High-alloy, high-performance super austenitic stainless steel characterized by pitting resistance equivalent PREN ≥ 40 usually refers to high-alloy, high-performance austenitic stainless steel with a mass fraction of 20-26% Cr, 18-30% Ni, 3-7% Mo, and further alloyed with Cu (≤4%) and N (≤0.5%), with ultra-low carbon, ultra-high cleanliness, and ultra-high uniformity.
The main grades and pitting corrosion resistance equivalents are:
00Cr20Ni18Mo6CuN (254SMO), PREN=43;
00Cr21Ni25Mo6CuN, PREN=48.8;
00Cr25Ni25Mo6CuN, PREN=52.8;
00Cr24Ni22Mo7CuN (654 SMO), PREN=56.1;
This type of super austenitic stainless steel has excellent comprehensive properties, high strength, excellent corrosion resistance in oxidizing and reducing media, resistance to seawater corrosion, resistance to comprehensive corrosion, pitting corrosion and stress corrosion in various chloride media, and good corrosion resistance in sulfuric acid and phosphoric acid.
Super austenitic stainless steel used in supercritical generator sets has excellent high-temperature endurance strength, which solves the problem of stainless steel creep occurring when used for a long time at temperatures above 520-580°C. It has good resistance to flue gas corrosion and steam oxidation, and can meet the use requirements of ultra-supercritical units with parameters of 605-650°C and pressure of 27-35MPa. It is often used as pipes for superheaters and reheaters of direct-current boilers of ultra-supercritical units.
Standard Steel Pipes
