The uniformity of the steel pipe wall of thick-walled straight seam steel pipes directly affects the quality of the subsequently processed parts. If the pipe wall uniformity is not controlled, the overall quality of the steel pipe cannot be strictly controlled. Small and medium-sized steel sections, wire rods, reinforcing bars, medium-diameter thick-walled straight seam steel pipes, steel wires and wire ropes, etc., can be stored in ventilated sheds, but with coverings and padding. Some small thick-walled straight seam steel pipes, thin steel plates, steel strips, silicon steel sheets, small-diameter or thin-walled straight seam steel pipes, various cold-rolled and cold-drawn thick-walled straight seam steel pipes, as well as high-priced and easily corroded metal products, can be stored in warehouses. Choosing a suitable site and warehouse: The site or warehouse for storing thick-walled straight seam steel pipes should be clean, well-drained, and far away from factories or mines that produce harmful gases or dust. The warehouse should be selected according to geographical conditions, generally using ordinary enclosed warehouses, i.e., warehouses with roofs, walls, airtight doors and windows, and ventilation devices. Warehouses require proper ventilation on sunny days and should be closed to prevent moisture during rainy days, maintaining a suitable storage environment at all times.
Thick-walled straight seam steel pipes are made by rolling steel plates. After rolling, welding is required, generally involving three steps: pre-welding, external welding, and internal welding. After welding, flaw detection is necessary. Exported steel pipes require beveling, painting, and capping. Length is processed according to customer requirements, generally divided into fixed lengths and non-fixed lengths. The main standards followed are GB/T3091, GB/T9711, and API. GB/T9711 is divided into three parts: steel, grade B steel, and grade C steel. Thick-walled straight seam steel pipes are a widely used and highly reliable type of steel pipe for oil and gas pipelines. Submerged arc welding straight seam steel pipe units, forming unit types include UOE, RBE, and JCOE. The main production process is as follows: Qualified steel plate – edge chamfering – edge pre-bending – forming – JCOE forming – continuous welding of steel pipe joints – arc welding of inner pipe joints – submerged arc welding of outer pipe joints – rounding and straightening – end chamfering and smoothing – weld bead inspection – repair of defective welds – weld bead X-ray inspection – hydrostatic testing – weld bead inspection – repair of defective welds – inner pipe surface drying – inner pipe surface rust removal – inner pipe surface rust prevention coating – outer pipe surface rust removal – outer pipe surface rust prevention coating – finished product.
The service life of a ship is generally about 20 years. There are many conventional systems, mainly including bilge water, ballast, drainage, injection, domestic water, fire protection, sewage, air, measurement, cargo oil, tank cleaning, ventilation, inert gas, heating, tank washing, foam fire extinguishing, water spraying, evaporative gas, liquid level telemetry, valve remote control, etc. Special ships also include dedicated systems for transporting liquefied petroleum gas (LPG) and liquefied natural gas (LNG). The service life of straight seam steel pipes used in marine engineering can reach at least 40 years. Besides conventional systems, marine engineering also includes specialized drilling and production systems, and systems for processing crude oil, liquefied petroleum gas (LPG), and liquefied natural gas. Statistics show that the annual consumption of large-diameter straight seam steel pipes for ships reaches 5 million tons, approximately 500,000 pipes, with standards including GB, YB, and CB. 70% of these pipes are connected together. A single 300,000-ton supertanker (VLCC) can require tens of kilometers of steel pipes and fittings. The total pipe usage alone is around 1,000-1,500 tons, although this is relatively limited compared to the steel pipe usage for a 40,000-ton hull structure. Furthermore, considering the need to build multiple ships of the same type, and many other vessels, a single 300,000-ton supertanker (FPSO) requires over 40,000 pipes, exceeding 100 kilometers in length, which is 3-4 times that of a ship of similar tonnage. Therefore, the shipbuilding industry has become a major user of steel pipes. In marine engineering, straight seam steel pipes are widely used in various structures beyond the conventional and specialized systems mentioned above. These include jacket supports, underwater steel piles, risers, mooring supports, helicopter platforms, and towers.
These straight seam steel pipes come in a variety of specifications and are made of high-quality materials. They are available in different diameters and wall thicknesses, and also feature numerous Y, K, and T-type pipe joints. For example, jacket supports, steel piles, and wellhead risers often use large-diameter straight seam steel pipes, typically rolled from steel plates. Besides dimensional requirements, marine engineering also places high demands on the durability of straight seam steel pipes. Because the steel pipes are in constant contact with water and various media within it, corrosion is severe. Therefore, anti-corrosion treatment is essential before the straight seam steel pipes are used. In the early days of the steel pipe industry, there were many tricks involved, but now people are more proficient in this field. For example, thick-walled straight seam steel pipes might have insufficient wall thickness, which could be concealed by using a gate to make the pipe end appear thicker with a hammer, but this would be exposed by actual measurement. Straight seam pipes could also be passed off as seamless. Straight seam pipes have fewer welds, usually only one longitudinal weld, and the entire pipe can be polished to appear seamless.
In the production of straight seam steel pipes, a product called glass lubricant is required. Before the use of glass lubricant, graphite was used as a lubricant because this product was not yet available on the market. However, long-term use revealed problems: graphite has very high heat transfer efficiency and very poor insulation. This causes the mold to heat up very quickly during operation, easily leading to wear and tear on the straight seam steel pipe, thus reducing the product’s lifespan. Therefore, manufacturers have been looking for a product that can replace graphite, namely, glass lubricant. But why use them? It’s because bogie furnaces have many advantages. First, they have relatively low heat transfer efficiency, which can play a role in heat preservation and extend the service life of the equipment.
Post time: Dec-08-2025