What is the principle of "high-frequency resistance welding" in the ERW process?
High-frequency resistance welding (ERW) is one of the most commonly used welding methods for steel pipes, especially suitable for the production of small and medium diameter steel pipes. Its principle is to heat the edge of the steel pipe to its melting point, and then weld the two ends of the steel pipe together under the action of high-frequency current and external pressure.
Why do most S235JR ERW welded pipes require weld heat treatment?
Because the high temperature during welding changes the metal structure in the weld area, causing it to harden and become brittle. Heat treatment (equivalent to "annealing" the weld) eliminates this brittleness, restoring it to a level of flexibility and mechanical properties similar to the base material, thus ensuring consistent strength throughout the pipe and making it safer to use.
What non-destructive testing methods are commonly used to ensure weld quality and reliability?
Non-destructive testing (NDT) is a systematic evaluation technique used to inspect materials, components, or structures without causing damage. The main advantage of NDT is that it maintains the integrity of the object being tested and minimizes production interruptions. The most commonly used methods are ultrasonic testing and eddy current testing. This is equivalent to performing an ultrasonic scan and electrocardiogram (ECG) inspection on the weld.
What are the advantages of S235JR high-frequency resistance welded pipe?
S235JR High-frequency resistance welded pipe combines high efficiency, low cost, and high precision, making it one of the most competitive products in modern pipe manufacturing. In non-high-pressure or non-extreme environments, it is gradually replacing traditional seamless pipes and becoming the mainstream choice in the market.
What are the application areas of S235JR high-frequency resistance welded pipe?
It is widely used in various structural and fluid transportation fields where pressure requirements are not extreme. Common applications include: structural components such as railings and supports in buildings, water pipes, heating pipes, and ventilation ducts in municipal engineering, and it is also commonly used as a conveying pipe for oil and gas lines in mechanical equipment.
