Which is better, SUS304 or SS 304?

 

SUS304 stainless steel is the designation of the most widely used austenitic stainless steel in the world according to the Japanese Industrial Standard (JIS), equivalent to ASTM 304 in the United States or 1.4301 in Europe. Commonly referred to as 18/8 stainless steel, it contains approximately 18% chromium and 8% nickel. It is generally non-magnetic in the annealed state, but may become slightly magnetic after cold working. Under intermittent use, it can maintain structural integrity at temperatures up to 870°C (1600°F); under continuous use, it can maintain structural integrity at temperatures up to 925°C (1700°F). It can be processed into various practical product forms, including plates, coils, pipes, bars, and wires.

 

 

The global equivalent for SS 304 (Stainless Steel 304) is the European standard EN 1.4301 (or X5CrNi18-10) and the Japanese JIS SUS304. It is also known commercially as 18/8 stainless steel due to its nominal composition of 18% chromium and 8% nickel.

 

 

Feature	ASTM A240 Type 304	JIS G4303 SUS304
Origin	USA (ASTM International)	Japan (Japanese Industrial Standards)
Product Form	Plate, Sheet, and Strip	Stainless Steel Bars
Common Use	Pressure vessels, storage tanks, architectural	Machined parts, fasteners, structural bars

 

SS 304 VS. SUS304 Stainless Steel: Chemical Composition (wt%)

ASTM A240 (SS 304): specifies a Si content ≤ 0.75%, JIS G4304 (SUS304): specifies a Si content ≤ 1.00%. In addition, ASTM usually has a clear upper limit requirement for nitrogen (N) content, while some JIS standards may not require it to be specified.

Element	ASTM A240 SS304	JIS G4304 SUS304
Carbon (C)	≤ 0.08	≤ 0.08
Manganese (Mn)	≤ 2.00	≤ 2.00
Phosphorus (P)	≤ 0.045	≤ 0.045
Sulfur (S)	≤ 0.030	≤ 0.030
Silicon (Si)	≤ 0.75	≤ 1.00
Chromium (Cr)	18.0 – 20.0	18.0 – 20.0
Nickel (Ni)	8.0 – 10.5	8.0 – 10.5
Nitrogen (N)	≤ 0.10	Not Specified

 

SS 304 VS. SUS304 Stainless Steel:Mechanical Properties

Property	ASTM A240 SS304	JIS G4303 SUS304
Tensile Strength (min)	515 MPa (75 ksi)	520 MPa
Yield Strength (0.2% Offset)	205 MPa (30 ksi)	205 MPa
Elongation (in 50mm, min)	40 %	40 %
Hardness (max)	HBW ≤ 201 or HRB ≤ 92	HB ≤ 187 (for solution treated)

 

Is there a difference in corrosion resistance between SS304 and SUS304?

Corrosion resistance primarily depends on the content of chromium (Cr) and nickel (Ni). Since their Cr (18.0-20.0%) and Ni (8.0-10.5%) ranges are exactly the same, they perform identically under the same corrosive environment.

 

SS 304 vs. SUS304 Stainless Steel: Heat Resistance

Both stainless steels offer excellent heat resistance, maintaining high strength and oxidation resistance in elevated-temperature environments. They can withstand continuous service temperatures of up to approximately 870°C and intermittent service temperatures of around 925°C.

Mechanical Properties at Elevated Temperatures

Temperature (°C)	Tensile Strength (MPa)	Yield Strength (MPa)	Elongation (%)
20	≥520	≥205	≥40
100	480	180	38
200	440	160	35
300	400	140	30
400	370	130	25
500	340	120	20
600	310	110	18
700	280	100	15

 

SS 304 vs. SUS304 Stainless Steel: Weldability

Both SS 304 and SUS304 have excellent weldability and can be welded using various techniques, including TIG welding, MIG welding, and arc welding. Their relatively high nickel content helps reduce the risk of heat-affected zone embrittlement, ensuring that mechanical strength is maintained after welding.

 

SS 304 vs. SUS304 Stainless Steel: Formability

Both grades provide good formability and are suitable for stamping, bending, and machining, making them ideal for manufacturing complex-shaped components. Due to its slightly lower work-hardening rate during cold working, SUS304 may offer a small advantage in cold forming applications.

 

SS 304 vs. SUS304 Stainless Steel: Applications

SUS304 is more commonly used in Japan and other Asian markets because it complies with JIS standards. Typical applications include food processing equipment, kitchen sinks and utensils, architectural cladding, and chemical containers.

SS304 is the standard stainless steel grade in North America and Europe and generally complies with ASTM standards. It is widely used in medical and pharmaceutical equipment, food and beverage processing tools, architectural decoration, and household appliances.

 

 

Why is SUS304 more expensive than SS304?

The price difference is usually not due to the "standard" itself, but rather because SUS304 manufactured in Japan may be more expensive due to logistics and brand premiums. It is also more stringent than ASTM in certain dimensional tolerances (such as thickness precision). For precision ultra-thin sheets used in the electronics industry, Japanese standard products often have more detailed requirements.

 

For most industrial applications, these two materials are considered interchangeable. GNEE stainless steels are typically "dual-certified," meaning they meet both ASTM and JIS standards.

ASTM A240 is only applicable to flat products (sheet/plate). If you require the JIS equivalent for sheet materials, please refer to JIS G4304 (hot-rolled) or JIS G4305 (cold-rolled).

 

 

As a specialized supplier, we provide materials featuring "dual certification," complying simultaneously with both the ASTM A240/A276 and JIS G4303/4304/4305 standards. This ensures that your products face no compliance barriers when exported to North American and Asian markets.

 

We maintain a substantial, year-round inventory of 304/SUS304 grade materials in various specifications, ready for immediate dispatch at any time. Global Logistics: We professionally handle all export documentation and offer flexible International Commercial Terms (Incoterms), including FOB, CIF, and DDP.

 

SUS304 Stainless Steel Plate Specifications

Feature	ASTM A240 SS 304	JIS G4304 / G4305 SUS304
Product Form	Plate, Sheet, and Strip	Hot Rolled (G4304) / Cold Rolled (G4305)
Thickness Range	0.3mm – 100mm	0.3mm – 100mm
Standard Finish	2B, BA, No.4, Hairline, No.1	2B, BA, No.4, HL, No.1
Tolerance Standard	ASTM A480	JIS G4304/4305 Standard
Edge Condition	Mill Edge / Slit Edge	Mill Edge / Slit Edge

 

 

Every shipment is accompanied by a Level 3.1 Mill Test Certificate (MTC) and undergoes 100% PMI (Positive Material Identification) testing prior to shipment.

Packaging Services:

We utilize reinforced, seaworthy packaging-such as wooden pallets or crates-to ensure that your goods remain undamaged throughout the entire transit process.