ASTM 304 vs. SUS304: Key Differences in Standards

Key Differences (Chemical Composition)

Origin Standard: ASTM (SS304) vs. JIS (SUS304).

Chromium (Cr): SUS304 (18-20%) vs. SS304 (17.5-19.5%) – SUS304 offers a slightly wider, potentially higher range.

Silicon (Si): SUS304 (≤1.00%) vs. SS304 (≤0.75%) – SUS304 allows for more Silicon.

Carbon (C): Both are low (≤0.08%), crucial for weldability, but ASTM 304 might have a tighter max (0.07%).

Nickel (Ni): Both are nearly identical (8-10.5%).

Key Similarities (Properties & Use)

Grade: Both are Type 304 stainless steel, the most common type.

Corrosion Resistance: Excellent due to high Chromium and Nickel content (18/8).

Weldability: Both offer good weldability.

Applications: General purpose, food processing, kitchenware, architectural.

In Simple Terms:
Think of them as twins from different countries; they look and act almost identically, but their birth certificates (standards) list slightly different tolerances for minor "features" (elements). For most projects, you can use them interchangeably, but for highly specific engineering, check the exact material specification.