Preparations for purchasing large-diameter straight seam steel pipes

    The purchase of large-diameter straight seam steel pipes should be communicated in advance. Before purchasing steel pipes, the pre-designed specifications, lengths, materials, wall thicknesses, welding standards and welding seam requirements should be followed. These should be communicated well before purchasing.

    The first is the specification. For example, 800mm is also called DN800, including 820mm and 813mm of A and B series, or the outer diameter of 800mm must be clearly specified to avoid unnecessary losses.

    The wall thickness of large-diameter straight seam steel pipe is required to be 16mm. It is possible that the actual thickness of the raw materials will be 15.75mm and 16.2mm, and there will be upper or lower differences. These are normal deviations. Because straight seam steel pipes are all ton prices, it is necessary to communicate in advance to avoid differences in weight.

    The normal length of large-diameter straight seam steel pipe is 12m. When it needs to be fixed, it needs to be communicated in advance, because the price of fixed length will be more expensive, or it needs to be 9.87m long without prior communication, and the manufacturer usually gives 9.9m directly

    The materials for purchasing large-diameter straight seam steel pipes should also be well communicated, and the materials cannot be OEM. In addition, the materials should be guaranteed, and the original material list of the steel mill should be provided. Any material problems will be returned and compensated.

    The welding standard for production and processing must be in accordance with automatic submerged arc welding LSAW GB/T3091-2015, and a product quality certificate is required. If the standard does not meet the requirements, the product fails.

    When purchasing large-diameter straight seam steel pipes, it is required to communicate in advance about the levels of weld flaw detection, because weld flaw detection will cost extra money, and it is a hassle to negotiate the price if there is no flaw detection after production.

    In addition, large-diameter straight seam steel pipes above 1020mm may produce two welds. Many projects will not accept two welds without prior communication, which will be called defective steel pipes.

    Therefore, it is necessary to communicate well in advance before purchasing any steel pipe, causing unnecessary disputes and economic losses.