At present, commonly used welded steel pipes can be divided into three types of continuous welding (forging) steel pipes, electric resistance welding steel pipes and arc welded steel pipes according to different welding processes used in production.
The arc welded steel pipe is a steel pipe produced by the arc welding method. Its characteristic is that the welded joint achieves a complete metallurgical bond, and the
mechanical performance of the joint can fully reach or approach the mechanical properties of the parent metal. After proper heat treatment and non-destructive inspection, the
conditions for the use of arc welded straight seam steel tubes can be used to replace seamless steel tubes.
According to the different types of welds, arc welded steel pipe can be divided into two kinds of longitudinal welded pipe and spiral welded pipe. According to the different
protection methods adopted during welding, arc welded steel pipes can be divided into two types: submerged arc welded steel pipes and melted gas shielded welded steel pipes.
The spiral seam welded steel pipe is in the welding process, the welding torch and the welding seam are in the relative motion of the combination of the rotary motion and the
linear motion, and the weld seam is spiral. Compared with the straight seam steel pipe, the weld line length is long, and the force of the weld seam is a two-dimensional
tensile stress. Therefore, it is generally applicable to non-toxic medium pipelines with a design temperature of 0°C to 200°C and a design pressure of no more than 1.0 MPa.
However, spiral welded pipe production can be continuous operation, high production efficiency, high material utilization, and facilitate large-scale production. At present,
the commonly used steel pipe standards are SY/T5037 "Spiral Seam Submerged-Welded Steel Pipes for Ordinary Fluid Conveying" and so on. The specification range of SY/T5037 is
DN250^DN2500, and the wall thickness is from 15mm to 5.0mm to 20.0mm. There are three types of materials: Q195, Q215, and Q235. The applicable medium is water, gas, air,
heating steam and other common fluids. .
Straight seam arc welded steel pipe commonly used standard GB12771-2008 "stainless steel welded pipe for fluid transport", HG50237.1 ~ 4 "austenitic stainless steel welded
pipe" and so on. Among them, GB12771 standard specifications range from DN6 ~ DN560, wall thickness from 0.3mm ~ 14.0mm total of 29 kinds of specifications, material grades
are 1Cr18Ni9, 0Cr19Ni9, 00Cr19Ni11, 0Cr18Ni10Ti, 0Cr17Ni12Mo2, 00Cr17Ni14Mo2 a total of 12 species. At present, China has no carbon steel pipe and alloy steel straight seam arc
welded steel pipe standards that are applicable to petrochemical plants. When this type of welded steel pipe is used in design, many manufacturing requirements are often
required in the design documents. This is very unlikely. convenient. Therefore, it is hoped that countries or industries will formulate such standards as soon as possible for
designers and manufacturers.
Under normal circumstances, straight seam welded pipe should not be used for extreme or highly hazardous media delivery.
Continuous welding (forging) steel tubes Continuous welding (forging) steel tubes are heated in a heating furnace, and then the formed edges are welded together with a pressurizing method to form a straight seam Steel pipe. It is characterized by high production efficiency and low production cost, but the metallurgical bonding of welded joints is incomplete, the quality of welds is poor, and the overall mechanical properties are poor. Current welded pipe is only used for water and compressed air systems in pressure pipes
What are the precautions for storing seamless steel pipes?
1. Choose a suitable venue and warehouse; 2. Reasonable stacking, advanced first; 3. Packaging and protective layers of protective materials; 4. Keep warehouse clean and strengthen material maintenance.
Significance of Proximity Effect on the Production of High-frequency Longitudinal Welded Pipes
In addition to the skin effect, the proximity effect is another feature of current. When alternating currents of equal magnitude and opposite directions pass through two adjacent conductors, the current will flow through the adjacent inner surface layers of the two conductors, and when the two conductors pass When alternating currents of the same size and direction, the current will flow through the outer surface layers of the two conductors. The proximity effect of the current makes the current in the conductors further uneven. It is this unevenness that makes the high-frequency welded pipe(ERW).
Summary of Advantages and Disadvantages of High-Frequency Welded Pipe Forming Methods
Advantages and disadvantages of high-frequency welded pipe forming methods
