The choice of thick-walled steel pipe welding method should be based on the material and wall thickness of the thick-walled steel pipe. Because different welding methods have different arc heat and arc force, different welding methods have different characteristics. For example: Tungsten arc welding

First, the principles of hot-dip galvanized steel pipes and galvanized steel pipes are different 1. Hot-dip galvanized steel pipe: To improve the corrosion resistance of steel pipes, ordinary steel pipes are galvanized. 2. Galvanized steel pipe: Galvanized steel pipe reacts molten metal with the iron matrix to produce an alloy layer, thereby combining the matrix and the coating. Second, the characteristics of hot-dip galvanized steel pipes and galvanized steel pipes are different 1. Hot-dip galvanized steel pipe: The surface of the galvanized steel pipe should have a complete galvanized layer, and there should be no uncoated black spots and bubbles. Small rough surfaces and local zinc tumors are allowed. 2. Galvanized steel pipe: To ensure the uniformity of the galvanized layer, the steel pipe sample must not turn red (copper-plated color) after being immersed in copper sulfate solution for 5 consecutive times. Third, hot-dip galvanized steel pipes and galvanized steel pipes have different uses 1. Hot-dip galvanized steel pipes: The iron pipes used for gas, greenhouses, and heating are also galvanized steel pipes. As water pipes, galvanized steel pipes produce a lot of rust and scale inside the pipes. The yellow water flowing out not only pollutes the sanitary ware but is also mixed with rough inner walls. The breeding of bacteria and rust causes excessive heavy metal content in the water, seriously endangering human health. 2. Galvanized steel pipe: widely used in agricultural greenhouses, fire protection, gas, water supply and drainage, and other fields.

ADVANTAGES: Higher strength to weight ratio than standard carbon steel pipe. Improved corrosion resistance in harsh environments. Excellent thermal conductivity. Good formability. The alloy has excellent weldability and machinability, making it suitable for a wide range of fabrication applica

FEATURES OF ALLOY STEEL P22 TUBES Alloy steel P22 pipes are made from a mixture of different metals, typically including iron & carbon. This combination allows for greater strength & toughness than other types of steel tubing. Alloy Steel P22 Tubes are also more heat resistant than other

ADVANTAGES OF S31803 DUPLEX STEEL TUBING ASTM A789 S32205 duplex steel tubes offer many advantages over other types of metal tubes. They have superior corrosion resistance, making them ideal for use in corrosive environments such as sewage treatment plants or marine applications where they are

Duplex steel S31803 tubes are one of the most popular and widely used alloys in the world. They are renowned for their superior strength, durability and corrosion resistance. Duplex steel S31803 is a duplex stainless steel containing 25% chromium and 7% nickel. It has a high strength to weight rat

They have many uses in both commercial and industrial environments. Petrochemical processing plants often use P22 tubing due to its high temperature resistance. Power stations often use P22 pipes to transport steam at extreme temperatures. P22 pipes can also be used in water treatment plants.

Alloy steel P22 pipes are widely used in industrial applications due to their excellent strength, durability and corrosion resistance. Manufacturers produce them from alloy and carbon steels and offer different sizes and grades to meet project requirements. P22 pipes are generally heat treated to

A flange is a part that connects steel pipes and is generally used for the connection between pipe ends. Flanges are mainly used in industry and play an important role in industrial manufacturing. Therefore, the market demand for flanges is relatively large. As an industrial part, flange plays an irreplaceable role. So, where is its role specifically reflected? What are the advantages of flange? Next, the editor will introduce the functions and uses of flange to you, so that you can better understand and become more familiar with flange, to provide Assistance with your production activities. Flange, also called flange or flange. It is a part that connects steel pipes. Connect to the pipe end. There are holes in the flange, and bolts can be inserted to tightly connect the two flanges. The flanges are sealed with gaskets. Flange pipe fittings refer to pipe fittings with flanges (flanges or adapters). It can be cast, threaded, or welded. Flange connection (flange, joint) consists of a pair of flanges, a gasket, and several bolts and nuts. The gasket is placed between the sealing surfaces of the two flanges. After the nut is tightened, the specific pressure on the surface of the gasket reaches a certain value and then deforms, filling the uneven spots on the sealing surface to make the connection tight and leak-proof. Some pipe fittings and equipment already come with flanges, which are also flange connections. Flange connection is an important connection method in pipeline construction. Flange connections are easy to use and can withstand greater pressure. In industrial pipelines, flange connections are widely used. Inside the home, pipes are small in diameter and low pressure, with no visible flange connections. If you are in a boiler room or production site, there are flange-connected pipes and equipment everywhere. The function of the flange is to fix and seal the pipe joints. The flange is mainly used to connect and fasten pipes, pipe fittings, etc., and maintain the sealing performance of the pipes and fittings; the flange is removable, making it easy to disassemble and inspect the pipe condition. Reducing flanges are corrosion-resistant, acid and alkali resistant, and can be used in water conservancy, electric power, power stations, pipe fittings, industry, pressure vessels, etc. Stainless steel flanges can be used in boiler and pressure vessels, petroleum, chemical, shipbuilding, pharmaceutical, metallurgy, machinery, food, and other industries to facilitate the replacement of a certain section of pipeline. The reducer flange is mainly used for the connection between the motor and the reducer, as well as the connection between the reducer and other equipment. Butt welding flanges are pipes used to transfer pressure, thereby reducing high-stress concentration on the flange base.

Simmered steel elbow weld locations The inner arc is at 45 degrees. The welded elbow is made of bent pipe and can be welded, so it is called a welded elbow. It does not mean that it has a weld itself. It is quite the opposite. Since the welded elbow is made of straight pipes, it is considered that For structural stress problems, seamless pipes are generally used. instead of welded pipe. The so-called seamless elbow is a casting and cannot be welded. What kind of pickling is commonly used for steel elbows? The commonly used pickling of welded elbows is the same in the quality process. The acids used for pickling include sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, chromic acid, hydrofluoric acid, and mixed acids. The most commonly used are sulfuric acid and hydrochloric acid. The pickling processes mainly include immersion pickling, spray pickling, and acid paste rust removal. Generally, the dipping and pickling method is used, and the spraying method can be used in mass production.

Defects that are prone to occur in the submerged arc welding zone include pores, hot cracks, and undercuts. 1. Bubbles. Bubbles mostly occur in the center of the weld bead. The main reason is that hydrogen is still hidden in the welded metal in the form of bubbles. Therefore, the measure to eliminate this defect is to first remove rust, oil, water, and moisture from the welding wire and weld. substance, followed by drying the flux well to remove moisture. In addition, increasing the current, reducing the welding speed, and slowing down the solidification rate of the molten metal is also very effective. 2. Sulfur cracking (cracks caused by sulfur). Cracks caused by sulfides in the sulfur segregation zone enter the weld metal when welding plates with strong sulfur segregation zones (especially soft boiling steel). The reason is that the sulfur segregation zone contains low melting point iron sulfide and the presence of hydrogen in the steel. Therefore, to prevent this situation, it is effective to use semi-killed steel or killed steel with less sulfur segregation zone. Secondly, it is also necessary to clean and dry the weld surface and flux. 3. Thermal cracks. In submerged arc welding, hot cracks can occur in the weld bead, especially in the arc starting and arc extinguishing craters. To eliminate this kind of crack, backing plates are usually installed at the arc starting and arc extinguishing points, and at the end of the plate coil butt welding, the spiral welded pipe can be reversed and welded into the stick welding. Hot cracks are prone to occur when the stress in the weld is very high, or when the pressure in the weld metal is very high. 4. Inclusion of welding slag. The inclusion of welding slag means that part of the welding slag remains in the weld metal. 5. Poor welding penetration. The metal overlap of the inner and outer welds is not enough, and sometimes the welding is not penetrated. This condition is called insufficient weld penetration. 6. Undercut. Undercut is a V-shaped groove appearing on the edge of the weld along the center line of the weld. Undercut occurs when welding speed, current, voltage, and other conditions are inappropriate. Among them, too high welding speed is more likely to cause undercut defects than inappropriate current.

Pushing elbows: The process of pushing steel elbows using machinery + mold inner tube + medium frequency heating method. However, it may be that the thickness of the inner and outer walls is difficult to control, and it is rarely used in practical applications. Socket weld elbow: Most are forged. In engineering, sockets are used when DN is less than or equal to 40 and there are no special requirements. A push elbow is a push-formed elbow. Nowadays, the most important elbow-forming production process is the push-formed elbow. First of all, the push-formed elbow is also a push-formed elbow production. The production speed is fast, and the push elbow can be produced in batches. The quality of the push elbow is good. The push elbow-forming process is now the most important elbow-forming production process. Socket elbow: It is a high-pressure elbow pipe connection fitting that is mainly formed by die-forging blanks of round steel or steel ingots, and then machined by a lathe. It is a type of forged socket series pipe fittings. Commonly used standards Commonly used standards for socket elbows include GB/T14383-93, GB/T14383-2008, American standard ASME B16.11, petrochemical standard SH3410, Ministry of Chemical Industry standard HG/T21634, etc. Specification form According to the form, it is divided into 45° socket elbow and 90° socket elbow. According to common standards, the specifications of socket elbows are DN6, DN8, DN10, DN15, DN20, DN25, DN32, DN40, DN50, DN65, DN80, and DN100. The commonly used ordering specifications are DN15----DN50. If there is anything beyond the scope of this specification, we can communicate with the customer for drawing design and processing. Pressure Level Distinguished according to pressure level: 3000LB, 6000LB, 9000LB or SCH80, SCH160, XXS Commonly used manufacturing materials Commonly used raw materials for socket pipe fittings are generally divided into carbon steel, stainless steel, alloy steel, etc. Commonly used grades of carbon steel include Q235, 20#, A105, etc.; Commonly used grades of stainless steel include 304, 304L, 316, 316L, 321, 00Cr17Ni14Mo2, etc.; Commonly used grades of alloy materials include 15CrMo, 1Cr5Mo, 16Mn, 12Cr1MoV, F11, F22, 10CrMo910, etc. Other materials: copper alloy, nickel alloy, etc.

1. Mainly use tools such as wire brushes to polish the steel surface. Cleaning and preheating the spiral welded pipe can remove loose or lifted scales, rust, welding slag, etc. The rust removal of hand tools can reach the Sa2 level, and the rust removal of power tools can reach the Sa3 level. If the iron oxide scale is firmly attached to the surface of the steel, the rust removal effect of the tool will not be ideal and the anchor pattern depth required for anti-corrosion construction will not be achieved. 2. Pickling uses solvents and emulsions to clean the surface of welded steel pipes (welded pipes) for low-pressure fluid transportation to remove oil, grease, dust, lubricants, and similar organic matter, but it cannot remove rust, oxide scale, and flux on the steel surface. etc., so it is only used as an auxiliary means in anti-corrosion production. 3. Generally, chemical and electrolytic methods are used for pickling treatment. Only chemical pickling is used for pipeline anti-corrosion, which can remove scale, rust, and old coatings. Sometimes it can be used as a reprocessing after sandblasting and rust removal. Although chemical cleaning can achieve the highest cleanliness and roughness on the surface, its anchor lines are shallow and it is easy to cause pollution to the spiral welded pipe stacking environment.

First: It may be due to the stress of spiral submerged arc welded steel pipes. That is, the residual stress and welding stress after the steel pipe is formed. Second: due to the presence of hydrogen. For example, the flux is not dried enough, the preheating temperature is insufficient preheating before welding is not carried out, and the interlayer temperature of multi-layer welding is not enough. Third: Metallurgical factors of spiral welded steel pipes. During the welding process, low melting point impurities enter, such as copper and copper alloys. The main source of copper is copper plated on the surface of the welding wire to prevent corrosion of the welding wire. These copper shavings enter the flux from the inner hole of the contact tip and contact the welding pool during the welding process, causing transverse cracks. Fourth: The welding process of spiral seam submerged arc welded steel pipe is unreasonable. For example, the weld forming coefficient is too small, the preheating temperature is not enough or no preheating before welding, the welding line energy is too large, the heat treatment after welding is improper, the holding time is too short, etc. If there is welding slag during spiral seam submerged arc welding of steel pipes, use argon arc welding, or wait for the stainless steel welded pipe to cool down and then hit it with a hammer and it will fall off. These two methods are relatively simple, but they may not be clean. Welding slag is relatively easy to clean, but splashed slag is difficult to clean. If you can use electric grinding to clean welding slag, use electric grinding. Otherwise, it will be difficult to clean off welding slag. As for some defects that occur when cutting spiral welded steel pipes, we can also remove them, but if we want to remove these defects, we must find a reasonable method. Only the correct method can make up for the defects of welded pipes. Corresponding solutions can be found for these defects, but if the method is not found correctly, it will make use more troublesome. Another way to clean welding slag from welded pipes is to use a file. Using a file can also clean the welding slag very cleanly. Another simpler and more labor-saving method is to take a saw blade or half heel, reach into the pipe, hold the pipe in your left hand, and the saw blade in your right hand, and pull it clockwise or counterclockwise. This allows the welding slag in the welded pipe to be cleaned very cleanly without wasting too much time, making it simple and convenient.

While the ASTM and ASME standards for steel and other metals are very similar, if not identical, there may be slight differences between A36 and SA36 grades depending on the criteria used by each organisation. In fact, ASTM A36 and ASME SA36 are the only two standards that exist, ASTM SA36 is not. For use in bridges and buildings that are riveted, bolted or welded, and for general structural purposes, ASME A36 specifies carbon steel shapes, rounds and bars, while ASME contains design standards for pressure applications. In most cases, ASME standards are based on ASTM standards, although their numbers are prefixed with the letter 'SA' rather than just the letter 'A' as in ASTM.

Monel Sheet and Plate Specification : ASTM B127 / ASME SB127 Dimension Standard : JIS, AISI, ASTM, GB, DIN, EN, etc. Width : 1000mm, 1219mm, 1500mm, 1800mm, 2000mm, 2500mm, 3000mm, 3500mm, etc. Length : 2000mm, 2440mm, 3000mm, 5800mm, 6000mm, etc. Thickness : 0.3mm to 120mm

Monel 400/K500 sheets and plates are valued for their dimensional accuracy and ease of installation. In fact, it is a sheet and plate that can be easily hardened by cold working. The product also has good ductility and even good thermal conductivity. So the machinability of these sheets and plates is somewhat difficult as it works on hardness during the time of machining. The product is very strong and has about three times the yield strength and about twice the tensile strength. And this is even compared to other elements. The property of resistance is also there, it is resistant to rust.

Stainless Steel Plates and Sheets Specification : ASTM A240 / ASME SA240 Dimension Standard : JIS, AISI, ASTM, GB, DIN, EN, etc. Width : 1000mm, 1219mm, 1500mm, 1800mm, 2000mm, 2500mm, 3000mm, 3500mm, etc. Length : 2000mm, 2440mm, 3000mm, 5800mm, 6000mm, etc. Thickness : 0.3mm to 120mm