stainless steel
special-shaped
pipe & tube
Stainless steel pipe & tube is all we do. Oval, D-shape, triangle and 30+ other profile families from 340+ existing dies — listed sizes carry no tooling charge; new dies are refunded once cumulative orders reach the agreed tonnage (typically 5–20 t), and samples ship 7–15 days after drawing sign-off.
For drawings, tooling, tolerance, and sample coordination, see our custom stainless steel tube fabrication service. Before you send an RFQ, use our special-shaped tube specification checklist to define the drawing, tolerances, finish and tooling.
Your Profile Is Probably Already Tooled: 340+ Existing Die Sizes Across 31 Profile Families
From standard oval and D-shape to custom architectural, handrail and industrial profiles.
Specifications
Specialty Tubing Shapes & Custom Cross-Section Profile Matrix
TeCarve engineers specialty stainless steel shaped tubing across standardized non-circular profiles and bespoke asymmetric cross-sections. Depending on profile complexity, wall thickness, and dimensional tolerances, shaped tubing is manufactured via continuous multi-pass roll forming or precision cold drawing over shaped dies and mandrels to achieve exact mechanical fitment.
| Profile Family | Cross-Section Geometry | Standard Size Envelope | Wall Thickness | Achievable Tolerance | Typical Applications |
|---|---|---|---|---|---|
| Oval & Flat Oval | Elliptical & flat-sided oval with continuous tangent radii | Major 15–200 mm Minor 10–100 mm | 0.6–4.0 mm | Major: ±0.15–0.30 mm Minor: ±0.10–0.20 mm | Architectural balustrades, aero struts, marine grab rails |
| D-Shaped Profile | Flat mounting base with 180° radius or rounded semi-circular crown | Base 12–150 mm Height 8–80 mm | 0.8–5.0 mm | Base: ±0.15–0.35 mm Flatness: ≤ 0.15 mm | Flush wall rails, medical catheter guides, automotive frames |
| Triangular / Delta | Equilateral & isosceles triangles with specified apex radii | Side 15–120 mm Corner R1.5–R6 mm | 0.8–3.5 mm | Side: ±0.15–0.30 mm Apex: ±0.5° | Lightweight spaceframes, architectural trusses, heat exchangers |
| Hexagonal / Octagonal | Multi-faceted polygonal tubes with sharp or radiused internal/external flats | Across Flats (AF) 10–100 mm | 1.0–5.0 mm | AF: ±0.10–0.25 mm Parallelism: ≤ 0.10 mm | Telescoping drive shafts, torque sleeves, tool handles |
| Grooved / Slotted Rail | Round, oval, or square with integrated glass-clamping channel | OD 38.1–76.2 mm Slot 14–26 mm | 1.2–2.5 mm | Slot width: ±0.20 mm Parallelism: ≤ 0.15 mm/m | Frameless architectural glass balustrades, showcase handrails |
| Bespoke Custom Profiles | Asymmetrical & multi-radii profiles engineered strictly per CAD/DWG | Envelope up to 200 mm (larger on request) | 0.5–5.0 mm | Cold-drawn: ±0.08–0.15 mm Roll-formed: ±0.20–0.40 mm | Food machinery tracks, transit interiors, custom heat dissipation |
Governing Standards & Mechanical Tolerances
Standard Application: N. America — Welded Stainless Steel Mechanical & Shaped Tubing
ASTM A554 covers welded stainless steel mechanical tubing supplied as round, square, rectangular, or special shapes (Section 1.3). The standard publishes tolerance tables only for round tubing (Tables 2 and 3) and for square and rectangular tubing (Table 5). For special shapes the dimensions are specified by the purchaser (Section 4.1.4.3), and straightness on special requirements is agreed between purchaser and producer (Section 9.4), so every shaped-tube tolerance is confirmed against the customer engineering drawing.
| Governing Clause | ASTM A554 Section 1.3 (Shapes: round, square, rectangular or special) & Section 6 (Materials and Manufacture: flat-rolled steel, automatic welding without filler metal) |
|---|---|
| Delivery Condition | As welded, welded and annealed, cold reduced, or cold reduced and annealed (Section 7.1) |
| Size Envelope | Major dimension up to 200 mm (approx. 8 in.); wall thickness 0.50 mm to 5.0 mm (0.020 to 0.200 in.) |
| Dimensional Tolerances | Major/minor axes: ±0.10 mm to ±0.35 mm (sizes ≤50 mm); ±0.25 mm to ±0.60 mm (sizes 50–150 mm) per blueprint |
| Wall Thickness Tolerance | ±10% of specified wall thickness (the wall tolerance ASTM A554 applies to round, square and rectangular tubing in Tables 2, 3 and 5) |
| Twist & Straightness | Agreed per drawing for special shapes (Section 9.4). For reference, A554 allows 0.76 mm straightness in any 0.9 m of round tubing (Section 9.4), and 2.1 mm per 1 m straightness with twist of 1.4–10.4 mm/m depending on size for square and rectangular tubing (Table 5) |
| Surface Finishes | Mill finish (as-welded), 180–320 Grit satin/hairline, 400–600 Grit mirror polish, or electropolished |
Standard Application: Europe — Welded Circular & Non-Circular Tubes for Mechanical Engineering
EN 10296-2 specifies welded stainless steel tubes for general mechanical and engineering applications across non-circular and custom profile cross-sections. Steel grades include 1.4301 (304), 1.4307 (304L), 1.4404 (316L), and 1.4541 (321), delivering superior corrosion resistance and ductility for structural metalwork.
| Standard Specification | EN 10296-2 & EN 10088-2 material grades (1.4301, 1.4307, 1.4401, 1.4404, 1.4541) |
|---|---|
| Delivery Conditions | Solution annealed, bright annealed (+AR / +AT), or cold-sized as-welded (+C) |
| Size Envelope | Cross-sectional envelope up to 200 mm; wall thickness 0.6 mm to 5.0 mm |
| Corner Radii Control | External corner radius R = 1.5t to 3.0t standard; sharp precision corners down to 1.0t achievable |
| Weld Seam Integrity | 100% automated inline eddy-current testing or optical bead inspection with internal scarfing/dressing |
| Inspection Documents | EN 10204 Type 3.1 inspection certificate with full heat charge traceability |
Standard Application: Japan & Asia-Pacific — Stainless Steel Pipes for Machine & Structural Purposes
JIS G3446 covers stainless steel pipes for machine, vehicle, building, and other structural purposes requiring high torsional rigidity and aesthetic architectural styling. Shapes include deformed ovals, polygonal tubes, and precision-drawn symmetric profiles.
| Standard Specification | JIS G3446 (SUS304, SUS304L, SUS316, SUS316L, SUS430) |
|---|---|
| Forming Methodology | Cold roll-forming or cold mandrel drawing with multi-roll precision sizing stands |
| Dimensional Range | Outer envelope up to 180 mm; wall thickness 0.8 mm to 4.5 mm |
| Profile Sizing Control | Across-flats / major-minor axes tolerance calibrated within ±0.12 mm to ±0.30 mm |
| Surface Quality | Uniform hairline, satin buffing (#400), or mirror buffing (#600) with zero longitudinal tooling scratches |
Standard Application: China & International Projects — Welded Stainless Steel Tubes for Structural Shapes
GB/T 12770 governs welded stainless steel tubes for mechanical and architectural structures, covering round, rectangular, and custom-shaped mechanical tubing with strict chemical composition and tensile strength requirements.
| Standard Specification | GB/T 12770 (06Cr19Ni10, 022Cr19Ni10, 06Cr17Ni12Mo2, 022Cr17Ni12Mo2) |
|---|---|
| Profile Envelope | Largest cross-sectional dimension up to 200 mm; wall thickness 0.5 mm to 5.0 mm |
| Mechanical Testing | Tensile strength ≥ 515 MPa, Yield strength ≥ 205 MPa, Elongation ≥ 35% (304/316L) |
| Flattening / Flare Test | Weld seam integrity verified via flattening and flaring tests per standard requirements |
| Trial Production MOQ | Flexible trial orders from 100–300 kg supported for standard and custom tooling profiles |
Cold Forming Processes for Specialty Stainless Steel Shaped Tubing
1. Continuous Progressive Roll Forming
Precision-slit stainless strip is gradually shaped through 8 to 14 multi-stand contour rolls into the target specialty tubing shape, followed by automated high-frequency TIG or laser seam welding. Turks-head finishing stands calibrate final squareness, straightness, and corner radii. This process delivers high manufacturing efficiency, consistent longitudinal geometry, and excellent cost efficiency for medium-to-high volume architectural and mechanical profiles.
2. Precision Cold Mandrel Drawing
Starting from an annealed round seamless or welded mother tube, the shell is drawn at room temperature through hardened tungsten carbide external profile dies and over calibrated internal shaped mandrels. Cold drawing achieves exceptionally tight dimensional tolerances (±0.08 mm), uniform wall thickness across complex geometry, smooth internal/external surface finishes (Ra ≤ 0.4–0.8 μm), and enhanced work-hardened yield strength for high-demand structural mechanisms.
For application-specific profiles and compliance requirements, see our solutions for pharmaceutical and medical and automotive and transportation applications.
For aesthetic architectural cladding, decorative railings, and polished ornamental tubing, see our Stainless Steel Decoration Pipe & Tube.
Standards
→ Scroll right for full chemistry & mechanical data
| Grade | US (UNS) | EN (W.Nr.) | Japan (JIS) | China (GB/T) | C % (Max) | Si % (Max) | Mn % (Max) | P % (Max) | S % (Max) | Cr % | Ni % | Mo % | Tensile σb (Min.) | Yield σ0.2 (Min.) | Elongation (Min.) | Hardness (Max) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 304 | S30400 | 1.4301 | SUS304 | 06Cr19Ni10 | 0.08 | 0.75 | 2.00 | 0.045 | 0.030 | 18.0-20.0 | 8.0-11.0 | — | 515 MPa (75 ksi) | 205 MPa (30 ksi) | 35% | ≤92 HRB / ≤215 HV |
| 304L | S30403 | 1.4307 | SUS304L | 022Cr19Ni10 | 0.030 | 0.75 | 2.00 | 0.045 | 0.030 | 18.0-20.0 | 8.0-12.0 | — | 485 MPa (70 ksi) | 170 MPa (25 ksi) | 35% | ≤92 HRB / ≤215 HV |
| 316 | S31600 | 1.4401 | SUS316 | 06Cr17Ni12Mo2 | 0.08 | 0.75 | 2.00 | 0.045 | 0.030 | 16.0-18.0 | 10.0-14.0 | 2.0-3.0 | 515 MPa (75 ksi) | 205 MPa (30 ksi) | 35% | ≤95 HRB / ≤215 HV |
| 316L | S31603 | 1.4404 | SUS316L | 022Cr17Ni12Mo2 | 0.030 | 0.75 | 2.00 | 0.045 | 0.030 | 16.0-18.0 | 10.0-14.0 | 2.0-3.0 | 485 MPa (70 ksi) | 170 MPa (25 ksi) | 35% | ≤95 HRB / ≤215 HV |
| 321 | S32100 | 1.4541 | SUS321 | 06Cr18Ni11Ti | 0.08 | 0.75 | 2.00 | 0.045 | 0.030 | 17.0-19.0 | 9.0-12.0 | — | 515 MPa (75 ksi) | 205 MPa (30 ksi) | 35% | ≤95 HRB / ≤215 HV |
| 430 | S43000 | 1.4016 | SUS430 | 10Cr17 | 0.12 | 1.00 | 1.00 | 0.040 | 0.030 | 16.0-18.0 | — | — | 450 MPa (65 ksi) | 205 MPa (30 ksi) | 22% | ≤89 HRB / ≤200 HV |
- Standards Conformance: ASTM A554/A312 · EN 10296/10088 · JIS G3446/G3468 · GB/T 12770/18705 · ISO 15510
- Delivery Condition: Solution Annealed & Pickled (AP) / Bright Annealed (BA) / Polished, or as requested.
- Mill Test Certificate: 100% full material traceability with EN 10204 3.1 MTC provided with every shipment.
Features
• Variety of custom cross-sectional shapes
• Excellent corrosion resistance and formability
• Decorative and structural versatility
• Tight tolerances and uniform wall thickness
• Architectural & decorative structures
• Custom equipment and machinery housings
• Furniture and automotive trim
• Public facilities and infrastructure
Applications
For custom profile and non-standard shaped tubing, check how buyers can verify our tooling customization, cold-drawing dimensional consistency, and pre-shipment inspection checklist.
Quality Control
Profile Metrology, Dimensional Verification & Quality Control
Non-standard shaped tubing requires specialized inspection tooling beyond conventional calipers. TeCarve enforces multi-stage dimensional verification to ensure total fidelity to customer CAD engineering files:
- Optical Contour Comparison & 3D CMM: Cross-sectional slices undergo digital optical profiling and Coordinate Measuring Machine (CMM) scanning to compare true radii, angle symmetry, wall uniformity, and face convex/concave deviation against native DXF CAD geometry.
- 100% Weld Seam NDT: Inline eddy-current testing (ET) to ASTM E426 verifies longitudinal weld fusion and detects internal/surface discontinuities. Under ASTM A554, nondestructive testing is a supplementary requirement (S3), so the test method and acceptance limits are stated in the order.
- Corner Radii & Twist Monitoring: Corner radius gauges check every corner against the drawing (ASTM A554 Table 5 sets maximum corner radii for square and rectangular tubing, measured as the effective corner radius in Fig. 1); twist and straightness are checked against the drawing or the A554 Table 5 limits.
- Traceable Material Certification: Authentic EN 10204 Type 3.1 Mill Test Certificates are provided with each production lot, detailing full heat charge chemical analysis, tensile strength, yield strength, and elongation.
TeCarve operates under accredited management systems certified by Shanghai Ingeer Certification Assessment Co., Ltd.: ISO 9001:2015 (Quality Management), ISO 14001:2015 (Environmental Management), and ISO 45001:2018 (Occupational Health & Safety).
• CNC-molded shaping for precision profiles
• Visual and dimensional inspection
• Surface finish quality grading
• Optional third-party certification available
Existing Die Catalogue: 31 Profile Families, 344 Tooling Sizes
Your required shape may already be tooled. Check the cross-section families below to eliminate tooling charges. For custom profiles not listed, new tooling fees are refunded once cumulative orders reach the agreed tonnage (typically 5–20 t).
| Cross-Section Profile Family | Dies | Size span (mm) | Parent round tube OD (mm) |
|---|---|---|---|
| Oval (Elliptical) Tube | 48 | a 10–70 × b 18.5–122 | Ø16–Ø96 |
| Flat Oval Tube | 47 | a 8–52 × b 15–110 | Ø12.7–Ø89 |
| Rectangular Tube | 59 | a 5–45 × b 10–120 | Ø9.5–Ø89 |
| Octagonal Tube | 6 | a 20–80 × b 39–98 | Ø38–Ø102 |
| Half-Round Tube | 8 | a 8–40 × b 16–80 | Ø12.7–Ø63 |
| Equilateral Triangle Tube | 6 | a 14.5–39 × b 14.5–39 (+ more parameters, see catalogue) | Ø14–Ø38 |
| Isosceles Triangle Tube | 9 | a 17–80 × b 17–80 (+ more parameters, see catalogue) | Ø19–Ø89 |
| Quarter-Round (Sector) Tube 1 | 6 | a 44–70 × b 20–40 | Ø38–Ø60 |
| Diamond Profile Tube | 3 | a 20–30 × b 20–30 (+ more parameters, see catalogue) | Ø23–Ø35 |
| Arch Tube | 19 | a 12–40 × b 20–70 | Ø18–Ø63 |
| Arch-Door Profile Tube | 16 | a 15–40 × b 20–70 | Ø20–Ø63 |
| Isosceles Trapezoid Tube | 6 | a 10–37 × b 17–83 (+ more parameters, see catalogue) | Ø38–Ø65 |
| Quarter-Round (Sector) Tube 2 | 10 | a 17–55 × b 17–55 (+ more parameters, see catalogue) | Ø19–Ø63 |
| Hexagonal Tube | 9 | a 16–55 × b 18–63 | Ø18–Ø63 |
| Handrail Profile | 1 | a 63 × b 43 | Ø63 |
| Wave-Top Handrail Profile | 5 | a 17–65 × b 31–47 | Ø28–Ø63 |
| Square Tube | 7 | a 9.3–45 × b 9.3–45 | Ø12–Ø57 |
| Rhombus Profile | 2 | a 15–50 × b 25–32 | Ø25–Ø50 |
| Handle Profile | 1 | a 12 × b 33 | Ø25 |
| Bullet Profile | 1 | a 20 × b 100 (+ more parameters, see catalogue) | Ø76 |
| Parallelogram Tube | 1 | a 25 × b 40 | Ø42 |
| Furniture Profile Tube | 1 | a 60 × b 55 (+ more parameters, see catalogue) | Ø63 |
| Heart-Shaped Tube | 1 | — | Ø19 |
| Irregular Profiles | 6 | a 38.5–91 × b 30–91 (+ more parameters, see catalogue) | Ø32–Ø102 |
| Pentagonal Profile Tube | 7 | a 40–100 × b 13–50 (+ more parameters, see catalogue) | Ø32–Ø89 |
| Right-Angle Trapezoid Tube | 3 | a 40–50 × b 24–40 (+ more parameters, see catalogue) | Ø45–Ø50 |
| Double-Arched (Barrel) Tube | 11 | a 9–30 × b 15–45 | Ø14–Ø48 |
| Elongated Hexagonal Tube | 7 | a 28–73 × b 11–42 | Ø22–Ø63 |
| Four-Lobe (Clover) Tube | 4 | a 14–20 × b 17–29 | Ø16–Ø29 |
| D-Shaped Tube | 4 | a 25–60 × b 25–64 | Ø28–Ø70 |
| Other Special Profiles | 30 | a 10–153 × b 15–152 (+ more parameters, see catalogue) | Ø18–Ø114 |
Online Catalogue Preview
Custom Special-Shaped Tube Manufacturing
Who manufactures custom special-shaped stainless steel tube?
TeCarve Tech Co., Ltd. is the sole export arm of two stainless steel tube factories in Foshan & Wenzhou. Our partner factories produce oval, D-shaped, triangular and other custom profiles in grades 201, 304, 304L, 316, 316L and 430, with wall thickness from 0.5mm to 5mm and lengths from 1m to 12m (custom lengths available).
What is the minimum order quantity (MOQ) for custom special-shaped tube?
MOQ is typically 100–300kg depending on the shape complexity and grade selected. Send us your drawing or sample for an exact quote.
What is the process from drawing to production?
1) Submit your technical drawing or sample, including cross-section profile, OD/wall thickness, tolerance, grade, and length. 2) Our engineering team reviews tooling feasibility and confirms MOQ and lead time. 3) Sample production and approval where required. 4) Bulk production with full material traceability (Mill Test Certificate provided). See our custom stainless steel tube fabrication service for drawing, tooling, and tolerance coordination.
Where is TeCarve's special-shaped tube manufactured?
Production takes place at TeCarve's two partner factories in Foshan, Guangdong and Wenzhou, Zhejiang, China. TeCarve Tech Co., Ltd., their sole export arm, coordinates export, quality control and logistics from Hangzhou.
packaging
PVC Wrapping
& End Caps
Custom Barcoding
& Labeling
Anti-Corrosion
& Moisture Protection
Seaworthy Wooden Cases & Pallets
Special-shaped Tube Inspection & Packaging Photos
Real product, inspection, packaging and loading photos.
Tailored Solutions, Timely Fulfillment
CUSTOMIZATION
& DELIVERY
Flexible Custom Manufacturing
We tailor stainless steel special-shaped pipe and tube by cross-sectional profile, including the page's oval, D-shaped, and triangular options, together with wall thickness, length, grade, and surface finish.
Low MOQ & Rapid Prototyping
Small batch customization and sample production are supported, helping you shorten your development cycle and market entry.
Optimized Lead Time
In-stock standard sizes ship within 7–10 days. Custom specifications typically ship within 10–25 days after deposit, depending on order volume, dimensions, and surface finish. The full cycle—from inquiry and drawing confirmation through sampling, production, inspection, and dispatch—typically takes 33–55 days for custom items.
Global Logistics & On-Time Delivery
For special-shaped tube shipments worldwide, seaworthy wooden cases and pallets protect formed profiles while custom barcoding and labeling identifies each requested shape.
How your order is made, checked and shipped
Tube forming at the partner factory
Heat treatment (annealing)
Dimensional inspection
Alloy verification with a handheld analyzer
Export packing
Container loading
What buyers say about shipments from our partner factories
“I've received the goods and everything is fine.”
“The goods already send to customers. I am waiting for the next order from them.”
“…there is no need of inspection this time… I trust in your product.”
Frequently Asked Questions
What are special-shaped stainless steel tubes?
Special-shaped (non-round) stainless steel tubes include hexagonal, D-shaped, elliptical, triangular, and fully custom profile tubes manufactured by cold drawing through custom dies from round tube preforms.
What profiles can TeCarve supply as special-shaped tube?
Our partner factories produce hexagonal, oval, D-shape, flat-sided oval, semi-circular, triangular, and fully custom cross-section tubes. Complex profiles are drawn to customer CAD drawings; tooling (die) investment is required for new custom profiles.
What grades are available for special-shaped stainless steel tube?
Special-shaped tubes are produced in grades 304, 304L, 316, 316L, and 321. The cold-drawing process improves dimensional accuracy and mechanical properties compared to standard welded round tube.
What is the minimum order quantity for custom-profile stainless steel tube?
For custom-profile stainless steel tube, TeCarve supports flexible trial orders starting from 100–300 kg depending on profile complexity, with first-article prototype samples available for dimensional and fitment validation before committing to full-scale production.
What industries use special-shaped stainless steel tube?
Applications include medical device shafts (D-profile catheter tubes), automotive trim and structural inserts, hexagonal lock cylinders, architectural handrail components, and specialty fluid handling systems requiring non-circular bore cross-sections.
How are tooling fees handled for custom special-shaped tubes?
We first check your required profile against our existing die catalogue (340+ sizes). If matched, there is no tooling charge. For new custom profiles requiring dedicated tooling, a one-time fee is charged, which is refunded once cumulative orders reach the agreed tonnage (typically 5–20 tons) or credited stepwise.
What is the sample lead time and mass production confirmation process?
First-article prototype samples are dispatched within 7–15 days following CAD drawing sign-off, depending on profile complexity. Before launching mass production, we provide cross-section slices and inspection reports for the client's written confirmation.
What dimensional tolerances apply to special shaped stainless tubes?
ASTM A554 Table 5 only provides tolerance tables for round and square/rectangular tubes, not irregular shapes. Per A554 §4.1.4.3, special shaped tube dimensions are to be specified by the purchaser, and tolerances are confirmed strictly per customer engineering drawings.
Upload CAD / DWG Drawings for Tooling & Sampling Evaluation
Need non-standard oval, D-shape, triangular, flat-sided, or complex asymmetrical tubing? We accept technical drawings in CAD (.dwg / .dxf), STEP, SolidWorks, and PDF for rapid tooling feasibility analysis, prototype sampling assessment, and flexible trial production (100–300 kg MOQ).
Direct review by our tooling engineers to evaluate roll-forming dies, cold-drawing passes, and dimensional limits within 1 business day.
Prototype sample pieces supported for physical fitment, corner radius, and surface finish validation prior to bulk roll-out.
No massive multi-tonne mill minimums. Test market feasibility or custom machine assemblies with low-risk trial quantities.
EN 10204 3.1 Mill Test Certificates with chemistry, dimensional tolerance CMM records, and raw material batch traceability.
Contact TeCarve