Sino Steel supplies seamless and welded stainless steel pipe and tube in 201, 304/304L, 316/316L, 309/309S, 321, 2205, 410 and 904 grades. As a stainless steel pipe manufacturer and supplier for project and regular purchasing, we can arrange cutting, end preparation, surface finishing, PMI, testing and export packing through the appropriate manufacturing route.
A clear RFQ starts with the size system already used on the drawing. Stainless steel pipe is often ordered by NPS / DN and Schedule, while stainless tube is commonly ordered directly by outside diameter and wall thickness.
Commonly specified by NPS or DN, Schedule, grade, manufacturing route and length.
Example: NPS 4, SCH 10S, 316L, seamless, 6 m.Commonly specified directly by OD × wall thickness × length, plus surface condition where required.
Example: OD 50.8 × WT 1.5 × 6000 mm, 304 welded tube, polished OD.A professional stainless steel pipe manufacturer does not treat seamless and welded products as interchangeable by default. The standard, size, pressure or service requirement and inspection route determine which factory manufacturing process fits the order.
No longitudinal weld seam. Used where the project or product standard specifies a seamless manufacturing route.
Produced from stainless strip or plate with a longitudinal weld. Weld condition becomes part of factory inspection and final release.
For applicable large welded stainless pipe, manufacturing class and weld inspection are confirmed from the specified standard and project requirement.
Send the grade exactly as written on the drawing or material list. Our supplier and factory review then matches that grade to the correct pipe or tube manufacturing route and applicable standard.
Regular manufacturing and supply grades for general piping, tube fabrication, equipment and project purchasing where these materials are specified.
Supplied as seamless or welded pipe / tube when the project calls for a 316-series stainless material route.
These grades are quoted from the actual temperature, fabrication and project requirement rather than grouped with ordinary 304 factory stock.
2205 follows a duplex pipe route, while 410 and 904 require their own product-standard and manufacturing review.
We keep standard numbers in the technical layer of the page. Buyers can start with grade and size; the manufacturer / supplier review confirms the applicable standard before quotation.
304, 2205 and 410 do not automatically follow the same pipe or tube specification. Product form, manufacturing route and project service conditions still have to match the chosen standard.
You do not need to convert your drawing into another size system before contacting the factory. Send the size in the format already used by your project.
| Buying Format | Example |
|---|---|
| NPS + Schedule | NPS 4, SCH 10S, 316L |
| DN + Wall Requirement | DN100, project wall / schedule specified |
| Metric Pipe | OD 114.3 × WT 3.05 × 6000 mm |
| Tube | OD 38 × WT 1.5 × 6000 mm |
SCH 5S, 10S, 40S and 80S are familiar purchasing designations, but final wall thickness is confirmed from the applicable standard and size.
Available OD, wall thickness and length depend on grade, seamless/welded manufacturing route and order quantity.
Pipe-end preparation affects welding, connection and installation. The manufacturer should receive the end requirement before cutting and final inspection.
Standard cut end for general fabrication or later preparation.
Prepared for welding when the project specifies bevel geometry.
Available for suitable tube / pipe sizes and connection requirements.
Factory cutting can be arranged when the buyer needs finished lengths rather than full production lengths.
A stainless steel pipe supplier may deliver the same grade with very different surface routes. The finish should match the project, fabrication process and final appearance requirement.
Common industrial route for stainless pipe where a clean, pickled mill surface is required.
Available on suitable tubing routes where a brighter, cleaner surface is part of the specification.
Factory polishing or brushing can be arranged where the outside surface remains visible after installation or fabrication.
Used only where a highly reflective surface is specifically required; it is not the default finish for ordinary industrial pipe.
Pickling, passivation and electropolishing serve different purposes from polished or brushed appearance. State the post-fabrication treatment separately on the RFQ.
Used where the manufacturing or fabrication route requires removal of suitable oxide scale, heat tint or surface contamination.
Available when the project calls for passivation of a properly cleaned stainless surface after processing.
Available for projects that specifically require electrochemical surface finishing rather than ordinary mechanical polishing.
Mechanical finish, pickling, passivation and electropolishing should be listed separately when the buyer needs more than one treatment.
Welded stainless pipe leaves the factory only after both pipe geometry and the specified weld inspection route have been reviewed. Not every welded class uses the same NDT or radiography requirement.
Visible weld appearance is checked together with the ordered surface and pipe geometry.
Relevant on applicable welded products where the inside seam affects service, cleaning or flow requirements.
UT, eddy current, radiographic or other testing is applied only when required by the standard, class or project specification.
A supplier should not promise one identical test package for every stainless pipe. The manufacturing standard, pipe class, grade and project requirement define the final test route.
Applied where the product standard or project requirement calls for pressure testing.
Used on applicable seamless or welded routes when required by the standard or buyer specification.
Used on applicable welded-pipe classes where the specified manufacturing route requires it.
OD, wall thickness, length, ovality, straightness, pipe ends and surface remain part of the final factory release check.
PMI helps verify alloy identity. Clean factory handling reduces avoidable contamination after the correct grade has already been produced. Both can matter on stainless pipe projects.
Useful where 304 / 316, 2205, 904 or mixed stainless material creates a real grade-mix risk. PMI does not replace the MTC.
Rusty racks, carbon-steel grinding dust and unsuitable contact surfaces should be kept away from controlled stainless surfaces where practical.
Factory inspection checks the dimensions and geometry that affect fit-up, fabrication and final use.
Mill and manufacturer records should stay connected to the heat number, pipe batch, MTC and finished cut lengths when traceability is required by the order.
The pipe manufacturer, heat identity, finished material and shipment records should remain consistent through the supply chain.
Industrial pickled pipe, polished tube and large-diameter welded pipe do not need the same packing route. A stainless steel supplier should protect the surface and ends the buyer actually ordered.
Suitable bundling, multiple straps, end protection where required and package identification.
Clean separators, sleeves or wrapping can be added where the visible surface needs more protection during transport.
Avoid rough steel-to-steel contact and use cleaner individual protection where the finished surface is especially sensitive.
Individual supports, chocks and appropriate lifting arrangements are selected for pipe size and transport method.
Send grade, seamless or welded route, NPS + Schedule or OD × wall thickness, length, quantity and destination. Add surface finish, pipe end, testing and post-fabrication treatment when required.
Yes, 316L is part of our regular stainless pipe supply. The final manufacturer route depends on the size, standard, seamless/welded requirement and project testing conditions.
Yes. 2205 follows a duplex stainless pipe route. Send the full grade, pipe size, seamless/welded requirement, length, testing and any PMI requirement for review.
Yes. These are separate surface-treatment routes. State them separately from visual finishes such as polished, brushed or mirror surfaces.
No. PMI supports physical alloy identification. The MTC contains broader manufacturer / mill test information for the heat or batch.
Grade, size, manufacturing route, quantity and destination are enough to start. Add pipe end, surface treatment, PMI or testing details when they matter to your project.
