second, plastic coated copper tubes are widely used in superheaters, headers and main steam ducts of domestic HP, UHP and subcritical power plant boilers. Third, the cost of ductile iron in Shanxi and the transaction was fair. With the increase of coke price, Henan Liaoning, Shandong and other regions has increased. In addition, with the gradual release of downstream demand, the inventory of iron plants is not large, and iron plants have successively raised their prices. There are few iron foundries in Shandong, Jiangsu, Hebei and Shanxi, and the inventory remains low. As the coke price rises and the cost increases, the price of iron foundries rises again.

Handle carefully to prevent damage and scratches. 2 When installing the keel, avoid collision between the basket and the keel. When installing the external wall hanging plate, protect it from impacting the medical copper pipe. 3 After the installation of thermal insulation curtain wall, in order to prevent personnel from approaching, special personnel should check the distance from the ground curtain wall. 4 For each process close to the curtain wall, the medical copper pipe shall be temporarily protected before construction and can be covered with fiberboard. Even after the construction is completed, some temporary protective measures should be taken to achieve the effect of later use. 3 On the premise of considerable cohesiveness, the exterior wall external thermal insulation decorative integrated board of high-rise buildings should meet the principle of flexible gradual change, and disperse and absorb seismic stress as far as possible to reduce the impact on medical copper pipes. 4 The medical copper pipe shall be made of waterproof and moisture permeable external insulation materials to avoid damage to the wall caused by water or steam migration. 5 Under the action of negative wind pressure, the volume expansion of the air layer in the insulation layer will damage the insulation layer. The aging of medical copper pipe will affect the use of building materials to a certain extent. When it reaches its service life, it needs to be replaced to prevent the trouble of aging in life. 6 The thermal expansion and cold contraction caused by the temperature difference change will cause the volume change of the non structure of the medical copper tube. Such medical copper tube has a shorter service life than the plate in normal use, and needs regular maintenance according to regulations.

.The price can be changed, and the transaction is affected. According to the feedback from the spot operation, the morning market transaction did not follow the temperature rise: after 9:00, the dealers took turns to raise the price, which was in disorder; Before ten o'clock, it was not as expected, and users were very cautious in purchasing; Around 11:00, the surrounding markets became loose and the price was low. High hanging, and low volume. The market transaction is carried out in such a trilogy,Dunaharazti310s stainless steel round steel, which is different from the opening. In this process, the mentality of traders has changed: from &turning to shipping&, after all, it has promoted the steel mill to sell before entering their own mouth? This is a &manic& market again: failed to continue to rise, spot prices rose; The construction site plan is not much, and the market transaction is weak - this week's trading days, the spot price rose, and the transaction was less than expected. As of noon, the sales volume of large inventory customers was hundreds of tons, and the shipment was not much. Judging from the transaction in the morning, the selling price of leading resources rose generally. Among the resources in Kuti, the base price of t2 copper tube was 5050 yuan/ton, and the price of earthquake resistant spiral snail was 5350 yuan; Among the resources provided by the factory, the basic price of threads of Zhongtian, Yonggang and Shagang is 5130 yuan, and the differential between spiral and t2 copper pipes is 360-380 yuan/ton. In terms of the market, the leading market Tangshan narrow band mainstream fell by 30-120 in the early opening. The overall trading situation of copper bars was weak. Some small factories cut prices significantly, and the low price trading was acceptable. Limited production continues market resources are average, weak market, and downstream procurement is cautious. 355 is the consolidation of the medium broadband market. Today's futures continue to fluctuate. Traders are less willing to ship at low prices and have a strong mood. However, under the pressure of futures, the trading atmosphere in the spot market is not good. Copper bars continued to fluctuate in the morning, and traders were affected by multiple factors to make a small weak tone trial deal. From the commercial account, we know that there are few high market transactions, few inquiry calls, and a slightly pessimistic attitude. The overall market transaction atmosphere is light, and most merchants operate on the market. At present, the downstream demand is still low, the demand for terminal replenishment is low, and the purchasing enthusiasm is not high. According to traders' feedback, the current market is in a weak situation of supply and demand. Downstream feedback shows that many projects are shut down and there is a great pressure on funds. However, the relevant economic data and side news are too bearish, so the futures market is difficult to rebound, and the spot market is mainly responsible for the subsequent drop. However, some traders are still willing to maintain their prices, which is mainly due to the high price of post settlement resources and the low inventory at present. The invention relates to a manufacturing method for a double seal socket flexible connection structure of a large diameter spiral welded steel pipe.

Some problems. For example, in the preliminary manufacturing of copper tubes for air conditioners for automobiles, the materials for air conditioners can be selected according to the actual size required by users, and then the copper tubes for air conditioners for automobiles can be manufactured, followed by pickling. The produced copper tubes for air conditioners are put into the pickling tank for pickling and then stretched. Then the pickled copper tubes for air conditioners are stretched according to their size requirements.

The materials of the packer shall be packed with steel strip and added according to the diameter and weight of the petroleum cracking pipe. The degreased copper pipe from the pipe can be packed without a packer. If there are wiring ports on both sides of the cracked oil pipe, external thread devices shall be provided for safety protection. Brush the nozzle with clean oil or anti rust oil. For the cracks on both sides of the petroleum cracking pipe, branch pipe safety protectors can be installed on both sides as required. If the oil cracking pipe is installed in the container, the container shall be lined with waterproof devices,DunaharaztiAluminium tube, such as woven cloth and straw mats. In order to better distribute the textile petroleum cracking tubes in the tank, the packer can weld the safety protection support frame inside the petroleum cracking tubes. Previous page: How to clean plastic coated copper tubes. What problems will be encountered when cutting plastic coated copper pipe. What problems will be encountered when cutting plastic coated copper pipe. What problems will be encountered when cutting plastic coated copper pipe. When plastic coated copper pipe is cut, the wound is uneven and cracked. Then I will introduce how to solve these problems. For the disconnection part of plastic coated copper pipe, the position and direction shall be drawn with tape or other measuring tools and the disconnection line shall be marked in combination with the construction drawing and site conditions. When the petroleum cracking pipe is disconnected, please fix the equipment with square steel pipes such as vises, and cut it after fixing. In the area to be disconnected, use a towel or soft cloth to crack the oil stain or dirt on the surface of the pipe. As we all know, if steel pipes are exposed outdoors for a long time, or there are some, they will damage the air oxide layer on the surface of the stainless steel plate, and then oxidize and rust in the cold. Gas. Therefore, the steel pipe shall be placed in the sealing area as far as possible. However, plastic coated copper tube has incomparable advantages, firm and smooth chromium rich air oxide film on its surface to prevent oxygen molecules from re penetrating and re oxidizing in the air, thus preventing rust. The description of the plastic coated copper pipe shows that the part with weak corrosion resistance of the transition film will produce pitting corrosion reaction due to the self-excited reaction, rust removal, phosphating and passivation

The second of the five application fields of red copper plate T2, red copper row and red copper tube: copper is widely used in the chemical industry to manufacture vacuum vessels, distillation pots, brewing pots, etc.

However, it may cause recoverable temporary damage to people who have been away from these radioactive sources for a long time. The DC brushless motor with small volume and large power is adopted, which can operate without fault for a long time even if it is opened or closed. Target There will be no sharp decline in the price of copper tubes in Linyi at the end of the month. The price of plastic coated copper pipe will continue. Pop up the position line and line, select PVD chromium nitride ring and molybdenum spraying ring as the matching materials for the plastic coated copper pipe, adhere to the wear form condition simulation criteria of the sample test, use the self-developed opposed reciprocating wear tester, wear test, lean oil test, and research the load. As for the corrugated process of the finished plastic coated copper pipe as claimed in claim 1, the radiation source for the engineering design of the integrated rigid flexible connection plastic coated copper pipe belongs to the low hazard source. Basically, it will not cause artificial damage. The basic principle of the foundation of the integral rigid flexible connection plastic coated copper pipe sluice discussed the influence of process parameters and heat treatment process on the microstructure, phase distribution and mechanical properties of the alloy, the pipe shed shall sweep and clean the hole with drill bit or high-pressure air, and the scum in the hole shall be removed, Ensure the aperture (The hole diameter shall not be less than 127cm, and the hole depth shall meet the requirements to prevent hole plugging. Most of the seamless steel pipes produced now are hot-rolled. Because of the high temperature, and generally the steel plate is used for rolling. In this operation, the detailed thickness of the steel plate shall also be considered. If it is about the harmful elements with relatively low accuracy requirements, plastic coated copper pipes must be required. The pipe shed can be installed, extended section by section, and What does plastic coated copper pipe with a diameter of 1 reflect in life when the weld length is added to 30 for the joint steel pipe of the pipe extension joint? Plastic coated copper pipe can also produce welded pipes with different pipe diameters from billets of the same width. However, it can be compared with straight seam pipes of the same length. The rental production rate is low.

Installation materials.The price can be changed, and the transaction is affected. According to the feedback from the spot operation, the morning market transaction did not follow the temperature rise: after 9:00, which was in disorder; Before ten o'clock, it was not as expected, and users were very cautious in purchasing; Around 11:00, the surrounding markets became loose and the price was low. High hanging, low selling, and low volume. The market transaction is carried out in such a trilogy, which is different from the opening. In this process, after all, it has promoted the steel mill to sell before entering their own mouth? This is a &manic& market again: failed to continue to rise, spot prices rose; The construction site plan is not much, and the market transaction is weak - this week's trading days, the spot price rose, and the transaction was less than expected. As of noon, the sales volume of large inventory customers was hundreds of tons, and the shipment was not much. Judging from the transaction in the morning the selling price of leading resources rose generally. Among the resources in Kuti, the base price of t2 copper tube was 5050 yuan/ton, and the price of earthquake resistant spiral snail was 5350 yuan; Among the resources provided by the factory, the basic price of threads of Zhongtian, Yonggang and Shagang is 5130 yuan, and the differential between spiral and t2 copper pipes is 360-380 yuan/ton. In terms of the market the leading market Tangshan narrow band mainstream fell by 30-120 in the early opening. The overall trading situation of copper bars was weak. Some small factories cut prices significantly, and the low price trading was acceptable. Limited production continues, market resources are average, and downstream procurement is cautious. 355 is the consolidation of the medium broadband market. Today's futures continue to fluctuate. Traders are less willing to ship at low prices and have a strong mood. However, under the pressure of futures, the trading atmosphere in the spot market is not good. Copper bars continued to fluctuate in the morning, and traders were affected by multiple factors to make a small weak tone trial deal. From the commercial account we know that there are few high market transactions, few inquiry calls, and a slightly pessimistic attitude. The overall market transaction atmosphere is light, and most merchants operate on the market. At present, the downstream demand is still low, the demand for terminal replenishment is low and the purchasing enthusiasm is not high. According to traders' feedback, the current market is in a weak situation of supply and demand. Downstream feedback shows that many projects are shut down and there is a great pressure on funds. However, the relevant economic data and side news are too bearish, so the futures market is difficult to rebound, and the spot market is mainly responsible for the subsequent drop. However some traders are still willing to maintain their prices, which is mainly due to the high price of post settlement resources and the low inventory at present. The invention relates to a manufacturing method for a double seal socket flexible connection structure of a large diameter spiral welded steel pipe.

In particular, it is an improved spray type passivation box for t2 copper pipe production line. The installation step of the connection structure 100 between t2 copper pipe and aluminum bar belongs to the improvement of the spray type passivation box structure for t2 copper pipe production line. The passivation solution spray box is set above the side of the passivation solution box, the passivation solution spray box with downward sloping bottom is connected with the inlet of the passivation solution box by the outlet set on the box wall at the bottom of the inclined bottom, the inlet of the passivation solution box is located on the box wall above the passivation solution box, the upper side of the passivation solution box is installed with a passivation pump, and the inlet pipe of the passivation pump is connected with the passivation solution box, The outlet pipe of the passivation pump is connected with the upper port of the passivation liquid spray box. With reasonable structure and convenient operation, it is convenient for operators to add passivation liquid to the passivation box, clean colloidal crystals at the bottom of the passivation box, avoid equipment blockage, avoid crystals adhering to the zinc layer on the surface of galvanized pipe, and improve the surface quality of galvanized steel pipe.

The utility model relates to a connecting structure, in particular to a connecting structure of a copper tube and an aluminum row. At present, most of the copper aluminum transition joints have not been effectively protected. In this way, under the condition of long-time electrification and heating and affected by the water vapor or corrosive gas in the air, the parts at the connection point are more likely to be oxidized, resulting in the reduction of the effective contact area of the connection point, the increase of the contact resistance, it refers to a kind of air conditioner copper tube with equal side length. The automobile air conditioner copper tube is made of strip steel as raw material, and then processed and rolled by relevant processes. It is generally made into a circle after the strip rod is unpacked, straightened, curled and welded. Among them, hardness is an index to measure the degree of hardness and softness of automotive air conditioner copper tubes. At present the commonly used hardness method for measuring product hardness in production refers to the use of an indenter with a certain geometric shape to measure the hardness value of the metal surface being tested under a certain load according to its degree of coverage. The air conditioner copper pipe in the automobile air conditioner copper pipe is also divided into weld and seamless. Seamless air conditioner copper pipe is a metal material formed by directly using seamless round pipe. The plasticity of the air conditioner copper pipe refers to the ability to deform under a certain load without its original performance. The copper pipe for automobile air conditioner is a hollow and square section. The light thin-walled copper pipe for air conditioner is also known as steel cold-formed profile. It is a square section steel made of strip or coiled plate after processing in the cold bending area and high-frequency welding. In addition to being used in the automobile industry, the air conditioning copper pipes are used in construction, machinery manufacturing, steel construction and other projects, shipbuilding, solar power generation support, steel structure engineering, electric power engineering, power plants, agricultural and chemical machinery, glass curtain walls, boiler construction, highway railings, housing construction, pressure vessels, oil tanks, bridges, power station equipment, lifting and transportation machinery and other high load welding structures. In addition to the thickening of the wall, the size and external straightness of the extra thick wall air conditioning copper tube can both exceed the water content of the resistance welded cold formed air conditioning copper tube. Therefore, this kind of automobile air conditioning copper tube has better comprehensive mechanical properties and has the advantages of hot processing, cold processing, weldability and corrosion resistance.

how much.Attention shall be paid to the purchase of red copper pipe in order to study the distribution law of pipeline crack stress field under internal pressure. The simulation ysis and experimental verification are carried out for pipes with cracks of different shapes, different directions, different internal pressures and different sizes. The results show that the stress at the crack tip is much greater than that at the crack center. The crack shape has little effect on the stress. With the increase of the included angle between the crack direction and the pipe axis, the stress at the crack tip first increases and then decreases. With the increase of the pipe internal pressure, crack depth, and crack length the stress at the crack tip increases linearly. Among them, the effect of crack length on the stress at the crack tip is smaller than that of internal pressure and crack depth. During the construction and operation of long-distance pipeline, due to the influence of pipe manufacturing defects, welding defects, internal and external loads, stress concentration, corrosion defects and other factors, the pipeline will produce cracks and expand cracks which is the most dangerous defect of long-distance pipeline and the main reason for pipeline failure. At present, pipeline cracks are mainly determined by internal testing and non-destructive testing after excavation. Among them, ultrasonic internal testing has a good identification rate for cracks with a length of more than 25 mm, a depth of more than 1 mm in the base metal or a depth of more than 2 mm in the weld; Magnetic flux leakage internal detection has a certain detection rate for cracks with opening more than 0.25mm, but it is difficult to identify and quantify. In NDT, magnetic particle, penetration, eddy current and radiographic methods have high detection and identification rate. The generation and propagation of cracks will cause local stress concentration in the pipeline, which is prone to brittle fracture, corrosion damage and other failure phenomena seriously affecting the service performance and reliability of long-distance pipeline. In this paper, the influence of crack shape, direction and size on the stress at the crack tip is yzed by studying the stress field distribution law of copper pipe cracks, which provides a reference for the prevention and control of pipe cracks. What problems will be encountered in the production of copper tubes. The production of copper pipe includes four steps: welding, forming, inspection and pipe expansion.

Establish the copper pipe pipeline maintenance evaluation specification.

Air conditioning copper pipe is a common metal material in daily work of industrial production. The conductivity, heat conduction and corrosion resistance are excellent, fusion welding and brazing are very good. The cutting of air conditioner copper pipe is a very energy consuming work. The following items need to be paid attention to in order to cut neat and beautiful parts. Before cutting the air conditioner copper pipe, so as to comprehensively consider and avoid problems. The polymer is thermally copolymerized with the polymer to form the big data of the molecules connected by the ion bond of the co thermal polymerization. The thermal copolymerization is carried out according to the DA reverse reaction. The disadvantage of such materials depends on the fact that if simple heat treatment process is improved without additional metal catalyst, chemical formula or other unusual surface treatment of metal materials will lead to ionic bond in the area to be repaired and can open the gap several times. Copper tube concrete based textile materials. Self repairing concrete is a basic concept that mimics the automatic basic metabolism of some chemicals of the injured part by biological tissues, so as to make the injured part heal. Hollow glass fiber or liquid core optical fiber may damage the hollow bag of concrete raw materials, damage the hollow glass fiber or liquid core optical fiber, and flow the adhesive to the damaged part, so that the gap medical copper tube can be healed again. Cause of surface damage of copper tube. Copper tube is also a kind of material commonly used in engineering. The surface shall also be protected from scratches. The surface of the copper tube is also easy to be damaged, whether it is processed or stored in the warehouse.

At the same time, it is also a necessary equipment in the family. With a table, no fingerprint disposal of medical copper tube is necessary in the catering industry. Only when you cook food can you have a place to enjoy it.

The degreased copper tube is made of oxygen free copper rod, which has good processing characteristics and can be punched bent and other process design requirements. The surface can be subject to anti-corrosion treatment, such as nickel plating, tin plating, zinc plating etc. The surface anti-corrosion can reach 72 hours of fog test. The surface tin plating is environment-friendly lead-free tin, and the surface tin layer supports soldering. T2 degreased copper tube is mainly used for communication cabinet, transformer, charging pile, box type substation and other electrical facilities. The copper bar is harder than the plastic pipe and has the degree of common metal (the strength of the cold drawn degreased copper pipe is equivalent to that of the steel pipe with the same wall thickness). It is not easy to corrode and is resistant to high temperature and high pressure. It can be used in various applications. The main material of copper bar is copper. The melting point of copper is as high as 1083 ℃, and the temperature of hot water can be ignored for degreased copper pipe, so as long as it is used correctly, there is no need to worry about safety. When choosing to decorate the house, the material of water supply pipeline will greatly affect people's health. T2 copper tube has strong capacity. Escherichia coli in the water supply will not continue to breed in the degreased copper tube, and more than 99% of the water will disappear after entering the degreased copper tube for 5 hours. This biological characteristic is that there is a small amount of copper ions dissolved in water in the degreased copper tube, and copper ions have a strong ability. Copper and zinc plating can avoid rusting and show a zinc protective film to metal materials. The conductive metal material repair and color enhancement care agent I can generate the thickness of the metal material epoxy protection layer and the pipeline cathodic protection layer, which can resist extreme weather and is suitable for the long-term surface of metal materials. The actual effect of salt and water corrosion resistance is good. The copper bar tin plating can prevent the air oxidation of the copper bar and the connection surface of the copper bar. In addition, the melting of metal tin and copper will produce aluminum alloy, which will improve the adhesion of copper strip coating. In addition, the conductivity of metal tin is good. The purpose of copper and tin plating: effectively prevent copper from becoming verdant due to moisture, and also prevent copper from oxidizing/sulfurizing and blackening and affecting electricity. The service life of the tinned copper tube is several times or even more than ten times, which greatly increases the service life of the copper and plays a considerable role in protecting the copper. The of tinned metal surface treatment on copper bar is to avoid air oxidation. As the air in industrial production air, marine climate or cold air is easy to turn black or produce copper green when oxidized, the copper bar surface shall be tinned for the total area, the resistance and conductivity of the steel bar lap surface.With the continuous development of industry, the demand for plastic coated copper tubes is gradually increasing. Then how to apply wood grain paint on alloy pipes. Wood like paint is a kind of wood like paint. It is used for spraying plastic coated copper pipe and its process flow. Plastic coated copper pipe is mainly used to manufacture high-pressure alloy pipe for heating surface of water tube boiler with high pressure and above. In the morning market, the mainstream spot price quoted by Lianzhong was 7900-7950 yuan/ton, and the tax inclusive base price quoted by Hongwang and Chengde was 8070-8150 yuan/ton. On a month on month basis, part of the producing areas recalled 50 yuan, and the mainstream tax inclusive base price in the market changed from strong to weak in the 7900-8100 plastic coated copper pipe supply and demand relationship. It was difficult for the price of plastic coated copper pipe in the Guangzhou market to fall sharply this week. Second, plastic coated copper tubes are widely used in superheaters, headers and main steam ducts of domestic HP, UHP and subcritical power plant boilers. Third, large diameter pipes are mainly used as headers and main steam pipes with steam parameters below 565 ℃.