Hygienic Stainless Steel Pipe

Shuangsen supplies Hygienic Stainless Steel Pipe from China factory direct. Internal mechanical polishing achieves Ra≤0.2µm with weld seam leveled and shadow-free. Full nitrogen shield welding and pure hydrogen annealing ensure weld zone strength matches base metal – tensile ≥690MPa, expansion >30%, flattening and flaring tests show no rupture. 1000h salt spray resistance verified. In-house NDT, hydrostatic testing, and roughness measurement per batch. ISO 13485 (medical), 9001, 14001, 45001 certified. 

Production equipment and process capabilities

The manufacturing facility for Hygienic Stainless Steel Pipe operates 133 complete welded pipe assembly lines. Each line integrates three foreign-level systems: online roundness control, internal weld leveling, and bright solid-melting heat treatment. These systems run continuously with automated monitoring of wall thickness, ovality, and weld consistency. Material input is restricted to 304, 304L, 316, and 316L coils, each with mill certificates and heat numbers.

Weld zone integrity is achieved through full nitrogen shielding during welding and pure hydrogen atmosphere during annealing. This sequence eliminates oxide formation and ensures the weld seam matches base metal in both mechanical strength and corrosion resistance. Tensile tests consistently show ≥690 MPa, with expansion rates exceeding 30% across all standard sizes.

Key process features

• Online roundness control – maintains OD tolerance within ±0.13mm to ±0.76mm per standard
• Internal weld leveling – removes bead shadow, creates smooth internal surface
• Bright solid-melting heat treatment – applied inline under pure hydrogen atmosphere
• Mechanical polishing – internal Ra ≤ 0.2 µm, external finish from mill to 320-grit
• Autogenous welding – no filler metal, seam composition matches parent alloy
• Solid solution treatment – applied to every length for uniform grain structure

Standard dimensions and tolerance classes

Standard OD range from 19.0mm (3/4") to 165.2mm (6½"). Wall thickness options span 0.89mm to 3.05mm, with specific tolerances applied per standard.

Custom dimensions outside this range are produced to drawing specifications. Tolerances follow JIS G3447 or ASTM A269/A270 based on the order requirement.

Inspection and testing protocol

Each batch of Hygienic Stainless Steel Pipe is subject to a fixed testing sequence before release:

• Transverse and longitudinal pressure leveling – confirms ductility and weld soundness
• Reverse flattening – detects weld seam separation or lamination
• Hydrostatic test or eddy current flaw detection – screens for pinholes and linear defects
• Mechanical property verification – tensile strength, yield point, and elongation
• Inner surface roughness measurement – Ra and Rz recorded per ASTM B912

Traceability is maintained from coil heat number through forming, welding, and finishing. Factory test reports are issued per batch. Third-party inspection (SGS, BV) can be engaged at the production site.

Order specification checklist

1. Product designation
2. Material grade (304, 304L, 316, 316L)
3. Dimensions and tolerance class
4. Quantity (pieces or total length)
5. Packing method (bundles, crates, or custom)
6. Heat treatment condition
7. Testing method (hydrostatic, eddy current, etc.)
8. External surface finish requirement
9. Internal wall roughness requirement (Ra, Rz)
10. Special marking or end protection

Industry applications and installation environments

The tubing is deployed in sectors requiring high surface finish and corrosion resistance:

• Dairy processing – raw milk, pasteurized products, and CIP return loops
• Pharmaceutical manufacturing – WFI distribution, SIP systems, and clean steam lines
• Beverage production – beer, juice, and carbonated soft drinks
• Data center cooling – chilled water loops for HUAWEI and Envicool thermal systems
• Building services – potable water supply and radiant heating networks

Certifications and regulatory alignment

Certifications held: ISO 9001:2015, ISO 14001:2015, ISO 45001:2018, ISO 13485:2016. National designations include "Specialized, Refined, Unique and New" Little Giant Enterprise and National High-Tech Enterprise.

Frequently asked operational questions

Can the Hygienic Stainless Steel Pipe be produced to non-standard dimensions or special requirements?
Yes. Custom production includes special OD, wall thickness, length, tighter ovality or straightness tolerances, special surface finishes (matte, bright annealed, pickled), OEM marking (laser etching, stenciling), and specific end preparations (beveled, threaded, or plain). Drawings or detailed specification sheets are used.

Is this a manufacturer or a trading operation?
Direct manufacturer. The facility operates 133 welded pipe lines and performs all key processes in-house: coil slitting, forming, welding, leveling, heat treatment, polishing, and testing.

Are samples available and what is the cost?
Samples are provided free of charge. The receiver covers freight. Sample lead time is typically 5–10 working days depending on size and surface requirement.

Can the factory be visited or inspected remotely?
On-site visits are welcome. For remote inspection, online video walkthroughs of the production line, testing lab, and packing area can be arranged. Real-time quality data can be shared.

What quality assurance procedures are in place?
Three inspection stages: (1) incoming coil verification (chemical composition, surface condition), (2) in-process checks (weld bead consistency, roundness, wall thickness), and (3) final inspection (NDT, mechanical tests, surface roughness, dimensional audit). A factory test report is issued per batch. Third-party inspection can be contracted.

What if there is no previous import experience?
Full export documentation is provided: commercial invoice, packing list, bill of lading, certificate of origin, and test reports. Customs clearance guidance is offered.

What packing options are available?
Standard: hexagonal bundling with anti-rust paper, plastic caps on both ends, and steel strips. Optional: wooden crates, steel frames, or shrink-wrapped pallets.

What surface finishes can be supplied?
External: mill finish, 180-grit brushed, 320-grit polished, or bright annealed. Internal: mechanical polished (Ra ≤ 0.2 µm) or pickled/passivated. Special roughness values (Ra ≤ 0.1 µm) can be achieved.

How is the weld seam treated and verified?
All welds are internally leveled and externally smoothed. The weld zone undergoes full solution treatment. No filler metal is used – autogenous welding ensures seam composition matches base alloy. Weld integrity verified via hydrostatic testing and eddy current inspection.

Is full traceability maintained from coil to finished tube?
Each coil is assigned a unique heat number. The heat number is recorded throughout forming, welding, and finishing. Full traceability to raw material certificate is maintained.

Why this tubing is selected for sanitary and high-purity lines

• 133 welded pipe lines with proprietary leveling and heat treatment equipment
• In-house NDT and mechanical lab – reduces external dependency and accelerates batch release
• ISO 13485 (medical devices) and national "Specialized and New" Little Giant recognition
• Proven 1000h salt spray resistance – suitable for humid or outdoor installations
• Non-standard sizes and gauges produced without minimum batch restrictions
• Full documentation package – supports audits and regulatory compliance
• Direct factory pricing – no trading margin

Shuangsen Pipe Industry – National High-Tech Enterprise. Building a world-renowned Chinese pipeline brand. Every tube, from 19mm to 165mm OD, reflects 25 years of continuous process refinement and strict hygienic manufacturing discipline.