The uniformity of wall thickness of thick-walled straight seam steel pipes will directly affect the post-processing of the parts. The wall thickness of thick-walled straight-seam steel pipes cannot be controlled, which means that the overall steel pipe cannot be strictly controlled. Small and medium-sized steel products, wire rods, steel bars, medium-diameter thick-walled steel pipes, steel wire ropes, etc. can be stored in a ventilated material shed, but the top is covered with thatch and the bottom is padded.
Some small thick-walled steel pipes, thin steel plates, steel strips, silicon steel sheets, small-diameter or thin-walled thick-walled steel pipes, various cold-rolled, cold-drawn thick-walled straight-seam steel pipes, and high-priced, corrosive metal products can be stored in the warehouse. Choose a suitable site and warehouse to store thick-walled steel pipes. The site or warehouse should be clean, well-drained, and away from factories and mines that produce harmful gases or dust. Warehouses should be selected based on geographical conditions. Generally, ordinary closed warehouses are used, that is, warehouses with walls on the roof, tight doors and windows, and ventilation devices. The warehouse is required to be ventilated on sunny days, sealed and moisture-proof on rainy days, and a suitable storage environment must be maintained at all times.
Thick-walled straight seam steel pipes are rolled from steel plates. After rolling, welding is required. Welding is generally divided into three steps: pre-welding, external welding, and internal welding. After welding is completed, flaw detection is required. Export steel pipes need to be beveled, painted and sealed. Processed according to customer's required length. Generally divided into fixed length and variable length.
The main implementation standards are GB/T3091, GB/T9711, and API. Among them, GB/T9711 is divided into three parts: steel, B-grade steel and C-grade steel. Thick-walled straight seam steel pipe is a kind of steel pipe used in oil and gas transmission pipelines with large usage and high reliability. Submerged arc welding straight seam steel pipe unit, forming unit types include UOE, RBE, JCOE, etc., the main production process is qualified steel plate - plate edge chamfering - plate edge pre-bending - forming - JCOE forming - steel continuous welded pipe seam – arc welding of inner pipe seam – submerged arc welding of outer pipe seam – rounding and straightening – pipe end chamfering and trimming – weld wave peak inspection – repair of unqualified weld bead – X-ray inspection of weld bead – hydrostatic test – Weld bead wave crest inspection - unqualified weld bead repair - pipe inner surface drying treatment - pipe inner surface rust removal treatment - pipe inner surface anti-rust treatment - pipe outer surface rust removal treatment - outer surface anti-rust coating Processing of pipe – finished product.
The service life of ships is generally about 20 years. There are many conventional systems, mainly including bilge water, ballast water, drainage, injection, domestic water, fire protection, domestic sewage, air, measurement, cargo oil, cabin cleaning, ventilation, inert gas, heating, tank washing, foam fire extinguishing, Sprinkling, evaporative gas, liquid level telemetry, valve remote control and other systems. Special ships also include special systems for transporting liquefied petroleum gas (LPG), liquefied natural gas (LNG) and other special systems.
A 300,000-ton ultra-large FPSO has more than 40,000 pipelines and a length of more than 100 kilometers, which is 3-4 times that of the same tonnage. Therefore, the shipbuilding industry has become a large user of the steel pipe industry. Regarding the application of straight seam steel pipes in marine engineering, in addition to the above-mentioned conventional systems and special systems, straight seam steel pipes are also widely used in various structures such as jackets, underwater steel piles, riser casings, and mooring devices.
