Requirements for straight seam steel pipes
Welded steel pipes should undergo mechanical performance tests, flattening tests, and flaring tests, and must meet the specified standards. The steel pipes should be able to withstand a certain internal pressure, and if necessary, a pressure test of 2.5 MPa should be conducted, maintaining for one minute without leakage.
Nov 14,2022
Welded steel pipes should undergo mechanical performance tests, flattening tests, and expansion tests, and must meet the requirements specified by standards. The steel pipes should be able to withstand a certain internal pressure, and if necessary, a pressure test of 2.5Mpa should be conducted, maintaining for one minute without leakage. The use of eddy current testing methods is allowed as a substitute for hydraulic testing. Eddy current testing is performed according to the GB7735 standard 'Eddy Current Testing Method for Steel Pipes'. The eddy current testing method involves fixing the probe on a frame, maintaining a distance of 3-5mm from the weld, and conducting a comprehensive scan of the weld through the rapid movement of the steel pipe. The testing signals are automatically processed and sorted by the eddy current testing instrument to achieve the purpose of flaw detection.
The welded pipes after flaw detection are cut to the specified length using a flying saw and then transferred to the flipping rack. Both ends of the steel pipe should be flat and beveled, marked, and the finished pipes are bundled and packaged in hexagonal shapes before leaving the factory.
The main processing methods for straight seam steel pipes are:
Forging steel: A pressure processing method that uses the reciprocating impact force of a hammer or the pressure of a press to change the shape and size of the blank into the desired form.
Extrusion: A processing method where metal is placed in a closed extrusion cylinder, and pressure is applied at one end to extrude the metal through a specified die hole, resulting in finished products with the same shape and size, commonly used for producing non-ferrous metal materials.
Rolling: A pressure processing method where metal blanks are passed through the gap of a pair of rotating rollers (of various shapes), causing the material's cross-section to decrease and length to increase due to the compression from the rollers.
Drawing steel: A processing method where already rolled metal blanks (shapes, pipes, products, etc.) are drawn through a die hole to reduce the cross-section and increase the length, mostly used for cold processing.
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