Advantages of duplex steel stainless steel pipes over austenitic stainless steel pipes

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This post was last edited by B0SS on 2017-12-15 at 18:31. Due to its high strength, duplex steel stainless steel pipes can often help save materials, such as by reducing the wall thickness of the pipes. Applications using SAF2205 and SAF2507W as examples. SAF2205 is suitable for chlorinated environments; it can be used in refining or other process media that contain chlorides. SAF2205 is particularly suitable for heat exchangers that use chlorinated aqueous solutions or brackish water as cooling media. This material is also suitable for diluted sulfuric acid solutions, pure organic acids, and their mixtures. For example: oil pipes in the oil and gas industry; crude oil desalination in refineries, purification of sulfur-containing gases, wastewater treatment equipment ； Cooling systems using brackish water or chlorinated solutions. 1. Compared with austenitic stainless steels, 1) its yield strength is more than twice that of ordinary austenitic stainless steels, and it possesses sufficient plasticity and toughness required for shaping. Using duplex stainless steel to manufacture storage tanks or pressure vessels reduces the required thickness by 30-50% compared to conventional austenitic stainless steels, which helps to lower costs. 2) It possesses excellent resistance to stress corrosion cracking, especially in environments containing chloride ions. Even duplex stainless steels with the lowest alloy content exhibit higher resistance to stress corrosion cracking than austenitic stainless steels; stress corrosion is a significant problem that is difficult to address in conventional austenitic stainless steels. 3) The corrosion resistance of 2205 duplex stainless steel, which is the most commonly used in many media, is superior to that of conventional 316L austenitic stainless steel. Super duplex stainless steels possess extremely high corrosion resistance; in some media such as acetic acid and formic acid, they can even replace highly alloyed austenitic stainless steels as well as corrosion-resistant alloys. 4) It possesses good resistance to localized corrosion; compared with austenitic stainless steel pipes with the same alloy content, it exhibits superior performance in terms of wear corrosion and corrosion fatigue resistance. 5) Austenitic stainless steel has a lower linear expansion coefficient compared to carbon steel, and it is close to that of carbon steel; this makes it suitable for bonding with carbon steel, holding significant engineering importance such as in the production of composite sheets or linings. 2. Compared with ferritic stainless steels, the advantages of duplex stainless steels are as follows: 1) Their overall mechanical properties are higher than those of ferritic stainless steels, especially in terms of plasticity and toughness. It is not as sensitive to brittleness as ferritic stainless steels. 2) Except for stress corrosion resistance, its other local corrosion resistances are superior to those of ferritic stainless steels. 3) Its cold working process properties and cold forming properties are far superior to those of ferritic stainless steels. 4) Its weldability is far superior to that of ferritic stainless steels; generally, no preheating is required before welding, nor is heat treatment necessary after welding. 5) Its application range is wider than that of ferritic stainless steels.