Burgan6063 aluminum barConstruction analysis

In addition, brass has a unique sound, so the gongs, cymbals, bells, horns and other instruments in the East, as well as the western brass instruments, which is a kind of non-ferrous metal processing bar, with good processing performance and high conductivity. It is mainly divided into copper tube (copper zinc alloy, cheaper). The manufacturing principle of copper tube: All elements without exception reduce the conductivity and thermal conductivity of the copper bar. All elements are dissolved in the copper bar, causing lattice distortion of the copper bar, causing wave dispersion when free electrons flow in a directional direction, increasing the resistivity. On the contrary, there are no or few elements with solid solution in the copper bar, which has little impact on the conductivity and thermal conductivity of the copper bar, Special attention should be paid to the fact that the solid solubility of some elements in the copper bar decreases sharply with the decrease of temperature. The precipitation of simple substances and metal compounds can not only strengthen the copper bar alloy by solid solution and dispersion, but also reduce the conductivity slightly. This is an important alloying principle for the study of high-strength and high conductivity alloys. Here, it should be pointed out that the alloy composed of iron, silicon, chromium and copper bar is a very important high-strength and high conductivity alloy; As the influence of alloy elements on the properties of copper bars is superposition, CoCrZr series alloys are * high-strength and high conductivity alloys; It is not easy to heat. Semi continuous casting copper tube has excellent conductivity. Copper tube has excellent conductivity. Alloy copper to ensure safety and fatigue resistance. Tin phosphor bronze jack adopts hard wire electrical structure without rivet joint or conflict contact, which can ensure excellent touch, good elasticity and smooth dial. Phosphor bronze has high corrosion resistance, wear resistance, and will not produce sparks when stamping. It is used for medium speed and heavy load bearings. The working temperature is up to 250 ° C, and the active centering is insensitive to deflection. The bearing force is uniform, and the bearing capacity is high. It can withstand radial load and self lubrication without protection. The company is a manufacturer specializing in the production of various bronze tubes, bronze plates and profiled bronze profiles. Technical advantages: The maximum diameter of bronze bars and pipes can reach 300mm, while that of plates can reach 600mm. The wall thickness of bronze tube can be as small as 4mm. The copper tube is a common bronze material. The aluminum content of copper tube generally does not exceed 5%. Sometimes an appropriate amount of iron, nickel, manganese and other elements are added to further improve the performance. It has high strength and good wear resistance. It is used for copper sleeves and wear resistant parts with high strength. The outstanding feature of t2 copper tube is its good wear resistance. The difference between copper tube and copper tube The copper tube is a copper based alloy with aluminum as the main alloy element. The copper tube is a copper based alloy with tin as the main alloy element. The mechanical properties of copper tube are higher than that of copper tube. The aluminum content of the copper tube in practical application is between 5% and 12%, the aluminum content is 5%, and the 7% copper tube has good plasticity and is suitable for cold working.

Pay attention to the following points when using flame heating brazing: the selection of welding materials The filler metal is wire or rod, with a diameter of about 35mm. The material is: the melting temperature of wire 221 is about 0905 ℃. Its chemical composition is FB10 The composition is 2331% H3BO3 and 6071% KBF The joint form of brazed copper pipe is mostly plug-in. Before cleaning the brazed copper pipe before welding, the edge of the pipe mouth must be corrected and deburred to ensure that the pipe mouth is free of cracks or other defects. And clean the surface of the inserted part. After the red copper pipe is assembled by tack welding, it shall be fixed by tack welding. The number, size and height of tack welds shall be symmetrically and evenly distributed along the circumference from top to bottom, and the tack welds shall be melted into the whole weld during brazing. When brazing the copper pipe, the flat angle position shall be used as far as possible to ensure continuous welding. Select the appropriate welding torch according to the size of the pipe joint. The flame of the former Han Dynasty should be neutral, because the oxidation flame has high oxygen content, which is easy to oxidize copper and cause cracks; The carbonization flame contains free hydrogen, which will cause pores. When heating pipes before welding, the flame shall be perpendicular to the heating surface, the pipe joints shall be heated evenly and the base metal shall be heated as quickly as possible to avoid excessive temperature and heating time of the through pipe joints. During the brazing of degreased copper tube, the brazing seam and filler metal shall be under the protection of flame. In addition, it shall be noted that the brazing seam shall be naturally cooled after welding, and the weldment shall not be moved before the brazing seam has solidified. After natural cooling after welding, hot water or wet cloth shall be used to wipe the brazing seam and remove welding slag to improve corrosion resistance and reliability of post welding inspection.

Burgan.Disadvantages: low output, which is the development direction of copper tube industry in the future.

In addition, brass has a unique sound, so the gongs, bells, horns and other instruments in the East, as well as the western brass instruments, are all made of brass, which is a kind of non-ferrous metal processing bar, with good processing performance and high conductivity. It is mainly divided into copper tube (copper zinc alloy, cheaper). The manufacturing principle of copper tube: All elements without exception reduce the conductivity and thermal conductivity of the copper bar. All elements are dissolved in the copper bar, causing lattice distortion of the copper bar, increasing the resistivity. On the contrary, there are no or few elements with solid solution in the copper bar, which has little impact on the conductivity and thermal conductivity of the copper bar, Special attention should be paid to the fact that the solid solubility of some elements in the copper bar decreases sharply with the decrease of temperature. The precipitation of simple substances and metal compounds can not only strengthen the copper bar alloy by solid solution and dispersion, but also reduce the conductivity slightly. This is an important alloying principle for the study of high-strength and high conductivity alloys. Here, it should be pointed out that the alloy composed of iron silicon, chromium and copper bar is a very important high-strength and high conductivity alloy; As the influence of alloy elements on the properties of copper bars is superposition, CoCrZr series alloys are * high-strength and high conductivity alloys; It is not easy to heat. Semi continuous casting copper tube has excellent conductivity. Copper tube has excellent conductivity. Alloy copper to ensure safety and fatigue resistance. Tin phosphor bronze jack adopts hard wire electrical structure without rivet joint or conflict contact, which can ensure excellent touch good elasticity and smooth dial. Phosphor bronze has high corrosion resistance, wear resistance, and will not produce sparks when stamping. It is used for medium speed and heavy load bearings. The working temperature is up to 250 ° C, and the active centering is insensitive to deflection. The bearing force is uniform, and the bearing capacity is high. It can withstand radial load and self lubrication without protection. The company is a manufacturer specializing in the production of various bronze tubes, bronze rods, bronze plates and profiled bronze profiles. Technical advantages: The maximum diameter of bronze bars and pipes can reach 300mm, an appropriate amount of iron, nickel, manganese and other elements are added to further improve the performance. It has high strength and good wear resistance. It is used for copper sleeves and wear resistant parts with high strength. The outstanding feature of t2 copper tube is its good wear resistance. The difference between copper tube and copper tube The copper tube is a copper based alloy with aluminum as the main alloy element. The copper tube is a copper based alloy with tin as the main alloy element. The mechanical properties of copper tube are higher than that of copper tube. The aluminum content of the copper tube in practical application is between 5% and 12%, the aluminum content is 5%, and the 7% copper tube has good plasticity and is suitable for cold working.

.The utility model relates to a connecting structure, 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, the increase of the contact resistance, and the excessive heating or even burning of the connection point.

In addition, the stress corrosion cracking inside the stainless steel plate will cause the transition film on the surface of the stainless steel plate. Therefore,Burgan321 stainless steel coiled plate, the surface of plastic coated copper pipe shall be cleaned to a certain extent to ensure its service life. The oil cracking tube circuit breaker must be selected. The fracture of the plastic coated copper pipe shall be kept on a true circle, and the fracture line shall be inclined to the pivot of the plastic coated copper pipe. Too large is the reason for cutting plastic coated copper pipe into flat or oval shape, so moderate energy shall be used when cutting square steel pipe. What matters should be paid attention to when purchasing plastic coated copper tubes.

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.

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, 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, 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, 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, because its surface is not easy to be oxidized, which is the key to constitute the raw material of plastic coated copper tube. The high-precision plastic coated copper pipe has an extremely thin, 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, and the small holes will form highly corrosive aqueous solution. The chloride ion content will accelerate the corrosion rate.

Corrosive agents such as calcium bicarbonate, inositol hexaphosphate, silicon phosphate crystal, etc. are added to the water to regulate the PH value of the water and the corrosion symptoms.

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, 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, 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 ℃.

Welcome calls .Pay attention to the following points when using flame heating brazing: the selection of welding materials The filler metal is wire or rod, with a diameter of about 35mm. The material is: the melting temperature of wire 221 is about 0905 ℃. Its chemical composition is FB10 The composition is 2331% H3BO3 and 6071% KBF The joint form of brazed copper pipe is mostly plug-in. Before cleaning the brazed copper pipe before welding, the edge of the pipe mouth must be corrected and deburred to ensure that the pipe mouth is free of cracks or other defects. And clean the surface of the inserted part. After the red copper pipe is assembled by tack welding, it shall be fixed by tack welding. The number, left to right, and the tack welds shall be melted into the whole weld during brazing. When brazing the copper pipe the flat angle position shall be used as far as possible to ensure continuous welding. Select the appropriate welding torch according to the size of the pipe joint. The flame of the former Han Dynasty should be neutral, which is easy to oxidize copper and cause cracks; The carbonization flame contains free hydrogen because the oxidation flame has high oxygen content, which will cause pores. When heating pipes before welding, the pipe joints shall be heated evenly, it shall be noted that the brazing seam shall be naturally cooled after welding the brazing seam and filler metal shall be under the protection of flame. In addition, and the weldment shall not be moved before the brazing seam has solidified. After natural cooling after welding, hot water or wet cloth shall be used to wipe the brazing seam and remove welding slag to improve corrosion resistance and reliability of post welding inspection.

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.

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 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 should be suitable for the intended use and avoid obvious and natural purification. If the customer stipulates that the surface layer of the cracked tubing should not be damaged by bumps, 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, 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, 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, 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 ℃.

Sincere service.The copper tube warehouse of automobile air conditioner shall not be stacked with acid, alkali, salt cement and other materials that are corrosive to steel. The air conditioning copper pipe is based on carbon structural steel. The phenomenon of torsional deformation of the air conditioning copper pipe requires weeds and all sundries on the site. One or more alloy elements shall be added appropriately to improve the mechanical properties, the coke market generally fell by about 50 yuan toughness and hardenability of the annealing steel.

This week, and the transaction was average. The purchase price of the first grade metallurgical coke of Nissan Iron and Steel Co., Ltd. dropped 50 to 2410, and the purchase price of the second grade metallurgical coke dropped 50 to 2250-2260; The purchase price of Wenfeng secondary metallurgical coke dropped 50% to 2160; The purchase price of secondary metallurgical coke of Xingtai Iron and Steel Group dropped 50% to 2115; The purchase price of Guofeng quasi first grade metallurgical coke dropped 50% to 2180 and the purchase price of third grade metallurgical coke dropped 50% to 2070; The purchase price of the first grade metallurgical coke of Tianjin Rolling First Standard has dropped 50% to 2300; Weigang's purchase price of quasi first grade metallurgical coke fell 30% to 2350

In future work, try to protect the surface of the copper tube.

Burgan.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, large solidification shrinkage, poor thermal conductivity and other casting properties, and poor casting performance; Before casting, 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, 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, the joint coating must be carefully carried out to avoid concentrated shrinkage cavities in the ingot. The red copper tube is a bar shaped object made of copper and zinc alloy, 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.

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 fatigue damage, 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.

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, 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,BurganComposite copper bar, 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.