Answers

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  What are the differences between high-frequency welded pipes and straight seam welded pipes?

  High-frequency welded steel pipes are produced by rapidly heating and melting the edges of the steel pipe with a high-frequency current, followed by welding under the action of extrusion rollers. This process is characterized by high welding speed and a small heat-affected zone, thus ensuring the overall performance of the steel pipe. Straight seam welded steel pipes, on the other hand, use welding rods or wires to directly weld the joints of the steel pipe. The welding process is relatively slower, and the heat-affected zone is larger.
  
  High-frequency welded steel pipes, due to the rapid heating and extrusion by the high-frequency current, have high-quality welds with high strength and a smooth appearance, making them less prone to welding defects. The high welding speed and small heat-affected zone also give the steel pipes better corrosion resistance and compressive strength during use. Furthermore, the high-frequency welding process ensures the dimensional accuracy and shape stability of the steel pipe.
  
  In contrast, the welds of straight seam welded steel pipes are relatively rough, and the weld strength may be affected by the welding process and the quality of the welding rods, resulting in some quality fluctuations. Straight seam welded steel pipes may be slightly inferior in terms of performance, especially in terms of corrosion resistance and compressive strength.
  
  Choose high-frequency welded pipe: When you need small to medium diameter, thin-walled, low-cost, high-efficiency pipelines for general transportation or structural support.
  
  Choose straight seam submerged arc welded pipe: When you need large diameter, thick-walled pipes that withstand high pressure or high stress, and where the requirements for weld quality and reliability are extremely high, such as oil and gas trunk lines and large-scale engineering structures.

  
  
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  Why do aluminum alloys require surface oxidation treatment?

  The surface oxide film on aluminum alloys can:
  a. Provide corrosion protection: The dense oxide film formed on the surface of aluminum alloys prevents corrosion from oxides in the atmosphere, thus extending their service life.
  b. Improve wear resistance: The high hardness of the oxide film improves the wear resistance and corrosion resistance of the aluminum alloy.
  c. Enhance appearance: The oxide film of different colors formed on the surface of aluminum alloys after oxidation treatment enhances their decorative and aesthetic appeal.
  d. Ensure color stability: The color of the oxide film on the surface of aluminum alloys is stable and does not easily change due to sun and rain exposure.

  
  
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  Do y have GOST 8732-75 standard, grade 20 steel, 32x3 gauge, 70 tons, FOB delivery?

  To provide you with accurate confirmation and a formal quote, we need to discuss several key details with you: We need to confirm your requirements regarding specific chemical composition, surface condition and processing, as well as transaction and logistics information. You can contact us using this contact information: +86 198 6196 1658. We can provide the standards you require.