A quick explanation of the stainless steel grades commonly seen at the workshop, their main composition and where they are suitable.
When you receive a quote for a gate or railing, you will see numbers like 201, 304, 316 and 430. These are stainless steel grades under a widely used classification system. A basic understanding helps you talk with the workshop with more confidence.
201 stainless steel
Austenitic family with low nickel content, compensated by manganese and nitrogen. Cheaper, with fairly good hardness. Its corrosion resistance is lower than 304 in humid, salty environments.
Commonly used for: indoor railings, frames and shelves; budget projects in dry places.
304 stainless steel
The most common austenitic grade, containing about 18% chromium and 8% nickel (nominal figures per the standard). It resists rust well under ordinary conditions, is easy to fabricate and weld, and has a good-looking surface.
Commonly used for: outdoor gates, railings and staircases, kitchen sinks, and equipment in contact with food.
316 stainless steel
Like 304 but with added molybdenum, so it resists salt and chemicals better. More expensive.
Commonly used for: coastal projects, brackish water, chemical environments, and salted food processing.
430 stainless steel
Ferritic family, containing chromium but almost no nickel. It is magnetic, low-priced, with moderate rust resistance.
Commonly used for: some household items and indoor cladding panels. Usually not chosen for outdoor gates and railings.
Letters that follow: 304L, 304H, 316L
- L (low carbon): lower carbon content, which limits the loss of corrosion resistance around welds when welding thick material.
- H: higher carbon, used for heat-resistant applications.
For ordinary gates and railings, you do not need to worry much about these suffixes.
Surface designations: 2B, BA, No.4, HL
These are surface treatments, not material grades:
- 2B: smooth cold-rolled surface, slightly matte.
- BA: bright annealed, shiny.
- No.4, HL (hairline): brushed finish that hides fingerprints well.
- Mirror: shiny like a mirror, beautiful but shows scratches easily.
Quick selection
| Conditions | Suggested grade | |---|---| | Indoors, dry, tight budget | 201 | | Ordinary outdoors, townhouse | 304 | | Riverside, seaside, brackish water, chemicals | 316 |
What to ask when you get a quote
- The material grade of each item (frame, bars, accessories).
- The thickness of tubes, box sections and sheets.
- The surface finish (polished, brushed, color-plated).
- Whether material certificates can be provided.
Put this information in the quote to avoid confusion at handover.
- #inox 201
- #inox 304
- #inox 316
- #inox 430
- #vật liệu
