304
General industrial
Good general corrosion resistance for hydraulic systems operating in relatively mild industrial environments.
Product form hub · Hydraulic tubing
Stainless Steel Hydraulic Tube
Specify stainless steel hydraulic tube by alloy, outside diameter, wall thickness, manufacturing route, heat-treatment condition, length, surface, tolerance and system requirements. The most reliable RFQ uses actual OD × wall dimensions rather than a nominal pipe size.
304 / 304L / 316 / 316L
Seamless · bright annealed
Metric & imperial OD sizes
Hydraulic tube · product visual
Common alloys304/304L · 316/316L
Common metric range3–42 mm OD · 0.5–4 mm wall
Common conditionSeamless · solution / bright annealed
Build the specification
01Choose grade
02Set OD × wall
03Choose tube route
04Set tolerance / finish
05Confirm system details
06Send RFQ
Product overview
What to define before buying stainless steel hydraulic tube
Hydraulic tubing is selected as a complete system component. Alloy and tube dimensions matter, but so do fitting compatibility, pressure design, bending, cleanliness, surface condition and documentation. State the actual tube OD and wall thickness, then add the application requirements that control the finished line.
Material316 / 316L
A common choice for corrosion-resistant hydraulic and instrumentation lines, especially where chloride exposure or process cleanliness matters.
GeometryOD × wall
Hydraulic tube is normally ordered by outside diameter and wall thickness rather than by nominal pipe schedule.
ConditionSeamless / annealed
Cold-finished seamless tubing with annealed or bright-annealed condition is widely used for bendable hydraulic lines.
SystemFitting compatibility
Confirm the tube OD, wall, hardness and surface condition suit the selected compression or bite-type fitting system.
M03 · Grade selection
Choose the grade from corrosion exposure and system duty
316/316L is common for demanding hydraulic service, while 304/304L remains useful for general industrial systems. The final grade should match fluid chemistry, external environment, temperature, welding or fabrication route and project specification.
304L
Low-carbon 304
Useful when welding or fabricated assemblies benefit from a low-carbon version of 304.
316
Improved corrosion resistance
A common hydraulic and instrumentation grade where molybdenum improves resistance in more aggressive environments.
316L
Common hydraulic choice
Widely specified for seamless hydraulic tubing where corrosion resistance, bending and welded-system compatibility are important.
M04 · Technical data
Common stainless steel hydraulic tube size reference
Representative metric sizes below reflect common commercial hydraulic / instrumentation tube geometry. Availability varies by grade, standard, wall and manufacturer, so treat the table as a quoting reference rather than a stock list.
| OD (mm) | Wall (mm) | Approx. ID (mm) | Common form | Specification note |
|---|---|---|---|---|
| 6 | 1.0 | 4.0 | Straight / coil | Compact control and hydraulic lines |
| 8 | 1.0 | 6.0 | Straight / coil | Common small-bore tube size |
| 10 | 1.0 | 8.0 | Straight / coil | Instrumentation and light hydraulic routing |
| 12 | 1.0 | 10.0 | Straight / coil | General hydraulic line reference |
| 12 | 1.5 | 9.0 | Straight | Heavier-wall option for system design |
| 16 | 1.5 | 13.0 | Straight | General equipment and process hydraulic lines |
| 18 | 1.5 | 15.0 | Straight | Medium-size hydraulic routing |
| 20 | 2.0 | 16.0 | Straight | Higher-flow hydraulic line reference |
| 25 | 2.0 | 21.0 | Straight | Industrial hydraulic / process line size |
| 30 | 2.0 | 26.0 | Straight | Larger hydraulic and utility routing |
| 38 | 3.0 | 32.0 | Straight | Heavy-duty system reference |
| 42 | 3.0 | 36.0 | Straight | Near the upper end of common metric hydraulic tube ranges |
Common commercial metric seamless ranges are roughly 3–42 mm OD with about 0.5–4 mm wall. Imperial hydraulic / instrumentation tubing is also widely supplied, commonly from 1/4 in through 1-1/2 in OD with multiple wall options. Working pressure is not stated here because it depends on material condition, tube size, design code, fittings, temperature and safety factor.
M05 · Dimensions and condition
Define tube dimensions, finish and installation condition
A hydraulic-tube RFQ should make the dimensional and installation requirements explicit. Tube hardness, surface condition, straightness and cleanliness can matter just as much as nominal dimensions when the tube will be bent and connected with precision fittings.
Dimensions
- Outside diameter
- Wall thickness
- OD / wall tolerance
- Straight length or coil
Material condition
- Seamless or welded route
- Solution annealed / bright annealed
- Hardness requirement if fitting-controlled
- Surface finish and scale condition
System details
- Hydraulic fluid / process medium
- Design pressure and temperature
- Fitting system and bend radius
- Cleanliness, plugging and documentation
M06 · Selection guide
Match the tube route to the hydraulic system
The correct tube is the one that satisfies corrosion resistance, fitting compatibility, bendability, system pressure design and documentation together. Use the system drawing and fitting supplier requirements as the final control.
General industrial304 / 304L can be suitable where the external and internal corrosion environment is relatively mild.
Corrosive / marine exposure316 / 316L is commonly preferred for improved resistance in chloride-bearing and demanding industrial environments.
Tube fittingsConfirm OD, wall, hardness, ovality and finish against the selected compression or bite-type fitting system.
High-pressure designDo not select only from a generic pressure chart; calculate the line to the applicable system code and actual fitting configuration.
Worked example
Example of a clear hydraulic tube specification
Quote-ready example
A complete request combines the tube dimensions with the material, delivery condition and system information needed to check suitability.
ProductStainless steel hydraulic tube
Grade316L stainless steel
StandardASTM A269/A269M
Size12 mm OD × 1.5 mm wall
ConditionSeamless, bright annealed, straight length
Length6 m
System noteFor hydraulic service; confirm fitting compatibility, design pressure, bend radius and documentation before final order
M08 · Applications
Where stainless steel hydraulic tube is commonly used
Industrial hydraulics
Rigid fluid lines on machinery, presses, actuators and production equipment where stainless corrosion resistance is required.
Marine systems
Corrosion-resistant tubing for hydraulic controls and equipment exposed to salt-laden or wet environments.
Offshore & energy
Hydraulic and instrumentation lines used in demanding process, offshore and energy-service environments.
Process equipment
Fluid-power and utility tubing routed through chemical, food, pharmaceutical or general process equipment.
Instrumentation
Closely related instrumentation lines where dimensional accuracy, fitting compatibility and cleanliness are important.
Mobile equipment
Rigid stainless sections for vehicles and mobile machinery when corrosion resistance and durable routing are required.
Important limitation: tube OD and wall thickness alone do not establish a safe hydraulic working pressure. Final pressure capability depends on grade, condition, temperature, fittings, bending, corrosion allowance, applicable design code and required safety factor.
M10 · Standards
Standards and purchasing references
Use the standard required by the project rather than treating “hydraulic tube” as one universal specification. The standard controls material condition, dimensional rules, testing and documentation.
Seamless and welded austenitic stainless steel tubing for general corrosion-resisting and low- or high-temperature service; commonly referenced for hydraulic and instrumentation tubing.
European route for seamless stainless steel tubes for pressure purposes and a common reference for metric stainless hydraulic tubing.
Use the project drawing and applicable system code to control pressure design, bend radius, fittings, inspection, cleanliness and documentation.
M11 · FAQ
Stainless steel hydraulic tube FAQ
How is stainless steel hydraulic tube sized?
It is normally specified by actual outside diameter and wall thickness, for example 12 mm OD × 1.5 mm wall. This differs from nominal pipe sizing.
Which stainless grade is most common for hydraulic tubing?
316 and 316L are very common where corrosion resistance is important. 304 and 304L are also used in less aggressive environments. The exact grade should follow the fluid, environment and project specification.
Is seamless tube required for hydraulic service?
Seamless tubing is widely used for hydraulic systems, but suitability depends on the applicable standard, system design and project requirements. Some applications can also use welded and drawn tubing when explicitly permitted.
Can I choose tube size from pressure alone?
No. Pressure design also depends on material strength, temperature, wall tolerance, fittings, bends, fatigue, corrosion and the safety factor required by the applicable code or equipment standard.
Why does hardness matter with hydraulic tube fittings?
Many compression and bite-type fitting systems require tubing within a specified hardness range so the ferrules or cutting rings can grip and seal correctly. Check the fitting manufacturer's tube requirements.
Product details
What buyers usually verify visually
Review representative hydraulic-tube inspection, system installation and packing evidence before finalizing the purchase specification.
Hydraulic tube bundleOD, straightness, surface condition and length
Tube end & surfaceWall thickness, bore, finish and cut quality
Packing & identificationProtect clean tube ends and maintain alloy / heat identification
Hydraulic tube resources
Continue from technical research to purchase
Material hubStainless Steel
Review the parent material hub and related stainless steel product forms.
Open stainless steel hub → TechnicalTechnical ResourcesUse standards, comparisons and engineering references to clarify the purchase specification.
Open technical resources → SourcingRequest a QuoteMove from a reviewed specification to a purchasing conversation.
Open RFQ page →M13 · Technical reference
Reference basis for this hydraulic tube guide
This page uses common commercial hydraulic / instrumentation tubing ranges together with stainless-tube standards used in purchasing. Representative metric commercial ranges are approximately 3–42 mm OD and 0.5–4 mm wall, with 316/316L among the most common hydraulic grades.
M14 · RFQ
Request a technical quote
For a faster review, include alloy, standard, OD × wall, seamless / welded route, condition, length, quantity, design pressure, temperature, fitting system, cleanliness and destination.
- Grade / standard
- Outside diameter × wall thickness
- Seamless / welded route and annealed condition
- Design pressure / temperature and fitting system
- Length, quantity, documentation and destination