GB/T 06Cr17Ni12Mo2 Stainless Steel: High-Performance Austenitic Grade for Corrosive Environments
GB/T 06Cr17Ni12Mo2 (equivalent to AISI 316) is a molybdenum-bearing austenitic stainless steel that offers superior corrosion resistance compared to conventional 304 grades. With a balanced composition of 16-18% chromium, 10-14% nickel, and 2-3% molybdenum, this alloy excels in chloride-rich environments, marine applications, and chemical processing equipment. This technical guide covers its chemical composition, mechanical properties, manufacturing processes, and industry-specific applications.
1. Chemical Composition (GB/T 20878-2007 Standard)
| Element | Content Range | Function |
|---|---|---|
| Carbon (C) | ≤ 0.08% | Minimized to prevent intergranular corrosion during welding |
| Chromium (Cr) | 16.00 – 18.00% | Forms protective Cr₂O₃ passive layer for oxidation resistance |
| Nickel (Ni) | 10.00 – 14.00% | Stabilizes austenitic structure; enhances ductility and low-temperature performance |
| Molybdenum (Mo) | 2.00 – 3.00% | Improves pitting and crevice corrosion resistance in chloride environments |
| Manganese (Mn) | ≤ 2.00% | Enhances hot workability and nitrogen solubility |
| Silicon (Si) | ≤ 1.00% | Improves high-temperature oxidation resistance and deoxidation |
| Phosphorus (P) | ≤ 0.045% | Controlled impurity to maintain toughness |
| Sulfur (S) | ≤ 0.030% | Minimized to prevent hot cracking during fabrication |
2. Mechanical Properties (Annealed Condition)
- Tensile Strength (σb): ≥ 520 MPa (minimum requirement per GB/T 20878)
- Yield Strength (σ0.2): ≥ 205 MPa (ensures structural integrity under load)
- Elongation (δ): ≥ 40% (excellent formability for complex shapes)
- Hardness (HB): ≤ 217 (Brinell hardness; suitable for machining and polishing)
- Impact Toughness (CVN): ≥ 31 J at -196°C (retains ductility in cryogenic applications)
3. Manufacturing Process Overview
- Melting: Electric arc furnace (EAF) + AOD (argon oxygen decarburization) refining to achieve precise alloy composition and low carbon content.
- Hot Rolling: Controlled at 1150-1260°C with rapid water quenching to maintain austenitic structure and prevent carbide precipitation.
- Cold Rolling: For thin gauges (≤ 6mm), multi-pass cold reduction with intermediate annealing at 1050-1100°C to achieve desired surface finishes (2B/BA/No.4).
- Heat Treatment: Solution annealing at 1010-1120°C followed by water quenching to dissolve intermetallic phases and restore corrosion resistance.
- Surface Finishing: Pickling in nitric-hydrofluoric acid mixture, followed by passivation to enhance the chromium oxide layer.
4. Key Application Areas
Marine & Coastal Environments
Shipbuilding components, offshore platform structures, and seawater desalination equipment where chloride resistance is critical.
Chemical & Pharmaceutical Processing
Reaction vessels, storage tanks, and piping systems for handling organic acids, alkalis, and halogenated solvents.
Medical & Food Processing
Surgical instruments, pharmaceutical production equipment, and food-grade processing machinery compliant with FDA/EC 1935/2004 standards.
Architectural & Structural
Exterior cladding, handrails, and structural components in high-humidity or industrial pollution environments.
5. Comparison with Related Grades
| Grade | Key Alloying Element | Primary Advantage | Typical Application |
|---|---|---|---|
| 06Cr17Ni12Mo2 | 2-3% Mo | Superior chloride pitting resistance | Marine, chemical processing, medical |
| 06Cr19Ni10 (304) | No Mo | Cost-effective general-purpose grade | Food equipment, architectural trim |
| 022Cr17Ni12Mo2 (316L) | 2-3% Mo, ≤0.03% C | Weldability without intergranular corrosion | Welded structures in corrosive environments |
| 06Cr17Ni12Mo2N | 2-3% Mo + N | Enhanced strength and corrosion resistance | High-pressure chemical reactors |
6. Selection & Fabrication Guidelines
- Welding Considerations: Use ER316L filler metal for welding; post-weld annealing recommended for maximum corrosion resistance in critical applications.
- Surface Finish Selection: 2B finish for general use, BA for decorative applications, and No.4 for anti-fingerprint requirements in architectural projects.
- Environmental Limitations: Avoid prolonged exposure to temperatures above 425°C to prevent sensitization; not recommended for concentrated sulfuric acid service.
- Quality Verification: Request material test certificates (MTC) confirming compliance with GB/T 20878 and ASTM A240 standards for critical applications.
7. Request a Customized Quote
For precision-cut 06Cr17Ni12Mo2 stainless steel products (sheets, coils, pipes, or custom profiles), contact our technical sales team. We provide mill-certified materials with full traceability and competitive pricing for global industrial projects.