Welded Stainless Steel Square Pipe
Longitudinally welded square hollow section in austenitic duplex and ferritic stainless grades
Specifications
Stainless Steel Pipe, Steel Pipe
Seamless Stainless Steel Square Tube for Pressure and Machining Work
Square hollow section with a continuous wall and no longitudinal weld line
Seamless stainless steel square pipe is a square hollow section shaped from a pierced and drawn tube, giving a continuous wall right around the perimeter with no longitudinal weld running down a face. It is called for by hydraulic component makers, fixture and jig builders and plant engineers working to specifications that exclude welded hollow sections in pressure, fatigue or corrosive service. Buying the section at the size the part needs means the machining allowance is planned rather than discovered, and the shop is not turning a stock section down to reach the wall thickness on the drawing. The order starts at 1 ton, with a free sample available first so the wall consistency and surface can be measured.
- Product Name — Seamless Stainless Steel Square Pipe
- Section Shape — Square hollow section
- Technique — Seamless
- Standard — ASTM A312 EN10216 JIS G3463
- Material Grades — 201 202 301 304 304L 309S 310S 316 316Ti 316L 410 430 2205 904L
Why It Is Specified
Key Benefits of Seamless Stainless Steel Square Pipe
Continuous Wall Around All Four Faces
With no seam, every face has the same structure and the same corrosion behavior. Nothing on the section has to be treated as a weaker line.
Accepted Where Welded Section Is Excluded
Client specifications and code work that prohibit a longitudinal weld in a hollow member can be satisfied directly. No concession request is needed at approval.
Predictable Stock for Machining Operations
The wall is drawn rather than formed and welded, so the machining allowance around the section stays consistent. Fixtures and manifold bodies come out to size with fewer setups.
Square Faces for Clamping and Flush Mounting
Flat faces locate directly in a vice or on a table without a saddle or a vee block. Assembly and machining setup time drops compared with round tube.
Grade Range Up to Duplex and Super Austenitic
304, 304L, 316, 316Ti, 316L, 309S, 310S, 2205 and 904L are all available so the section can be matched to the temperature and chloride level of the duty.
ISO9001 BV SGS and RoHS on the Certification Set
The stated certification covers ISO9001, BV, SGS and RoHS. Ask for the mill test certificate so the ordered grade is documented against the part number.
Problems It Solves
What This Material Removes From Your Process
Specifications That Exclude Welded Hollow Sections
A project specification that bars a longitudinal seam blocks the cheaper welded route. Seamless square pipe answers the clause without a technical query and without a schedule delay.
Uneven Machining Allowance Around a Section
Formed and welded sections can vary in wall around the perimeter, which shows up as an inconsistent finish after machining. A drawn seamless section holds a more even wall to work from.
Pitting Attack Concentrated at a Weld Line
In chloride and acid service the seam of a welded section is where attack begins. Removing the seam removes that concentration from the design.
Turning Solid Bar to Make a Hollow Part
Starting from solid bar removes most of the metal as swarf. A drawn hollow section arrives closer to the finished geometry and cuts both material and cycle time.
No Chance to Verify Before a Container Ships
A free sample can be released and orders start at 1 ton, so wall consistency and surface condition can be verified before the full quantity is committed.
Application Scenarios
Where It Is Used
Hydraulic Manifold and Cylinder Bodies
Square sections machined into manifold blocks and housings where internal pressure makes a seam unacceptable.
Machine Fixtures Jigs and Load Frames
Square members used as fixture columns and load frame uprights where a consistent wall keeps the machined result predictable.
Corrosive Process Plant Members
Supports and equipment members in 316L, 2205 and 904L inside chemical units where a seam would pit first.
Furnace and Heat Treatment Equipment
310S and 309S square members around hot equipment where oxidation resistance matters more than room temperature strength.
Marine Deck and Offshore Fittings
Duplex 2205 square sections for deck fittings and supports exposed to continuous salt spray.
Instrument and Test Rig Structures
Square tube used for rigid instrument mounts and test stands that need dimensional stability over time.
Who It Is For
Buyers Who Specify This Product
- Hydraulic component makers buying seamless square stock for manifold and housing machining
- Tooling and fixture shops buying square section for jigs columns and load frames
- Chemical plant engineers buying 316L and 904L members for corrosive process areas
- Furnace equipment builders buying 310S square section for hot zone structures
- Offshore fabricators buying duplex 2205 square tube for deck level fittings
- Inspection led procurement teams buying seamless because the specification excludes a welded hollow section
Technical Data
Specifications and Technical Features
Values below come from the product data published by Shandong Tianyu Metal Products. Confirm the exact grade and size against your order.
| Product Name | Seamless Stainless Steel Square Pipe |
|---|---|
| Section Shape | Square hollow section |
| Technique | Seamless |
| Standard | ASTM A312 EN10216 JIS G3463 |
| Material Grades | 201 202 301 304 304L 309S 310S 316 316Ti 316L 410 430 2205 904L |
| JIS Designations | SUS304 SUS304L SUS321 SUS316 SUS316L SUS309S SUS310S |
| EN Material Numbers | 1.4372 1.4373 1.4301 1.4833 1.4845 1.4401 1.4571 1.4404 |
| Size | Customized |
| Delivery | Within 7-10 working days after receiving the deposit or according to order quantity |
| Minimum Order | 1 ton or free sample |
| Certification | ISO9001 BV SGS RoHS |
| Price Term | TT or LC |
| Place of Origin | China |
Technical Features
- Seamless square hollow section shaped from a pierced and drawn tube
- Standards ASTM A312 EN10216 and JIS G3463
- Grades 201 202 301 304 304L 309S 310S 316 316Ti 316L 410 430 2205 and 904L
- JIS designations SUS304 SUS304L SUS321 SUS316 SUS316L SUS309S and SUS310S
- EN material numbers 1.4301 1.4372 1.4373 1.4401 1.4404 1.4571 1.4833 and 1.4845
- Outside dimension wall thickness and length customized
- No longitudinal weld seam in any face
- Certification ISO9001 BV SGS and RoHS
Materials
- Austenitic 304 304L 316 316L and titanium stabilized 316Ti
- Heat resistant 309S and 310S for oxidizing high temperature duty
- Duplex 2205 for chloride bearing and offshore exposure
- Super austenitic 904L for sulfuric and phosphoric acid handling areas
- Ferritic 430 and martensitic 410 for dry and lower cost applications
Certification
- ISO9001
- BV
- SGS
- RoHS
Manufacturing
How It Is Made and Processed
Piercing the billet into a hollow mother tube
Cold drawing the tube to the required wall thickness
Shaping the round tube into the square profile through forming passes
Solution annealing and pickling after forming
Sizing and straightening to the ordered outside dimension
Cutting to length and deburring the ends
Marking bundling and packing for container export
Quality Control
Checks Before It Ships
- Grade confirmed against the nominated ASTM EN or JIS designation
- Wall thickness measured on each face and at the corner radii
- Outside dimension squareness and corner radius checked to the order
- Surface inspected after pickling for drawing marks and scale
- Length straightness and end finish verified before bundling
Customization
What We Can Change on Your Order
- Square outside dimension and wall drawn to your part drawing
- Cut lengths supplied against your machining list
- Grade selected from 304 316L 310S 2205 or 904L to match the duty
- Standard nominated as ASTM A312 EN10216 or JIS G3463
- Free sample supplied for wall and surface verification before the order
- Bundle marking and protection arranged for the machine shop that receives it
Comparison
Seamless Stainless Steel Square Pipe Against the Alternatives
| Welded stainless square pipe | There is no seam on any face, which is what a pressure, fatigue or corrosive duty specification normally demands and what machining benefits from. |
|---|---|
| Solid stainless square bar | The hollow drawn section removes most of the metal that would otherwise be turned into swarf, cutting both purchase weight and machining time. |
| Seamless round pipe | Flat faces clamp and locate directly in a vice or on a table so setups are quicker and mounting details are simpler. |
| Carbon steel seamless square tube | Corrosion resistance is inherent rather than coated, so machined faces and drilled holes do not need repeated protection in service. |
Use Guide
Specifying Handling and Welding Notes
- Specify the wall tolerance you need if the section is going straight onto a machine after delivery
- Choose 310S rather than 304 where the operating temperature causes scaling on ordinary austenitic grades
- Use duplex 2205 where chlorides are present and check the upper temperature limit for the grade
- Passivate faces that have been machined milled or drilled before the part enters corrosive service
- Keep the sections on nonferrous or stainless racking so the surface does not pick up iron
- Send the drawing with outside dimension wall and cut length so the sections arrive near the finished size
Questions Buyers Ask
Seamless Stainless Steel Square Pipe FAQ
Why choose seamless square rather than welded square pipe?
Seamless carries no longitudinal weld, which is what pressure, fatigue and corrosive duty specifications normally require. For ordinary frame work a welded section is usually sufficient.
Can you make the square section to a non standard outside dimension?
Yes. Size is customized, so supply the outside dimension, wall thickness and cut length and the section is produced to that.
Which grades hold up best at high temperature?
309S and 310S are the heat resistant grades in the range and are normally chosen for furnace and heat treatment equipment.
What quantity do you need to start production?
Minimum order is 1 ton, and a free sample can be released beforehand so you can check the wall and surface.
Is the material suitable for machining into manifold bodies?
The drawn wall is consistent around the section, which is why hydraulic component makers use it as machining stock for manifolds and housings.
What certificate will come with the shipment?
Certification covers ISO9001, BV, SGS and RoHS. Ask for the mill test certificate so the ordered grade is recorded for your part file.
How quickly can you deliver after the deposit?
Within 7-10 working days after the deposit is received, or according to the order quantity where the tonnage is larger.
Same Range
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