Connection methods of the industrial spiral steel pipes

In most applications, spiral steel pipes are connected by welding, as welded joints are cost-effective and suitable for the majority of project requirements. However, in certain projects, factors such as tight construction schedules, site constraints, operating conditions, or complex geographical environments may limit the use of welding. In such cases, alternative connection methods—such as threaded, flanged, socket, and grooved connections—are adopted.

Below is an overview of the main non-welded connection methods used for spiral steel pipes and their characteristics:

1. Flange Connections for Spiral Steel Pipes

Flange connections are relatively quick to assemble, easy to install, and require only basic tools. However, their sealing performance and overall safety generally do not meet the requirements of most medium- to high-pressure systems. As a result, flange connections are typically used for low-pressure pipelines or systems that require frequent disassembly, such as sludge discharge pipelines or temporary piping.

2. Grooved Connections for Spiral Steel Pipes

Grooved (clamp-type) connections have become a widely accepted solution for liquid and gas steel pipeline systems. Although this technology was introduced later in some markets, its technical advantages have driven rapid adoption. Grooved pipe fittings significantly simplify and accelerate the traditionally complex steel pipe connection process, representing a major advancement in pipeline installation technology.

Grooved steel pipe fittings can be divided into two main categories:

Sealing fittings: rigid couplings, flexible couplings, mechanical tees, and grooved flanges

Transition fittings: elbows, tees, crosses, reducers, blind flanges, and other grooved components

A typical grooved connection consists of three key parts: a rubber sealing ring, a clamp housing, and fastening bolts. The rubber gasket is placed around the pipe ends and seated within the pre-formed grooves. The clamp is then installed over the gasket and secured with bolts. This design provides excellent sealing performance, which improves as internal fluid pressure increases.

Compared with traditional methods, grooved connections simplify installation, enhance construction safety, improve system reliability, and facilitate future maintenance. While the unit cost of grooved fittings may be higher, the overall installation efficiency and reduced labor time often result in lower total project costs than flange connections.

3. Clamp Connections for Spiral Steel Pipes

Clamp connections are an advanced pipe-joining method suitable for both above-ground and buried installations. They are available in rigid and flexible designs, offering broad adaptability across different systems. Due to their versatility and reliability, clamp-type connections are widely used in fire protection systems, HVAC hot and chilled water systems, water supply networks, petrochemical pipeline systems, thermal power facilities, military pipeline systems, and sewage and wastewater treatment pipelines.

By selecting the appropriate connection method based on operating conditions, pressure requirements, and installation constraints, spiral steel pipe systems can achieve optimal safety, efficiency, and cost performance.