The welded pipe is a steel pipe made of steel plate or strip steel after being crimped and welded, generally with a length of 6 meters. The production process of welded steel pipe is simple, the production efficiency is high, there are many varieties and specifications, and the investment in equipment is small, but the general strength is lower than that of seamless pipe.
1. When welding steel pipes, it should be done according to the purpose. Pay attention to the problem of shrinkage cracks during the welding process. For the mechanical properties of the pipes in the heat-affected zone, there should be no excessive changes due to the influence of welding operations.
2. Pay attention to the wall thickness of the welded pipe. If the wall thickness of the steel pipe is relatively thin, high-frequency welding can be used; for some thin-wall steel pipes, protective gas welding can be used, and for thicker steel pipes, manual arc welding can be used.
3. Weld according to the size of the pipe. If the welded pipe is relatively small and can only be welded on one side, it can be drilled into the pipe for welding; but if it is welded on one side, it must pass the steel ball test, so as to ensure that the cross-sectional area meets the design requirements for weld formation.
4. If the steel pipe is a high-strength alloy steel with good wear resistance, temperature resistance, and pressure resistance, the welding process must be implemented to avoid cracking tendencies due to high-temperature welding operations.
5. When welding steel pipes, it is necessary to minimize the welding swing, and the arrangement of the welds should have an annealing effect on the heat-affected zone as much as possible. It can be cooled slowly after welding, and then covered with asbestos cloth.
Welded pipes are widely used in water supply engineering, petrochemical industry, chemical industry, electric power industry, agricultural irrigation, urban construction, etc. Compared with the welded pipe, the steel pipe dimension can reach 650mm, and the minimum diameter is 0.3mm.
Because the multi-wire submerged arc welding of longitudinally welded pipes has the characteristics of large undercooling and fast welding speed, the equilibrium state is basically eliminated.
If the same chemical composition as the base metal is used as the welding material, the weld metal will have low plasticity, Low toughness, high strength mechanical properties.When operating the oil and gas transportation longitudinally welded pipes(lsaw steel pipe) with high technical requirements, if the safe operation of the pipeline is to be fully ensured, it is necessary to have good impact toughness and plastic welds, in order to avoid the crack resistance, plasticity and toughness of the welded joints.
Therefore, when choosing welding materials, you need to consider the weld The crack resistance, plasticity and toughness of metals in all directions.At the same time, when welding large-diameter straight seam steel pipes and other medium-thick plates with greater rigidity, in order to prevent cracks from being caused by greater joint restraint, within the allowable design range, choose a slightly lower strength Welding materials based on the base metal, that is, the use of low-matching joints.
This method can prevent the actual strength of the weld from being reduced due to the decrease in the strength of the welding material, thereby greatly increasing the toughness of the weld and reducing the tendency of the joint to crack , Increase the comprehensive mechanical properties of the joint weld.Welding wires of different diameters have different current adaptation ranges in submerged arc welding.
The melting amount of the welding wire will increase with the increase of the current within this range, which will affect the welding seam forming effect, and the adjustment effect of the arc itself will be due to the inability to reach The current in this range is affected and the arc is unstable.
Longitudinal welded pipes with multi-wire submerged arc The welding quality of welding is also affected by many factors, such as the dry elongation of the welding wire, the inclination of the welding wire, the spacing of the welding wire and the arrangement of the welding wire.
Read on the below-given article to know about fabrication and welding.
"Fabrication," especially when applied to industry, refers to the construction of buildings, machinery, goods, or another type of equipment by just stamping, cutting, shaping, connecting, and perhaps even assembling the components made of raw materials, most commonly metals.It is usual to believe that a fabrication process involves welding as well, however, I have opted to split this out because some welding procedures are now highly specialized skills that need their own part in this article.Fabrication FirmsA fabrication shop seems to be a small firm that specialized in this sort of activity, however, it should be emphasized that individual components and metalworking operations will usually overlap with the machine shop work as well as sheet metal engineering or otherwise sheet metal work.
Welding and fabrication Boston MA has been doing outstanding work.What appears to be a basic action, like cutting metal, can refer to a variety of processes ranging from shearing as well as sawing through cutting torches and otherwise water jet cutters and, eventually, laser-cut tables as well as plasma cutting.
You would always need to research the particular capabilities as well as capacities of the specific fabrication facility which you want to employ, based on the speed and precision of what you actually want, as well as the cost as well as quality requirements.In general, the Fabrication, as well as Welding Shop, will most likely encompass several of the following cases:• Cutting • Bending• Shearing • Forming • Milling• Turning• Welding • SolderingWelding has been often used in metal production, and many produced components, as well as assemblies, are tack welded together before being tested for correctness and fit.Welding seems to be a manufacturing process that primarily involves connecting metals or otherwise thermoplastics by producing coalescence, which is typically accomplished by melting the components and then adding a filler material to actually form the welding pool, which, whenever cooled, produces a highly strong connection.
This differs from brazing as well as soldering, which don't cause the primary components to melt but instead melt a substance between them to establish a connection.Other than the particular gas flame that most of us are familiar with, there are several other types of energy that may be utilized for welding, including laser, electric arc, electron beam, friction, and ultrasonic.
Welding seems to be a professional activity that necessitates many safety precautions for avoiding burns, shocks, eye-damaging, fumes, and other hazards.Starting with particularly forging welding within the blacksmith shops, protected metal arc welding does seem to be probably the most common type of welding used today, along with semi as well as fully automated procedures like gas metal arc welding as well as flux-cored welding process, and otherwise as technology advances, so do the particular welding systems like laser beam welding as well as electron beam welding.
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