Liquid cooling pipes are the core fluid channels of liquid cooling systems, responsible for transporting coolant, distributing flow, and connecting components such as cold plates, cabinets, and CDUs. They directly determine the system's heat dissipation efficiency and reliability. The following details their classification, materials, specifications, selection, and applications.
Core Classifications (by Material/Structure)
1. Metal Liquid Cooling Pipes (High Pressure/Fixed/Long Life)
Stainless Steel Pipes (304/316L)
304 Stainless Steel Liquid Nitrogen Cooling Piping
Product Overview
304 stainless steel is a general-purpose austenitic stainless steel, also known as 18/8 stainless steel (18% chromium, 8% nickel). It possesses excellent corrosion resistance, heat resistance, and low-temperature performance, making it the fundamental choice for liquid nitrogen cooling piping in AI data centers.
Suitable for AI data center cooling systems in normal environments, it can operate stably within a temperature range of -196°C to 300°C and has good machinability and weldability.
Key Advantages:
Excellent resistance to atmospheric and freshwater corrosion
Exceptional low-temperature toughness, no embrittlement in liquid nitrogen environments
Good weldability, enabling seamless connections
High cost-effectiveness, offering significant performance advantages
Applicable pipe diameter range: DN10 ~ DN300
316L Stainless Steel Liquid Nitrogen Cooling Pipes
Product Overview
316L stainless steel is an austenitic stainless steel with added molybdenum compared to 304 stainless steel. Also known as marine-grade stainless steel, it boasts excellent corrosion resistance, particularly against pitting corrosion, intergranular corrosion, and stress corrosion.
Designed specifically for AI data centers in high-humidity, highly corrosive environments, with an operating temperature range of -196°C to 400°C, it offers higher strength and a longer service life, making it the preferred choice for high-end AI computing clusters.
Key Advantages:
Molybdenum-enhanced, improving resistance to pitting and intergranular corrosion by over 50%
Excellent resistance to seawater and chemical media corrosion
Higher high-temperature strength and creep strength
Service life 30-50% longer than 304 stainless steel
Applicable pipe diameter range: DN10 ~ DN500
Key Specifications
Pipe Diameter (DN / inches): DN8–DN200 (1/4"–8"), calculated by flow rate: Pipe Diameter = √(4Q/(πv)), commonly used flow velocity for liquid cooling: 0.6–1.2m/s.
Wall Thickness: Selected according to pressure and material; Stainless steel 1.5–3mm, Polymer 1–2mm.
Connection Methods
• Metal: Butt welding, socket welding, flange, ferrule, quick-connect.
• Polymer: Quick-connect, clamp, threaded, and specialized connectors.
Standards
• GB/T 12459, ASME B16.9, GB/T 3091, ISO 14001.
Selection Logic (Scenario Matching)
• High pressure/Fixed/Long lifespan → Select 316L stainless steel.
• Dynamic connection/Vibration/Lightweight → Select stainless steel corrugated pipe or EPDM flexible hose.
• High cleanliness/Strong corrosion → Select PTFE/FEP.
• Cost-sensitive/Normal operating conditions → Select EPDM or PA12.
Typical Application Scenarios
• Data centers/AI servers: Cold plate/immersion liquid cooling, main piping uses 316L stainless steel, internal connections use EPDM/FEP flexible hose.
• Energy storage systems: Containerized liquid cooling, PA12 composite pipe + stainless steel main piping, suitable for -40℃~120℃.
• New Energy Vehicles: Battery/Motor liquid cooling, stainless steel + rubber hoses, vibration and temperature resistant.
• Industrial/Semiconductor: Precision equipment cooling, PTFE/titanium tubing, high cleanliness, strong corrosion resistant.
Installation and Maintenance Points
• Metal Piping: Welds require beveling and flaw detection; corrugated pipes should avoid excessive bending; support spacing should be reasonable to prevent sagging.
• Flexible Piping: Bending radius ≥ 5D (FEP)/8D (PTFE); avoid sharp friction; regularly check for aging/leakage.
• System: After installation, perform pressure testing (1.5 times working pressure) and flow testing to ensure no leaks and compliant flow resistance.
Differences from Ordinary Industrial Piping
• Liquid-cooled piping emphasizes low flow resistance, high cleanliness, leak prevention, resistance to coolant corrosion, and adaptability to vibration/thermal expansion.
• Commonly uses long concentric/eccentric reducers, Y-tees, corrugated pipes, and specialized fittings, rather than ordinary industrial pipe fittings.
