304 Stainless Steel: Performance, Grades, and Full-Scenario Application Analysis
304 stainless steel is the most widely used austenitic stainless steel in the world, accounting for more than 50% of global stainless steel consumption. With balanced performance and moderate cost, it has become the preferred material in household, food, construction, industrial, and other fields. Most people only know it for "rust resistance", but in fact, mastering the details of its grades and performance can help you avoid mistakes when selecting materials.
I. What is 304 Stainless Steel?
304 stainless steel, also known as "18/8 stainless steel", has a core composition of about 18% chromium and 8% nickel. It is an austenitic stainless steel, non-magnetic in the annealed state, easy to process and weld. A self-repairing passive film can be formed on its surface, providing good corrosion resistance.
Its international equivalent grades are clear; you can recognize the following when purchasing: UNS S30400 (USA), EN 1.4301 (Europe), SUS304 (Japan), 06Cr19Ni10 (China).
II. Core Performance of 304 Stainless Steel
The performance of 304 stainless steel is determined by its precise composition ratio. The core components and key mechanical properties are as follows, and all data comply with international standards:
- Core composition: C≤0.07%, Cr 17.50–19.50%, Ni 8.00–10.50%, balancing strength and corrosion resistance;
- Mechanical properties: Tensile strength 515–625 MPa, yield strength 205 MPa, elongation 40%, hardness ≤201 HB, suitable for most processing scenarios;
- Physical properties: Density 7.93 g/cm³, melting point 1400–1450℃, suitable for high and low temperature environments.
III. Core Differences Between 304, 304L, and 304H (Key for Material Selection)
The core difference among the three lies in carbon content, which directly affects welding and high-temperature performance, and they are suitable for different scenarios. The specific comparison is as follows:
| Grade | Carbon Content | Core Features | Typical Applications |
| 304 | ≤0.07% | General-purpose, highest cost-performance | Home appliances, building structures, ordinary industrial pipelines |
| 304L | ≤0.03% | Excellent welding performance | Food equipment, thick plate welded parts |
| 304H | 0.04–0.10% | High-temperature strength | Heat exchangers, pressure vessels |
IV. Main Applications of 304 Stainless Steel and Simple Comparison with 316
304 stainless steel is widely used, with core scenarios including: food and beverage (kitchenware, processing equipment), building decoration (wall panels, railings), industrial equipment (pipes, fasteners), petrochemical industry (non-chloride ion environment).
Comparison with 316 stainless steel: 304 does not contain molybdenum, so its salt and chloride ion resistance is weaker than 316, but its cost is lower; 316 is suitable for corrosive environments such as marine and chemical industries, and 304 is more cost-effective for daily general scenarios.
V. Key Tips: Identification & Maintenance
Avoid counterfeits and extend service life with these simple tips:
Identification: Annealed 304 is non-magnetic; use professional 304 identification reagents or check the manufacturer's material test reports (MTC) to avoid counterfeits.
Maintenance: Avoid contact with corrosive substances (such as bleach, seawater); clean regularly with neutral detergent and a soft cloth, do not use hard steel wool or abrasive cleaners to prevent scratching the passive film.
Frequently Asked Questions (FAQ)
- Q: Is 304 stainless steel food-grade?
- A: Yes, 304 and 304L are widely used in food equipment.
- Q: Can 304 be used outdoors?
- A: It can be used in ordinary atmospheric environments, but not recommended for coastal high-salt environments.
- Q: Is 304 magnetic?
- A: Non-magnetic in the annealed state, magnetic will increase slightly after cold working.