Seamless steel pipe is made of a single piece of metal and has no jointed steel pipe on the surface, which is called seamless steel pipe. According to the production method, the hot rolled tube, the cold rolled tube, the cold drawn tube, the extruded tube, the top tube and the like are seamlessly divided. According to the cross-sectional shape, the seamless steel tube is divided into two types: round and irregular, and the special-shaped tube has a variety of complex shapes such as square, oval, triangular, hexagonal, melon-shaped, star-shaped and finned tubes. The maximum diameter is 650mm and the minimum diameter is 0.3mm. According to different uses, there are thick-walled tubes and thin-walled tubes. Seamless steel tubes are mainly used as petroleum geological drilling tubes, cracking tubes for petrochemical industries, boiler tubes, bearing tubes, and high-precision structural steel tubes for automobiles, tractors, and aviation.
Seamless steel pipe is widely used. General purpose seamless steel tubes are rolled from ordinary carbon structural steels, low alloy structural steels or alloy structural steels with the highest yield, and are mainly used as pipes or structural parts for conveying fluids.
Depending on the use of three different types of supply: a, according to chemical composition and mechanical properties of the supply; b, according to the mechanical performance of the supply; c, according to the water pressure test supply. Pipes supplied by Types a and b, if used to withstand liquid pressure, are also subject to hydrostatic testing.
The special-purpose seamless pipes include seamless pipes for boilers, chemical power, seamless pipes for geological use and seamless pipes for petroleum.
Seamless steel tubes have a hollow cross-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, steel pipes have a lighter weight when subjected to the same flexural and torsional strength and are economical cross-section steels.
Widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipe, automobile drive shaft, bicycle frame and steel scaffold used in construction, etc. The manufacture of ring-shaped parts using steel pipes can improve the material utilization, simplify the manufacturing process, save materials and processing Working hours have been extensively manufactured with steel pipes.
Seamless steel pipe has no longitudinal weld seam. The manufacturing of seamless steel pipe requires a mechanism to force the hole into the billet.
Rotary piercing and rolling is the most common method for producing seamless steel pipe today. The process starts with a conditioned steel round bar, which is heated, pierced, and worked. The bar is made to flow around a piercer point in order to form a hollow billet. The interior of the pipe is supported with a mandrel or a plug while the billet roller is elongated. Sizing of the steel pipe is achieved by additional rolling on the outside diameter.
Seamless steel pipe has 20% higher ASME (American Society of Mechanical Engineers) working pressures compared to welded steel pipe of the same material and size due to having no welded seam. The welded and drawn steel pipe can also have a visible seam that may concern end users.
Another advantage of seamless steel pipe is that it can offer superior corrosion resistance because it has little potential for impurities. Using seamless steel pipe allows you to avoid the potential for defects and d
Welded steel pipe, also called welded pipe, is a steel pipe made by welding a steel plate or strip steel after crimping. The length is generally 6 meters. Welded steel pipe production process is simple, high production efficiency, variety specifications, equipment investment, but the general strength is lower than the seamless steel pipe.
The blanks used for welded steel tubes are steel plates or strips, which are classified into furnaces, electric (resistance welding) tubes and automatic arc tubes because of their different welding processes. Because of its different welding methods, it is divided into two types: straight seam welded pipe and spiral welded pipe. Because of the shape of its end is divided into round welded pipe and shaped (square, flat, etc.) welded pipe.
The welded steel pipe production process begins with the rolling of a steel coil to the desired gauge thickness. The outcome is a coil of a flat strip. The next step involves cutting the strip according to the width that corresponds with the size of the pipe to be produced.
The pipe is formed by moving the cut coil through a series of rollers, and the seam of the pipe is then welded in a chemically neutral environment. A rolling application is used to forge the welded seam, and a heat treating process is used to finish the welded pipe. Welded pipes can then be drawn over mandrels and ground if needed to smooth the welded seam and make it nearly impossible to see with the naked eye.
Because less drawing and annealing are needed in the manufacture of a welded and drawn pipe, the cost of welded and drawn steel pipe can be less expensive than seamless steel pipe and can typically be procured quicker than seamless steel pipe (although stocking of intermediate size starting stock for seamless steel pipe can reduce this lead time as well).
