Tubes and Accessories
Precision steel tube 38 mm outer diameter – seamless, galvanized and in stainless steel 1.4571
Looking for a seamless precision steel tube with 38 mm outer diameter and need the right wall thickness, the right material and matching fitting technology? At STASTO you'll find the complete 38 mm size range from a single source: bright seamless steel tube per DIN 2391/C and EN 10305-4 in wall thicknesses of 2.5 / 3 / 4 / 5 mm, the white zinc-plated version for corrosion-prone environments, and seamless stainless steel tube in 1.4571 per EN ISO 1127. All tubes are designed per DIN 2391 for use with fittings and can be combined with cutting ring fittings per ISO 8434-1 (DIN 2353) into a continuous pipeline.
Ø 38 mm at a Glance
Why STASTO
One outer diameter, three materials, all pressure ratings
STASTO's 38 mm size range covers all common applications, from bright precision steel tube to 1.4571 stainless steel tube – including matching cutting ring fitting technology per ISO 8434-1 (DIN 2353).
One size, all pressure ratings
The outer diameter stays at 38 mm – wall thickness determines the rating: 38x2.5 with 166 bar, 38x3 with 198 bar, 38x4 with 264 bar, and 38x5 with 330 bar maximum operating pressure. This lets you select the pressure margin you need without changing tube size or fitting size.
Seamlessly manufactured and tested
The bright tubes are manufactured to DIN 2391/C as well as DIN 2445-2 / DIN 1630 and EN 10305-4, phosphated and eddy-current tested. Material St37.4. Seamless means: no longitudinal weld seam, uniform wall thickness, and a clean cutting ring seat around the full circumference.
Material matched to the environment
Bright phosphated for protected installation locations, electro-galvanized and blue chromated on the outside (bright inside) for humid environments, or seamless 1.4571 stainless steel tube – heat-treated, pickled, tolerance class D4/T3. We're happy to clarify suitability for your specific medium on a case-by-case basis.
Tube, fittings and mounting from a single source
Alongside the tube, STASTO also supplies the connection and mounting technology: cutting ring fittings to ISO 8434-1 (DIN 2353) in galvanised steel (series C-DPR, C-B4, C-B7) and stainless steel 1.4571 (A-DPR-71, C-DPR-71, C-B4-71), weld cones series C-SKA for tube 38x3 to 38x8, plus pipe clamps.
Guide
Specifying 38 mm Correctly – Three Decisions
Outside diameter, wall thickness, material and connection technology are interrelated. This overview guides you through the key selection criteria for precision steel tube Ø 38 mm.
Choosing Wall Thickness – Pressure vs. Weight
- 38x2.5
- 166 bar maximum operating pressure – the economical standard choice for moderate pressures.
- 38x3
- 198 bar – an intermediate grade with noticeably more reserve at almost the same handling.
- 38x4
- 264 bar – also available as a white zinc-plated version 38X4WV.
- 38x5
- 330 bar – for special-purpose machinery and test benches with high pressure requirements.
- Sizing Rule
- Besides operating pressure, pressure spikes, bend radii and vibration also matter. When in doubt, choose the next higher wall thickness – the fitting size stays the same.
Choosing Material – Environment Beats Price
- Plain phosphated
- St37.4, eddy-current tested – the economical standard solution for protected installation locations.
- Zinc-plated (white)
- Electro-galvanized and blue chromated on the outside, plain bore inside – for visible or moisture-exposed installation.
- Stainless steel 1.4571
- Heat-treated, pickled, tolerance class D4/T3 per EN ISO 1127 / DIN 17456-58 – for corrosion-prone applications.
- Material pairing
- Always select the material together with the fitting: stainless steel tube should sensibly be paired with fittings made of 1.4571.
Matching connection technology – DIN 2391 meets DIN 2353
- DIN 2391
- According to the product description, all 38 mm tubes are designed per DIN 2391 to suit tube fittings.
- Tolerance class D4/T3
- The stainless steel variant is additionally specified with D4/T3 – the basis for a defined cutting ring seat.
- ISO 8434-1 (DIN 2353)
- Connection via cutting ring fittings; within the STASTO range, the 38 mm connection technology is assigned to the heavy series (S).
- Series selection
- Which cutting ring series is suitable depends on material, assembly method and pressure level – we check the correct assignment for your configuration.
Processing notes
- Cutting to Length
- Cut pipe ends square, deburr, and clean before assembly.
- Pre-Assembly
- Pre-assemble the cutting ring according to the manufacturer's specifications for the respective fitting series.
- Support
- Support lines with pipe clamps so that no bending moments act on the fitting.
Comparing the Variants
All 38 mm variants at a glance
Same outer diameter, different wall thickness and design: the table shows the manufacturer's specifications for material, wall thickness, maximum operating pressure and standard.
| 38X2.5 | 38X3 | 38X4 | 38X5 | 38X4WV | 38X4/71 | 38X5/71 | |
|---|---|---|---|---|---|---|---|
| Design / Material | seamless bare, phosphated, St37.4 | seamless bright, phosphated, St37.4 | seamless bright, phosphated, St37.4 | seamless bright, phosphated, St37.4 | white zinc-plated, blue chromated, bright inside | seamless stainless steel 1.4571, pickled | seamless stainless steel 1.4571, pickled |
| Wall thickness | 2.5 mm | 3 mm | 4 mm | 5 mm | 4 mm | 4 mm | 5 mm |
| max. operating pressure | 166 bar | 198 bar | 264 bar | 330 bar | 264 bar | 309 bar | 371 bar |
| Standard | DIN 2391/C, EN 10305-4 | DIN 2391/C, EN 10305-4 | DIN 2391/C, EN 10305-4 | DIN 2391/C, EN 10305-4 | DIN 2391/C, EN 10305-4 | EN ISO 1127, DIN 17456/58 | EN ISO 1127, DIN 17456/58 |
| Tolerance class | per DIN 2391 | per DIN 2391 | per DIN 2391 | per DIN 2391 | per DIN 2391 | D4/T3 | D4/T3 |
| Availability | Standard item | Standard item | Standard item | Standard item | Standard item | Standard item | on request |
Product range
38 mm tubes and matching system components
From seamless precision steel tube through the white zinc-plated version to the stainless steel variant 1.4571 – including cutting ring fittings to ISO 8434-1 (DIN 2353) and pipe clamps.
Applications
Where 38 mm Precision Steel Tube Is Used
The 38 mm outer diameter is a common size in pipeline and plant engineering – from fixed piping runs to retrofits of existing installations.
Machine and Plant Engineering
Fixed piping for compressed air and control lines with a defined inner diameter and reproducible routing.
Ring Mains in Production
Ring mains and branch lines, where a consistent size throughout the facility simplifies spare parts inventory.
Retrofit and Maintenance
Replacement of damaged pipe sections: same outer diameter, same fitting size, no impact on the rest of the installation.
Special-Purpose Machinery and Test Rigs
Wall thicknesses of 4 and 5 mm when higher pressure reserve is required – up to 330 bar at 38x5.
Corrosive Environments
Zinc-plated white finish or 1.4571 stainless steel, depending on the medium, cleaning process, and ambient conditions.
Demanding Cleaning Regimes
Seamless stainless steel tube 1.4571, pickled and heat-treated, when surface finish and material grade are critical. We'll clarify suitability based on your application.
Ordering
Ordering, Cutting and Availability
You can order all 38 mm pipes directly through the STASTO shop or via our technical sales team. Standard variants such as 38X2.5, 38X3, 38X4, 38X5, 38X4WV and 38X4/71 are listed at regular sale price; special versions and individual wall thicknesses are calculated on request.
Availability
Varies depending on variant and material – you can check the current status on the respective product page, or we will check it for you. Individual variants such as 38X2WV and 38X5/71 are available on request.
Quantities and Call-offs
We coordinate project requirements, tiered quantities and recurring call-offs on an individual basis.
Cutting and Special Lengths
Cutting and special lengths on request; material certificates and documentation can be requested depending on the item and batch.
Application Engineering Support
We provide support in selecting wall thickness, material and the appropriate fitting series according to ISO 8434-1 (DIN 2353).
In three steps
How to Get the Right 38 mm Pipeline
From sizing to the finished pipeline – structured, with technical support all the way.
Define wall thickness and material
Operating pressure, pressure spikes and ambient conditions determine the wall thickness (2.5 to 5 mm) and the version: bright, white zinc-plated or stainless steel 1.4571.
Match the connection technology
Select cutting ring fittings to ISO 8434-1 (DIN 2353), heavy series (S), in the matching material – stainless steel tube with fittings in 1.4571.
Order and install
Order standard items directly in the shop, request special versions and cutting to length. Cut tube ends square, deburr, and support with pipe clamps free of stress.
Frequently Asked Questions
FAQ on steel tube with 38 mm outer diameter
Answers on wall thicknesses, materials, standards and the right fitting technology.
What wall thicknesses are available for the steel tube with 38 mm outer diameter?
For the 38 mm outer diameter, wall thicknesses of 2.5 / 3 / 4 / 5 and 6 mm are available in bright (uncoated) finish, plus 2 mm and 4 mm white zinc-plated as well as 4 mm and 5 mm in stainless steel 1.4571. The outer diameter stays constant throughout, so fitting size and tube clamps remain the same – only the inner diameter and pressure reserve change.
What working pressure can a 38x3 tube withstand?
For the seamless steel tube 38x3 made of St37.4, the manufacturer specifies a maximum working pressure of 198 bar. For comparison: 38x2.5 is rated at 166 bar, 38x4 at 264 bar and 38x5 at 330 bar. The permissible operating limit of your line also depends on the fitting, medium and application conditions.
What does DIN 2391 mean for precision steel tubes?
DIN 2391 is the dimensional and manufacturing standard for seamless precision steel tubes designed for use with fittings. The bright 38 mm tubes are manufactured to DIN 2391/C as well as DIN 2445-2 / DIN 1630 and EN 10305-4, phosphated and eddy-current tested; the tolerances ensure the defined seating of the cutting ring.
Do the 38 mm tubes fit cutting ring fittings to DIN 2353?
Yes – according to the product description, all 38 mm tubes comply with DIN 2391 for use with fittings and can be connected using cutting ring fittings to ISO 8434-1 (DIN 2353). In the STASTO range, the 38 mm connection technology is assigned to the heavy series (S); the exact series assignment depends on material, assembly method and pressure level.
When is the white zinc-plated version the right choice?
The white zinc-plated version is suitable for exposed installations and environments with fluctuating humidity. It is electro-galvanized and blue chromated on the outside, bright on the inside; in 38 mm it is available with 2 mm wall thickness (on request) and 4 mm wall thickness (264 bar).
What is the difference between the 1.4571 stainless steel tube and the bright steel tube?
The seamless stainless steel tube 1.4571 is heat-treated, pickled and specified to tolerance class D4/T3 per EN ISO 1127 / DIN 17456-58 – it is used when corrosion resistance, media compatibility or cleanliness requirements are decisive. In 38 mm, 4 mm wall thickness (309 bar) and 5 mm (371 bar, on request) are available; it is best combined with fittings made of 1.4571.
Are cutting to length and special lengths possible?
Cutting to length and special lengths are available on request. We also arrange tiered quantities and recurring call-offs individually; material certificates can be requested depending on item and batch.
What neighboring sizes are available besides 38 mm?
Besides 38 mm, STASTO offers further sizes in the precision steel tube range, including 28, 30 and 42 mm outer diameter. You can find the selection in the Tubes and Accessories category; we will assign the matching fitting technology on request.
Also suitable
Related categories in the STASTO shop
Further nominal sizes, connection and pipeline components for pipework construction.
Next step
Select 38 mm tube or have your design reviewed
Choose your wall thickness and version directly in the shop – or have our application engineering team review wall thickness, material and fitting series for you.