OsnablukT2 copper barWhat is the code name and laying method of

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, 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, 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, large diameter pipes are mainly used as headers and main steam pipes with steam parameters below 565 ℃.

The process flow of plastic coated copper pipe: the settlement price of 904l stainless steel plate is on the high side, and the price is stable. 904l stainless steel plate: last Friday, the steel plant made all the orders. As for the guide price, the market price rose slightly on Monday due to the positive sentiment after the festival. The working efficiency of t2 copper pipe after the expansion from Tuesday to Friday should be the same. Between the upper and lower clamping groove bodies of the alloy pipe to be flared, the end of the alloy pipe to be flared faces the flaring die, extends a certain length (depending on the flaring length), and then drives the upper clamping groove body to move down through the oil cylinder. Then the flaring hydraulic cylinder drives the flaring die to the alloy pipe, so that the t2 copper pipe flaring die will stretch the alloy pipe port to expand its inner diameter in the alloy pipe port at the front end. The length of flared section can be 20200 mm. How to solve the crack of plastic coated copper pipe? How to solve the common fault of crack in case of improper operation during the construction of plastic coated copper pipe project? If it is not handled in time, there is a serious risk. Therefore, I will carry out practical operations in strict accordance with the engineering construction specifications and requirements related to immediacy, find more practical welding processes and then ensure the welding quality of electric welding. If we continue to develop plastic coated copper pipe materials under such circumstances we will find that the price difference of plastic coated copper pipe with low-grade anti rust materials is different, and there are many reasons for the price difference. First, there are significant differences in production. Although it is made of stainless steel, the plastic coated copper pipe can be compared with the plastic coated copper pipe on the market.

Osnabluk.As the passivation effect of copper material on the agent is weak, the dissolved oxygen and air bubbles in it will corrode it.

There are also some serious corrosivity, and some fine sand or vegetable oil coating will appear when the plastic coated copper tube packaging materials and packaging are stored according to special requirements. It can adhere to the surface layer and form excellent passivation effect on the surface layer of the plastic coated copper pipe. When cleaning, a cleaning plan is required. The plastic coated copper pipe must transport some raw oil in the industry. The plastic coated copper pipe has good air tightness to ensure no leakage of gasoline and diesel. It is a good transmission pipeline.

.When I need to use more quantity, what are the factors that cause the surface corrosion of copper tubes. Introduce the factors that cause the surface corrosion of copper tubes. Surface pollution: The oil, dust, acid, alkali, salt, etc. attached to the surface of the workpiece will be converted into corrosion medium under certain conditions, which will react with some components in the stainless steel parts to produce chemical corrosion and rust.

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.

Four in one formula and process conditions Preparation of solution Take formula 1 as an example: mix the calculated amount of water for zinc oxide into a paste, slowly add it into the calculated amount of phosphoric acid under stirring until it is completely dissolved,Osnabluk321 stainless steel coiled plate, then add zinc nitrate and tartaric acid, dilute it with water to 2/3 of the total volume, add sodium alkosulfonate and OP emulsion, and stir to make it completely dissolved. Then add chromium dihydrogen phosphate dissolved in dilute phosphoric acid, and add titanium sulfate. After all materials are added, dilute them to the total volume, stir them to make the solution even, cool them to room temperature, put a large amount of iron filings in the solution, and soak them for 2-3 days to make them contain enough ferrous ions. When the content of ferrous ion reaches above 7g/L, adjust the free acidity and total acidity of the solution to the specified value, and then the solution can be used at elevated temperature. When the ferrous ion reaches the above value, the phosphating speed is fast, the solution is stable, and the phosphating film is fine and dense. During operation, attention shall be paid to controlling the temperature. If the temperature is higher than 70 ℃,Osnabluk304L stainless steel plate, the degreasing technology of degreased copper pipe. How to make degreased copper pipe? The process flow of degreased copper tube? What are the characteristics of degreased copper tubes? Use of degreased copper tube? There are too many questions. Let's solve them at once. Everyone knows the copper tube. Nitrate reacts easily. The heater should be installed on the two walls of the tank, not on the bottom of the tank, to prevent local overheating. Stainless steel pipe or iron pipe should be used for heater, and lead pipe or copper pipe should not be used to avoid contamination of solution by impurities. What is degreased copper pipe? &The advantages of degreased copper pipe's comprehensive treatment of grease, rust removal, phosphating and passivation are described. This comprehensive treatment process can simplify the process, reduce the work area, save equipment costs, shorten working hours, improve labor productivity and reduce costs. This method can only be used in the occasions where the requirements for coating quality are not high.However, in actual production, due to the amount of oil contamination, light and heavy rust, the consumption rate of each component in the solution is different, so attention should be paid to adjustment and control to maintain its due role. What is the degreasing copper tube? &I have roughly known the degreasing methods of degreasing copper tubes: solvent degreasing, alkali degreasing, ultrasonic degreasing, high pressure hot water degreasing, electrolytic degreasing, etc. 1 Solvent degreasing: use degreasing solvent to dissolve the oil on the surface of red copper pipe, collect it together into a container, volatilize collect and reuse the volatile solvent, which has problems such as low cleaning efficiency, difficult maintenance, and environmental pollution. In recent years, many kinds of surfactants have been developed.

There are also some serious corrosivity, and some fine sand or vegetable oil coating will appear when the plastic coated copper tube packaging materials and packaging are stored according to special requirements. It can adhere to the surface layer and form excellent passivation effect on the surface layer of the plastic coated copper pipe. When cleaning, a cleaning plan is required. The plastic coated copper pipe must transport some raw oil in the industry. The plastic coated copper pipe has good air tightness to ensure no leakage of gasoline and diesel. It is a good transmission pipeline.

Common defects in copper strip production?

Manufacture gear, shaft sleeve, worm gear and other high-strength wear-resistant parts and high corrosion resistance elastic components. Key points of semi continuous casting process for copper tube: The copper tube has strong air absorption, easy oxidation and slag formation, poor thermal conductivity and other casting properties, some alkaline earth metal compounds, such as Na3A lF6 and NaF mixture, are used as slag removers to purify the copper liquid, which is effective for improving the purity of liquid metals and the crystal structure of ingots. The pouring temperature of copper pipes is generally 1120~1180 ℃, and the pouring temperature of large-sized ingots is generally lower. The casting speed of the copper tube is low, and the metal level in the mold can be cast in an open flow manner without any protection; The melt needs to enter the mold through the hole at the bottom of the funnel. The design of funnel aperture should meet two conditions at the same time: one is to ensure the flow matching the casting speed; Second, ensure that the liquid level in the funnel is always kept at a certain height, so that the scum on the liquid level cannot flow into the crystallizer from the funnel hole; The copper tube ingot is easy to produce air holes and concentrated shrinkage cavities. At the end of pouring, named after its yellow color. Copper content is 56%~68% brass, and its melting point is 934967 degrees. Brass has good mechanical properties and wear resistance, and can be used to manufacture precision instruments, ship parts, gun casings, etc. Different zinc content also has different colors. For example, when the zinc content is 18%, 20% will be red and yellow, while when the zinc content is 20%, 30% will be brown and yellow.

Welcome calls .The demand for t2 copper tubes is increasing. At the same time in the market, the quality identification method of t2 copper tube for grid fittings is currently accompanied by rapid economic development. There are many kinds of sales, different types, different purposes, and different quality. Therefore, when purchasing, you should be clear and have certain selection skills. Here we introduce the quality identification method of t2 copper tube. The color of t2 copper tube depends on the color of t2 copper tube. Although the external color is a visible factor, the color of the product is closely related to its production process and quality control. If the product is bright in color and high in glossiness, it is generally superior to the product with poor color. The t2 copper tube with uniform thickness should be selected. Because some small manufacturers are limited in technology and process, it is difficult to ensure that the product thickness is uniform and neat. Therefore, the thickness is also an important factor to test the quality of the pattern plate. Later, the casting process of t2 copper tube.

However, for some important parts, it is also considered that the yield ratio should be smaller to improve their safety and reliability. However, at this time, the utilization rate of materials is also low. Common sense: copper pipes for air conditioners are mainly used for conveying liquid, gas and steam; Boiler pipes and steam transmission pipes are used for the piping, structure and steam transmission of steam boilers, including the transmission of high-temperature and high-pressure steam; Structural pipe, widely used in aviation, automobile, tractor and other industrial sectors; Pipe for petroleum industry mainly used for oil and gas exploitation, such as casing, drill pipe and tubing, and pipe for petroleum refining and processing; Pipe for mechanical manufacturing, which is used to manufacture the race of ball bearing, the plunger, rotating shaft and body of air pump and hydraulic pump; High pressure vessel, used for manufacturing bottles, boilers, shells, etc. At present, copper pipes for air conditioners are mainly used in three aspects in practical applications. First, medical copper pipes are widely used in industrial plants, high-rise civil buildings, municipal engineering oil platforms, bridges, railway vehicles and other fields. Because of their good plasticity, high structural stability and strong resistance to natural disasters, they are particularly suitable for building structures in earthquake prone areas. Second, the air conditioning copper pipe has high tensile strength and toughness, high buildings bridges and other steel structures have good cold bending performance and welding performance, and the section size and surface quality are well controlled, so it is widely used in vehicle manufacturing, large bridge construction, mechanical manufacturing, industrial plant components and many other industries. Third, air conditioning copper pipes are mainly used to make transmission line towers, microwave transfer station towers, construction crane towers, elevator supports, etc. The idea is to use weather resistant steel when making iron towers to meet the service conditions of both normal temperature and low temperature. PPM pressure roll piercer used for air conditioning copper pipe tapping rolling is not replaced by inclined roll piercer used for square steel billet. The advantage of the conical piercer is that it has the consequence of rotary euphemism casting and the of restraining the shear deformation of the square circumference and the square back. Therefore, it can prevent the defects outside the steel pipe. It can be used for the perforation of agricultural materials, especially not for the reaming and fat wall perforation. When using a general piercer, the wall thickness/pitch diameter ratio (T/D limit is about 6%, while when using a square cone piercer, the T/D limit can be 2%. Tianjin Precision Steel Tube Factory will give you a brief introduction.

Copper tube has good bearing capacity. For example in large cities, road bridges and undersea bridges often appear. Most road bridges are built with plastic coated copper pipes. With plastic coated copper pipes, engineering construction in large cities will become stronger and stronger. The actual operator shall carry out the actual operation of the heating furnace, yze the materials of the heating furnace, determine the cleaning, and select the type and concentration of cleaning solution. Pay attention to the cleaning time and temperature to develop more effective solutions, and also develop some safety protection measures. An obvious feature of plastic coated copper pipe is heat resistance, because this kind of seamless steel pipe for heating furnace is mainly used for machining parts. Because the seamless steel pipe must be heated at high temperature during production and processing. What are the plastic coated copper tubes to prevent wear. What are the plastic coated copper tubes to prevent wear. We all know that all objects will wear in application, so how to prevent the wear of oil cracked pipes. Now let's introduce it to you. The packaging of petroleum cracking tubes shall be able to prevent and damage during normal loading, unloading, transportation and storage. If the Demander has special requirements for packaging materials and packages of petroleum cracking tubes it shall be indicated in the contract; If it is not marked, the supplier shall select packaging materials and packaging. Packaging materials shall comply with relevant requirements. If the material is not packaged, it can be considered to repair and install the cracked tubing in the middle. Rubber sleeves, tree trunks, straw ropes, fiber cloth, plastics, pipe caps, etc. can be used for maintenance and installation. The thick wall petroleum cracking pipe can choose the internal fulcrum or external structure. Because thick walled tubes are thin. The supporting frame and frame are made of steel, which is inconsistent with the plastic coated copper pipe. If the customer needs a packer, the petroleum cracking tube can be weighed in a decentralized way. However, the specification must be 159MM500MM.

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, carry out the load level test, wear 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, and obtained some important research results. The number of joints of steel pipes and plastic coated copper pipes on the same section shall not exceed 50% of the number of pipes. Before installation 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, the deformation resistance is relatively small, 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.

Safety production.The operation is very convenient. The forward and reverse switches are set on the front panel and can be toggled up and down. The advantage is power saving (efficiency 90%, time saving (only two thirds of the time of the original rectifier, or even shorter), material saving (at the same time, raw materials can be saved 30%, and efficiency is high (more than one third of the output value of each savings). The degreased copper tube has less deformation resistance and is easier to form. The original color of copper should be orange or rose, so it is also called degreasing copper tube. In terms of conductivity and thermal conductivity, brass rod has no hardness of copper rod, and degreased copper tube is inferior to copper wire. The defatted copper tube Huangtong brand has its own advantages and disadvantages, but the differences are also luminous points. Can affect people's lives, because it can be applied to different aspects. As the conductivity of copper is better than aluminum, copper bus is widely used in electrical equipment, especially in complete power distribution equipment. The UVW phase bus and PE bus in the general distribution cabinet are copper bus; In use, copper bus bars are generally marked with colored letters or painted with colored paint.

The blowpipe shall be perpendicular to the lead pipe during welding, high strength and corrosion resistance. The plastic coated copper pipe is made of glass fiber with resin base weight, which is wound on the rotating hollow floor step by step according to the processing technology regulations, and the stone sand is laid on the ground evenly for a long distance in the middle of the chemical fiber as the intermediate weathering layer. The price quotations of plastic coated copper pipes with different thicknesses are also different. Here, we will explain the factors that determine the thickness of the plastic coated copper pipe design scheme. Appearance and specification of mpp cable duct 1 Color: generally orange red, other colors can be implemented according to the contract of both parties. 2 Appearance quality: The inner and outer walls of the pipe fittings shall be smooth, clean and even, and shall be free of steam bubbles, cracks, cracks, molting, and obvious marks dents, residues, which can also be negotiated by both parties. The specification error shall conform to dl/t801; The bending degree of the hose shall not exceed 1% of the nominal pressure. Some key points in the process of embedding plastic coated copper pipe: the embedding process of plastic coated copper pipe is very worthy of great attention. Although the actual operation in the process of embedding is relatively simple, In other words, if the road surface is seriously uneven, it is seriously affected by external forces. Relevant countermeasures must be taken, and fine sand and dirt should also be prohibited from seeping into the pipe during the burial process, so as to diligently maintain its compliance with the regulations during the burial process. The process of embedding the plastic coated copper pipe involves the problem of marking. In fact, the marking that can be carried out according to this marking in the process of maintenance and repair is the key inspection index value of the commodity. If it is found that there is a problem with a certain section of cable, it is only necessary to find matching marks for immediate maintenance. Number of layers of cloth stacking: all layers are made strictly according to the design scheme, without additional construction, which increases the cost. 2 Resin: high temperature resistance, not easy to deform under stress. Plastic coated copper pipes are generally assembled from high-quality SMC water tank plates. Its characteristic is that it can select food grade stainless steel resin. Therefore, in view of the good water body clean up the natural environment and zero pollution, the commodity development trend has certain characteristics such as high compressive strength, light weight, corrosion resistance, beautiful and generous appearance design scheme, long service life, and more convenient management methods in maintenance. Cloth quality: the specification of cloth surface is the same, pure platinum cloth is thick, and it is thick with blended cloth or pure old coarse cloth. The thickness of fiberglass filament winding: our products are high-tech support points of fiberglass anti-corrosion ring, which ensures the bearing pressure of the products. In addition, if you must select the thickened type, you can yze the vertical cross type difficult winding when winding the winding machine, until the thickness and compressive strength of the thickened type are basically achieved.

Osnabluk.Air conditioning copper pipe is a common metal material in daily work of industrial production. The conductivity, heat conduction and corrosion resistance are excellent, and the W shape trend of air conditioning copper pipe is depressed due to the high copper content. Good machinability, 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, the cutting machine should carry out calibration and other operations. You can try to use scrap metal first to prevent machine problems from causing me to cut off defective products.

The plastic coated copper pipe is pollution-free, so the GRP sand pipe can be used to transport domestic water, and it is not easy to have the odor generated by the pipe itself.As we all know, the pipeline leakage problem is a problem that I can not always ignore. The area where GRP sand pipe is very easy to leak is leakproofness. The pH value of slurry in the desulfurization tower must be controlled within the range. If it is too low, the slurry will lose its absorption; On the other hand, if it is too high, the system software will cause relatively serious adverse effects of scale blocking, and the PH value will be adjusted according to the dynamic characteristics of dolomite feeding line. Relative density of desulfurization tower slurry. The thickness of plastic coated copper pipe is mainly determined by the four difficult problems: the number of layers of cloth, resin, cloth quality, and the thickness of glass fiber filament winding. The production and manufacturing of plastic coated copper pipe in China has a fast development trend, the total number is gradually rising, high strength and corrosion resistance. The glass fiber with resin based weight relief shall be wound on the rotating hollow floor step by step according to the processing technology regulations, and the stone sand shall be used as the intermediate weathering layer on the long distance uniform pavement in the middle of the chemical fiber.

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, 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, 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, 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 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 ℃.