Alloy 28，Incoloy 028 ，UNS N08028,E FORU

British Specs:，American Specs:，German Specs:WS 1.4563

**Product Name:** Alloy 28 / Incoloy® 028 | UNS N08028 **Material Type:** Nickel-Iron-Chromium-Molybdenum Austenitic Stainless Steel **Standard:** ASTM B668, B690, B464 | ASME SB668, SB690, DIN 2.4603, EN 1.4563 --- ### **Overview** Alloy 28 (UNS N08028), commercially known as **Incoloy® 028**, is a nickel-iron-chromium-molybdenum austenitic stainless steel specifically designed to resist corrosion in sulfuric acid and other aggressive chemical environments. With high chromium and significant molybdenum content, this alloy offers superior resistance to pitting, crevice corrosion, and stress corrosion cracking, making it ideal for chemical processing, oil and gas, and pollution control applications. --- ### **Key Advantages** - **Excellent Sulfuric Acid Resistance:** Superior performance in sulfuric acid environments - **Outstanding Chloride Resistance:** Enhanced resistance to pitting and crevice corrosion - **Good Stress Corrosion Cracking Resistance:** Suitable for chloride-containing environments - **Enhanced Molybdenum Content:** Provides superior localized corrosion resistance - **Excellent Fabricability:** Good weldability and formability characteristics - **High Temperature Capability:** Maintains strength and corrosion resistance at elevated temperatures --- ### **Chemical Composition (Typical Weight %)** | Element | Content (%) | Element | Content (%) | |---------|-------------|---------|-------------| | Nickel (Ni) | 29.0-32.0 | Chromium (Cr) | 26.0-28.0 | | Iron (Fe) | Balance | Molybdenum (Mo) | 3.0-4.0 | | Copper (Cu) | 0.6-1.4 | Manganese (Mn) | ≤2.0 | | Silicon (Si) | ≤1.0 | Carbon (C) | ≤0.03 | | Nitrogen (N) | 0.15-0.25 | Phosphorus (P) | ≤0.03 | | Sulfur (S) | ≤0.03 | | | --- ### **Physical & Mechanical Properties** #### **Physical Properties** - **Density:** 8.0 g/cm³ (0.289 lb/in³) - **Melting Range:** 1370-1400°C (2500-2550°F) - **Thermal Expansion Coefficient:** 15.5 × 10⁻⁶/°C (20-100°C) - **Modulus of Elasticity:** 200 GPa (29 × 10⁶ psi) - **Thermal Conductivity:** 12.0 W/m·K at 100°C - **Specific Heat Capacity:** 450 J/kg·K at 100°C #### **Mechanical Properties (Annealed Condition)** | Property | Typical Value | |----------|---------------| | Tensile Strength | 600-750 MPa (87-109 ksi) | | Yield Strength (0.2% Offset) | 300-400 MPa (44-58 ksi) | | Elongation | 35-50% | | Hardness | 170-220 HB | | Impact Strength (Charpy V) | ≥100 J (74 ft-lb) | --- ### **International Standards & Certifications** - **UNS:** N08028 - **ASTM/ASME:** B668/SB668, B690/SB690 - **EN:** 1.4563 (X1NiCrMoCu31-27-4) - **DIN:** 2.4603 - **ISO:** 15156-3 (NACE MR0175) - **Certifications:** NACE MR0175, PED 2014/68/EU --- ### **Applications** #### **Chemical Processing Industry** - Sulfuric acid production equipment - Phosphoric acid evaporators and heat exchangers - Chemical reactors and process vessels - Acid concentration systems - Piping systems for aggressive chemicals #### **Oil & Gas Industry** - Downhole tubing and casing - Heat exchangers in refining operations - Process piping in sour service - Offshore platform components - Flue gas desulfurization systems #### **Pollution Control** - Flue gas desulfurization (FGD) systems - Scrubbers and absorbers - Waste water treatment equipment - Chemical waste processing #### **Pulp & Paper Industry** - Digester vessels - Bleaching equipment - Chemical recovery systems #### **Industrial Applications** - Heat exchangers - Condensers - Evaporators - Industrial furnace components --- ### **Corrosion Resistance** #### **Chemical Resistance** - **Excellent:** Sulfuric acid (various concentrations and temperatures) - **Good:** Phosphoric acid, nitric acid, organic acids - **Resistant:** Chloride pitting and crevice corrosion - **Limited:** Hydrochloric acid, hydrofluoric acid #### **Special Features** - High chromium content provides excellent oxidation resistance - Molybdenum enhances resistance to localized corrosion - Copper addition improves resistance to sulfuric acid - Balanced composition for wide range of corrosive environments --- ### **Fabrication Characteristics** #### **Welding** - **Recommended Methods:** GTAW, GMAW, SMAW - **Filler Metals:** Alloy 28, ERNiCrMo-4, ENiCrMo-4 - **Preheat:** Not required - **Post-Weld Heat Treatment:** Generally not necessary #### **Machining** - **Machinability:** Similar to other austenitic stainless steels - **Tooling:** Positive rake angles recommended - **Coolant:** Essential for optimal tool life - **Speeds:** Moderate speeds with good feed rates #### **Forming** - **Cold Working:** Good capabilities - **Hot Working:** 1150-1250°C (2100-2280°F) - **Annealing:** 1150-1200°C (2100-2190°F) followed by rapid cooling --- ### **Product Forms Available** - Plate, Sheet, and Strip - Bar and Wire - Pipe and Tubing - Fittings and Flanges - Forgings - Welding Consumables --- ### **Quality Assurance** #### **Testing & Certification** - Chemical analysis certification - Mechanical property testing - Corrosion testing per ASTM G48 - Non-destructive examination - Full material traceability #### **Quality Standards** - Mill test certificates to EN 10204 3.1/3.2 - NACE MR0175/ISO 15156 compliance - PED certification for pressure equipment - ISO 9001 Quality Management --- ### **Design Allowable Stresses** | Temperature (°C) | Maximum Allowable Stress (MPa) | |------------------|-------------------------------| | -29 to 38 | 138 | | 100 | 138 | | 150 | 130 | | 200 | 122 | | 250 | 115 | --- ### **Conclusion** Alloy 28/Incoloy® 028 represents a premium choice for applications requiring exceptional corrosion resistance in sulfuric acid and chloride-containing environments. Its balanced composition of nickel, chromium, molybdenum, and copper provides superior performance in aggressive chemical processing, oil and gas, and pollution control applications. The alloy's excellent fabrication characteristics combined with its proven reliability make it an ideal material for critical equipment operating in the most demanding corrosive conditions. --- *Incoloy® is a registered trademark of Special Metals Corporation. All technical data are typical values and should be verified for specific applications. Consult manufacturer's specifications for project-specific requirements and applicable codes and standards.*

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 2690 gallon liquid totes Special package is available on request.