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Utilizing 26 high-precision cold rolling mills and 6 cold drawing machines, we ensure dimensional accuracy and superior mechanical properties.
Hydraulic System Stainless Steel Pipes
ASTM A312 / A790 | TP316L / S32205 / S32750 | High-Pressure Hydraulic Service | 2× MWP Tested
ISO 9001 | ASME B31.3 | DNV | NACE CertifiedRelated Products
Introduction
Modern hydraulic power transmission systems — spanning mobile construction and mining equipment, offshore subsea actuator systems, industrial press and forming machinery, aircraft flight control systems, and precision hydraulic test equipment — operate at working pressures that have increased dramatically over the past three decades as hydraulic system designers have pursued higher power density, faster response times, and reduced system weight through elevated operating pressures that now routinely reach 350–700 bar in standard industrial systems and exceed 1,000 bar in specialized applications. At these elevated operating pressures, the hydraulic line material must simultaneously satisfy demanding requirements across three distinct performance dimensions: it must provide adequate burst pressure safety margins above the maximum operating pressure with the wall thickness that keeps system weight and space envelope manageable; it must resist the corrosive attack of hydraulic fluids, moisture contamination, and ambient environments that progressively degrade carbon steel hydraulic lines through internal corrosion, external atmospheric attack, and galvanic coupling at dissimilar metal connections; and it must withstand the fatigue loading imposed by the cyclic pressure fluctuations that occur in every pressurization-depressurization cycle, potentially accumulating to hundreds of millions of fatigue cycles over the operating life of high-cycle hydraulic systems in aerospace, offshore, and industrial machinery applications. Hydraulic System Stainless Steel Pipes address all three performance dimensions in a single material solution — combining the intrinsic corrosion resistance of austenitic and duplex stainless alloys with the mechanical properties required for pressure containment and fatigue resistance in hydraulic service, eliminating the maintenance burden of corrosion protection systems required for carbon steel hydraulic lines and providing the long service life that justifies the material cost premium in any application where hydraulic line replacement involves significant downtime or access difficulty.
The grade selection for hydraulic stainless steel pipes is a pressure-performance optimization exercise that must balance yield strength (which determines achievable pressure rating for a given wall thickness), corrosion resistance (which determines the service environment capability), and weldability (which determines the ease and reliability of field connections and fabricated manifold assemblies). For standard industrial hydraulic systems operating at pressures below 300 bar, TP316L austenitic stainless pipe in Schedule 80S wall thickness provides adequate pressure containment with conservative safety margins at a cost-effective material price. At pressures from 300 to 700 bar, duplex S32205 — with its minimum yield strength of 450 MPa compared to TP316L's 170 MPa — allows equivalent pressure ratings to be achieved with approximately 40% thinner walls, translating directly to lighter, more compact hydraulic lines that are particularly valued in mobile machinery and aerospace applications where weight and space are premium commodities. For the highest-pressure hydraulic applications above 700 bar — encountered in deep-sea ROV hydraulic systems, hydraulic press intensifier circuits, and specialized testing equipment — super duplex S32750 with its 550 MPa minimum yield strength and PREN exceeding 42 provides both the pressure rating and the corrosion resistance required in the most demanding combined high-pressure and high-corrosivity service environments that exist in global industry.
The fatigue performance of hydraulic stainless steel pipes is a design parameter that is often underestimated by engineers accustomed to the static pressure vessel design methodology, but which is critically important in hydraulic systems where cyclic pressure loading occurs at frequencies determined by the hydraulic pump stroke frequency, system valve cycling rates, and machine operating cycles. A hydraulic cylinder operating at 1 Hz in a manufacturing press completes 2.6 million pressure cycles per month — a fatigue loading spectrum that would cause failure in a hydraulic line with surface defects, material discontinuities, or stress concentration features at poorly designed connection joints long before corrosion would become the dominant failure mechanism. Seamless stainless steel hydraulic pipe eliminates the weld seam of ERW-welded alternatives, removing the primary stress concentration and microstructural discontinuity that initiates fatigue cracks in welded hydraulic lines. The smooth, defect-free internal surface of cold-drawn seamless stainless hydraulic pipe — verified by 100% hydrostatic pressure testing per the applicable standard — ensures that the interior surface provides no crack initiation sites that would reduce fatigue life below the design expectation. Our hydraulic pipe production includes mandatory hydrostatic pressure testing at 2× the stated maximum working pressure as a standard supply condition, providing documented proof of burst pressure safety margin for each pipe length delivered.
Our hydraulic system stainless steel pipe program covers TP316L, duplex S32205, and super duplex S32750 in outside diameters from 6mm to 114.3mm with wall thicknesses from Schedule 10S through Schedule 160 and custom heavy-wall configurations for specialized high-pressure hydraulic applications. All pipes are manufactured to ASTM A312, A790, or EN 10216-5 standards with supplementary hydraulic pressure testing at 2× stated MWP. ASME B31.3 pressure-temperature ratings are documented for each grade-dimension combination. For aerospace and offshore hydraulic applications requiring full material traceability and elevated testing requirements, we supply to AMS, NACE MR0175, and DNV qualification standards with third-party inspection available. Our technical engineering team provides hydraulic line sizing support — calculating minimum wall thickness for required working pressure, verifying fatigue life against cyclic pressure loading spectra, and optimizing grade selection between austenitic and duplex grades for specific hydraulic circuit cost-performance targets.
Specifications
| Available Grades | TP316L, S32205 Duplex, S32750 Super Duplex |
| Standard | ASTM A312, A790, EN 10216-5 |
| Outer Diameter | 6mm - 114.3mm |
| Wall Thickness | Sch 10S to Sch 160, Custom Heavy Wall |
| Pressure Testing | 2× MWP Hydrostatic (Standard) |
| Finish | Pickled & Passivated / Bright Annealed |
Chemical Composition (S32205 Duplex)
| Element | C | Cr | Ni | Mo | N | Mn | Si |
| Value (%) | ≤0.030 | 22.0-23.0 | 4.5-6.5 | 3.0-3.5 | 0.14-0.20 | ≤2.00 | ≤1.00 |
Up to 700+ bar RatedFatigue Resistant2× MWP Tested
Mechanical Strength (S32205)
Comprehensive Info
| MOQ | 100kg (Negotiable for project quantities) |
| Lead Time | 15 - 35 Days |
| Packaging | Plywood Crates / Individual Wrapping |
| Certifications | ISO 9001, ASME B31.3, DNV, NACE |
| Raw Materials | Premium Duplex / Austenitic Seamless Billet |
| Customization | Grade, OD/WT, Pressure Rating, End Prep |
Applications
Subsea ROV Hydraulic SystemsS32750 super duplex hydraulic pipe for ROV thruster, manipulator, and tooling hydraulic circuits in deepwater seawater service
Industrial Press & Forming MachineryTP316L and S32205 hydraulic lines for forging press, injection molding machine, and metal forming equipment hydraulic circuits
Offshore Platform Hydraulic LinesS32205 hydraulic piping for offshore topside deck cranes, riser tensioner systems, and blowout preventer hydraulic supply lines
Aircraft Ground Support EquipmentTP316L stainless hydraulic lines for aircraft maintenance jacks, fuel handling equipment, and ground support vehicle hydraulic systems
High-Pressure Water InjectionS32205 hydraulic-rated pipe for seawater or produced water injection pump discharge lines in offshore reservoir pressure maintenance systems
High-Pressure Test RigsHeavy-wall S32750 stainless pipe for pressure testing equipment, hydraulic test intensifiers, and burst testing apparatus
Advantages
Eliminates Corrosion Maintenance
Stainless hydraulic lines require no external corrosion protection coating, cathodic protection, or periodic painting — eliminating the maintenance cost, scaffold access, and production interruption that carbon steel hydraulic line corrosion protection demands throughout the system service life.
High-Cycle Fatigue Resistance
Seamless tube construction and smooth defect-free bore provide superior fatigue resistance in high-cycle hydraulic systems — no weld seam stress concentrations, no ERW weld quality variability, and no surface defects that initiate fatigue cracks at design pressure fluctuations accumulated over millions of cycles.
Duplex Weight Reduction
S32205 duplex achieves equivalent pressure ratings to TP316L at ~40% reduced wall thickness — directly translating to lighter hydraulic line weight that reduces topside structural load on offshore platforms and improves power-to-weight ratio in mobile hydraulic equipment.
2× MWP Proof Test
Standard hydrostatic pressure test at 2× stated maximum working pressure provides documented burst pressure margin for every pipe supplied — confirming structural integrity beyond the design operating pressure before the hydraulic system is commissioned and pressurized.
About Jiangsu Jend Tube Co.,Ltd.
As China Hydraulic System Stainless Steel Pipes Manufacturers and Wholesale Hydraulic System Stainless Steel Pipes Factory, Established in 2011 and is a manufacturing enterprise with a complete manufacturing cycle from raw material selection to finished product delivery. The company currently has more than 100 employees, covers an area of 30015 square meters, and has a registered capital of 48 million yuan, annual production capacity of 3800 tons.
The company has passed ISO9001:2015 quality certification, domestic pressure vessel TS certification, and foreign pressure vessel PED certification. With rich experience and mature technology, we have been expanding our market internationally. At present, our products are exported to more than 50 countries and regions including Europe, America, Southeast Asia, and the Middle East.
The company adheres to different production norms and standards such as the American standard (ASTM), the European standard (EN), the German standard (DIN), the Japanese standard (JIS), the Russian standard (GOST), and the Chinese standard (GB).
Our company specializes in and customizes various specifications of Martensite TP410 (0Cr13, 1Cr13), Ferrite TP405 (1Cr13Al), TP430 (1Cr17), TP444 (0Cr18Mo2), TP439, TP409 (0Cr11Ti), It is also proficient in manufacturing Austenitic seamless stainless steel pipes of series such as TP304(L/H), TP316(L/H/Ti), TP310S, TP317, TP321(H) and TP347(H). Duplex such as S31803, S2205, S32750, S32304, and Nickel-based alloys Monel400, Monel600, Monel800, GH3030, 904L, Inconel 625, etc.
The company mainly produces seamless steel pipes with the following specifications: outer diameter: 3.18mm to 406.4mm, wall thickness: 0.3mm to 20mm, and the longest length is 25000mm. Additionally, it can customize seamless steel pipes with special materials and specifications according to customer requirements. The company attaches great importance to scientific innovation. The staff of the company vigorously develop technological research and development.
Jiangsu Jend Tube Co.,Ltd. will continuously accumulate professional knowledge and capabilities, striving to become a leader in the domestic market and even the world market. Strive to be the most reassuring pipe manufacturing enterprise for customers.
Precision Manufacturing and Process Optimization
We rely on precision equipment and optimized production technologies to achieve outstanding mechanical performance and consistent product quality.
Cold Rolling and Cold Drawing
Solution Heat Treatment
Natural gas solution treatment furnaces and BA solution treatment furnaces optimize the material's grain structure, enhancing corrosion resistance.
Precision Straightening and Polishing
10 straightening machines and 8 finishing polishing machines guarantee product surface smoothness and dimensional accuracy.
Automated Inspection and Quality Assurance
Real-time monitoring systems ensure the stable quality of every batch of products.
Product Usage Tips
Hydraulic Line Sizing
Select hydraulic stainless pipe wall thickness using Barlow's formula (P = 2S×T/OD) with S = allowable stress = yield strength / safety factor. For ASME B31.3 process piping, the safety factor on yield is typically 1.33 for static systems. For cyclic fatigue-loaded hydraulic systems, apply an additional fatigue reduction factor based on expected cycle count — ASME VIII Div.2 fatigue curves provide guidance for austenitic grades, and apply a further 0.85 de-rating factor if welds are present in the high-stress zones of the hydraulic circuit.
Welding Hydraulic Stainless Pipe
For hydraulic system manifold and line welds, use TIG root with TIG fill for pipe below 12mm wall, and TIG root with SMAW or orbital TIG fill for heavier wall sections. For duplex S32205 hydraulic pipe welds, verify ferrite content in 35–65% range on production welds — insufficient ferrite creates austenite-rich weld metal vulnerable to SCC in chloride-containing hydraulic fluid environments encountered in seawater-exposed offshore system installations.
Hydraulic Fluid Compatibility
TP316L and duplex stainless are compatible with mineral hydraulic oils, water-glycol hydraulic fluids, phosphate ester fluids (Skydrol), and water-based emulsion hydraulic fluids. For fire-resistant water-based hydraulic fluids, confirm chloride content — water-based hydraulic fluids recycled through open systems can accumulate chloride from water contamination at concentrations sufficient to cause pitting of TP316L stainless at warm operating temperatures. High-chloride water-based hydraulic fluid service may require duplex or super duplex grade hydraulic lines.
Flushing Before Commissioning
Before commissioning stainless hydraulic systems, flush the complete line system with clean hydraulic fluid at system operating pressure for a minimum of 30 minutes to remove machining debris, weld spatter, and particulate contamination from the bore. Filter particulate content of flushing fluid through a 10-micron bypass filter to NAS 1638 cleanliness Class 6 or ISO 4406 cleanliness 18/16/13 before certifying the hydraulic system as clean for commissioning.
Value-Added Processing Services
We provide hydraulic system-ready processing for offshore, industrial, and subsea hydraulic pipe applications:
Precision Cutting & Beveling
Cut-to-length with ASME B16.25 weld-end bevel preparation for hydraulic manifold assembly welding.
2× MWP Hydrostatic Test
Standard 2× MWP hydrostatic pressure testing with individual test record for every pipe length supplied.
Pressure Rating Documentation
ASME B31.3 working pressure rating calculations for each grade-dimension combination supplied.
UT Testing for Heavy Wall
Ultrasonic volumetric testing for heavy-wall hydraulic pipe above 10mm WT for complete through-wall defect detection.
Payment & Shipping
Payment Terms
- T/T (Telegraphic Transfer)
- L/C at Sight (Letter of Credit)
- Western Union
- Flexible terms for long-term partners
Shipping Options
- Sea Freight (FCL/LCL)
- Air Freight for urgent offshore orders
- Express for small samples
- Seaworthy plywood crates with end caps and hydraulic test records attached
Certifications & Standards
Our hydraulic system stainless steel pipes are qualified to offshore, industrial, and subsea hydraulic engineering standards:
ISO 9001:2015
ASME B31.3
DNV Offshore
NACE MR0175
ASTM A312 / A790
EN 10204 3.1 MTR
Frequently Asked Questions
Why use stainless steel for hydraulic lines instead of carbon steel?
Stainless hydraulic lines eliminate external corrosion that progressively degrades painted or galvanized carbon steel lines in marine, offshore, and humid industrial environments — avoiding corrosion-induced hydraulic line failures that cause costly production shutdowns. The corrosion resistance of stainless also eliminates the periodic repainting maintenance programs required for carbon steel hydraulic lines in corrosive environments, providing a superior total lifecycle cost despite the higher initial material price.
At what pressure should I upgrade from TP316L to S32205 duplex?
The crossover point depends on the specific OD and wall thickness, but as a practical guide: at pressures above 300 bar in standard OD sizes, S32205 duplex provides equivalent or better pressure rating at approximately 40% reduced wall thickness compared to TP316L, reducing weight and improving system compactness. Above 600 bar, S32750 super duplex is recommended to achieve adequate safety margins without excessively thick walls.
Is seamless pipe required for hydraulic applications or can welded pipe be used?
Seamless pipe is strongly preferred for high-pressure hydraulic applications because the absence of a weld seam eliminates the stress concentration and microstructural discontinuity at which fatigue cracks initiate in welded alternatives. For low-pressure hydraulic applications below 150 bar, ASTM A249 welded and annealed pipe is acceptable if the weld is 100% radiographically tested. For pressures above 150 bar and in fatigue-loaded applications, seamless pipe is the correct specification.
What is the standard hydrostatic test pressure for hydraulic stainless pipe?
We standard-test hydraulic stainless pipes at 2× the stated maximum working pressure — higher than the ASTM A312 minimum hydrostatic test pressure — to provide documented burst safety margin verification at 2× design pressure. For high-pressure applications above 500 bar, we recommend specifying the hydrostatic test pressure explicitly in the purchase order at 1.5× the design proof pressure to ensure the test record directly confirms the safety margin required by your hydraulic system design code.
Can stainless hydraulic pipe be bent without annealing?
TP316L austenitic stainless hydraulic pipe can be cold bent to a minimum bend radius of 3× OD without intermediate annealing, with acceptable wall thinning on the extrados for standard hydraulic system configurations. Duplex S32205 requires more careful cold bending — minimum bend radius 5× OD with post-bend ferrite content verification. For both grades, induction hot bending with post-bend solution annealing is preferred for bend radii tighter than these minimums in pressure-critical hydraulic applications.
Do you supply stainless hydraulic pipe with NACE MR0175 sour service qualification?
Yes, NACE MR0175 sour service compliance documentation is available for TP316L and S32205 duplex hydraulic pipes where H₂S is present in the hydraulic fluid (water injection from sour produced water) or the external environment (offshore H₂S-containing atmosphere). Hardness verification per NACE MR0175 maximum limits is included in the documentation package for sour service hydraulic pipe qualification.
What is the lead time for stainless hydraulic pipe?
Standard TP316L hydraulic pipe in common OD and schedule combinations is available within 15–20 days. S32205 duplex hydraulic pipe is available within 20–30 days. S32750 super duplex heavy-wall hydraulic pipe requires 30–50 days for production. For urgent offshore maintenance requirements, contact our team for stock availability assessment in the specific dimensions needed.
Do you supply to subsea ROV hydraulic system OEMs?
Yes, we supply S32750 super duplex and TP316L stainless hydraulic pipe to subsea ROV manufacturers, work-class ROV tooling OEMs, and offshore equipment fabricators with full DNV material certification, 2× MWP hydrostatic test records, NACE MR0175 documentation, and material traceability from melting through finished pipe for deepwater ROV and subsea equipment qualification programs.
Ready to Order Hydraulic System Stainless Steel Pipes?
2× MWP tested, duplex high-pressure grades, offshore and subsea certified — contact us for hydraulic stainless pipe supply
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