Introduction to stainless steel tubes used for liquid cooling in data centers

Data Center Liquid Cooling Heat Dissipation Using Stainless Steel Tubes - Comprehensive Analysis

I. Liquid Cooling Heat Dissipation System and Stainless Steel Tubes

Liquid Cooling Principle: Utilizing liquids (water / ethylene glycol mixture / fluorinated liquid) instead of air as the heat exchange medium, through circulation to remove the heat from high-density heat-generating components such as CPUs/GPUs in the data center. The efficiency is 3-5 times that of traditional air cooling, and the PUE can be reduced to 1.07-1.15.

Role of Stainless Steel Tubes: As the "blood vessels" of the liquid cooling system, they are responsible for the transportation, distribution, and return of the cooling liquid, being the core component ensuring the reliability of the system. They are widely used in:

Cold plate connection pipelines (direct contact with CPUs/GPUs)

CDU (Cooling Capacity Distribution Unit) internal pipelines

Dry coolers / heat exchanger coils

Particular liquid collectors in cabinets

Main supply and return water pipelines

II. Core Materials: 304 vs 316L

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III. Technical Parameters and Performance Advantages

1. Key Parameters

Specification range: outer diameter 6-610mm, wall thickness 0.15-10mm, common DN25-DN150

Pressure-bearing capacity: standard type ≥ 1MPa, high-pressure type up to 25MPa

Temperature range: -196℃ to 300℃, suitable for extreme conditions

Thermal conductivity: approximately 15-25W/m・K (copper about 400W/m・K), but can be significantly improved through structural optimization

2. Five Core Advantages

① Excellent Corrosion Resistance: Chromium elements form a dense passivation film, resistant to chloride ion erosion, with a lifespan of up to 50 years, no need for frequent replacement

② Ultra-High Strength: 3 times harder than copper tubes, capable of withstanding greater pressure (10-25 times) and mechanical impact, reducing leakage risks

③ Excellent Stability: Does not deform in the -40℃ to 85℃ wide temperature range, excellent seismic performance, suitable for complex data center environments

④ Hygienic and Clean: Smooth inner walls, less prone to scaling, reduces microbial growth, ensures the purity of the cooling liquid, prolongs system lifespan

⑤ Environmentally Friendly and Sustainable: 100% recyclable and reusable, in line with the "carbon neutrality" strategy

IV. Detailed Application Scenarios

1. Cold Plate Liquid Cooling System (Mainstream, accounting for approximately 48%)

Cold plate connection pipelines: 316L stainless steel corrugated pipes, wall thickness only 0.15mm, burst pressure > 120Bar, capable of withstanding 200L/min flow impact, compensating for ±30mm thermal expansion and contraction

CDU internal pipelines: Select 304/316 seamless pipes, working pressure 0.7-1MPa, ensuring reliable sealing

Manifold (distributor): High-strength stainless steel integral forging, strong pressure-bearing capacity, ensuring uniform flow distribution

2. Immersion Liquid Cooling System

Immersion coils: 316L stainless steel spiral tubes, utilizing the boiling phase change of cooling liquid to absorb heat, improving heat dissipation efficiency by 40%

Storage tank pipeline system: All stainless steel pipelines + Victaulic connection, leak-proof design, leakage rate <0.5ppm

3. Dry Coolers / Heat Exchangers

Heat exchange coils: Stainless steel finned tubes, expanding the heat exchange area, capable of running completely dry (zero water consumption) in water-deficient areas

Cooling water pipelines: Upgrade from traditional copper pipes to stainless steel, lifespan increased by 3-5 times, maintenance costs reduced by 60%

V. Processing Technology and Connection Techniques

1. Precision Manufacturing Technology

Cold drawing / cold rolling: Control the outer diameter tolerance within ±0.1mm, straightness per meter <15C, ensuring uniform fluid flow

Inner wall treatment: Spiral micro-slot design to increase flow velocity to 3m/s, inner weld lines leveled to reduce flow resistance Solution treatment: Water quenching at 1040-1100℃ to ensure uniform distribution of alloy elements and enhance corrosion resistance (salt spray test > 1000 hours)

2. Reliable connection solutions

Double compression connection: Leakage rate <0.1%, easy to install, suitable for on-site construction

Vacuum brazing: Used for connecting corrugated pipes and joints, with high weld strength and good sealing performance

Quick-change joints: Internal connection in liquid-cooled servers, supporting hot swapping, improving maintenance efficiency by 50%

Flange connection: Large-diameter system, high pressure-bearing capacity, easy for disassembly and maintenance

VI. Market prospects and development trends

Demand explosion: The demand for stainless steel microchannel cooling tubes will exceed 500,000 meters in 2025, with an annual growth rate of 25%+

Market share: In 2023, stainless steel cooling tubes accounted for 41% of sales volume, but contributed 63% of profits, with the high-end market dominant

Domestic substitution: Enterprises such as Jiusili Tepro and Xineli Yingcai have achieved technological breakthroughs, with prices only 60-70% of imported products, and the core component autonomy rate has increased from 35% to 60%

VII. Selection suggestions

Choose based on cooling medium

Pure water / ordinary water: 304 stainless steel

Chlorine-containing cooling liquid / fluorinated liquid: Must be 316L

Seawater / high-salt environment: Super austenitic stainless steel (such as 254SMO)

Choose based on system pressure

Low pressure (<1MPa): Thin-walled 304 welded pipe

Medium pressure (1-5MPa): 316 seamless pipe

High pressure (>5MPa): Thick-walled 316L or duplex stainless steel

Choose based on installation environment

High-vibration areas: Stainless steel corrugated pipe

Fixed pipes: 304/316 straight seam welded pipe

Space-constrained: Customized elbows / special-shaped pipes Summary

The stainless steel tubes used for liquid cooling in data centers have become the preferred cooling pipeline material in the era of high-power AI computing due to their three core advantages: corrosion resistance, high strength, and long lifespan. With the continuous increase in computing density, stainless steel tubes will play a more crucial role in liquid cooling systems, driving data centers towards the direction of efficiency, sustainability, and reliability. 

Note: When purchasing, please ensure to recognize the material certification (such as 316L must have the S31603 mark) and the pressure test report to ensure the safety and reliability of the system.