Metal Pipelines Unveiled: The 4 Critical Classifications for Global Engineering Projects

Metal pipelines serve as the backbone of industrial infrastructure and construction worldwide. This comprehensive guide dissects their classification across four pivotal dimensions—material types, application fields, medium conditions, and connection methods—integrating international standards and real-world case studies for professional engineering reference.

I. Classification by Material Characteristics

1.1 Ferrous Alloy Pipelines

1.1.1 Carbon Steel Pipelines

Carbon steel pipelines, composed primarily of iron and carbon, are classified by carbon content: low-carbon steel (C≤0.25%), medium-carbon steel (0.25%<C≤0.6%), and high-carbon steel (C>0.6%). Low-carbon grades like ASTM A106 Grade B seamless pipes (ASTM A106 standard) dominate water and steam transportation (≤425℃) in municipal projects across the U.S. and Europe (AWWA standards).

1.1.2 Alloy Steel Pipelines

Alloy steel pipelines incorporate elements like chromium (Cr), molybdenum (Mo), and vanadium (V) for enhanced performance. For instance, ASTM A335 P91 steel (9% Cr, 1% Mo, ASTM A335 standard) withstands 580℃ high-pressure conditions in main steam systems of large power plants in North America and Asia (IEA power sector reports).

1.1.3 Stainless Steel Pipelines

Stainless steel pipelines excel in corrosion resistance and hygiene, complying with ASTM A240 standard:

1.2 Non-Ferrous Metal Pipelines

1.2.1 Copper & Copper Alloy Pipelines

Copper pipelines offer excellent thermal conductivity and corrosion resistance. ASTM B88 TP2 copper pipes (ASTM B88 standard) are widely used in North American and European refrigeration systems, while brass (e.g., C27200) dominates gas transportation in South America and Southeast Asia (International Copper Alliance).

1.2.2 Aluminum & Aluminum Alloy Pipelines

Lightweight and high-strength aluminum pipelines, such as ASTM B241 6061-T6 (ASTM B241 standard), are applied in Australia and the Middle East for lightweight industrial projects like solar power coolant systems (World Bank energy reports).

1.2.3 Titanium & Titanium Alloy Pipelines

Titanium pipelines shine in corrosive environments. ASTM B338 Grade 2 titanium pipes (ASTM B338 standard) are used in Gulf of Mexico offshore platforms and Nordic chemical plants for seawater and strong acid/alkali transportation (Offshore Magazine).

II. Classification by Application Fields

2.1 Industrial Pipelines

Industrial pipelines serve petroleum, chemical, and metallurgical sectors. For example, Middle Eastern and Russian oil networks use API 5L X70 steel (API 5L standard) for long-distance crude transportation, while German and Japanese chemical plants prefer 316L stainless steel for corrosive media (ICCA reports).

2.2 Energy Pipelines

Energy pipelines cover power and new energy fields. Supercritical power plants in Europe and North America employ 9Cr-1Mo steel for high-temperature steam, while LNG terminals in Australia and South Africa use 9% nickel steel (ASTM A353, ASTM A353 standard) for -162℃ cryogenic transport (IRENA case studies).

2.3 Building & Municipal Pipelines

Building pipelines handle internal systems (e.g., CPVC pipes in U.S. and Canadian residences), while municipal pipelines serve urban infrastructure. Cities like London and Tokyo rely on ductile iron pipes (complying with ISO 2531 standard). As a leading ductile iron pipe manufacturer and supplier, Tiegu delivers high-strength, corrosion-resistant solutions for global water supply projects, ensuring infrastructure reliability.

III. Classification by Medium Conditions

3.1 Core Parameters of Medium Conditions

• Temperature: Cryogenic (-162℃ LNG requires low-temp materials) vs. high-temp (600℃ steam needs heat-resistant alloys; ICTES cold material research).

• Pressure: From low-pressure (≤1.6MPa) to ultra-high-pressure (≥100MPa, e.g., deep-sea oil pipelines).

• Corrosion: Media with Cl⁻ ions require duplex SS or titanium (NACE corrosion standards).

3.2 Classification by Fluid Dynamics

• Single-phase flow: Laminar flow (Re<2300) for pharmaceutical fluids; turbulent flow (Re>4000) for urban water supply (ASCE fluid mechanics standards).

• Multiphase flow: Gas-liquid/solid mixtures in Brazilian and West African offshore oil pipelines, requiring anti-erosion designs.

IV. Classification by Connection Methods

4.1 Welding Connections

• GTAW (TIG welding): For stainless steel, complying with ASME Section IX for food/pharmaceutical hygiene.

• SAW (submerged arc welding): For large-diameter pipes in North American and Asian oil pipelines (IIW case studies).

4.2 Mechanical Connections

• Flange connections: Following ASME B16.5, widely used in European and U.S. chemical plants.

• Coupling connections: AWWA C606-compliant (AWWA standards) for fire protection systems in North America and Australia.

This classification framework empowers engineers and project managers to optimize pipeline selection for international projects. For specialized ductile iron pipe solutions or material consultations, visit Tiegu’s official website to explore our global project portfolio.