Seamless stainless steel pipes supplied by ZEMSS cover 304, 316L and high-temperature grades in fluid-transport and process-piping quality, sourced from major Chinese mills under the GB standard system with full mill documentation (EN 10204 3.1 type, heat-number traceable). From our Taiyuan facility we add cutting-to-length, beveling and end preparation so pipe arrives ready for welding and installation.
Product Specifications
| Parameter | Specification |
|---|---|
| Grades | 304 · 316L · 321 · 310S (other grades on request) |
| Standards | GB/T 14976 (seamless stainless pipes for fluid transport), ASTM A312 equivalent |
| Outside diameter | 6 – 426 mm typical mill range (confirm availability per size) |
| Wall thickness | 1 – 30 mm depending on OD |
| Length | 5.5 – 7 m standard · cut-to-length and beveling available |
| Surface | Pickled & passivated (standard) · as-rolled · polished · bright-annealed on request |
| Certification | Mill test certificate, EN 10204 3.1 type, heat-number traceable |
International Grade Equivalents
Pipes are supplied to Chinese GB standards — the table maps our grades to international designations for your specifications:
| Grade we quote | GB designation | UNS | ASTM (A312 type) | EN number | JIS |
|---|---|---|---|---|---|
| 304 | 06Cr19Ni10 | S30400 | TP304 | 1.4301 | SUS304 |
| 316L | 022Cr17Ni12Mo2 | S31603 | TP316L | 1.4404 | SUS316L |
| 321 | 06Cr18Ni11Ti | S32100 | TP321 | 1.4541 | SUS321 |
Every delivery’s chemistry and mechanical properties are verified against the mill certificate, so an ASTM-specified order is satisfied by the equivalent GB grade with documented proof.
Size Range Overview
| OD range | Typical wall thickness | Typical application |
|---|---|---|
| 6 – 32 mm | 1 – 3 mm | Instrumentation lines, sampling lines, small-bore process piping |
| 33 – 114 mm | 3 – 9 mm | Process and utility piping, food and pharma transfer lines |
| 133 – 273 mm | 4 – 20 mm | Main process headers, chemical transport |
| 299 – 426 mm | 6 – 30 mm | Large headers, special industrial service |
Stock rotates by size — confirm availability with your enquiry; mill-range sizes can be ordered with 3–6 week lead time.
Surface Finish Options
| Finish | Description | Best for |
|---|---|---|
| Pickled & passivated | Mill-scale removed, passive layer restored — the seamless standard | Process piping, corrosion-critical service |
| As-rolled / black | Mill finish, economical | Concealed runs, painted systems, cost-driven projects |
| Polished | Mechanical polish on OD/ID as specified | Food, beverage and pharmaceutical lines, visible installations |
| Bright-annealed | Smooth bright surface from controlled-atmosphere annealing | Hygienic and instrument tubing on request |
Mechanical Properties (annealed, ASTM A312 equivalent)
| Grade | Yield strength ≥ | Tensile strength ≥ | Elongation ≥ |
|---|---|---|---|
| 304 | 205 MPa | 515 MPa | 35% |
| 316L | 170 MPa | 485 MPa | 35% |
| 321 | 205 MPa | 515 MPa | 35% |
Grade Selection Guide: What We Recommend
| Grade | Key characteristics | Choose it when |
|---|---|---|
| 304 | Best cost-performance; good general corrosion resistance; excellent weldability | Water, food and general process lines without chlorides |
| 316L | Molybdenum-alloyed for chloride and acid resistance; low carbon for weld safety | Chemical process lines, coastal plants, pharma and dairy piping |
| 321 | Titanium-stabilized — resists sensitization at elevated temperature | Hot process lines, exhaust and heat-service piping up to ~800 °C |
Typical Applications
- Fluid transport and process piping in chemical and light-industry plants
- Food, beverage and dairy transfer lines (polished finish)
- Pharmaceutical process piping with documented surface quality
- Heat-exchanger and boiler tube circuits (see our heat exchanger products)
- Instrumentation and sampling lines
- Structural and mechanical tubing where welded pipe is not acceptable
Fabrication & Value-Added Services
- Cut-to-length with square or beveled ends for weld fit-up
- Beveling and end preparation to your welding procedure
- Bundling, marking and export packing with heat-number labels matching the certificates
- For plate and profile components in the same order, see our full product range — one supplier, one shipment
FAQ
What standards do the pipes meet?
Seamless pipes are supplied to GB/T 14976, the Chinese national standard for seamless stainless pipes for fluid transport, with mechanical and chemical properties equivalent to ASTM A312 grades. The mill certificate documents the proof.
Do pipes ship with certificates?
Yes — every delivery carries the mill test certificate (EN 10204 3.1 type) with heat-number traceability covering chemistry, mechanical properties and hydro test where applicable.
Can you cut and bevel pipes to my lengths?
Yes. Cut-to-length and weld-bevel preparation are standard services from our Taiyuan facility.
What is the minimum order?
Single lengths can be supplied from stock where available; full-bundle quantities receive mill-direct pricing. Confirm with your enquiry.
Seamless or welded pipe — which should I choose?
Seamless is preferred for high-pressure, high-temperature or critical-corrosion service and where specification excludes weld seams. Welded pipe is economical for low-pressure utility service. Tell us the service conditions and we will recommend honestly.
How to Order
Send OD, wall thickness, grade, quantity and end-preparation requirements — you receive a line-item quotation within two working days with stock confirmation and lead time. Mill certificates travel with every delivery. Request a quote or browse our full product range.
