We help the world growing since 1983

Knowledge of steel (seamless steel pipe and plate)

1.Seamless steel pipe: seamless pipe is a kind of long steel with hollow section and no seam around. Steel pipe has hollow section, which is widely used to transport fluid, such as oil, natural gas, gas, water and some solid materials. Compared with solid steel such as round steel, seamless pipe has the same bending and torsion strength and lighter weight. It is widely used in the manufacture of structural parts and mechanical parts, such as petroleum drill pipe, automobile transmission shaft, bicycle frame and steel scaffold used in construction. It can improve the material utilization rate, simplify the manufacturing process, save materials and processing time by using seamless pipe to manufacture ring parts, such as rolling bearing ring, jack sleeve, etc. Seamless tube is also an indispensable material for all kinds of conventional weapons. Barrel and barrel are made of steel tube. According to the shape of cross-sectional area, steel pipes can be divided into round pipe and special-shaped pipe. Because the area of the circle is the largest under the condition of equal perimeter, more fluid can be transported by the circular tube. In addition, when the ring section bears internal or external radial pressure, the force is more uniform. Therefore, most seamless tubes are round tubes, which are divided into hot rolling and cold rolling. Common materials: 20 #, 45 #, Q345, 20g, 20Cr, 35CrMo, 40Cr, 42CrMo, 12CrMo, 12Cr1MoVG, 15CrMoG, etc; Stainless steel series is a kind of hollow long round steel, which is widely used in petroleum, chemical, medical, food, light industry, mechanical instruments and other industrial pipelines and mechanical structural parts. In addition, when the bending and torsion strength are the same, the weight is lighter, so it is also widely used in manufacturing mechanical parts and engineering structures. Also commonly used for furniture, kitchenware, etc., common materials: 201, 304, 316, 316L, 310, 310S, etc.

2. Steel plate: it is a flat steel cast with molten steel and pressed after cooling. It is flat and rectangular, and can be directly rolled or cut from wide steel strip. Steel plate is divided into hot rolling and cold rolling according to rolling. According to the thickness of steel plate, thin steel plate < 4 mm (the thinnest 0.2 mm), medium thick steel plate 4 ~ 60 mm, ultra thick steel plate 60 ~ 115 mm. The width of the sheet is 500-1500 mm; The width of thick plate is 600-3000 mm. According to the types of steel, there are ordinary steel, high-quality steel, alloy steel, spring steel, stainless steel, tool steel, heat-resistant steel, bearing steel, silicon steel and industrial pure iron sheet; According to professional use, there are oil barrel plate, enamel plate, bulletproof plate, etc; According to the surface coating, there are galvanized sheet, tinplate, lead plate, plastic composite steel plate, etc. Common materials: Q235, 16Mn (q355b), 20 #, 45 #, 65Mn, 40Cr, 42CrMo, 304, 201, 316, etc.

3. Welded pipe: welded steel pipe, also known as welded pipe, is a steel pipe made of steel plate or strip after curling and forming, with a general fixed length of 6 meters. The production process of welded steel pipe is simple, the production efficiency is high, the varieties and specifications are more, the equipment investment is less, but the general strength is lower than seamless steel pipe. Welded steel pipe is divided into straight welded pipe and spiral welded pipe according to the form of weld. Classification by production method: process classification – arc welded pipe, resistance welded pipe, (high frequency, low frequency) gas welded pipe, furnace welded pipe. Straight seam welding is used for small diameter welded pipe, while spiral welding is used for large diameter welded pipe; According to the end shape of steel pipe, it can be divided into circular welded pipe and special-shaped (square, rectangular, etc.) welded pipe; According to different materials and uses, it can be divided into mine fluid conveying welded steel pipe, low-pressure fluid conveying galvanized welded steel pipe, belt conveyor roller welded steel pipe, etc. Straight welded pipe production process is simple, high production efficiency, low cost, rapid development. The strength of spiral welded pipe is generally higher than that of straight welded pipe. It can be used to produce larger diameter welded pipe with narrower blank, and it can also be used to produce different diameter welded pipe with the same width blank. But compared with the same length of straight seam pipe, the weld length increases by 30 ~ 100%, and the production speed is lower. Large diameter or thick welded pipe is usually made of steel billet directly, while small welded pipe and thin-walled welded pipe only need to be welded directly by steel strip. Then after a simple polishing, wire drawing is OK. In order to improve the corrosion resistance of steel pipe, general steel pipe (black pipe) was galvanized. There are two kinds of galvanized steel pipe, hot-dip galvanizing and electro galvanizing. The thickness of hot-dip galvanizing is thick, and the cost of electro galvanizing is low. Common materials of welded pipe are: Q235A, Q235C, Q235B, 16Mn, 20Mn, Q345, L245, L290, X42, X46, X60, X80, 0Cr13, 1Cr17, 00cr19ni11, 1Cr18Ni9, 0cr18ni11nb, etc.

4. Coiled pipe: coiled pipe is committed to the production of various types of coiled pipes and steel penstocks with circumferential seams and longitudinal rings, and is transformed on the basis of the same specifications and models of traditional coiled pipe equipment. The function of increasing the parameters of the tube rolling equipment by 30% fills the gap that the traditional rolling equipment can not produce. It can produce steel pipes with diameter of more than 400 and wall thickness of 8-100 mm. Coiled pipe is widely used in petroleum, chemical, natural gas transmission, piling and urban water supply, heating, gas supply and other projects. The main materials are Q235A, Q345B, 20, 45, 35cimo, 42cimo, 16Mn, etc

Post time: Jul-03-2021