Zhan6063 aluminum barPay 10,000 for one fake

it is an improved spray type passivation box for t2 copper pipe production line. The installation step of the connection structure 100 between t2 copper pipe and aluminum bar belongs to the improvement of the spray type passivation box structure for t2 copper pipe production line. The passivation solution spray box is set above the side of the passivation solution box

In particular, the passivation solution spray box with downward sloping bottom is connected with the inlet of the passivation solution box by the outlet set on the box wall at the bottom of the inclined bottom, the inlet of the passivation solution box is located on the box wall above the passivation solution box, the upper side of the passivation solution box is installed with a passivation pump, and the inlet pipe of the passivation pump is connected with the passivation solution box, The outlet pipe of the passivation pump is connected with the upper port of the passivation liquid spray box. With reasonable structure and convenient operation, it is convenient for operators to add passivation liquid to the passivation box, clean colloidal crystals at the bottom of the passivation box, avoid equipment blockage, avoid crystals adhering to the zinc layer on the surface of galvanized pipe, and improve the surface quality of galvanized steel pipe.

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, 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,ZhanBronze plate, 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 ℃, 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, 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, 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.

Zhan.According to the market feedback, there was no problem in the first half of the market circulation in September, but there was significant pressure in the second half of the month, mainly due to the impact of futures. From the perspective of steel mills, at present, there is a great pressure to receive orders in October. Fortunately, the inventory situation is relatively optimistic, and some steel mills have increased their export volume, so short-term prices are still partially supported. At present, the short-term weak balance will be reflected. At present, the divergence point of * * * * is that the cold system products continue to hang upside down and the pressure accumulates to see whether the cold rolling can drive the hot rolling downward.

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, 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.

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

When cutting the copper pipe of air conditioner, use tools such as clamps to fix the copper bar and then cut it, to prevent shaking and resulting in irregular cutting. 3 After the cutting of the air conditioner copper pipe is completed, and then processed again after cooling, otherwise oxidation will occur due to high temperature. Liu Shuchen, director of the Resource Analysis Office of the Information Center of the Ministry of Land and Resources, the mining super cycle driven by China's demand has not changed, especially the growth rate of the country's economy. After the global economy may improve in the second half of the year, the global mining industry will rise again,Zhan7075 aluminum bar, and the W-shaped trend will fully emerge. In the second half of the year there were signs of stabilizing and rebounding. In terms of the macro factors affecting the bulk commodities, the factors affecting the European market of tinned copper bars have gradually weakened, and the economic conditions of China and the United States have become the key factors affecting the bulk commodities. The European economic recession is a foregone conclusion, and the possibility of a crisis in the next period of time is also reduced. In recent years, the American market economy has shown the characteristics of better than expected in the first quarter and weaker than expected in the second quarter. Since January, the global price of medical copper tubes has gradually got rid of the main tone of this year's shock and decline. &Air conditioning copper tubes show signs of stabilizing and rebounding. The three-month copper on the London Metal Exchange once rebounded nearly 7% from the year's low point, and the market price has rebounded to around 7600 dollars per ton. Driven by this, products including aluminum, zinc and other products have also rebounded. Only nickel, a basic metal product, has remained weak.

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, and users were very cautious in purchasing; Around 11:00, the surrounding markets became loose and the price was low. High hanging, low selling, which is different from the opening. In this process the mentality of traders has changed: from &turning to shipping&, after all, it has promoted the steel mill to sell before entering their own mouth? This is a &manic& market again: failed to continue to rise, spot prices rose; The construction site plan is not much, and the market transaction is weak - this week's trading days, the spot price rose, 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,Zhan5052 aluminum bar, 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.

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 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.

For internally threaded tubes with the same inner diameter, the thickness of ferrous metal is not required for copper tubes.

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, 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, 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 the active centering is insensitive to deflection. The bearing force is uniform, bronze rods, 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.

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

It is applicable to the removal of thin liquid oil stain and light rust and the generation of phosphating film with certain corrosion resistance. See Table 3 for example of formula and operating conditions. Table 3 Degreasing, rust removal, phosphating and passivation

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

Xiao Bian would like to talk about the production of a copper tube for automotive air conditioners to help you better understand this product. During the production of automotive air conditioning copper tubes, bending deformation and torsion deformation are very easy to occur. Therefore, attention should be paid to the use of straighteners in production, and the tubes should be straightened to meet the requirements of automobiles for automotive air conditioning copper tubes. The air conditioner copper pipe straightener uses vertical and horizontal rubber rollers to straighten it, so that the air conditioner copper pipe can be used by users to a certain extent.Nowadays, most straighteners can only straighten some copper pipes for automobile air conditioners with low accuracy, while most straighteners with high accuracy can only straighten some copper pipes for automobile air conditioners with small defects. Therefore, the straightening equipment used for rectangular pipes with different bending degrees is different, some other construction processes should be used, To solve some problems arising from the above production. For example, in the preliminary manufacturing of medical copper tubes for automobiles, the air conditioner copper tube materials can be selected according to the actual size required by the user, followed by pickling, putting the produced air conditioner copper tube materials into the pickling tank for pickling, and then stretching, and then stretching the pickled air conditioner copper tubes according to their size requirements. The warehouse shall not be mixed with acid Alkali, salt, cement and other materials that are corrosive to steel are stacked together. Air conditioning copper pipe is based on carbon structural steel. The phenomenon of torsional deformation of 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, toughness and hardenability of the annealing steel. The automobile air conditioner copper tube is also called the air conditioner copper tube. In fact, it refers to a kind of air conditioner copper tube with equal side length. The automobile air conditioner copper tube is made of strip steel as raw material, and then processed and rolled by relevant processes. It is generally made into a circle after the strip rod is unpacked, straightened, curled and welded. Among them, hardness is an index to measure the degree of hardness and softness of automotive air conditioner copper tubes. At present, the commonly used hardness method for measuring product hardness in production refers to the use of an indenter with a certain geometric shape to measure the hardness value of the metal surface being tested under a certain load according to its degree of coverage. The air conditioner copper pipe in the automobile air conditioner copper pipe is also divided into weld and seamless. Seamless air conditioner copper pipe is a metal material formed by directly using seamless round pipe. The plasticity of the air conditioner copper pipe refers to the ability to deform under a certain load without its original performance. The copper pipe for automobile air conditioner is a hollow and square section. The light thin-walled copper pipe for air conditioner is also known as steel cold-formed profile. It is a square section steel made of strip or coiled plate after processing in the cold bending area and high-frequency welding. In addition to being used in the automobile industry, the air conditioning copper pipes are used in construction, machinery manufacturing, steel construction and other projects, shipbuilding, solar power generation support, steel structure engineering, electric power engineering, power plants, agricultural and chemical machinery, glass curtain walls, boiler construction, highway railings, housing construction, pressure vessels, oil tanks, bridges, power station equipment, lifting and transportation machinery and other high load welding structures. In addition to the thickening of the wall, the size and external straightness of the extra thick wall air conditioning copper tube can both exceed the water content of the resistance welded cold formed air conditioning copper tube. Therefore, this kind of automobile air conditioning copper tube has better comprehensive mechanical properties and has the advantages of hot processing, cold processing, weldability and corrosion resistance.

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

T2 copper bar is applicable to bath water heaters, gaskets, handicrafts, building materials, chemical industry and electrical terminals. Product parameters: product status: M (soft), Y2 (1/2 hard), Y (hard), T (extra hard) and other statuses. Product thickness: 0.05-0mm (tolerance: ± 0.005 - ± 0.02mm). Product diameter: 0.5-200mm (tolerance: ± 0.05mm).

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.

Zhan.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 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, the specification must be 159MM500MM.

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

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 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.