Bhutan310s stainless steel plateMostly used in industrial inspection rooms

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, 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, and the excessive heating or even burning of the connection point.

Copper tube has good bearing capacity. For example, 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, 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, the petroleum cracking tube can be weighed in a decentralized way. However, the specification must be 159MM500MM.

Bhutan.Dissolved oxygen in water is a major factor in copper pipe corrosion.

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, 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, inspection and pipe expansion.

.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,BhutanH65 brass plate, 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, 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.

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

What problems should we pay attention to in each production. It is a key process to weld copper pipe with correct process. Welding materials, welding speed of t2 copper pipe, welding current, welding voltage, wire arrangement, spacing, inclination and other process parameters will affect the performance of the weld. The residual stress of final welded pipe affected by forming is divided into anti-corrosion performance of copper pipe. Copper pipe is a kind of production of pipe material, which is processed into seamless square pipe. The physical properties of copper tubes are slightly weaker than those of hot-rolled steel tubes. The copper tube adopts a two-step push tube expanding machine, which integrates cone die tube expansion, data medium frequency induction heating and hydraulic press. With effective processing technology, low energy consumption, less infrastructure construction, good products, wide application fields of raw materials and products, and what are the production batches suitable for copper tube testing. When purchasing copper tubes, we pay more attention to their general possibilities and observations, but this is effective for a few customers, and may not be able to accurately distinguish between them. For such problems, it is recommended to conduct a large number of inspections within a small scope of procurement, and then the following is how to conduct inspections. The dimension tolerance of the cleanliness and wall thickness of the inner cavity of the copper tube is strict. However, in the whole process of electric welding, due to the role of the molten metal material of the air conditioning copper pipe, the thickness of the pipe at the welding point will be uneven, and the inside and outside of the welding will be uneven. This will cause energy consumption of the conveyor. At this time, the internal welding ground must be used for leveling. Next, we will take you to the production process of copper pipe - internal welding and calibration. At present, many materials are also used in the life of red copper pipes. Be as judgmental as possible when buying. In fact, there are many things to pay attention to when purchasing copper tubes. Want to keep high when buying. What should we pay attention to when buying copper tubes next. The daily use and market are calculated according to the weight, so you should decide how much to use before buying.

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 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, 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.

If the copper tube is blocked during use, it is also very important to dredge it in time.

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

Home page recommendation.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, 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, 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 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.

It is still necessary to pay attention to the materials used for pipes and the hardness of materials, 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.

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,Bhutan6063 aluminum tube, slowly add it into the calculated amount of phosphoric acid under stirring until it is completely dissolved, then add zinc nitrate and tartaric acid, 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, and soak them for 2-3 days to make them contain enough ferrous ions. When the content of ferrous ion reaches above 7g/L, 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 ℃, 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, phosphating and passivation are described. This comprehensive treatment process can simplify the process rust removal, 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 and separate the pollutants from the circulation system. This method was used in the early stage, 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.

Design brand.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, 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, 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, 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.

Dissolved oxygen in water is a major factor in copper pipe corrosion.

Plastic coated copper pipe is a kind of non-metallic material pipe with light weight, 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, dissolved discoloration lines and uneven colors. The inner holes of the pipe shall be laser cut and leveled and vertical to the pipe centerline. The inner holes shall be smooth and free of burrs. Specification: The length of pipe fittings is generally 6000 or 9000mm, 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, there may be many key points. Pay special attention to the leveling and straightness of the road surface when threading, 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, 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.

Now let me talk about the damages that are easy to occur on the surface of the copper tube. In order to prevent the accumulation of process agents or products and/or dirt, scratches and other rough surfaces, mechanical cleaning must be carried out. If the copper pipe is heated to a certain high temperature in the air during welding or grinding, chromium oxide heat return color will appear on both sides, lower surface and bottom of the weld. The color after tempering is thinner than that of the oxidation protective film, and is clearly visible. The color depends on the thickness. The thicker oxide can be found in the rainbow color, purple to brown. It is usually black. It is caused by being at high temperature or being at high temperature for a long time. When any of these oxide layers exist, the chromium content on the metal surface will, and the corrosion resistance of these areas will. In this case, it is not only necessary to heat temper the color and other oxide layers, but also to clean the chromium poor metal layer under it. Free iron on the surface of t2 copper tube will rust, causing corrosion of stainless steel. Therefore, the powder that must float can usually be removed together with the dust. Some are very sticky and must be treated as embedded iron. In addition to dust, there are many surface iron sources, including cleaning with ordinary carbon steel wire brush and shot peening with sand, glass beads or other abrasives previously used on ordinary carbon steel, low alloy steel or cast iron, or regrinding non stainless steel products attached to copper pipe components and equipment. If there is no protection during cutting or hoisting, the wire ropes, slings and iron on the working surface can easily be embedded or dirty the surface. The copper tube shall be boiled in boiling water for 30 seconds before cold treatment. The effective internal stress is about 15%, and the residual austenite reaches the effect. Then the cold treatment can be carried out as usual. Of course, the second suggestion is to choose the normal treatment at minus 60 degrees, and then conduct deep cooling at minus 120 degrees. The lower the treatment temperature is, the retained austenite will be rapidly transformed into martensite, but it cannot be transformed. Through experiments, it can be found that there will be about 2% of retained austenite. At this time, retained retained austenite can achieve a certain buffer effect. After cold treatment, which can effectively heat about 40% of the cold treatment stress. Tempering and cold treatment should be carried out as soon as possible after gradual heating, and most of them can avoid cracks as soon as possible, so as to ensure that the products will not deform in later use and facilitate daily storage. The transformation characteristics of the area of each layer of the copper tube during empty drawing affect the asymmetry of the deformation of the metal material. One of its characteristics is that the natural widening of each layer along the wall thickness is not consistent. Of course, the external layer of the copper tube is less the internal surface layer of the copper tube is larger, and the natural widening of the middle layers is slow from the external layer to the internal surface layer.The technical level of degreasing copper tube for mechanical equipment With the substantial improvement of the manufacturing level of mechanical equipment and the degree of control automation in China, there is still some gap between the technical level of domestic degreasing copper tube production line and the products of foreign counterparts. After years of reform and opening up. The quality of all aspects of degreased copper pipe has also risen by several grades,BhutanLow alloy plate, significantly narrowing the quality gap with the imported production line. The aluminum hose production line and aluminum can production line developed and produced by the company break the technological monopoly of foreign companies, can provide stable and reliable production equipment for domestic and international markets, and make great contributions to the aluminum packaging industry. With the continuous improvement of people's living standards, there will be more and more demand for degreased copper tube products, and its market potential is huge. Problems such as incomplete penetration, deformation, cracks and air holes are easy to occur during the fusion welding of degreased copper tubes. Compared with fusion welding, wood is not melted during brazing, which reduces the impact of large thermal conductivity of base metal on welding quality, prevents the formation of incomplete penetration, reduces the tendency to produce pores and cracks, and ensures the performance of weld. Because the base metal is not melted, the structure and properties of the base metal are almost unchanged, so that the original service properties of the base metal can be maintained.

Now let me talk about the damages that are easy to occur on the surface of the copper tube. In order to prevent the accumulation of process agents or products and/or dirt, scratches and other rough surfaces, chromium oxide heat return color will appear on both sides, lower surface and bottom of the weld. The color after tempering is thinner than that of the oxidation protective film, and is clearly visible. The color depends on the thickness. The thicker oxide can be found in the rainbow color, blue, purple to brown. It is usually black. It is caused by being at high temperature or being at high temperature for a long time. When any of these oxide layers exist, the chromium content on the metal surface will, and the corrosion resistance of these areas will. In this case, it is not only necessary to heat temper the color and other oxide layers, but also to clean the chromium poor metal layer under it. Free iron on the surface of t2 copper tube will rust, the powder that must float can usually be removed together with the dust. Some are very sticky and must be treated as embedded iron. In addition to dust, there are many surface iron sources, including cleaning with ordinary carbon steel wire brush and shot peening with sand, low alloy steel or cast iron, or regrinding non stainless steel products attached to copper pipe components and equipment. If there is no protection during cutting or hoisting, the wire ropes, slings and iron on the working surface can easily be embedded or dirty the surface. The copper tube shall be boiled in boiling water for 30 seconds before cold treatment. The effective internal stress is about 15%, and the residual austenite reaches the effect. Then, the cold treatment can be carried out as usual. Of course, the second suggestion is to choose the normal treatment at minus 60 degrees, and then conduct deep cooling at minus 120 degrees. The lower the treatment temperature is, the retained austenite will be rapidly transformed into martensite but it cannot be transformed. Through experiments, it can be found that there will be about 2% of retained austenite. At this time, retained retained austenite can achieve a certain buffer effect. After cold treatment, the air conditioning copper pipes need to be taken out and put into hot water for heating, which can effectively heat about 40% of the cold treatment stress. Tempering and cold treatment should be carried out as soon as possible after gradual heating, and most of them can avoid cracks as soon as possible, so as to ensure that the products will not deform in later use and facilitate daily storage. The transformation characteristics of the area of each layer of the copper tube during empty drawing affect the asymmetry of the deformation of the metal material. One of its characteristics is that the natural widening of each layer along the wall thickness is not consistent. Of course, the external layer of the copper tube is less, the internal surface layer of the copper tube is larger, and the natural widening of the middle layers is slow from the external layer to the internal surface layer.The technical level of degreasing copper tube for mechanical equipment With the substantial improvement of the manufacturing level of mechanical equipment and the degree of control automation in China there is still some gap between the technical level of domestic degreasing copper tube production line and the products of foreign counterparts. After years of reform and opening up. The quality of all aspects of degreased copper pipe has also risen by several grades, significantly narrowing the quality gap with the imported production line. The aluminum hose production line and aluminum can production line developed and produced by the company break the technological monopoly of foreign companies, can provide stable and reliable production equipment for domestic and international markets, and make great contributions to the aluminum packaging industry. With the continuous improvement of people's living standards, there will be more and more demand for degreased copper tube products and its market potential is huge. Problems such as incomplete penetration, deformation, cracks and air holes are easy to occur during the fusion welding of degreased copper tubes. Compared with fusion welding, wood is not melted during brazing, which reduces the impact of large thermal conductivity of base metal on welding quality, prevents the formation of incomplete penetration, reduces the tendency to produce pores and cracks, and ensures the performance of weld. Because the base metal is not melted, the structure and properties of the base metal are almost unchanged, so that the original service properties of the base metal can be maintained.