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The influence of raw materials on stainless steel welded pipes

by:HHGG     2021-04-11
The influence of raw materials on stainless steel welded pipes 2018-06-22 Considering the factors that affect the quality of stainless steel welded pipes, the raw materials must be controlled first, so how many factors affect the quality of raw materials? Mainly include the unstable mechanical properties of steel strips and steel There are three aspects, such as the appearance shortcomings of the belt and the large geometric scale errors. Therefore, we should focus on these three aspects. 1. The influence of the mechanical properties of steel strips on the quality of steel pipes. The commonly used steel grades for welded steel pipes are carbon structural steels. The primary grades are Q195, Q215, Q235 SPCC SS400 SPHC, etc. If the yield point and tensile strength of the steel strip are too high, it will be difficult to form the steel strip, especially when the pipe wall is thick, the resilience of the material is large, the steel pipe has a large deformation stress during welding, and the weld is simply cracked. When the tensile strength of the steel strip exceeds 635 MPa and the elongation is less than 10%, the weld seam of the steel strip is prone to cracking during the welding process. When the tensile strength is lower than 300 MPa, the steel strip is simply wrinkled in appearance due to the soft raw material during the forming process. It can be seen that the mechanical properties of the data have a great influence on the quality of the steel pipe, and the quality of the steel pipe should be effectively controlled from the aspect of the strength of the data. 2. The influence of the appearance defects of the steel strip on the quality of the steel pipe. The appearance defects of the steel strip are more common, such as sickle bend, wave shape, slitting gnawing, etc., sickle bend and wave shape usually appear in the rolling process of cold-rolled steel strip. It is caused by improper control of the reduction amount. In the steel pipe forming process, the sickle bend and the wave shape will cause the strip to deviate or turn over, which simply causes lap welding of the steel pipe weld and affects the quality of the steel pipe. The gnawing edge of the steel belt (that is, the appearance of jagged edges of the steel belt) is usually present on the slitting belt. The reason is that the cutting edge of the slitting machine is blunt or not sharp. Because of the gnawed edges of the steel strip, there is a local lack of meat from time to time, which makes the steel strip prone to cracks and cracks during welding, which affect the stability of the weld quality. 3. The influence of the geometric dimensions of the steel strip on the quality of the steel pipe. When the width of the steel strip is less than the allowed error, the extrusion force when welding the steel pipe is reduced, which makes the weld of the steel pipe weak, showing cracks or open pipes; when the steel strip When the width of the steel pipe is larger than the allowable error, the extrusion force when welding the steel pipe is increased, and there are welding defects such as sharp beak, lap welding or burr at the steel pipe weld. Therefore, the fluctuation of the width of the steel strip not only affects the accuracy of the outer diameter of the steel pipe, but also seriously affects the appearance quality of the steel pipe. For steel pipes that request the same section wall thickness difference not to exceed the specified value, that is, the steel pipe with a high degree of wall thickness uniformity, the fluctuation of the thickness of the steel strip will transfer the allowed value of the thickness difference of the same coil to the wall thickness difference of the product steel pipe. , The thickness of a large number of steel pipes exceeds the permitted error and is rejected. The fluctuation of the thickness not only affects the thickness accuracy of the product steel pipe, but also, because the thickness of the steel strip is different, the extrusion force and the welding temperature of the steel pipe are unstable when the steel pipe is welded, and the quality of the weld of the stainless steel welded pipe is unstable. In addition, because there are material shortcomings such as interlayer, impurities, and trachoma inside the steel, it is also an important factor that affects the quality of the steel pipe. Therefore, before the steel strip is welded, it is necessary to check the appearance quality and geometric dimensions of each coil of steel strip. If the quality of the steel strip does not meet the requirements of the specification, do not produce it to avoid unnecessary losses. Stainless steel welded pipe manufacturers have insisted on using refining furnace steel belts since the establishment of the factory. The chromium content of the refining furnace steel belt reaches 13.2%-14.5%, and the nickel content reaches 1.01%-1.28%. It has high chromium and nickel content and stable quality. A series of advantages such as high copper content to ensure that every stainless steel welded pipe we produce is a high-quality product. The stainless steel welded pipe manufacturer welcomes new and old customers to call the factory for consultation and consultation. The hotline:!  
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