What is the difference between SUS316 and SUS304?

When selecting stainless steel for industrial, marine, or food-grade applications, SUS316 and SUS304 are two of the most common choices. While both are austenitic stainless steels with excellent corrosion resistance, there are key differences in chemical composition, performance, and cost that can directly affect your project's lifespan and efficiency.

 

 

What is SUS304 stainless steel?

SUS304 is a Japanese Industrial Standard (JIS) designation for 304 austenitic stainless steel, commonly known as 18/8 stainless due to its composition of roughly 18% chromium and 8% nickel. It is the most versatile, widely used, non-magnetic stainless steel, renowned for excellent corrosion resistance, high durability, and good formability in food, chemical, and household applications.

 

What does SUS316 mean?

SUS 316 refers to a Japanese Industrial Standard (JIS) grade of austenitic stainless steel, equivalent to AISI 316. It is a high-performance, marine-grade, and corrosion-resistant steel alloy (containing 16-18% chromium, 10-14% nickel, and 2-3% molybdenum) commonly used for its superior resistance to chlorides and acidic environments, such as in marine, chemical, and medical applications.

 

 

SUS316 vs. SUS304：Chemical Composition 

SUS304 contains 18% chromium and 8% nickel, while SUS316 contains 16% chromium, 10% nickel, and 2% molybdenum. This molybdenum content in SUS316 significantly enhances its corrosion resistance, particularly in chloride-rich environments, making it more suitable for marine applications and chemical processing.

Grade	Chromium (Cr)	Nickel (Ni)	Molybdenum (Mo)	Carbon (C)	Manganese (Mn)	Other Elements
SUS304	18.0–20.0%	8.0–10.5%	-	≤0.08%	≤2.00%	Si ≤1.00%, N ≤0.10%
SUS316	16.0–18.0%	10.0–14.0%	2.0–3.0%	≤0.08%	≤2.00%	Si ≤1.00%, N ≤0.10%

 

SUS316 vs. SUS304: Mechanical Properties

Property	SUS304	SUS316
Tensile Strength (MPa)	≥ 520	≥ 520
Yield Strength (MPa)	≥ 205	≥ 205
Elongation (%)	≥ 40	≥ 40
Density (g/cm³)	7.93	7.98
Max Operating Temp (°C)	~870	~870

 

Are SUS304 and SUS316 magnetic?

SUS304 and SUS316 are primarily non-magnetic austenitic stainless steels in their annealed state, as their high nickel content stabilizes a non-magnetic crystal structure. However, they can exhibit weak magnetism, especially after cold working, machining, or welding, which causes partial conversion to magnetic martensite, with 304 often being slightly more susceptible than 316.

 

Can SUS304 and SUS316 be welded easily?

Yes, both SUS304 and SUS316 stainless steels can be welded easily, as they are austenitic, highly malleable, and possess excellent welding characteristics using common methods like TIG or MIG. They do not require post-weld heat treatment, though using appropriate fillers is necessary to maintain corrosion resistance in the welded zone.

 

What's the temperature limit for SUS304 and SUS316?

The maximum continuous service temperature for SUS304 and SUS316 stainless steels is typically between 870°C and 925°C (1598°F to 1697°F), above which their oxidation resistance is affected. Although their high-temperature limits are similar, SUS316 has slightly better high-temperature strength, while both are suitable for low-temperature environments down to approximately -200°C (328°F).

 

Is SUS316 worth the extra cost compared to SUS304?

SUS316 is generally worth the extra 20–40% cost over SUS304 if the application involves exposure to salt (marine environments, coastal areas), harsh chemicals, or high acidity, due to superior corrosion resistance from molybdenum. For general, indoor, or non-corrosive uses, SUS304 is more cost-effective and sufficient.

 

How to choose between SUS316 and SUS304?

If you need economical, general-purpose stainless steel for indoor, dry, or mild environments (e.g., kitchen equipment, food processing, decorative panels), choose SUS304.If your application involves saltwater, chemical processing, or high-chloride environments (e.g., offshore platforms, desalination plants, chemical storage tanks), choose SUS316.

 

Why Choose GNEE 

GNEE supplies both SUS304 and SUS316 stainless steel in multiple product forms, including coils, sheets, pipes, profiles, and custom parts, all meeting ASTM, JIS, and EN standards.
We offer:

Thickness: 0.3mm – 80mm

Width: 1000mm / 1219mm / 1500mm / 1800mm or customized

Surface: 2B, BA, No.4, HL, Mirror, Embossed, Tread

Processing: Laser cutting, bending, punching, welding

MOQ: Flexible for bulk and trial orders

Fast Delivery: Stock available for standard sizes

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