The Workhorse Of Modern Industry:SUS304 Stainless Steel Chemical Composition And Standards
2026-06-27
Introduction: Why SUS304 Remains the Most Widely Used Stainless Steel
SUS304 stainless steel Among all stainless steel grades as the undisputed industry leader. Often synonymously referred to as “18/8 stainless steel” for its nominal composition of 18% chromium and 8% nickel, this austenitic grade has become nearly synonymous with “stainless steel” itself in fields ranging from kitchenware to chemical equipment, construction to medical devices
SUS304 is defined under the Japanese Industrial Standard (JIS) G4303, while its counterpart 304 falls under ASTM A276/A276M (U.S.) and 06Cr19Ni10 under GB/T 20878 (China). Although these designations originate from different standard systems, their compositions and performance characteristics are nearly identical, making them mutually interchangeable in most practical applications
1. Chemical Composition: The Foundation of Performance
The balanced chemical makeup of SUS304 is the foundation of its exceptional corrosion resistance and formability. According to JIS G4303, the standard chemical composition is as follows:
| Element* | Symbol | Content (wt%) |
|---|---|---|
| Carbon | C | ≤0.08 |
| Manganese | Mn | ≤2.00 |
| Silicon | Si | ≤1.00 |
| Phosphorus | P | ≤0.045 |
| Sulfur | S | ≤0.03 |
| Chromium | Cr | 18.00–20.00 |
| Nickel | Ni | 8.00–10.50 |
| Molybdenum | Mo | – (not required) |
2. Physical and Mechanical Properties
Type 304 stainless steel offers a robust combination of strength, ductility, and fabricability. The following data are based on JIS G4303 and supplementary references:
| Property | Value |
|---|---|
| Tensile Strength (σb) | ≥520 MPa |
| Yield Strength (0.2% offset, σ0.2) | ≥205 MPa |
| Elongation (δ5) | ≥40% |
| Reduction of Area (ψ) | ≥60% |
| Hardness | ≤187 HB / ≤90 HRB / ≤200 HV |
| Density (at 20°C) | 7.93 g/cm³ |
| Melting Range | 1398–1454°C |
| Specific Heat (0–100°C) | 0.50 kJ·kg⁻¹·K⁻¹ |
| Thermal Conductivity (100°C) | 16.3 W·m⁻¹·K⁻¹ |
| (500°C) | 21.5 W·m⁻¹·K⁻¹ |
| Coefficient of Thermal Expansion (0–100°C) | 17.2 × 10⁻⁶·K⁻¹ |
| (0–500°C) | 18.4 × 10⁻⁶·K⁻¹ |
| Electrical Resistivity (20°C) | 0.73 × 10⁻⁶ Ω·m²/m |
| Modulus of Elasticity (20°C) | 193 GPa |
These properties enable SUS304 to perform reliably across a wide spectrum of service conditions. The grade retains good ductility and toughness even at cryogenic temperatures, making it suitable for low‑temperature storage and handling equipment. At elevated temperatures, it offers excellent oxidation resistance up to 870°C for intermittent service, though prolonged exposure in the sensitization range (425–870°C) may promote chromium carbide precipitation, which can be mitigated by using the low‑carbon variant 304L or post‑weld annealing
Summary
SUS304 stainless steel has earned its reputation as the most versatile and widely used stainless steel grade through a rare combination of balanced properties: excellent corrosion resistance, outstanding formability and weldability, robust mechanical strength, and cost‑effectiveness. Underpinned by well‑established global standards (ASTM 304, JIS SUS304, GB/T 06Cr19Ni10, EN 1.4301), the alloy serves as a foundational material across nearly every industrial sector.
For international buyers, manufacturers, and engineers, a thorough understanding of SUS304’s compositional nuances, equivalent designations, and performance limits is essential for successful material selection. Given the evolving cost landscape, tightening trade policies, and emerging growth opportunities in green energy and advanced manufacturing, SUS304 remains—and will continue to remain—an indispensable workhorse in the global materials economy.
