With the development of the national economy in our country, the submerged arc steel pipe is becoming more and more popular with its advantages of high bearing capacity, low resistance, low-temperature resistance, corrosion resistance, convenient installation and maintenance, and so on. Submerged arc steel pipe refers to steel pipe with joints on the surface, which is welded by bending the steel strip or steel plate into a round or square shape. The strength of submerged arc steel pipe is generally higher than that of steel pipe, and the welded pipe with a larger diameter can be produced with a narrower billet, and the welded pipe with a different diameter can also be produced with the same width billet. But compared with the same length of straight seam pipe, the weld length is increased by 30~1, and the production speed is lower. Therefore, the welded pipe of small caliber mostly adopts straight seam welding, and the welded pipe of large caliber mostly adopts spiral welding. Spiral welded steel pipe refers to steel pipe with joints on the surface, which is welded by bending the steel strip or steel plate into a round or square shape. According to different welding methods, it can be divided into arc welding pipe, high-frequency or low-frequency resistance welding pipe, gas welding pipe, furnace welding pipe, Bondi pipe, and so on. According to the weld, the shape can be divided into steel pipe and submerged arc steel pipe.

Submerged arc steel pipe is used in oil drilling and machinery manufacturing. If the submerged arc steel pipe is rusted, the steel surface is polished with a wire brush and other tools. Cleaning and preheating spiral pipes can remove loose or warped oxide skin, rust, welding slag, and so on. Manual tools can reach the Sa2 level, power tools can reach the Sa3 level, if the spiral pipe surface is firmly attached to the oxide sheet, the tool rust removal effect is not ideal, and can not reach the construction requirements of anchor grain. New applications are added on the basis of the traditional application, which makes the submerged arc steel pipe more useful, but also reduces the cost of using the submerged arc steel pipe. The radio frequency sensor provides 200 volts, 50 amps of electrically flowing through submerged arc steel pipe to heat the test sample by induction.

First, outline the steps of submerged arc steel pipe forming:

(1) Pre-bending edge: the pre-bending machine is used for plate edge pre-bending so that the plate edge has the required curvature;

(2) Plate probe: After the steel plate used to make submerged arc steel pipe enters the production line, the first line of the whole plate acoustic inspection;

(3) Forming: in the JCO molding machine at first will prebend half of the steel plate after several steps of stamping, is pressed into a "J" shape, and then the other half of the steel plate is also bent, pressed into a "C" shape, and then form the opening of the "O" shape;

(4) Edge milling: the two edges of the steel plate are double-sided by the edge milling machine to achieve the required plate width, plate edge parallelism, and groove shape;

Second, analysis of metallurgical properties of submerged arc steel pipe materials

(1) Submerged arc steel pipe is made of steel plate, while submerged arc steel pipe is made of hot rolled coil plate. The rolling process of a hot strip mill has a series of advantages and has the metallurgical process ability to produce excellent pipeline steel. For example, a water cooling system is installed on the output bench to accelerate cooling, which allows the use of low alloy components to achieve special strength levels and low-temperature toughness, thus improving the weldability of the steel.

(2) But this system is basically absent in steel plate manufacturing plants. The alloy content (carbon equivalent) of coil plates is often lower than that of similar grades of steel plates, which also improves the solderability of submerged arc steel pipes.

(3) It is important to note that because the rolling direction of submerged arc steel pipe is not perpendicular to the axis direction of the steel pipe (its clamping depends on the spiral Angle of the steel pipe), and the rolling direction of the steel plate of straight seam steel pipe is perpendicular to the axis direction of the steel pipe, the cracking resistance of submerged arc steel pipe material is better than that of straight seam steel pipe.

The submerged arc steel pipe itself will not become hot, but the temperature of the test sample will increase significantly. Radio-frequency sensors will provide more control when heating exceeds ARF, allowing the home to adjust the specific composition of the alloy. The submerged arc steel pipe has good pressure and plasticity, which is convenient for welding and processing. General submerged arc steel pipe for low-pressure fluid transportation is made by double-sided automatic submerged arc welding or single-sided welding method for water, gas, air, steam, etc. Submerged arc steel pipe market demand is not a disorderly growth trend that will not change fundamentally. Whether the submerged arc steel pipe market can keep the development of the hub depends on the change in demand. Macroeconomic regulation at the policy level will slow down the growth rate of the market in the future. The main raw materials are molten iron and scrap steel. The content of sulfur and phosphorus in steel is higher than that of fine carbon structural steel, with sulfur ≤0.050% and phosphorus ≤0.045% in general. The content of other alloying elements, such as chromium, nickel, and copper, brought into the steel by the raw material generally does not exceed 0.30%, as required by composition and properties. Q" is the capitalized Chinese alphabet prefix of the yield "qu" character, followed by the number of the smaller yield point (σs) value of the grade, followed by the symbol of the steel according to the content of impurities (sulfur, phosphorus) from high to low and accompanied by the change of carbon, manganese elements are classified into A, B, C, D four levels.

Cangzhou Shenlong Pipe is specialized in the production of direct-seam submerged arc welding steel pipe, the product range is 406-3000mm, the maximum wall thickness of 60mm, product quality control is strict, fast delivery is the qualified supplier of PetroChina, BP oil.