Key Metal Pipes: Properties, Applications and Performance Comparison

Metal pipes are indispensable components in construction, machinery, aerospace, and water supply industries, with different materials and structures tailored to specific operational needs. This article focuses on four widely used types: galvanized steel pipe, aluminum alloy pipe, seamless steel pipe, and telescopic pipe, exploring their characteristics, practical applications, and performance differences.

Classification and Core Characteristics of Metal Pipes

Carbon Steel-Based Pipes: Durability for Heavy-Duty Scenarios

 

Galvanized Steel Pipe

Galvanized steel pipe is a carbon steel pipe treated with hot-dip galvanizing or electro-galvanizing, forming a zinc layer (0.1–0.2 mm thick) on the surface to resist corrosion. The zinc layer acts as a sacrificial anode, protecting the steel substrate from rusting, extending the service life to 20–50 years (depending on the environment). It has a tensile strength of 300–500 MPa and is suitable for medium-pressure applications (≤1.6 MPa). However, the zinc layer may degrade in acidic or high-humidity environments, limiting its use in chemical media.
Traditional applications include residential water supply, fire-fighting systems, and outdoor scaffolding. With the rise of environmentally friendly materials, it is gradually replaced by plastic pipes in domestic water supply but remains irreplaceable in industrial and construction fields due to its high load-bearing capacity.

Seamless Steel Pipe

Seamless steel pipe is manufactured via hot rolling or cold drawing without welding seams, ensuring uniform wall thickness and high structural integrity. Made of low-carbon or alloy steel, it boasts a tensile strength of 400–800 MPa and excellent pressure resistance, capable of withstanding pressures up to 10–80 MPa and temperatures ranging from -200℃ to 600℃. Its seamless structure avoids leakage risks caused by weld defects, making it ideal for high-pressure and high-temperature scenarios.
It is widely used in oil and gas transmission, thermal power plant boilers, and hydraulic systems of heavy machinery. For example, API 5L seamless steel pipes are the standard for long-distance oil pipelines, accounting for over 60% of global oil transmission pipe usage.

Lightweight and Functional Pipes: Aluminum Alloy and Telescopic Types

Aluminum Alloy Pipe

Aluminum alloy pipe is composed of aluminum mixed with magnesium, silicon, or copper, balancing lightweight properties and strength. Its density (2.7 g/cm³) is only 35% of carbon steel, while tensile strength reaches 200–600 MPa (depending on the alloy grade). It has excellent corrosion resistance (natural oxide film formation) and thermal conductivity (120–200 W/(m·K)), making it suitable for weight-sensitive and heat-exchange applications.
Key applications include aerospace (aircraft hydraulic pipelines), automotive cooling systems, and architectural decoration. For instance, 6061 aluminum alloy pipes are used in aircraft fuselages, reducing overall weight by 15–20% compared to steel pipes. They are also preferred in marine environments due to their resistance to saltwater corrosion.

Telescopic Pipe

Telescopic pipe is a modular pipe with adjustable length, made of materials like aluminum alloy, steel, or plastic. Its core structure features nested sections with locking mechanisms (spring buttons or threaded joints), allowing length adjustment within a specified range (typically 50–500 cm). Metal telescopic pipes (aluminum or steel) combine adjustability with load-bearing capacity, while plastic ones are used for lightweight scenarios.
Common uses include mechanical arms, telescopic ladders, camera tripods, and ventilation systems. For example, steel telescopic pipes in construction cranes can extend to 30 meters, adapting to different operation heights. Aluminum alloy telescopic pipes are favored in household tools (e.g., vacuum cleaners) for their portability.

Performance Comparison of Four Pipe Types

Pipe Type	Density (g/cm³)	Tensile Strength (MPa)	Service Life (Years)	Typical Application Pressure (MPa)	Cost (USD/m, Φ50mm)
Galvanized Steel Pipe	7.85	300–500	20–50	≤1.6	8–15
Aluminum Alloy Pipe	2.7	200–600	30–60	≤4.0	12–25
Seamless Steel Pipe	7.85	400–800	25–60	10–80	18–40
Aluminum Telescopic Pipe	2.7	200–350	15–30	≤1.0	20–35

Selection Guidelines Based on Application Scenarios

 
The choice of pipe depends on factors like pressure, weight, corrosion environment, and cost. For low-pressure water supply and outdoor construction, galvanized steel pipes offer cost-effectiveness and durability. Seamless steel pipes are mandatory for high-pressure industrial systems (oil, boilers). Aluminum alloy pipes are optimal for aerospace and automotive industries where weight reduction is critical. Telescopic pipes are the first choice for adjustable-length needs, with metal types suitable for load-bearing tasks.
In conclusion, these four pipe types play irreplaceable roles in modern industry, with their unique properties meeting diverse operational requirements. Future developments will focus on enhancing corrosion resistance (e.g., composite galvanized layers) and improving the adjustability of telescopic pipes for broader applications.