Website large image
Website large image
Website large image
Website large image

Company News

Steel Pipe Knowledge

Company News

Applications of 3PE Polyethylene Anti-Corrosion Insulated Pipes

2019/08/29

Applications of 3PE Polyethylene Anti-Corrosion Insulated Pipes

At present, pipeline anti-corrosion technologies have received widespread acclaim in practical market applications. These technologies are employed across a wide range of industrial sectors, including construction, petroleum, power generation, metallurgy, national defense, transportation and storage, boilers, heat exchangers, fans, and vehicles and ships. Among them, anti-corrosion and thermal‑insulation pipe technology typically involves applying an external anti-corrosion coating to the outer surface of spiral‑wound pipes to mitigate corrosion and extend service life. Currently, the primary external anti-corrosion coatings used for spiral pipes include three‑layer polyethylene (3PE), epoxy powder, and epoxy coal tar pitch; accordingly, products such as epoxy‑powder‑coated thermal‑insulation pipes and epoxy‑coal‑tar‑pitch‑coated steel pipes can be manufactured. The use of three‑layer polyethylene and epoxy powder coatings offers several advantages: excellent waterproofing and corrosion resistance, electrical insulation, and low‑temperature performance. In many European and North American countries, these coatings are the standard choice for underground pipelines. Considering factors such as overall service life and maintenance costs, China currently prioritizes the three‑layer polyethylene composite anti-corrosion coating. The specific manufacturing process for three‑layer polyethylene‑coated spiral anti‑corrosion and thermal‑insulation pipes is as follows: medium‑frequency heating of the spiral pipe, shot blasting for rust removal, quality inspection of the blast‑cleaned surface, medium‑frequency heating, application of epoxy powder, coating with an adhesive, extrusion of polyethylene, water‑cooling treatment, leak testing of the coating, and finally stacking the coated pipes.

View Details >

Introduction to Polyurethane Direct-Buried Insulated Pipes

2019/08/29

Introduction to Polyurethane Direct-Buried Insulated Pipes

Polyurethane direct‑buried insulated pipes are prefabricated, directly buried insulation solutions that offer excellent thermal performance, high safety and reliability, and low installation costs. These pipes not only surpass traditional trench‑laying and overhead‑suspended pipelines in advanced technology and practicality but also deliver significant social and economic benefits, serving as an effective measure for heating energy conservation. The adoption of direct‑buried heating pipeline technology marks a new milestone in the development of China’s heating pipeline engineering. As global energy resources dwindle and demand continues to rise, energy efficiency, emission reduction, and environmental protection have become worldwide trends. National and local governments alike are vigorously promoting the development, application, and industrialization of energy‑saving, emission‑reducing, and environmentally friendly products. In the construction sector, rigid polyurethane foam insulation materials represent an important segment of the polyurethane industry, distinguished by their versatility—providing simultaneous thermal insulation, waterproofing, and other functions. Since their introduction into European construction in the 1960s, these products have enjoyed a history spanning four decades; some countries have even enacted legislation designating polyurethane as the preferred material for both insulation and waterproofing in building applications. In recent years, with the rapid expansion of China’s building energy‑efficiency market, rigid polyurethane foam insulation has found widespread use in thermal insulation and waterproofing, emerging as one of the leading insulation and energy‑saving products on the market. As an integrated thermal insulation and waterproofing material, rigid polyurethane foam breaks away from the conventional limitation of single‑purpose building materials—where waterproofing fails to insulate, and insulation fails to waterproof—and eliminates the common issue of insulation losing its effectiveness once the waterproofing layer develops leaks. Compared with other single‑function insulation or waterproofing materials, rigid polyurethane foam offers distinct advantages: 1. It combines multiple functions in one material, providing thermal insulation, waterproofing, soundproofing, vibration absorption, and more. 2. Its thermal insulation performance is outstanding: among all domestic building materials, it boasts the lowest thermal conductivity (≤0.024) and the highest thermal resistance, with a thermal conductivity only half that of EPS expanded polystyrene boards. 3. Rigid polyurethane foam features a continuous, dense surface skin and nearly 100% closed-cell structure with strong interconnections, delivering ideal impermeability. When applied via spray‑on methods, it creates seamless, joint‑free waterproofing and insulation layers, forming leak‑proof roofs and monolithic exterior wall insulation shells with superior water‑resistance and anti‑seepage properties. 4. It exhibits exceptionally strong self‑adhesive properties—requiring no additional bonding agents—ensuring firm adhesion to roofing and exterior walls while offering excellent resistance to wind uplift and negative wind pressure. Full‑area spray application completely eliminates “thermal bridges” and “cold bridges,” and its flexible gradient technology effectively prevents cracking of the waterproofing layer. Mechanized operations, automated batching, consistent quality, rapid installation, and short project timelines further enhance efficiency. 5. Chemically stable with a long service life, it does not pollute the surrounding environment; it self‑extinguishes upon exposure to open flames and, when burned, chars rather than dripping, with the size and shape of the charred layer remaining largely unchanged. This helps block air ingress and inhibit fire spread, ensuring excellent fire‑safety performance. As the only integrated thermal insulation and waterproofing material currently available, rigid polyurethane foam is still in its early stages of adoption within China’s construction industry. Fortunately, to accelerate innovation in building insulation materials and promote the wider application of rigid polyurethane foam in energy‑efficient construction, the Ministry of Construction has established a dedicated “Polyurethane Building Energy‑Efficiency Application Working Group” to advance the use of this material across China’s energy‑saving construction sector. Polyurethane insulated pipes possess numerous outstanding characteristics, including light weight, high strength, excellent thermal insulation, soundproofing, flame retardancy, cold resistance, corrosion resistance, non‑absorbency, and ease and speed of installation, making them indispensable for thermal insulation, waterproofing, sealing, and leak‑prevention in industries such as construction, transportation, petroleum, chemical processing, power generation, and refrigeration. (For steel pipe purchases, contact Chengyuan.) 1. Low thermal conductivity: Among insulation materials, polyurethane foam exhibits the lowest thermal conductivity, thereby minimizing heat loss in applications.

View Details >

What are the acceptance criteria for longitudinal welded pipes?

2019/08/29

What are the acceptance criteria for longitudinal welded pipes?

In practice, welded pipes can be used to convey various low-pressure fluids. The products are typically manufactured from Q195, Q215A, and Q235A steels, as well as Q235B carbon steel. They can also be made from easily weldable materials such as 0317‑standard grade 6012 and mild steel grade 755. After production, welded pipes must undergo hydraulic pressure, bending, flattening, and other tests, while also meeting specific surface‑quality requirements.

View Details >

Recent market trends for spiral steel pipes

2019/08/29

Recent market trends for spiral steel pipes

Recently, railway construction has once again become a focal point, entering a new phase of rapid development. The renewed surge in western China’s railway projects is driving overall regional economic growth. Meanwhile, urban rail transit construction is also accelerating. Together, railway and urban rail‑transit projects are poised to serve as key engines of near‑term economic expansion, which will positively boost demand for related steel products.

View Details >

How to assess the quality of anti-corrosion spiral steel pipes

2019/08/29

How to assess the quality of anti-corrosion spiral steel pipes

When the material of an anti-corrosion spiral steel pipe comes into contact with a grinding wheel, it produces distinct sparks. By observing these sparks, we can identify the specific material of the anti-corrosion spiral steel pipe. This method can be used to test anti-corrosion spiral steel pipe strips, plates, bars, wires, and pipes…

View Details >

Causes and Solutions for Common Defects in Spiral Welded Steel Pipe Joints

2019/08/10

Causes and Solutions for Common Defects in Spiral Welded Steel Pipe Joints

The common defects in spiral steel pipe welds mainly arise from the following causes. Let’s take a look at what they are and how to address them. The first common issue is uneven weld bead width or curvature. This can result from inconsistent welding speed, unstable welding voltage, uneven wire feed rate, poor conductivity of the welding wire, contamination on the wire surface, unreliable conductivity of the contact tip, excessive oxide scale along the groove edges, improper flux cup and rubber baffle, or overly large flux particles and excessive powder. To remedy this, maintain stable welding parameters, troubleshoot any malfunctions in the wire‑feeding mechanism, clean oil and contaminants from the wire surface, replace the contact tip with one of appropriate diameter—ensuring the internal conductive section is not excessively long—thoroughly clean the groove, properly position the flux cup and rubber baffle, and ensure uniform flux particle size. The second common problem is excessive weld reinforcement. This occurs when the current is too high while the voltage is too low, the uphill welding angle is excessively steep, or the wire feed rate is too fast, leading to excessive wire melting. Solutions include adjusting the welding parameters, modifying the uphill welding angle, and fine-tuning the wire feed speed. The third frequent defect is undercut. It arises from improper wire positioning or angle, excessive current combined with low voltage, overly rapid welding speed, misalignment during forming, excessive buildup, uneven wire feeding, inadequate fixation of the welding torch, or torch oscillation during welding. Remedies involve adjusting the wire position or angle, optimizing process settings—avoiding excessive current—eliminating misalignment or excessive buildup, replacing the wire feed roller or bearings, inspecting and repairing the electrical system, and securely fixing the welding torch. The fourth common issue is lack of fusion. This typically results from misaligned wire placement,偏于坡口一侧 (biased toward one side of the groove), excessive local curvature of the weld, or insufficient welding current. Corrective measures include adjusting the wire position, focusing attention and executing precise operations, and fine-tuning the welding current. The fifth frequent problem is incomplete penetration. Causes include misaligned wire placement, significant deviation from the intended position, insufficient welding current or excessive voltage, overly rapid welding speed, excessively blunt groove edges or too small groove angles, inadequate cleaning of the weld root, and overly narrow forming gaps. Solutions involve restoring the wire to its proper position, adjusting both welding current and voltage, regulating welding speed, correcting the groove’s blunt angle and included angle, thoroughly cleaning the weld root, and optimizing forming gap dimensions. The sixth common defect is slag inclusion. This occurs when edge surfaces are not clean, interpass slag removal is incomplete in multi‑layer welding, welding current is too low, welding speed is too fast, wire positioning is improper, molten slag and metal fail to separate adequately, the weld bead’s width‑to‑depth ratio is too small, undercut is severe, groove angles are too shallow, or the flux is contaminated with foreign matter. Typical remedies include cleaning both edges of the strip steel, ensuring thorough interpass slag removal, adjusting welding current and voltage, repositioning the wire, increasing the weld bead’s width‑to‑depth ratio, enlarging the groove angle, and removing impurities from the flux.

View Details >

Classification of Spiral Welded Steel Pipes

2019/04/17

Classification of Spiral Welded Steel Pipes

Pressure‑bearing fluid conveyance: spiral‑seam submerged‑arc welded steel pipe, conforming to SY 5036‑2000, is primarily used for oil and natural gas pipelines. Spiral‑seam high‑frequency welded steel pipe, specified in SY 5038‑2000, is manufactured by high‑frequency lap welding and likewise employed for pressure‑bearing fluid transport. These pipes exhibit strong pressure resistance, good ductility, and are easy to weld and form. For general low‑pressure fluid conveyance, spiral‑seam submerged‑arc welded steel pipe, designated as SY 5037‑2000, is produced via double‑sided automatic submerged‑arc welding or single‑side welding. It is intended for transporting water, coal gas, air, steam, and other common low‑pressure fluids. Common standards for spiral‑welded steel pipes generally include: SY/T 5037‑2008 (a ministry‑level standard, also known as spiral‑seam submerged‑arc welded steel pipe for ordinary fluid conveyance); GB/T 9711.1‑2008 (a national standard, referred to as the technical delivery requirements for steel pipes used in the petroleum and natural gas industries—Part I: Grade A steel pipe; stricter requirements apply to GB/T 9711.2 Grade B steel pipe); API 5L (the American Petroleum Institute standard, also called line pipe, with two grades—PSL1 and PSL2); and SY/T 5040‑2008 (spiral‑welded steel pipe for pile applications). SY/T 5037‑2008, established by the Ministry of Petroleum, is commonly referred to as a “ministry standard.” GB/T 9711.1‑2008 specifies national spiral‑welded pipes for the petroleum and natural gas industries, classified as Grade A. General low‑pressure fluid‑conveying spiral‑seam high‑frequency welded steel pipe (SY 5039‑2000) is fabricated from hot‑rolled steel strip coils serving as tube blanks, formed into spirals at ambient temperature, and welded using high‑frequency lap welding. Spiral‑welded steel pipe for pile applications (SY 5040‑2000) is made from hot‑rolled steel strip coils as tube blanks, shaped into spirals at room temperature, and manufactured through either double‑sided submerged‑arc welding or high‑frequency welding. It is utilized as foundation piles in civil engineering structures, wharves, bridges, and similar applications.

View Details >

How to maintain and enhance the stability of spiral steel pipes

2019/04/17

How to maintain and enhance the stability of spiral steel pipes

How to Maintain and Enhance the Stability of Spiral Steel Pipes I. Medium- and small-sized structural steel, wire rod, reinforcing bars, medium‑diameter steel pipes, steel wires, and steel ropes may be stored in well‑ventilated sheds, provided they are covered on top and supported on the bottom. II. Certain small‑size steel products—such as thin steel plates, steel strips, silicon steel sheets, small‑diameter or thin‑walled steel pipes, various cold‑rolled and cold‑drawn steel items—as well as high‑value, corrosion‑prone metal goods, may be kept indoors in a warehouse. III. The site or warehouse for storing spiral steel pipe products should be located in a clean, well‑drained area, away from factories and mines that generate harmful gases or dust. The ground must be cleared of weeds and all debris to keep the steel clean. IV. Large‑section structural steel, rails, heavy steel plates, large‑diameter steel pipes, forgings, and similar items may be stacked outdoors. V. Warehouses must not store steel together with corrosive materials such as acids, alkalis, salts, or cement. Different grades of steel should be stored separately to avoid confusion and prevent contact corrosion. VI. Warehouse selection should be based on local conditions; generally, standard enclosed warehouses are preferred—structures with roofs, perimeter walls, tightly sealed doors and windows, and adequate ventilation systems. VII. Warehouses should ensure proper ventilation on sunny days and be kept closed to prevent moisture ingress during rainy weather, maintaining an appropriate storage environment at all times.

View Details >

< 1...131415...18 >

Guangxi Nanning Canghai Steel Co., Ltd. All rights reserved

by:www.300.cn

Skype
WhatsApp

8613768885388
tel

13768885388
wechat
WeChat

WeChat

Link
customize

Sorry, there is currently no content in this section.

You can view other sections.

Business license