SSAW Pipe

In automobiles, there's a material that may go unnoticed, but it's crucial—like the car's "blood vessels" and "skeleton," supporting the powertrain and ensuring safety. That material is seamless steel pipe. From the engine to the exhaust system, from the chassis to the drive shaft, seamless steel pipes play a role in almost every critical part of a car.Compared to welded pipes (such as ERW pipes), seamless steel pipes do not have the potential weak point of weld seams. What is a seamless steel pipe? A seamless steel pipe, as the name suggests, is a steel pipe without any weld seams. It's generally made by piercing a solid steel billet and then hot-rolling or cold-drawing it. The absence of weld seams means the entire pipe is a single, continuous piece, making it stronger, more reliable, and more durable than welded pipes. In automobiles, stainless steel seamless pipes are mainly used in the exhaust system, accounting for more than ha...

For welded tubes of special materials, heat treatment must be carried out before and after welding, which is very important to the welding quality. The pre-heating of welded pipes made of special materials can not only slow down the cooling rate after welding, but also help hydrogen diffuse and escape from the weld metal to avoid hydrogen-induced cracking. At the same time, the degree of hardening of the weld seam and the heat-affected zone is reduced, and the crack resistance of the welded joint is improved. It can also reduce the welding stress, uniform local or overall preheating, and reduce the temperature difference between the weldments in the welding area, so that on the one hand, the welding stress is reduced, and on the other hand, the welding strain rate is reduced, which is beneficial to avoid welding cracks. It can reduce the degree of restraint of the welded structure, especially for reducing the degree of restraint of the fillet joints. As the preheating temperature incre...

 What is welding slag inclusion? Welded pipe slag inclusions are slag that remains inside the weld. Welding slag inclusions are generally divided into two categories: The first category is metal slag inclusions. The second category is non-metallic slag, which refers to the slag remaining in the weld after welding, including electrode coating or flux, sulfide, oxide and nitride. According to its formation, it can be divided into point-like slag inclusions, linear slag inclusions, chain-like slag inclusions and dense slag inclusions. Slag inclusions will reduce the plasticity and toughness of steel pipe welds, and slag inclusions with sharp corners will cause stress concentration at the tip, and the tip will develop into a crack source, especially in welds with a large tendency to air quenching. Under the action of stress on the steel pipe, cracks will first appear at the slag inclusions in the weld and develop along the way, resulting in a decrease in strength and cracking of the we...

    Copper pipe is an important raw material for refrigeration equipment, which is mainly used for making heat ex-changers and connecting pipes and fittings. Refrigeration and air-conditioning welded pipe fittings are mostly copper (purple) pipes. Common types of solder are copper-phosphorus solder, silver-copper solder, and copper-zinc solder. According to the characteristics of the pipe material, the correct solder should be selected and operated skillfully to ensure the quality of the welding.     1. Welding of similar materials     (1) Brazing of copper and copper     You can choose phosphor copper solder or phosphor copper solder with low silver content, such as 2% or 5% silver-based solder. This type of solder is relatively cheap and has a good solution. It uses caulking and wetting processes and does not require flux.     (2) Welding of steel and iron     Optional brass bar solder plus appropriate flux. When s...

    J55 oil jacket fusion zone defect:     After the ERW oil jacket, the welded pipe in the heat affected zone of the fusion line was found to be unqualified. Metallographic analysis, scanning electron microscopy and process research were carried out. The results show that the J55 welded pipe is on the fusion line. There is a certain depth of crack defect at the edge of the original plate in the heat affected zone. During the pipe making process, the user has a small pipe diameter and insufficient trimming amount, resulting in a significant increase in crack defects. The crack at the edge of the hot rolled original sheet originates from the corners of the cast slab and the subcutaneous bubbles.

    There are two types of steel pipes, one is seamless steel pipe, and the other is ordinary steel pipe, also called welded pipe. The seamless steel pipe has no joint gap on the body of the steel pipe, and the ordinary steel pipe is made by welding. Although the gap on the body of the steel pipe is invisible to the naked eye, it does exist. Among them, welded pipe is our most common steel.     Although its strength is not as good as that of seamless steel pipes, the currently used steel pipes generally do not use directly processed welded pipes. All of them have to undergo a certain treatment. After treatment, its performance will be improved. After forming a kind of steel pipe. Welded pipes can be said to be ubiquitous in our lives.     Welded pipes are used wherever they are not visible, so what are the advantages of welded pipes that make them used in various places?     1. The materials are simple. When producing seamless steel pipes, t...

　　There are many kinds of pipes and their production methods are various. The common production methods are as follows： 　　(1) Production of pipes by thermal pressure processing. There are many ways to produce hot rolled seamless pipes. The tubes used for hot rolled tubes are hollow billets, solid billets or steel ingots. In hot rolling production, the punching is to pass the heated pipe blank into a thick-walled capillary tube on a perforating machine, and roll the thick-walled capillary tube into a finished tube on the pipe rolling machine to the required wall thickness and accuracy, and then pass the sizing, reduction or expansion Diameter, and finally cooling and finishing.The hot-pressing method is mainly used for rolling pipes, but for non-ferrous metals, rare metals that are difficult to deform, and precious metal machines, special-shaped profile pipes are produced by extrusion. 　　(2) Pipes are produced by cold pressure processing. The cold-pressure processing method mainly r...

　　 Welded pipe is a common seen pipe which usually be used on fluid conveyance. Generally, it is defined to as the large diameter solder pipe, in accordance with the welding as a way for tube, the solder steel pipe consist spiral pipe and straight seam welding tube. 　　Based on the application, it can be divided into general welded pipe, galvanized welded tube, oxygen blowing metric pipe, welded tubes, wire casing, roller tube, deep well pump tubes, auto tube, transformer, electric soldering thin wall pipe, welded pipe and spiral welded tube. 　　Spiral welded pipe is the low carbon structural steel and low alloy structural steel strip according to certain helix Angle rolled into a tube billet, and then solder pipe joints made up, it can use a narrow strip in the production of large diameter steel tube, straight seam solder pipe is hot rolled plate after molding machine molding, roll deformation of steel coil for round cylinder, using frequent current skin effect and proximity effect...

　 　Advantages of welded pipe 　　Structural welded pipe (tubing) can be used for a wide variety of mechanical applications. It may be used either statically or dynamically. Its close tolerances, good finish, and dense structure make it ideal for parts such as structural support and parts, frames, racks, trailer beds and trailer components, structural components and supports for buildings, bridges, and highways, conveyors, machine parts, ornamental usages and a wide range of applications in industrial, construction, automotive, appliance and agricultural industries. 　　Welded pipes are generally more cost effective than the equivalent seamless alternative. They are significantly more available both from distributor and mill stocks and from a mill production lead time perspective. With longer lead times seamless tubes can be exposed to unknown alloying price extras that can fluctuate substantially, hence it can be difficult to plan and predict the true costs for the material. Therefore ...

　 　Uses of Welded pipe 　　1. General welded pipes are used for the transportation of generally lower pressure fluids such as water, gas, air, oil and heating steam. 　　2. Ordinary carbon steel wire casing pipe (GB3640-88) is a steel pipe used to protect electric wires in electrical installation projects such as industrial and civil construction, installation machinery and equipment. 　　3. Straight seam welded pipe (YB242-63) is a steel pipe whose weld is parallel to the longitudinal direction of the steel pipe. Usually divided into metric electric welded pipe, welded thin-walled pipe, transformer cooling oil pipe and so on. 　　4. Spiral-slit submerged arc welded pipe (SY5036-83) for pressurized fluid conveying is a hot-rolled steel strip coil for tube blank, which is often spiral-formed by a double-sided submerged arc welding method for spiral conveying of pressurized fluid. Seam steel pipe. The steel pipe has strong pressure bearing capacity and good welding performance. It is saf...

　　The straightening method of DSAW tube: 　　One, the DSAW tube is bent in the same direction 　　Reason: Welding normalization is insufficient, the pipe has thermal stress on the welding side, and bent in one direction after cooling. 　　Solutions: 1, adjust the middle roller, properly increase the deflection curve; 2, two straightening; 3, the whole tempering pipe can not be straightened directly. 　　Two. The DSAW tube is unrule bending 　　Reasons: 1. the pressure between the three rollers is not consistent; 2. the straightening roller wears a lot. 　　Solution: check whether the adjustment of the straightening roller is loose, and use the sample rod to straighten the contact line length between the three. 　　Third, the length of the DSAW tube is short 　　The reason is that the angle of the three roller straightening roller is different, and the straightening pressure is larger. 　　Solution: adjust the rolling angle as much as possible and adjust the straightening pressure prope...

　　The surface heat treatment technology of the 45th thick-walled seamless steel pipe is constantly being innovated, and the current technology has been developed more and more sophisticated. Let's take a look at several methods of 45-thick thick-walled seamless pipe processing. 　 　1. Surface hardening: 　　Rapid heating of No. 45 thick-walled seamless pipe by different heat sources, when the surface temperature of the part reaches above the critical point (when the temperature of the 45# seamless pipe core is below the critical point), it is quickly cooled, so that 45# seamless The surface of the tube is hardened and the heart remains in its original tissue. The most widely used in the industry is induction heating and flame heating surface quenching. 　　 2. Chemical heat treatment: 　　The 45# seamless tube is placed in a medium containing active elements to heat and keep warm, so that the active atoms in the medium penetrate into the surface layer of the 45-thick thick-walled ...

　　The magnitude of the tissue stress is related to the cooling rate, shape, and chemical composition of the workpiece in the martensitic transformation zone. The faster the cooling rate, the higher the carbon content and alloy composition, the greater the uneven plastic deformation caused by thermal stress during cooling, and the greater the residual stress formed. 　　On the other hand, in the process of heat treatment, when steel changes to austenite to martensite, the increase of specific volume is accompanied by the expansion of the volume of the workpiece, and the parts of the workpiece are successively transformed, resulting in inconsistent volume growth and tissue formation. stress. The final result of the change in tissue stress is the tensile stress on the surface layer and the compressive stress on the core, just opposite to the thermal stress. 　　When the large-diameter straight-welded welded pipe is finished at the end of cooling, the core portion of the surface is not pul...

　　In the production process of erw steel pipe, when the roll is damaged or worn seriously, some rolls need to be replaced on the unit, or a certain quantity is continuously produced in sufficient quantity, and the entire set of rolls needs to be replaced. At this time, the rolls should be adjusted to obtain good steel pipe quality. If the roll is not well adjusted, it is easy to cause the torsion of the steel pipe joint, lap welding, edge wave, embossing and scratching on the surface of the drum and the pipe body, and the ovality of the steel pipe is large. Therefore, the roll adjustment should be mastered when changing the roll. skill. 　　1) Replace the steel pipe specifications, generally replace the entire set of rolls. The method of adjusting the roll is to use a steel wire to pull a center line from the inlet to the outlet of the unit, and make adjustment so that each hole type is on a center line, and the forming bottom line meets the technical requirements. After changing the s...

　　The erw steel pipe production process requires a series of processes from raw materials to finished products. To complete these processes, various mechanical equipments and welding, electrical control and testing devices are required. These devices and devices have various rational arrangements according to different process requirements. 　　High-frequency welding is a type of welding method in which the resistance of the high-frequency current flowing through the continuous contact surface of the workpiece is heated by the electric resistance and the forging force is applied to realize the mutual connection between the workpiece metals. It is similar to ordinary resistance welding, but there are many important differences. 　　High-frequency welding has been used in carbon steel welded pipe production for more than 40 years. High-frequency welding has a large power supply, and can achieve a higher welding speed for steel pipes of different materials, calibers and wall thicknesses (...

　　 LSAW steel pipe quality check methods, during which the physical approach is the most commonly used inspection methods, physical examination is the use of physical phenomena to determine or check the method. 　　 Magnetic force 　　Magnetic flaw detection can only find the appearance and appearance of magnetic straight seam welded pipe shortcomings, and the shortcomings can only do quantitative analysis, the nature and depth of the shortcomings can only be based on experience to estimate. Magnetic inspection is the use of magnetic field magnetization of ferromagnetic Longitudinal Welded Pipe leakage occurred to find the shortcomings. According to the measurement of magnetic flux leakage method is not the same, can be divided into magnetic powder method, magnetic induction method and magnetic recording method, during which the most widely used magnetic powder method. 　 　Soaked inspection 　　Penetration test is the use of some of the liquid permeability and other physical properti...

　　Precision seamless steel tube is a kind of high precision steel tube material after quenching or cold rolling.Because of no oxide layer of the surface, precision seamless steel pipe has the advantages of high-pressure, high-precision, high-grade finish, which can be used to manufacture cylinders and welded pipes. 　　Compared to other solid steel material, seamless steel pipe is lighter with the same flexural torsional strength. It is an economic section of steel, widely used in the manufacture of structural and mechanical parts. Precision seamless steel pipe also has some of their own characteristics. They have been widely used to manufacture ring parts, can improve the utilization of materials, simplify the manufacturing process, save materials and processing time, such as rolling bearing rings, jack sets. 　　Generally, the industry require a higher precision, they often use precision seamless steel pipe, others mainly use seamless steel pipe if there is no precision requirements....

　　During the construction of natural gas and oil pipeline stations, the installation of valves, meters and flanges should be tapped in the main channel. It is difficult to identify the straight seam position of the base pipe by high-frequency resistance welding. The installation of some lugs is very close to the welding seam. Therefore, it is very necessary to deeply study and analyze the influence of the boss on the basic pipeline. In this paper, the residual stress distribution of high frequency longitudinal resistance welded pipe is analyzed, and the influence of welding position of different boss on residual stress is analyzed. The stress increases sharply and the longitudinal welding residual stress is affected when the boss installed on the ERW pipe is much larger than the parent pipe. 　　ERW pipeline 　　The distribution of residual stress in welded pipe is closely related to the forming process. HFW resistance welding is the cross section of a circular tube after rolling, whic...

　　A process for producing hot rolled strips with a thickness of 1.2-8 mm on a hot strip mill. The strip width of 600mm is referred to as narrow strip steel; the width of strip steel is more than 600mm. The first strip hot rolling mill was put into operation in the United States in 1905, producing a 200 mm wide strip. 　　The strip hot rolling mill has superior technical and economic indicators and it has developed rapidly. In industrialized countries, before 1950, the output of hot-rolled wide-band steel accounted for about 25% of the total steel output, and it had reached about 50% in the 1970s. The raw material of the hot strip is continuously cast slab or green rolled slab, thickness 130-300mm. 　　After the slab is heated in a heating furnace, it is sent to a rolling mill and rolled into a strip of 1.00-25.4 mm in thickness and rolled into coils. Rolled steel grades are plain carbon steel, low alloy steel, stainless steel and silicon steel. Its main purpose is to make cold-rolled s...

    High frequency straight seam welded pipe fracture, hydraulic (pneumatic) parts used in mechanical performance design, brittle fracture and the use of temperature-related components.     It is found that when the temperature is lower than a certain temperature value, it is found that the data will change into brittle state, the impact absorption work decreased significantly, this phenomenon is called cold brittle, high-strength metal materials occurred in the low stress brittle fracture The organization of the data is far from uniform isotropic tissue will have cracks, there will be inclusions, pores and other defects, these defects can be seen as micro-cracks in the material. Therefore, the design should also be based on the operating temperature of the component to select the appropriate data of the cold and brittle transition temperature.     In general, it is assumed that the data is uniform and continuous isotropic. According to this method, the...