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GB/T 022Cr19Ni10 Stainless Steel: Chinese Standard Equivalent to AISI 304 for Industrial & Sanitary Applications
GB/T 022Cr19Ni10 stainless steel, designated under China’s national standard (equivalent to international AISI 304/EN 1.4301), represents the most universally applied austenitic stainless steel grade in Chinese industrial sectors. Its optimized 18/8 chromium-nickel composition delivers superior corrosion resistance, cryogenic toughness, and fabrication versatility, making it the primary material choice for food processing, pharmaceutical equipment, and architectural applications. This technical article examines its standardized chemical properties, mechanical performance metrics, production methodologies, and critical application considerations under GB/T 20878 and GB/T 3280 specifications.
1. Standardized Chemical Composition (GB/T 20878-2007)
| Element | Content Range (wt%) | Metallurgical Function |
|---|---|---|
| Carbon (C) | ≤ 0.08 | Minimized to prevent sensitization; ≤0.07% for welded applications |
| Chromium (Cr) | 18.00 – 20.00 | Forms passive Cr₂O₃ film (minimum 10.5% Cr required for stainless classification) |
| Nickel (Ni) | 8.00 – 11.00 | Stabilizes austenitic microstructure; enhances low-temperature ductility |
| Manganese (Mn) | ≤ 2.00 | Improves hot workability; partial Ni substitute in cost-sensitive formulations |
| Silicon (Si) | ≤ 1.00 | Deoxidizer; enhances high-temperature oxidation resistance |
| Phosphorus (P) | ≤ 0.045 | Controlled impurity; excess reduces weldability and toughness |
| Sulfur (S) | ≤ 0.030 | Minimized to prevent hot cracking during welding/fabrication |
| Nitrogen (N) | ≤ 0.10 | Optional addition to stabilize austenite and improve strength |
2. Mechanical Properties at Ambient Temperature (GB/T 3280-2015)
- Tensile Strength (Rm): ≥ 520 MPa (solution-annealed condition)
- Yield Strength (Rp0.2): ≥ 205 MPa (0.2% proof stress)
- Elongation (A): ≥ 40% (50mm gauge length; indicates exceptional formability)
- Hardness (HB): ≤ 201 (Brinell); ≤ 92 HRB (Rockwell)
- Impact Energy (KV2): ≥ 100 J at -196°C (cryogenic toughness for LNG applications)
- Density: 7.93 g/cm³ (standard austenitic stainless steel density)
3. Manufacturing Process Flow
- Melting: Electric arc furnace (EAF) primary melting with AOD (argon oxygen decarburization) refining to achieve ultra-low carbon content and precise alloy composition control.
- Continuous Casting: Produces slabs/blooms with optimized dendrite structure; electromagnetic stirring prevents centerline segregation.
- Hot Rolling: Multi-stand reversing mill at 1100-1250°C followed by water quenching to maintain single-phase austenite structure.
- Cold Rolling: For thin gauges (0.3-6.0mm), 4-high or 6-high mills with intermediate annealing at 1050-1100°C to achieve 2B/BA/No.4 surface finishes.
- Solution Annealing: 1010-1120°C soaking with rapid water quenching to dissolve chromium carbides and restore corrosion resistance.
- Surface Treatment: Pickling in HNO₃/HF mixture (20-70°C) to remove oxide scale; optional electropolishing for sanitary applications.
4. Key Application Sectors
Food & Pharmaceutical Processing
Complies with GB 4806.9-2016 and GB 9684 standards for direct food contact: dairy processing tanks, brewery fermentation vessels, pharmaceutical cleanroom piping, and surgical instrument manufacturing.
Architectural & Structural
Used in exterior cladding (GB/T 3280 2B/BA finishes), handrails, and structural components where atmospheric corrosion resistance (C3-C4 per ISO 9223) is required.
Chemical & Petrochemical
Suitable for mild chemical environments: storage tanks for organic acids, heat exchangers in non-chloride media, and flue gas desulfurization components (operating below 60°C).
Transportation & Automotive
Exhaust system components, railway vehicle interiors, and automotive trim where combination of strength and corrosion resistance is critical (meets GB/T 24511 requirements).
5. Comparison with International Equivalents
| Standard | Designation | Key Carbon Specification | Primary Application Difference |
|---|---|---|---|
| GB/T (China) | 022Cr19Ni10 | ≤ 0.08% C | General-purpose; dominates Chinese domestic market for food/architectural applications |
| AISI/ASTM (USA) | 304 | ≤ 0.08% C | Identical composition; ASTM A240 specifies slightly wider Ni range (8-10.5%) |
| EN (Europe) | 1.4301 | ≤ 0.07% C | Stricter carbon control; preferred for welded structures in EU pressure equipment (PED) |
| JIS (Japan) | SUS304 | ≤ 0.08% C | Common in Japanese automotive and electronics industries; often includes 0.10% N max |
6. Technical Selection Guidelines
- Corrosion Limitations: Avoid continuous exposure to chloride concentrations >200ppm or temperatures above 60°C in chloride environments (risk of pitting/crevice corrosion).
- Welding Procedures: Use ER308/ER308L filler metal; maintain interpass temperature 6mm).
- Surface Finish Selection: 2B for general fabrication, BA (bright annealed) for decorative applications, No.4 for anti-fingerprint architectural panels.
- Certification Requirements: Request GB/T 20878-2007 compliance certificates and mill test reports (MTR) verifying actual vs. specified composition.
- Alternative Grades: For chloride environments, consider GB/T 022Cr17Ni12Mo2 (316 equivalent); for high-temperature (>500°C), use 07Cr19Ni10 (304H equivalent).
7. Request a Technical Quote
For customized GB/T 022Cr19Ni10 stainless steel products—including sheets, coils, pipes, and bars—contact our metallurgical specialists. We provide full certification packages (GB/T 20878, EN 10204 3.1) and technical support for your specific application requirements.
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