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Company News


2016/10/11

A 90-degree elbow is a pipe fitting used at pipe bends.

Among all pipe fittings used in piping systems, 90-degree elbows account for the largest share, approximately 80%. Typically, different forming techniques are selected depending on the material and wall thickness of the elbow. Currently, the most commonly employed forming methods for manufacturing 90-degree elbows include hot pushing, stamping, and extrusion. The deformation characteristic of a 90-degree elbow is determined by the principle that the volume of metal remains constant before and after plastic deformation; thus, the diameter of the tube blank is chosen smaller than the elbow’s nominal diameter. A mandrel controls the blank’s deformation, ensuring that the metal compressed along the inner arc flows to compensate for thinning in other regions caused by diameter expansion, thereby producing an elbow with uniform wall thickness. A 90-degree elbow is a type of fitting used at pipe bends. It represents the largest proportion—about 80%—of all fittings in piping systems. Different forming processes are usually selected based on the material and wall thickness of the elbow. Today, common forming techniques for 90-degree elbows include hot pushing, stamping, and extrusion. The cost of a 90-degree elbow is directly proportional to its nominal diameter: the larger the diameter, the higher the cost of the forming process. This is because the steel plate used to fabricate such elbows must first be heated over coal-fired furnaces and then shaped using specialized dies. Moreover, larger diameters require correspondingly larger molds, while orders for large-diameter welded elbows tend to be relatively small. A 90-degree elbow, also known as a reduced‑diameter elbow or seamless elbow, is formed by cold‑drawing seamless tubes made from high‑quality carbon steel, stainless steel, acid‑resistant steel, or low‑alloy steel within specially designed dies. Stamped elbows, or stamped‑welded elbows, are produced by stamping sheet metal of the same material as the pipe into semi‑circular segments, which are then assembled and welded together to form a complete elbow. Among these types, the hot‑pressed 90-degree elbow exhibits superior pressure resistance, excellent temperature and pressure tolerance, good flexibility, and strong heat resistance—outperforming other plastic pipe materials. It is easy to install, has good thermal conductivity, making it suitable for underfloor heating systems, and is recyclable. Furthermore, pressed‑type elbows possess outstanding impact resistance, can be joined via hot‑melt welding or mechanical connections, and offer better thermal conductivity than PB‑PP‑R pipes. In terms of long‑term pressure resistance, considering only design stress levels, pressed‑type elbows demonstrate the best performance. In actual production and manufacturing, 90-degree elbows are fabricated according to specific technical standards and dimensions, ensuring they deliver reliable performance and value in practical applications. By fully leveraging their unique characteristics and advantages, and adhering to standard manufacturing procedures, these products can be exported to various countries and regions, contributing to China’s rapid economic growth and development, and holding significant importance for manufacturing enterprises.

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2016/10/11

The large-diameter spiral steel pipe factory employs numerous protective measures for spiral steel pipes during the winter.

Winter protection measures for large-diameter spiral steel pipe plants: Professional pipeline maintenance agents can be used regularly to clean, disinfect, and sterilize sewer pipes, ensuring unobstructed flow and preventing the pipes from becoming breeding grounds for pathogens. When cleaning pipelines, it is essential to use specialized pipeline maintenance products to achieve effective disinfection, odor removal, and prevention of blockages. When selecting maintenance and unclogging products, prioritize safety and choose those with high bactericidal efficacy that have been evaluated by reputable professional authorities. Currently, demagnetization of large‑diameter spiral steel pipes typically employs a DC demagnetizing coil placed after the magnetic particle inspection machine; however, this method often fails to meet customer expectations. The issue lies in the fact that the DC demagnetizing field generates only a reverse half‑cycle magnetic field, which can only partially offset the residual magnetism inside the pipe, leaving the external residual magnetism within acceptable limits—resulting in an unstable effect. Often, the process meets specifications on site, but after relocation or impact, the residual magnetism exceeds allowable levels again. For flaw detection in the welds of large‑diameter spiral steel pipes, pulse‑echo ultrasonic testing is a relatively effective technique. Since the primary concern is determining the presence of defects, we employ a scanning ultrasonic flaw detector. This device exploits the reflection characteristics of ultrasonic waves: on the display screen, the vertical axis represents the amplitude of the reflected echoes, while the horizontal axis indicates the travel time of these echoes. By analyzing the amplitude and timing of defect‑related reflections, the size and location of defects can be accurately determined. In terms of specific manufacturing materials, large‑diameter spiral steel pipes exhibit certain unique properties that distinguish them from conventional piping materials. Their defining feature is the hollow cross‑section; this hollow structure provides a substantial internal surface area, making these pipes highly suitable for widespread application in pipeline transportation. Such pipes offer numerous advantages and, as a specialized material, have earned considerable recognition in the transport sector. During production, edge misalignment frequently occurs, influenced by many factors. In practice, such misalignment often leads to downgrading of the pipe. Therefore, it is crucial to analyze the causes of edge misalignment in small‑diameter spiral steel pipes and develop appropriate preventive measures. All welded joints—whether butt welds or T‑joints intersecting spiral welds—are inspected using X‑ray fluoroscopy or radiographic imaging. Each pipe also undergoes a hydrostatic pressure test, with radial sealing employed as the pressure‑bearing mechanism. Structural steel pipes, including various welded and seamless types, particularly large‑diameter spiral steel pipes, possess an ideal annular cross‑section that confers strong resistance to local buckling, making them among the best lightweight components for withstanding both internal and external radial pressures. Columns, beams, and other basic structural elements fabricated from steel pipes can serve independently or be assembled into diverse structural systems, such as frames, trusses, and space frames.

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2016/10/11

Profit margins across all stages of the stainless steel elbow industry chain have been squeezed.

The raw material for stainless steel elbows is steel that resists corrosion from weak corrosive media such as air, steam, and water, as well as from chemically aggressive media like acids, alkalis, and salts. In practical applications, steel resistant to mild corrosive environments is commonly referred to as “stainless steel,” while steel capable of withstanding chemical corrosion is called “acid‑resistant steel.” Due to differences in their chemical compositions, the former does not necessarily resist all chemical media, whereas the latter generally exhibits excellent corrosion resistance. Stainless steel remains one of the highest‑strength metallic materials used in construction. Its outstanding corrosion resistance ensures that structural components maintain their intended integrity over long service lives. Over several decades of development within China, the stainless steel elbow industry has made significant strides in product quality, output volume, technological advancement, durability, and safety. Moreover, its corporate services have aligned with international standards, meeting the demands of the modern era. With the advent of the new century, the industry has progressively shifted toward low‑consumption, high‑efficiency, and intelligent automation, achieving notable results that have greatly enhanced its competitiveness both domestically and internationally. The stainless steel elbow sector has now moved beyond a decade of rapid growth. As competition among companies intensifies, profit margins across all stages of the supply chain have been squeezed, leaving limited room for further price reductions. At the same time, international markets are increasingly raising their expectations for Chinese stainless steel elbow products, demanding higher standards in quality, packaging, and delivery schedules—requirements that are gradually extending even to production processes and product R&D. Stainless steel elbow fabrication is a manufacturing process that employs conventional or specialized stamping equipment to apply forming forces directly to sheet metal within dies, thereby shaping it into parts with specific dimensions, configurations, and functional properties. Sheet metal, dies, and equipment constitute the three essential elements of stamping operations. Thanks to their smooth inner surfaces, low hydraulic resistance, resistance to acids and alkalis, long service life, and ease of installation, stainless steel elbow pipes have seen widespread adoption in heating systems in recent years. National‑standard stamped elbows, as next‑generation piping specifically designed for heating applications, are steadily becoming mainstream in the heating market. Thickening‑wall stainless steel elbows refer to fittings whose wall thickness varies along the pipe’s length, with gradual increases in wall thickness tailored to enhance performance and convenience during use, while also providing assurance of consistent quality. Each of these processing methods possesses distinct characteristics, requires different technical conditions, and entails unique considerations. Pipe fitting fabrication represents an organic integration of machining and metal forming; superior coordination between these processes makes fabrication more rational and better suited to the actual needs of end‑use applications.

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