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2024-10-12 17:09:10.0
< On October 12, the price of galvanized spiral welded pipe fell slightly in Shanghai. Q235B (ASTM A36) Yongda 426*8mm 781.08, down 2.83. (USD/ton)
2024-10-12 17:07:35.0
< On October 12, the price of stainless steel angle rose sharply in Wenzhou. 316L Qingshan 50*50*3mm 3579.95, up 70.75. (USD/ton)
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2024-10-12 17:04:15.0
< On October 12, the price of square steel did not fluctuate in Shanghai. Q235B (ASTM A36) Fugang 10*10mm 591.47. (USD/ton)
2024-10-12 17:02:48.0
< On October 12, the price of plastic mold steels in Shanghai remained stable. 3Cr2Mo/P20 (ASTM P20) Baosteel 100-300*850-1600 (hot rolling, oxide) 1032.95. (USD/ton)
2024-10-12 16:55:28.0
< On October 12, the price of spiral welded pipe has dropped by 7.08 in Foshan. 1820*12 mm 580.23 (USD/ton)
2024-10-12 16:55:17.0
< On October 12, the price of welded steel pipe has dropped by 2.83 in Guangzhou. Q215 (ASTM A283 Gr.C) DN32(1.25"*3.25mm) 588.72 (USD/ton)

Answers

  • How to distinguish inferior thick-walled seamless stainless steel pipes?

    1. Inferior thick-walled seamless stainless steel pipes are more likely to fold. Folding refers to various fold lines on the surface of thick-walled seamless stainless steel pipes. This generally runs through the entire longitudinal direction of the product. The reason for the folding is that inferior manufacturers, in pursuit of efficiency, press down too much, produce ears, and fold during the next rolling. The folded product will crack after bending, and the strength of the thick-walled seamless steel pipe will drop significantly.

    2. Inferior thick-walled seamless stainless steel pipes are more likely to be scratched, because the equipment and facilities of inferior manufacturers are relatively simple, which is easy to produce burrs and scratch the surface of thick-walled seamless stainless steel pipes. Deep scratches may reduce the strength of thick-walled seamless stainless steel pipes.

    3. The surface of inferior seamless stainless steel pipes is more likely to crack. The reason is that the quality of the blanks is poor. Most of them are adobes, which have many pores. The adobes are cracked due to the effect of thermal stress during the cooling process, and cracks appear after rolling.

    4. Scarring is easy to occur on the surface of inferior seamless stainless steel pipes because the material of inferior thick-walled seamless stainless steel pipes is uneven, there are many impurities, and generally the equipment and facilities of inferior thick-walled seamless stainless steel pipe manufacturers are relatively backward, which is easy to stick to the steel. These impurities bite the rollers and easily cause scarring.


  • Why do both stainless steel welded pipes and seamless pipes need to be solution annealed?

    In the field of stainless steel pipes, there are two main types: stainless steel welded pipes and stainless steel seamless pipes. Stainless steel welded pipes are welded by straight seam welding after the steel strip is curled and formed by the unit and die; In contrast, stainless steel seamless pipes are made of round steel perforated into tube embryos as raw materials and then made by cold rolling, cold drawing, or self-pressing production processes. However, in the process of producing both types of stainless steel pipes, solid solution treatment is required.
    Stainless steel pipes
    The purpose of solid solution annealing of stainless steel pipes is mainly two: first, to eliminate work hardening, which is conducive to subsequent processing, such as bending and flaring. Through solid solution annealing, the distortion in the lattice is restored, the extended and broken crystals will recrystallize, the internal stress is eliminated, the tensile strength of the steel pipe is reduced, and the elongation is increased.
    Secondly, the corrosion resistance of stainless steel itself is restored. Since carbide precipitation and lattice defects may occur during cold working, the corrosion resistance of stainless steel pipes is reduced. After solid solution annealing, the corrosion resistance of stainless steel pipes will be restored to the best state. Typically, stainless steel tubes used in heat exchangers and condensers need to be solution annealed to meet actual application requirements.


  • Why is edge shielding used in the production process of hot-rolled strip steel?

    1. Improve the shape of the strip steel.

    2. Improve the edge cracking after cold rolling.

    3. Edge shielding can effectively improve the performance uniformity of the strip steel surface, thereby improving the "earing" defect at the user's end and winning the user's reputation and market image.

    4. Save production line investment and operating costs.

    5. Improve technical awareness and form the core competitiveness of the production line.


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