20 Plus Alloy,C 20 Plus Alloy,UNS N08020,super-austenitic alloy,E FORU

### **Product Introduction: 20 Plus Alloy (C-20 Plus, UNS N08020)** **20 Plus Alloy (C-20 Plus, UNS N08020)** is a super-austenitic stainless steel alloy specifically designed to provide exceptional corrosion resistance in severe corrosive environments, particularly in sulfuric acid and other aggressive chemical media. This nickel-iron-chromium alloy with additions of molybdenum and copper represents an enhanced version of earlier 20-type alloys, offering superior performance against pitting, crevice corrosion, and stress corrosion cracking. The alloy's optimized chemical composition delivers outstanding resistance to both oxidizing and reducing chemicals while maintaining excellent fabricability and mechanical properties. The alloy's balanced chemistry provides exceptional versatility across a wide range of temperatures and concentrations, making it particularly valuable for chemical processing, pharmaceutical, and industrial applications where reliability in corrosive service is critical. --- #### **1. Chemical Composition (Weight %)** The typical chemical composition of 20 Plus Alloy per UNS N08020 is as follows: | Element | Content (%) | Element | Content (%) | |---------|-------------|---------|-------------| | **Nickel (Ni)** | 32.0 - 38.0 | **Chromium (Cr)** | 19.0 - 21.0 | | **Iron (Fe)** | Balance | **Molybdenum (Mo)** | 2.0 - 3.0 | | **Copper (Cu)** | 3.0 - 4.0 | **Manganese (Mn)** | 2.00 max | | **Silicon (Si)** | 1.00 max | **Carbon (C)** | 0.07 max | | **Niobium (Cb)** | 8xC - 1.00 | **Sulfur (S)** | 0.035 max | | **Phosphorus (P)** | 0.045 max | **Other Elements** | 0.50 max | --- #### **2. Physical & Mechanical Properties** **Physical Properties:** | Property | Metric Units | Imperial Units | |----------|-----------------|------| | **Density** | 8.08 g/cm³ | 0.292 lb/in³ | | **Melting Range** | 1370 - 1400 °C | 2500 - 2550 °F | | **Thermal Conductivity** | 12.9 W/m·K | 89.4 Btu·in/hr·ft²·°F | | **Coefficient of Thermal Expansion** | 15.9 μm/m·°C | 8.8 μin/in·°F | | **Specific Heat** | 450 J/kg·K | 0.107 Btu/lb·°F | | **Electrical Resistivity** | 0.90 μΩ·m | 540 Ω·cir mil/ft | | **Modulus of Elasticity** | 186 GPa | 27.0 x 10⁶ psi | **Mechanical Properties (Annealed Condition):** | Property | Value | |----------|-----------------| | **Tensile Strength** | 620-690 MPa | 90-100 ksi | | **Yield Strength (0.2% Offset)** | 275-415 MPa | 40-60 ksi | | **Elongation** | 30-50% | | **Hardness (Rockwell B)** | 80-90 HRB | **Elevated Temperature Properties (at 315°C/600°F):** | **Tensile Strength** | 515 MPa | 75 ksi | | **Yield Strength** | 205 MPa | 30 ksi | --- #### **3. Key Characteristics & Product Applications** **Key Characteristics:** - **Exceptional Sulfuric Acid Resistance**: Superior performance across wide concentration and temperature ranges - **Excellent Pitting Resistance**: Outstanding resistance to chloride-induced pitting corrosion - **Good Crevice Corrosion Resistance**: Performs well in stagnant and crevice conditions - **Stress Corrosion Cracking Resistance**: Excellent resistance to chloride stress corrosion cracking - **Versatile Chemical Resistance**: Effective in both oxidizing and reducing environments - **Excellent Fabricability**: Good weldability and formability characteristics **Product Applications:** 20 Plus Alloy serves critical functions in aggressive chemical environments: - **Chemical Processing Industry**: - Sulfuric acid production equipment - Phosphoric acid evaporators - Chemical reactors and vessels - Heat exchangers and condensers - **Pharmaceutical Manufacturing**: - Process equipment and vessels - Mixing tanks and reactors - Pharmaceutical intermediate production - Specialty chemical synthesis - **Petrochemical Industry**: - Acid handling systems - Petrochemical processing equipment - Refinery components - Chemical storage and transportation - **Industrial Applications**: - Pickling equipment and tanks - Acid recovery systems - Industrial heating systems - Pollution control equipment --- #### **4. International Standards & Specifications** 20 Plus Alloy complies with the following international standards: **Primary Specifications:** - **UNS N08020**: Unified Numbering System - **ASTM B463**: Sheet, Strip, and Plate - **ASTM B464**: Welded Pipe - **ASTM B468**: Welded Tube - **ASTM B472**: Nickel Alloy Billets and Bars **International Equivalents:** - **EN**: 2.4660 (NiCr20CuMo) - **DIN**: 2.4660 - **ASME**: SB-463, SB-464, SB-468 - **ISO**: 15156-3 (Corrosion-resistant alloys) --- #### **Summary of Key Advantages** - **Superior Corrosion Performance**: Exceptional resistance to sulfuric acid and other aggressive chemicals - **Enhanced Alloy Composition**: Optimized chemistry for maximum corrosion resistance - **Proven Reliability**: Extensive service history in demanding chemical applications - **Excellent Fabricability**: Good welding and forming characteristics - **Versatile Applications**: Suitable for wide range of corrosive environments - **Comprehensive Standardization**: Meets international quality and performance standards **Technical Note**: 20 Plus Alloy exhibits excellent weldability using matching filler metals and conventional welding processes including GTAW, GMAW, and SMAW. The alloy is not prone to sensitization during welding due to its niobium stabilization, making it suitable for as-welded construction in most applications. Post-weld heat treatment is generally not required. The material demonstrates particularly excellent resistance to sulfuric acid across all concentrations up to boiling temperatures, as well as good performance in phosphoric, nitric, and organic acids. Proper cleaning after fabrication is essential to maintain optimum corrosion resistance. The alloy's copper content provides enhanced resistance to sulfuric acid, while the balanced nickel-chromium-molybdenum composition ensures good general corrosion resistance.

Packing of Standard Packing: Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and steel drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 3183 gallon liquid totes Special package is available on request.