If you walk into any factory or commercial kitchen, 70% of the stainless steel you see is Grade 304 (or SUS304 under JIS standards). Although it is the most common grade, from an engineering perspective, it offers the perfect balance of properties. In this article, Trinity Dynamic unpacks the "Technical Specifications" to reveal what exactly makes up Grade 304 and why it is the most cost-effective choice.
1. Chemical Composition
The secret to its rust resistance lies in its "recipe." According to the ASTM A240 standard, the composition for Grades 304 and 304L is specified as follows:
| Element | Type 304 (%) | Type 304L (%) | Primary Function |
|---|---|---|---|
| Chromium (Cr) | 18.0 - 20.0 | 18.0 - 20.0 | Creates the rust-proof film |
| Nickel (Ni) | 8.0 - 10.5 | 8.0 - 12.0 | Increases ductility and formability |
| Carbon (C) | Max 0.08 | Max 0.03 | Strength (Lower in "L" for better welding) |
*To understand which one to choose, read our detailed comparison: 304 vs 304L In-Depth Guide
2. Mechanical Properties
For structural engineers, these values are critical for design calculations:
- Tensile Strength: ≥ 515 MPa (Excellent load-bearing capacity)
- Yield Strength: ≥ 205 MPa
- Elongation: ≥ 40% (Highly flexible, bends without cracking)
- Hardness: ≤ 201 HB (Not overly brittle)
3. Grade 304 Product Forms We Supply
Trinity Dynamic stocks Grade 304 in every shape to meet the demands of any industry:
1. Flat Products (Plates & Sheets)
- 2B Finish: For tanks, kitchenware, flooring
- No.1 Finish: For heavy plates, flanges
- Hairline/Mirror: For architectural decoration
2. Long Products (Bars & Tubes)
- Round Bar: For machined components
- Angle/Flat Bar: For factory structures
- Tubes: Both Industrial (A312) and Ornamental (A554)
Conclusion: Why is 304 the "King of Stainless"?
It represents the perfect intersection of Price and Performance. Unless your application is located near the sea or involves harsh chemicals (which requires Grade 316), Stainless Steel 304 remains the most cost-effective and reliable choice.
Need Mill Test Certificates (MTC) for Grade 304?
We guarantee the quality of our materials. Every production lot comes with verified ASTM A240 / JIS G4305 certificates for 100% traceability.
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