Facts about Seamless pipes

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You must be in struggle to decide between Electric Resistance Welded pipes and seamless pipes for your project and this struggle is very much common in every industry that intricately is involved with the piping solution. Each of the two has various advantages and disadvantages, which needs pondering to take a proper decision. Before heading to a seamless pipe factory or an ERW pipe manufacturing unit, go through these quick pointers.

ERW pipes have become a promising alternative to seamless pipes in the last few years, both in terms of price and performance, due to the modern welding technologies like HFI and HFW are adopted by ERW pipe manufacturers. The advanced welding technologies have reduced the technical superiority of seamless pipes, making them replaceable at least in some applications (low/medium pressure and temperature). Definitely, seamless pipes will always be beneficial in terms of superior mechanical strength of steel billets than coils and plates.

SEAMLESS PIPE: PROS AND CONS

  • Seamless pipes are manufactured out of a solid steel billet and do not have any weld seam, which may represent a weaker area (prone to corrosion, erosion and, general failure)
  • In comparison with welded pipes, Seamless pipes have more predictable and precise shapes, in terms of roundness and ovality.
  • The major disadvantage of seamless pipes is the higher cost than ERW pipes of the same size and grade (Seamless vs. ERW pipe, in the range 2inches – 20 inches)
  • Delivery times are generally longer, as there are less number of seamless pipe factory than welded pipes (lower entry barriers exists for welded pipes vs. seamless pipes)
  • Seamless pipes can have an inconsistent wall thickness across their length, indeed the general tolerance is +/- 12.5%

 

ELECTRIC RESISTANCE WELDEDPIPE: PROS AND CONS

  • Welded pipes are much cheaper than seamless (ERW HFI type), as they are manufactured from steel coils, in less complex manufacturing plants
  • Welded pipes have shorter lead times than seamless ones, as the manufacturing base is larger
  • Welded pipes generally have a consistent wall thickness, as they are manufactured using coils (ERW) or plates (LSAW), both are with tight tolerance control
  • The major “defect” point of welded pipes is the presence of a weld seam that constitutes a weakness factor. But, hopefully this is becoming less and less true with the advances of the welding technologies in the last 10 years.

 

Conclusion:

At present, advanced ERW-HFI welded pipes are absolutely a valid alternative to seamless pipes. They help the end-users reduce prices and lead times between 20% and 25%. Pipes along with the valves are the most impactful piping cost element in plant construction (as a thumb-rule, piping covers 5-7% of the total plant cost, and pipes represent approx. 60% to 70% of this cost, valves 15% to 25%). These figures indicate the average values applicable for the oil & gas industry and carbon steel materials (the weight of piping can be higher for stainless steel, duplex, and nickel-alloys piping classes). If you are opting for longevity, then selecting your required products from a gold-standard seamless pipe factory would be a wise decision, while EWR will be suitable if you prefer a cost-effective product.

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