At the coming moment, Tube China will be held in Shanghai China from 14th -16th June 2023, This is the first large-scale pipe fair after 3 years of COVID-19, and it will be a good business gathering.  

The 10th China International Tube Exhibition (Tube China) was successfully concluded in Shanghai New International Expo Center on June 16 with the care and support of all walks of people.

Straight seam welded steel pipes are divided into high frequency resistance welding and submerged arc welding according to the welding process. Straight seam submerged arc welding is referred to as LSAW, and longitudinal high frequency resistance welding is referred to as ERW.Compared with submerged arc welding, high frequency electric resistance welded steel pipes (ERW steel pipes) do not add any welding materials during the welding process in the ERW process, and the weld formation does not undergo a thermal melting state, but the weld metal undergoes a recrystallization process. Therefore, the formed weld seam is completely consistent with the chemical composition of the base metal. After the steel pipe is welded, it is annealed to produce the cold working internal stress and welding internal stress. Therefore, the comprehensive mechanical properties of the ERW steel pipe are better.

SSAW (Spiral Submerged Arc Welding) and LSAW (Longitudinal Submerged Arc Welding) are two different methods used for manufacturing welded steel pipes. Here's a comparison of the main differences between SSAW and LSAW pipes:Formation process:SSAW Pipe: The spiral welding process involves forming the steel strip into a spiral shape and then welding the edges using the submerged arc welding method.LSAW Pipe: The longitudinal welding process involves forming a straight, cylindrical pipe from a single steel plate or coil and then welding along the length of the pipe using the submerged arc welding technique.

Brief description and comparison of LSAW, SSAW and ERW pipes-lsaw steel pipeSSAW pipes have greater residual stresses than LSAW pipes. The straight seam submerged arc welded pipe undergoes a uniform expansion process.The stress concentration phenomenon of SSAW pipe welds belongs to the severe category. SSAW pipes have a larger heat affected zone than LSAW pipes. The heat-affected zone is considered a weak point where failure may begin.The geometric accuracy of LSAW pipe is better than that of SSAW pipe, which is the key to ease of installation.LSAW pipe has approximately 60% fewer welds than SSAW pipe. ASTM A252 Piling Pipe application in buildings and retaining wallsBrief description and comparison of LSAW, SSAW and ERW pipesQuality steel pipe is produced by three (3) manufacturing processes: Seamless, LSAW (Longitudinal Submerged Arc Welding) and ERW (Electric Resistance Welding). LSAW and ERW tubes are highly regarded for their wide range of applications. They are widely used in basic solutions and systems, marine construction, structural construction, and various applications in the fields of hydraulic engineering, petrochemical, chemical and power industries, agricultural irrigation, and urban construction.LSAW pipe comes in two types: longitudinal (single or double straight seam weld, DSAW) and helical (also known as SSAW, HSAW or SAWL). LSAW pipe differs from other LSAW pipes in that LSAW pipe has a seam weld on the inside and outside of the pipe, while the latter has only one seam weld on the outer surface, longitudinal or cross-section.SSAW and LSAW pipes are manufactured using a common manufacturing process known as the "JCOE and UOE Forming Process". The difference is that SSAW pipes are welded in a helical or helical position while LSAW pipes are welded longitudinally.The SSAW pipe is wound and welded by steel strip, its rotation direction is inclined to the axis or the center of the pipe, and the weld seam is helical. LSAW pipe is made by forming a steel plate into a cylinder and joining the ends together by straight-line welding.LSAW pipe diameters typically range from 16" to 60" (406mm to 1500mm). They have good high pressure and low temperature corrosion resistance.However, CSC Steel can supply pipe with diameters between 1 inch and 167 inches (21 mm and 4267 mm) and thicknesses between 3/32 inch and 4 inches (2.1 mm and 100 mm). ESC steel pipe is manufactured using LSAW in maximum diameter and thickness and is highly recommended for load bearing piles, composite wall piles and other applications. In the oil and gas industry, large diameter API 5L LSAW pipe is used to efficiently transport hydrocarbons over long distances.HSAW (Spiral Submerged Arc Welding) or SSAW pipe diameters typically range from 20" to 100" (406 mm to 2540 mm). One of the advantages of SSAW is the possibility of obtaining different diametersERW pipeERW Tube Forming SSAW pipe is made from standard size steel strip without cutting. On the other hand, the length of the spiral weld is much longer than the length of the pipe, the cost is higher, and it is prone to cracks, pores, slag inclusions, partial welding, etc.HSAW or spiral welded pipe is used in non-critical applications such as water distribution and not for oil and gas. CSC recommends SSAW pipes as main piles and dredging pipes for our composite walls.

Longitudinally Submerged Arc Welding pipe(abbreviated as LSAW pipe). The Longitudinally Submerged Arc Welding (LSAW) is produced by using a single plate as a raw material, pressing (rolling) the steel plate into a pipe blank in a mold or a molding machine, and adopting double-sided submerged arc welding and expanding the diameter. The finished product has a wide range of specifications, and the weld has good toughness, plasticity, uniformity and compactness, and has the advantages of large pipe diameter, thick pipe wall, high pressure resistance, low temperature resistance and corrosion resistance.

Longitudinally Submerged Arc Welded Process FlowLSAW (Longitudinally Submerged Arc Welded Steel pipes) in leaflets plate as raw material, the steel plate in the mold or molding machine pressure (volume) into using double-sided submerged arc welding and flaring from production.The LSAW process of welded tube includes UOE and JCOEUOE LSAW pipe forming process:The three main forming processes of UOE LSAW steel pipe forming process include: steel plate pre-bending, U forming and O forming. Each process adopts a dedicated forming press to complete the three processes of pre-bending the edge of the steel plate, U forming and O forming in sequence to deform the steel plate into a circular tube.

LSAW and SSAW are variants of SAW (submerged arc welded) pipes. The difference between them is the way they are welded. In LSAW pipes, the welding is longitudinal, which means that steel (hot rolled coil plate) is rolled into a pipe and the seam is welded longitudinally. In the SSAW type, steel coils are welded spirally, like a helix, so that the coil (strip) assumes the shape of a pipe. SAW pipes are used mainly in oil and gas transportation. On the other hand, seamless (non-welded) pipes are mainly application in oil and gas exploration projects.An LSAW pipe (“submerged arc welding”) is manufactured by cutting, bending, and welding steel plates (JCOE process). The two main types of LSAW pipes are the longitudinal (with a single or double straight seam weld, DSAW) and the spiral type (called, HSAW, SSAW or SAWL pipe).

High quality steel pipes are produced from three (3) manufacturing processes: Seamless, LSAW (longitudinal-seam submerged arc welding), and ERW (electric resistance welding). LSAW and ERW pipes are highly regarded for their numerous fields of application. They are tremendously used in foundation solutions and systems, marine construction, structural construction, and diverse applications in water projects, petrochemical, chemical, and power industry, agricultural irrigation, urban construction, and more.

Steel tube (and Steel Pipe) has evolved over history. Specifically, metal tube has been around since around 3000 BC. In fact, Egyptians made the first metal pipe from copper.As Early as 2500 BC Chinese used bamboo pipe as a way to transport gasAs early as 2500 BC, Chinese used bamboo pipe as a way to transport natural gas to light Peking, their capital. Rome and Persia created aqueducts to bring water to city centers for bathing, washing and drinking.Furthermore, pipe (or tubing) is made with many different materials and methods. Hollowed stone, fired clay, bamboo, palm, redwood, lead, bronze, copper, and rubber are just some of the materials that makeup tubing.In the mid-1800’s the modern steel industry was bolstered with the Bessemer process. The Bessemer process represented the first inexpensive method for mass production of steel pipe. Subsequently, seamless tube was born in 1895. Quickly followed by manufacturing of auto, bicycle, and machinery for oil production which began in full force.

High quality steel pipes are produced from three (3) manufacturing processes: Seamless, LSAW (longitudinal-seam submerged arc welding), and ERW (electric resistance welding). LSAW and ERW pipes are highly regarded for their numerous fields of application. They are tremendously used in foundation solutions and systems, marine construction, structural construction, and diverse applications in water projects, petrochemical, chemical, and power industry, agricultural irrigation, urban construction, and more.

Steel pipes are cylindrical steel tubes that are used in the manufacture and infrastructure of several different styles. They are the most used steel industry product. The key use of pipe is in the underground movement of liquid or gas, including oil, gas and water. However in the development and construction process pipes of different sizes are used. The narrow steel pipe that operates the cooling system in refrigerators is a typical example of household development. Building uses heating and plumbing tubing. It is possible to create structures using steel pipes of various sizes like handrails, bike racks or pipe pads.The pioneer of steel pipe fabricators is believed to be William Murdoch. In 1815 he mixed barrels of muskets with a burning system of coal lamps. In his revolutionary piping method, Murdoch used coal gas to be brought to lamps on London’s streets.Since the 1800’s, significant advances have been made in steel pipes technology, including the advancement of production processes, development of applications for their use and the development and qualification of regulations and standards.

Seamless steel pipes are produced by piercing a solid billet of steel to form a hollow tube. The billet is heated to a temperature that allows it to be easily pierced by a piercing mill. The mill contains a mandrel, which is a cylindrical tool that supports the inside of the tube during the piercing process.Once the billet is pierced, it is rolled and stretched to achieve the desired shape and size of the tube. This process is known as the extrusion process. The extrusion process can produce seamless pipes of various sizes and thicknesses, making them suitable for a range of applications.The main advantage of seamless pipes is that they have a smooth surface finish, which is essential for industries such as water supply, where cleanliness is crucial. Seamless pipes are also stronger and more durable than welded pipes, making them suitable for applications where high pressure and high temperatures are involved, such as in the oil and gas industry.

Seamless steel pipes obtained by hot extrusion are the result of a manufacturing process in which the acting force is compression. In hot extrusion, steel billets are pushed through so-called “passage lights” that are shaped and arranged on special tools, called matrices, so as to obtain the desired shape.This type of processing takes place at high temperatures to reduce the necessary forces and operate more easily on materials that, by nature, would not be especially ductile if processed at room temperature.

Billet-Heating-Mannesmann piercer-Elongator-Plug mill-Reeler-Reheating-SizerWhen a seamless pipe is made by rolling, the rolling method involves piercing the material while it is being rolled, and is suitable for mass production. The figure shows the manufacturing process used in the Mannesmann plug mill, which is a typical rolling process. The Mannesmann-type piercer reduces the material by rolls that are inclined obliquely to each other. When the round billet is rotated while being compressed in the diametric direction, the central part of the billet becomes loose, which makes it easy to pierce a hole through the center. This is called the Mannesmann effect. The pierced portion is expanded by the elongator, and the wall thickness is then thinned and elongated by the pug mill. The internal and external surfaces are smoothed by the reeler, and the final dimensional adjustments are made by the sizer.

Four different welding processes are typically used for making tube. Since there is no filler metal in these welds, the welds are at least as strong as the parent metals.High Frequency (HF) Welding. Today, most mild steel and aluminum tube is welded with HF welders, which are also suitable for 400 series stainless and even 300 series if the tubing is for decorative use.Nearly 95 percent of the HF welders sold are solid-state, using transistors to generate the alternating frequency current. Research has been undertaken to weld products less than 1/4 inch in diameter and to extend the ability of the welder to produce a pressure-quality weld on 300 stainless steel at high line speeds.

The production process of general seamless steel pipes(smls pipe) can be divided into two types: cold-drawn and hot-rolled. The production process of cold-rolled seamless steel pipes is generally more complicated than that of hot rolling. In the sizing test, if the surface does not respond to cracks, the pipe must be cut by a cutting machine and cut into a blank of about one meter in length. Then enter the annealing process. Annealing needs to be pickled with acidic liquid. When pickling, pay attention to whether there is a lot of blistering on the surface. If there is a lot of blistering, it means that the quality of the steel pipe does not meet the corresponding standards. In appearance, cold-rolled seamless steel pipes are shorter than hot-rolled seamless steel pipes. The wall thickness of cold-rolled seamless steel pipes is generally smaller than that of hot-rolled seamless steel pipes, but the surface looks brighter than thick-walled seamless steel pipes. Much rough, without too many burrs.

Hot rolled seamless steel pipe can damage the casting structure of the steel ingot, refine the crystal grains of the steel, and eliminate the defects of the microstructure. In this way, the steel organization is compacting and the mechanical properties would be improved.This improvement is reflected in the rolling direction, so that the steel is no longer isotropic to a certain extent; bubbles, cracks and looseness formed during casting can also be welded under high temperature and pressure.

The production method of seamless pipe is roughly divided into the cross-rolling method (Mennesmann method) and the extrusion method. The former method is to first perforate the tube with a skew roll, and then extend it with a rolling mill. This method has a fast production speed, but requires higher machinability of the tube blank, and is mainly suitable for the production of carbon steel and low-alloy steel tubes. The latter method is to pierce the tube blank or ingot with a piercing machine, and then extrude it into a steel pipe with an extruder. This method is less efficient than the skew rolling method and is suitable for the production of high-strength alloy steel pipes. Both the skew rolling method and the extrusion method must first heat the tube blank or ingot, and the produced steel tube is called a hot-rolled tube. Steel pipes produced by hot working methods can sometimes be cold worked as needed.

The use of steel pipes was started by a Scottish inventor in 1815 connecting the tubes to convey gas for lights. In 1836, the United Kingdom had a patent for the production of seamless steel pipes by the extrusion method, but it was not until 1885 that the German Mannismann brothers invented the process of directly producing seamless pipes from bar steel. The Mannismann brothers first invented the second in 1885. The roll cross-rolling piercing machine, invented the periodic tube rolling machine in 1891, and in 1903, the Swiss R Stiefel (RCStiefel) invented the automatic tube rolling machine (also known as the head-type tube rolling machine). Later, continuous tube rolling appeared All kinds of extension machines, such as machine and pipe jacking machine, began to form the modern seamless steel pipe industry.