The high-frequency welded pipes are divided into the following four types. The definitions, functions and standard codes are as follows:

Hot dip galvanized square tubes are steels used in hot dip galvanizing processes. This process is a maintenance of steel itself. The medium of steel is prone to oxidation problems, and the application of hot dip galvanizing technology can prevent oxidation of steel. A thick, dense layer of pure zinc masks the exterior of the steel, preventing contact with any solution and keeping the steel substrate from corrosion.

To talk about the centralized classification of galvanized square tubes, we first look at the production process, which can be divided into hot-dip galvanized square tubes and cold-galvanized square tubes. It is precisely because of the difference in the addition of these two galvanized square tubes that they have many different physical and chemical properties. In general they have many differences in strength, tolerance and mechanical function.

High-pressure boiler steel pipe: high-quality carbon structural steel, alloy structural steel and stainless heat-resistant steel seamless steel pipe used for steam boiler pipes mainly used for manufacturing high pressure and above. These boiler tubes work under high temperature and high pressure by the party.

It is a long strip of steel with a hollow section and no seams around it. Steel pipes have a hollow section and are used in large quantities as pipes for transporting fluids, such as pipes for transporting oil, natural gas, gas, water and certain solid materials. Compared with solid steel such as round steel, the steel pipe is lighter in weight when it has the same bending and torsional strength. It is an economical section steel and is widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipes, automobile transmission shafts, bicycles. Shelf and steel scaffolding used in construction. The use of steel pipes to manufacture ring-shaped parts can improve material utilization, simplify manufacturing processes, save materials and processing man-hours, such as rolling bearing rings, jack sleeves, etc., and have been widely used in steel pipes. Steel pipes are also indispensable materials for various conventional weapons, and barrels, barrels, etc. are all made of steel pipes. Steel pipes can be divided into round pipes and shaped pipes according to the shape of the cross-sectional area. Since the area of the circle is the largest under the condition of equal circumference, more fluid can be transported by the circular tube. In addition, the circular section is subjected to a relatively uniform force when subjected to internal or external radial pressure, and therefore, most of the steel pipes are round pipes.

　With the continuous development of China's economy, the country vigorously develops the energy industry. Long-distance oil and gas pipelines are an important way of energy security. In the process of anti-corrosion construction of oil (gas) pipelines, the surface treatment of steel pipes is the key factor determining the service life of pipelines. First, it is the premise of whether the anti-corrosion layer and the steel pipe can be firmly combined. According to the research institute's verification, the life of the anti-corrosion layer depends on the coating type, coating quality and construction environment. The surface treatment of the steel pipe affects the life of the anti-corrosion layer by about 50%. Therefore, it should be strictly in accordance with the anti-corrosion layer specification. The requirements of the surface of the steel pipe are continuously explored and summarized, and the surface treatment method of the steel pipe is continuously improved.

Stainless steel pipes of United Steel Industry Co., Ltd. are divided into ordinary carbon steel pipes, high-quality carbon structural steel pipes, alloy structural pipes, alloy steel pipes, bearing steel pipes, stainless steel pipes, and bimetallic composite pipes for saving precious metals and meeting special requirements. Plating and coating tubes, etc. Stainless steel tubes are available in a wide variety of applications, with different technical requirements and different production methods. The outer diameter of the currently produced steel pipe ranges from 0.1 to 4500 mm and the wall thickness ranges from 0.01 to 250 mm. In order to distinguish the characteristics, the steel pipes are usually classified as follows.

Raw materials rose drop alternating large diameter welded pipe prices continue to wait and see

Effective measures to prevent secondary oxidation of molten steel with large diameter seamless pipes

The main cause of corrosion in large diameter welded pipes

Describe the cold treatment cracking of large diameter steel pipe and preventive measures

Large-diameter seamless pipe prices fall back to the market with a wait-and-see attitude

According to the German Business Daily reported in May 11th, June 1st is approaching. In order to avoid the escalation of trade frictions between the United States and Europe, the EU is willing to negotiate with the US side on the "import quota" with the United States, in exchange for permanent exemption status, and the EU will also give up the previously announced tariff retaliation measures. It is reported that the plan is currently in the scope of consideration, but it is not the final plan, the premise is that the limit of "import quota" is enough to be loose enough to cause significant damage to European steel production enterprises. The US side has not yet made a statement. In addition, the proposal is best proposed by the United States, otherwise the agreement will not comply with the WTO rules.

Stainless steel pipe elbow has excellent corrosion resistance, stainless steel surface thin and strong oxide film so that all stainless steel in all water quality has excellent corrosion resistance, even buried also has excellent corrosion resistance. So it is suitable for a variety of water quality, in addition to disinfection and sterilization, do not need to control the water quality, at the same time, there is no corrosion and excessive exudate, to maintain clean water quality, to prevent secondary pollution, can withstand up to 30 meters per second The impact of high water flow.

Galvanized seamless steel pipe galvanized layer and small, only 10-50g / m2, the corrosion resistance of its hot-dip galvanized pipe is poor, hot-dip galvanized pipe. Ordinary galvanized pipe manufacturers use cold galvanized pipe as quasi-cold water and gas pipelines. Galvanized steel cold galvanized layer galvanized, layered zinc layer and the steel matrix. A thin layer of zinc, zinc layer simply attached to the steel substrate. Therefore, its corrosion resistance is poor. In new houses, galvanized steel is prohibited as a cold water supply.

The advantages of straight seam welded pipe compared with seamless steel pipe are as follows:

X-ray Inspection Operate of Wall Thickness SSAW Steel Pipe

Recently, the price of 45# seamless steel pipe has skyrocketed and plummeted. After the violent rise, the market quickly returned to calm. According to industry analysts, the current stock market of 45# seamless steel pipe is still low, and the market is steadily rising. It is worth looking forward to the recent surge in the price of 45# seamless steel pipe. After the violent rise, the market quickly returned to calm. According to industry analysts, the current stock market of 45# seamless steel pipe is still low, and the market is steadily rising.

Q345B seamless steel pipe leads to increased cost of seamless steel pipe industry. The high cost brought by iron ore has always been the thorn of domestic seamless steel pipe enterprises. The loss of domestic seamless steel pipe industry is also often attributed to the cost of raw materials such as iron ore. The engulfing of corporate profits. In the following table, we made a superimposed comparison and found that the Tianjin 16mn seamless steel pipe resources have no adjustment space. The decline in the price from July to the present has already overdrawn the effect of the ex-factory price of the seamless steel pipe factory. From the cost consideration, if the price does not have a bubble in the downside, the price adjustment has been put in place.

High-precision steel pipes In the conventional quenching method, the cold wind speed is not as fast as oil cooling, and is also lower than the isothermal and graded quenching molten salt. Therefore, increasing the pressure in the refrigerating chamber, increasing the flow rate, and applying the molar mass ratio of nitrogen to argon gas and hydrogen are common developments in vacuum absorption technology today. The vacuum carbonization temperature is generally higher than that of conventional gas carbonization. Usually, the penetration and diffusion of 920~1040 °C can be shown in two stages. It can also be used for pulse ventilation, heat preservation and multi-phase dispersion dispersion. The effect is better due to high temperature, especially surface. The clean, active, and vacuum carbonized layer formation rate is faster than conventional gas, liquid, and rapid carbonization. This is a reinforcing material, especially the use of heat treatment to strengthen the material, which is a more important means. Second, the cold deformation enhancement contributes to the uniformity of the metal deformation, because the deformed portion of the precision steel tube is hardened, and the portion where the deformation or deformation is small continues to develop. Third, the cold deformation strength can improve the safety of the member during use, and when the member is overloaded, plastic deformation occurs, thereby preventing the member from suddenly breaking due to strength.