Seamless tubes and pipes are produced from steel billets that are heated and perforated to create the tubular section. The word “seamless” means the absence of joints or seam welds.
Seamless steel pipes have different applications within the oil & gas industry:
- Upstream, OCTG pipes
- Midstream (transmission and distribution of fluids like oil,steam, gas, slurries, acids)
- Downstream (piping to refine oil and gas to derive products)
- General plumbing solutions for utility services
The most common specifications of pipes used in the oil&gas industry are (ASTM pipe specifications):
- ASTM A53, A106, A333, and API 5L (carbon steel pipes for high and low-temperature carbon steel)
- ASTM A335 Grades P5 to P91 (alloy steel pipes for high pressure and temperature, used inrefineries and power plants)
- ASTM A312 Series 300 and 400 (stainless steel pipes in grades 304, 316, 321, 347)
- ASTM A790/A928 (duplex and super duplex pipes with double ferritic and austenitic structure)
- Different types of nickel alloys material specifications (Inconel, Hastelloy, Cupronickel, Monel, Nickel 200)
- Specifications for non-ferrous pipes (copper , aluminium, brass, cupro-nickel)
- Some specifications cover only seamless pipes (example ASTM A106), others apply both to seamless and welded pipes (example ASTM A53).
In Seamless tubes and pipes, Carbon steel pipes (A53, A333, A106, and API 5L) have the largest market share, as they are applicable in most high and low-temperature applications.The main application of stainless steel pipes is for corrosive sectors. Higher grades are used wherethe pressure and the temperature and increases, or when the conveyed fluid is much aggressive).
SEAMLESS PIPE SIZES
The ASME B36.10 and B36.19 specifications cover the dimensions and weights of seamless pipes for the petrochemical industry (the specifications apply to welded pipes too):
- The ASME B36.10 specification of carbon and low-alloy seamless pipes sizes (dimensions and weights) between 1/8 -24 inches
- The ASME B36.19 specification, instead, covers the dimensions and weights of stainless steel, duplex, nickel-alloy seamless and welded pipes
- Commercial seamless pipes are designated with a nominal pipe size (representing the approximate fluid conveyance capacity of the pipe) and with a “schedule”, which refers to the thickness of the pipe (the most common are schedule 40, STD, XS, XXS for carbon/alloy pipes, and 10S, 40S and 80S for stainless and nickel alloy pipes).
SEAMLESS PIPE PRICE
Seamless pipes have higher price per ton than ERW pipes, generally 20% to 30% higher as their fairly production process is fairly more complex. And the other reason is that the number of seamless tubes and pipes manufacturers is rather limited.
For that reason, it would be wrong to estimate pipe prices using a standard price for all “carbon steel” or “stainless steel” pipes. The actual wall thickness, diameter, and specific grade: all factors shall be taken into consideration to prevent cost overruns during the execution of the project. Moreover, prices fluctuate daily (especially for alloyed pipes, which contain chemical elements like Molybdenum, Nickel, Copper, Chromium traded daily on the London Metal Exchange or the Ferro-Alloy markets).
Seamless steel pipes can’t be mixed up with seamless tubes. Indeed, there are a few important differences between pipes and tubes from different aspects. In general, the word “pipe” applies to any tubular used to convey fluids, whereas the word “tube” applies to tubular sections (of various shapes, round, oval, squared) used for structural/mechanical applications, instrumentation systems, and the construction of pressure equipment like heat exchangers, super heaters and boilers.
