Alloy 20, commonly known as UNS N08020 in the United States, is a nickel-iron-chromium-based austenitic alloy. Due to its excellent resistance to sulfuric acid corrosion, it is often colloquially referred to as "sulfuric acid-resistant stainless steel" or "Alloy 20." HT PIPE is a astm b729 uns n08020 Pipe supplier with 15+ export experience. Contact us for more information and quotes for free!
Background of alloy n08020 pipe
Alloy 20 was originally developed to address the corrosion problem posed by sulfuric acid. As early as the 1950s, the rapid development of the global chemical industry placed higher demands on materials. Alloy 20 emerged at the right time, successfully filling the performance and cost gap between ordinary stainless steel and higher-end nickel-based alloys such as Hastelloy.
uns n08020 tubing Core Performance Characteristics
- Resistance to general corrosion and pitting corrosion: Particularly in media such as sulfuric and phosphoric acid, Alloy 20 far outperforms 316L. The addition of copper makes it particularly effective in sulfuric acid at moderate concentrations and temperatures.
- Resistance to stress corrosion cracking (SCC): The high nickel content provides strong immunity to chloride-induced stress corrosion cracking, a Achilles' heel of 316L stainless steel.
- Strong resistance to intergranular corrosion: Stabilized with niobium, it maintains excellent resistance to intergranular corrosion even after exposure within the sensitizing temperature range (450-850°C).
- Mechanical properties and machinability: It possesses high strength and toughness, allowing it to be fabricated, formed, and welded using standard processes.
Alloy 20 vs. 316L vs. 904L
Alloy 20 vs. 316L stainless steel:
Advantages: Corrosion resistance far exceeds that of 316L in sulfuric acid environments, resistance to chloride stress corrosion cracking is significantly enhanced, the addition of copper is a key differentiator.
Alloy 20 vs. 904L stainless steel:
Comparison: 904L (UNS N08904), also a high-alloy austenitic stainless steel, has a higher molybdenum content (~4%) and generally has a higher pitting resistance equivalent (PREN) value than Alloy 20. In pure chloride environments, 904L may have a slight advantage.
Advantages: Alloy 20 contains stabilized niobium, which provides improved resistance to intergranular corrosion, and its copper content offers unmatched value for money in sulfuric acid environments. Alloy 20 is generally more cost-effective than 904L.
