Spiral welding involves the creation of steel pipes from coiled material with a spiral weld seam. These pipes, welded from high-strength steel plates, offer robustness and resilience, capable of enduring substantial internal and external pressures. The forming process ensures smooth deformation of the steel plate, resulting in minimal residual stress and surface imperfections. Spiral welding techniques find crucial applications in various industries, including pipelines, construction, and infrastructure, where their strength, durability, and resistance to deformation are paramount for reliable performance in demanding environments.

Fundamentals of Spiral Welding

Brief History and Development

Spiral welding has evolved significantly since its inception in the early 20th century. Initially utilized for the manufacturing of steel pipes for industrial applications, it gained prominence during the mid-20th century with advancements in welding technologies. Over time, innovations in welding techniques, equipment, and materials have refined the process, enhancing its efficiency, quality, and versatility.

Basic Principles and Working Mechanism

Spiral welding involves the continuous joining of coiled steel strips or plates along a helical seam to form a pipe or tube. This process typically employs techniques such as submerged arc welding (SAW), gas metal arc welding (GMAW), or laser welding. The coiled material is fed through a series of rollers and formed into a cylindrical shape, where the welding apparatus applies heat and pressure to create a fusion bond along the spiral seam. The controlled manipulation of welding parameters ensures consistent weld quality and integrity.

Types of Materials Suitable for Spiral Welding

Spiral welding is adaptable to a wide range of materials, including carbon steel, stainless steel, alloy steel, and non-ferrous metals like aluminum and copper. The choice of material depends on factors such as the intended application, environmental conditions, and desired mechanical properties. High-strength steel plates are commonly used for applications requiring robustness and durability.

Equipment and Tools Used in Spiral Welding

The equipment used in spiral welding includes a coil processing line for feeding and forming the coiled material, welding machinery equipped with appropriate welding heads or torches, and ancillary tools for material handling, edge preparation, and quality control. Advanced welding systems may incorporate robotic arms or automated processes for increased precision and efficiency. Additionally, specialized tools such as weld seam tracking systems and non-destructive testing devices are employed to ensure weld quality and integrity throughout the manufacturing process.

Traditional Spiral Welding Techniques

Continuous Spiral Welding

1）Process Overview:

Continuous spiral welding involves the continuous joining of coiled steel strips or plates along a helical seam to form a pipe or tube. The coiled material is fed through rollers and progressively welded along the spiral seam using techniques such as submerged arc welding (SAW) or gas metal arc welding (GMAW). This process allows for the efficient production of long-length pipes with consistent weld quality.

2）Advantages and Limitations:

Advantages:

• High production efficiency
• Consistent weld quality
• Suitable for a wide range of materials and pipe diameters
• Cost-effective for large-scale production

Limitations:

• Limited to specific pipe diameters and thicknesses
• Setup and tooling costs can be significant for small-scale production
• Weld quality may be affected by variations in material properties and process parameters

Submerged Arc Welding (SAW)

1）Technique Explanation:

Submerged arc welding (SAW) involves the formation of a weld pool beneath a layer of flux, which protects the molten metal from atmospheric contamination. The welding arc is submerged beneath the flux layer, resulting in efficient heat transfer and deep penetration. SAW is commonly used in spiral welding due to its high deposition rates and suitability for welding thick materials.

2）Pros and Cons:

Pros:

• High deposition rates
• Deep penetration capabilities
• Excellent weld quality and mechanical properties
• Suitable for welding thick materials

Cons:

• Requires specialized equipment and setup
• Limited to flat or horizontal welding positions
• Flux handling and disposal can be challenging

Gas Metal Arc Welding (GMAW)

1）Procedure Description:

Gas metal arc welding (GMAW), also known as MIG welding, involves the formation of an arc between a continuous wire electrode and the workpiece, while a shielding gas protects the weld pool from atmospheric contamination. GMAW is a versatile welding process suitable for a wide range of materials and thicknesses.

2）Advantages and Disadvantages:

Advantages:

• High welding speeds
• Minimal post-weld cleanup
• Suitable for welding thin materials
• Good control over weld bead appearance

Disadvantages:

• Susceptible to weld defects such as porosity and spatter
• Limited to indoor or controlled environments due to shielding gas requirements
• Not suitable for welding thick materials or vertical/horizontal positions

Shenlong's Advanced Spiral Welding Techniques

Spiral Welded Steel Pipe Advantages

• Uniform Wall Thickness and Nondestructive Testing:
• Shenlong's spiral welded pipesfeature uniform wall thickness and undergo 100% nondestructive testing of the weld seam, ensuring consistent quality and structural integrity.
• 

Short Delivery Time and Extensive Stock

With more than 30,000 tons of steel pipes in stock year-round and a complete range of specifications, Shenlong offers short delivery times to meet customer demands promptly.

Comprehensive Quality Assurance Measures

Shenlong implements 6 testing procedures to guarantee the quality of products leaving the factory, ensuring that all products meet stringent quality standards.

Efficient Production Capacity

With 10 production lines in operation, Shenlong can efficiently manufacture spiral welded pipes to meet fast delivery requirements.

Spiral Welded Steel Pipe Quality Inspection

• Visual Inspection:

Surface inspection detects weld surface defects and ensures dimensional accuracy.

• Physical Testing:

Ultrasonic, radiographic, and magnetic permeability testing further verifies the integrity of the spiral steel pipe.

• Strength Testing:

Pressure testing confirms the tightness of weld seams, ensuring the strength of the spiral steel pipe.

• Density Testing:

Various tests, such as kerosene testing, load testing, and flush water testing, detect defects like penetrating cracks, pores, slag, incomplete penetration, and loose organization.

• Hydrostatic Testing:

Hydrostatic testing checks each pipe for leaks under high internal pressure conditions, ensuring reliability in demanding applications.

Spiral Welded Steel Pipe Features

• SSAW (Spiral Submerged Arc Welding) steel pipe is produced from strip coil through temperature extrusion molding and automatic double-wire double submerged arc welding.
• The process involves strip rolling, forming a circular gap opening, and adjusting the weld gap to 1-3mm for flush ends.
• Spiral steel pipes exhibit excellent structural integrity and are suitable for various applications due to their precise manufacturing process and uniform weld quality.

Applications of Spiral Welding Techniques

Pipelines and Piping Systems

Spiral welded pipes play a crucial role in constructing pipelines that transport oil, gas, water, and various fluids across extensive distances. With their sturdy build, consistent wall thickness, and resistance to corrosion, these pipes are favored for both underground and above-ground pipeline installations.

Pressure Vessels and Tanks

Industries like petrochemicals, chemical processing, and power generation rely on spiral-welded steel pipes for crafting pressure vessels and storage tanks. Renowned for their high strength and reliability, these pipes can effectively contain liquids, gases, and other substances under considerable internal pressure.

Structural Components in Aerospace and Automotive Industries

In aerospace and automotive sectors, spiral welded tubes are instrumental in fabricating essential structural components such as roll cages, chassis, and framework. Thanks to their lightweight yet durable characteristics and precise manufacturing tolerances, these tubes enhance structural integrity while minimizing overall weight.

Marine and Offshore Structures

Spiral welded pipes find extensive application in marine and offshore settings, contributing to the construction of offshore platforms, underwater pipelines, and marine structures. Their ability to withstand corrosion, high tensile strength, and resilience against harsh environmental conditions make them indispensable in marine engineering endeavors.

Final Words

Spiral welding techniques offer significant advantages across various industries, including pipelines, pressure vessels, aerospace, automotive, marine, and offshore structures. With their uniform wall thickness, high strength, and resistance to corrosion, spiral welded pipes and tubes ensure reliable performance in demanding applications. Moreover, advancements in quality assurance measures and production processes further enhance the integrity and longevity of these products. As technology continues to evolve, the potential for innovation in spiral welding opens doors to even more efficient, sustainable, and versatile solutions for diverse engineering challenges. Overall, the widespread adoption of spiral welding techniques underscores their indispensable role in modern infrastructure and manufacturing.