Hastelloy C22 (UNS N06022) and Alloy 20 (UNS N08020) represent two different solutions for dealing with severe corrosive environments. Although both alloys belong to the category of nickel-based corrosion-resistant materials, they have significant differences in composition design philosophy, microstructural characteristics and basic physical properties.
Alloy 20 and alloy c22 plate Physical and Mechanical Properties
nickel alloy 20 and nickel alloy c22 Density
Hastelloy C22 has a higher density (8.69 g/cm³), which is about 8.6% higher than Alloy 20's 8.00 g/cm³. This property means that C22 sheet has a greater weight for the same volume.
UNS N08020 Plate and UNS N06022 Plate Thermal Properties
In terms of thermal properties, the melting point range of C22 (1325-1370°C) is slightly higher than Alloy 20 (about 1390°C), but the thermal expansion coefficient of Alloy 20 (8.16×10⁻⁶/°C) is slightly lower than C22 (about 9.0×10⁻⁶/°C) at 70°F. This means that Alloy 20 may show better dimensional stability in temperature fluctuation environments.
hast. c22 plate and alloy 20 sheet Room temperature mechanical properties
Hastelloy C22 plate has higher strength properties in the solution annealed state, and its minimum tensile strength (≥690 MPa) and yield strength (≥310 MPa) are significantly higher than Alloy 20 (551.6 MPa tensile strength, 241.3 MPa yield strength). However, Alloy 20 shows better ductility, and its elongation at break can reach 50%, which is higher than C22's 45%.
n08020 plate and n06022 sheet Chemical composition comparison
| Element | Hastelloy C22 | Alloy 20 |
| Ni | ≥56 | 32.5-35.0 |
| Cr | 20.0-22.5 | 19.0-21.0 |
| Mo | 12.5-14.5 | 2.0-3.0 |
| W | 2.5-3.5 | - |
| Fe | 2.0-6.0 | - |
| Cu | - | 3.0-4.0 |
| Nb | - | ≥1.0 |
c22 alloy and 20 alloy plate Comprehensive corrosion performance comparison
Sulfuric acid environment: In sulfuric acid with a concentration of ≤70%, Alloy 20 shows excellent corrosion resistance, and the corrosion rate is usually less than 0.1 mm/year. However, in a boiling 10% sulfuric acid environment, the corrosion rate of Alloy 20 will increase significantly to more than 0.5 mm/year, while Hastelloy C22, with its high molybdenum content, can maintain an extremely low corrosion rate of ≤0.1 mm/year.
Hydrochloric acid and other reducing acids: In reducing acid environments, in hydrochloric acid containing chloride (≥1000 ppm) (temperature ≤50°C), the corrosion rate of C22 is ≤0.3 mm/year. For mixed acid environments, the high alloy composition of C22 provides a wider safe operating window, while Alloy 20 may face serious corrosion risks.
alloy 20 steel plate and n06020 steel plate Localized corrosion resistance
Pitting and crevice corrosion: Hastelloy C22 has a critical pitting temperature (CPT≥85°C) and a critical crevice corrosion temperature (CCT≥65°C) that far exceeds Alloy 20 (CPT is about 35-40°C). In seawater or high chloride ion environments, C22 plates can be safely used in conditions below 85°C, while Alloy 20 is only suitable for environments below 50°C.
Stress Corrosion Cracking (SCC): Hastelloy C22 showed no signs of cracking in 25% NaCl + 0.5% H₂S solution at 80°C tested according to NACE TM0177 standard. Alloy 20 relies on its 33% nickel content to provide good resistance to chloride ion stress corrosion, which is better than 304/316 stainless steel, but it may still crack in high temperature (>80°C) and high concentration chloride environment.
astm alloy 20 plate and astm hastelloy c22 High temperature corrosion and special environment
Oxidizing media: Hastelloy C22 is one of the few materials that can resist corrosion in strong oxidizing environments such as wet chlorine, hypochlorite or chlorine dioxide. Alloy 20 may corrode excessively in similar environments, especially at high temperatures.
High temperature stability: In an air environment at 600°C, Hastelloy C22 exhibits excellent oxidation resistance, with an oxidation weight gain rate of ≤0.5 mg/cm²·h2. When exposed to the temperature range of 540-870°C for a long time, no σ phase or μ phase precipitation was observed for C22, and the toughness in the aged state (impact energy ≥ 100 J) remained good. However, when Alloy 20 was used for a long time in the temperature range of 450-850°C, the toughness and corrosion resistance may decrease due to the precipitation of σ phase.
alloy n06022 and carpenter 20 plate cold forming
Alloy 20 has obvious advantages in cold forming processes due to its higher ductility (elongation 50%) and relatively low work hardening rate. In contrast, the high strength and high work hardening rate of Hastelloy C22 require larger tonnage equipment and intermediate annealing treatment during cold forming.
20cb3 material and c22 alloy Hot forming
In the field of hot forming, the recommended processing temperature range of C22 is 950-1200°C, which is narrower than the 900-1170°C range of Alloy 20, and the control requirements are more stringent.
Alloy 20 and Hastelloy c22 Plate Manufacturer, Supplier
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