SUS304 vs SUS316 Stainless Steel: Which Is Better for Marine Environments?
Dec 24, 2025
Leave a message
From offshore platforms to shipyards and desalination plants, stainless steel is exposed to chlorides, moisture, salt spray, and biofouling, which can accelerate corrosion if the wrong grade of steel is chosen. The two most common choices are SUS304 (EN 1.4301, AISI 304) and SUS316 (EN 1.4401, AISI 316). Although they appear similar, their alloy compositions differ significantly in terms of resistance to chloride corrosion, directly impacting service life, maintenance costs, and safety.
What is SUS304 Stainless Steel?
SUS304, commonly referred to as 304 stainless steel, is one of the most widely used austenitic stainless steels. It is known for its excellent corrosion resistance, formability, and weldability, making it suitable for a variety of general-purpose applications. However, while SUS304 is durable in many environments, it is less resistant to chloride-induced corrosion compared to SUS316.
Key Features of SUS304:
Corrosion Resistance: Resistant to oxidation and mild corrosive environments.
Formability: Easy to form and weld, making it suitable for complex shapes.
Applications: Used in kitchen equipment, chemical processing, and general industrial applications.
What is SUS316 Stainless Steel?
SUS316, or 316 stainless steel, is an upgraded version of SUS304, with the addition of molybdenum to enhance its corrosion resistance. The molybdenum content gives SUS316 superior resistance to chlorides, making it the material of choice for marine environments where saltwater exposure is a significant concern.
Key Features of SUS316:
Corrosion Resistance: Superior resistance to chloride-induced corrosion, making it ideal for marine and coastal applications.
Durability: High resistance to pitting, crevice corrosion, and stress corrosion cracking.
Applications: Used in marine hardware, offshore platforms, medical devices, and chemical processing.
SUS304 vs SUS316 Stainless Steel: Differences
SUS304 vs SUS316 Stainless Steel: Chemical Composition (Typical Ranges)
|
|
|
|
|---|---|---|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
SUS304 vs SUS316 Stainless Steel:Mechanical Properties (Annealed Condition)
|
|
|
|
|---|---|---|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Which is better for seawater SUS304 or SUS316?
For seawater and marine atmospheres, SUS316 is the better choice because its 2–3% Mo significantly improves resistance to chloride‑induced pitting and crevice corrosion; typical seawater service therefore specifies SUS316 for seawater piping, pumps, valves, and splash‑zone components, while SUS304 is reserved for dry, low‑chloride, or non‑contact areas.
Is SUS316 less corrosive than SUS304 in salty air?
Yes,in salt‑laden atmospheres, SUS316 typically shows lower corrosion rates than SUS304 due to Mo‑stabilized passive films that better resist chloride deposition and pitting; in accelerated ASTM B117 neutral‑salt‑spray testing, SUS316 commonly withstands about 1000 hours with minimal corrosion, whereas SUS304 often shows significant corrosion after around 500 hours under comparable conditions.
SUS304 vs SUS316 price per kg
On average, SUS316 costs about 15–30% more than SUS304 in today's market; reported 2025 domestic plate prices are roughly 18.5 RMB/kg (304) and 28.8 RMB/kg (316), a spread of about +55%, with actual quotes varying by form, size, and mill.
SUS316 stianless steel suppliers
GNEE is a comprehensive enterprise specializing in the wholesale of stainless steel raw materials, integrating trade, processing, warehousing, and transportation. We primarily deal in 304 stainless steel, 304L stainless steel, 316L stainless steel, and other stainless steel plates, coils, strips, and flat bars. We maintain a large inventory of over 1000 tons of materials with a wide range of specifications and ample supply. We also provide various stainless steel processing services according to customer requirements, including leveling, slitting, drawing, mirror polishing, oil grinding, polishing, stamping, bending, straightening, cutting, rolling, and punching.
Send Inquiry