Surface treatment of thick-wall straight seam steel pipe

The uniformity of the pipe wall of the thick-walled straight seam steel pipe will directly affect the post-processing parts. The pipe wall of the thick-walled straight seam steel pipe cannot be controlled, and the overall steel pipe cannot be strictly controlled. Small and medium-sized steel bars, wire rods, steel bars, medium-diameter thick-walled steel pipes, steel wires, and wire ropes can be stored in a ventilated shed with thatch on top and bottom on top. 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. The site or warehouse for storing thick-walled steel pipes should be selected in a clean and well-drained place, away from factories and mines that produce harmful gases or dust. The warehouse should be selected according to geographical conditions. Generally, an ordinary closed warehouse is used, that is, a warehouse with a roof, a wall, tight doors and windows, and a ventilation device. The warehouse requires ventilation on sunny days, is closed and moisture-proof on rainy days, and a suitable storage environment is always maintained.

Thick-walled straight seam steel pipes are rolled from steel plates and need to be welded after rolling. Generally, there are three steps of welding: pre-welding, external welding, and internal welding. Flaw detection is required after welding is completed. Exported steel pipes need to be grooved, painted, and capped. Length processing according to customer's requirements. It is generally divided into fixed length and indeterminate 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-wall straight seam steel pipe is a steel pipe for oil and gas transportation pipelines with large consumption and high reliability. Submerged arc welding straight seam steel pipe unit, forming unit forms include UOE, RBE, JCOE, etc. The main production process is qualified steel plate - plate edge chamfering - plate edge pre-bending - forming - JCOE forming - continuous welding of steel pipe seams - arc welding of pipe inner seams - submerged arc welding of pipe outer seams - full circle and straightening - pipe ends Chamfering and smoothing-weld wave inspection-unqualified weld bead repair-weld bead X-ray inspection-hydraulic test-weld bead wave inspection-unqualified weld bead repair-drying treatment of the inner surface of the pipe-de-rusting treatment of the inner surface of the pipe-inner surface of the pipe Anti-rust coating treatment-pipe outer surface rust removal treatment-pipe outer surface anti-rust coating treatment-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, domestic sewage, air, measurement, cargo oil, tank stripping, ventilation, inert gas, heating, tank washing, foam fire extinguishing, water sprinkler, boil-off gas, liquid level remote measurement, valve remote control and other systems, and special ships also include special systems such as liquefied petroleum gas (LPG) and liquefied gas (LNG) for transportation. The service life of straight seam steel pipes in marine engineering can reach at least 40 years. In addition to conventional systems in marine engineering, there are special drilling equipment systems, crude oil, liquefied petroleum gas, and liquefied petroleum gas processing systems. According to statistics, the annual consumption of large-diameter straight seam steel pipes for ships reaches 5 million tons, about 500,000 pieces. The standards are GB, YB, and CB, and 70% of the steel pipes are connected. Only one 300,000-ton ultra-large oil tanker can use tens of kilometers of steel pipes and fittings. Only the amount of steel pipes (included) is about 1000-1500 tons. Of course, the amount of steel pipes used for the hull structure of 40,000 tons is relatively limited. Also, considering the same kind of ship, there are several to be built, and there are many others. And a 300,000-ton ultra-large FPSO has more than 40,000 pipes and a length of more than 100 kilometers, which is 3-4 times that of the same tonnage level. Therefore, the shipbuilding industry has become a large user of the steel pipe industry. In the application of straight seam steel pipes in marine engineering, in addition to the above-mentioned conventional systems and special systems, many structures use straight seam steel pipes in large quantities, such as jackets, underwater steel piles, water risers, mooring supports, helicopter platforms, towers, etc.

This type of straight seam steel pipe has many specifications, high material, the same diameter, different diameters, different wall thicknesses, and a large number of Y, K, and T-shaped pipe joints. As jackets, steel piles, wellhead water barriers, etc., are mostly straight seam steel pipes with large diameters, and are generally made of steel plates. In addition to the size requirements for straight seam steel pipes in marine engineering. The requirements for its durability are also very high. Because the steel pipe has been in contact with water and various media in the water for a long time, the corrosion of the steel pipe is very serious. Therefore, the straight seam steel pipe should be treated with anti-corrosion technology before it is used. In the early days of the steel pipe industry, there were many tricks, but now people are more proficient in this industry. The wall thickness of the steel pipe is not enough to use the gate method. It looks thicker if the mouth of the steel pipe is shielded with a hammer, but it is easy to measure it with an instrument. will be revealed. Use a straight seam as a seamless steel pipe. There are fewer straight seams and only one longitudinal weld. The whole steel pipe is polished by a machine, commonly known as polishing, and it looks like there is no gap to act as a seamless pipe.

In the production process of straight seam steel pipes, a product needs to be used for cooperation, that is, glass lubricant. Before using glass lubricant, it was produced with graphite, because there was no such product in the market at that time. Therefore, graphite can only be used as a lubricant, but after long-term use, everyone will find some problems, that is, the heat transfer efficiency of graphite is very high, and the heat insulation effect is also very poor. In this way, the temperature of the mold will become very fast, which will easily cause the wear of the straight seam steel pipe, so that the product cannot be used for a long time. Therefore, manufacturers have been looking for a product that can replace graphite, that is, glass lubricants, but why use them, it is because there are many advantages to the trolley furnace, first of all, the heat transfer efficiency is relatively low, so that it can Play the role of heat preservation, but also can prolong the service life of the equipment.