Effect Of Welding Process On Mechanical Properties and Corrosion Behaviour Of Super Duplex Stainless Steels

Abstract

xi newlineABSTRACT newlineStainless steels are engineering materials that can meet a wide range of design requirements. newlineThey are resistant to corrosion, strong at high temperatures, tough at cryogenic temperatures, newlineand cost-effective than other materials. These characteristics made them user-friendly, which newlineresulted in a broad range of possible applications from power generation, manufacturing, newlinetransportation, chemical processing sectors to food handling industry and pharmaceuticals. newlineThey are preferred over many other materials due to their ability to operate in even the most newlinevolatile situations. For applications of stainless steel, welding is the most common method to newlinejoin parts made of stainless steel. However, stainless steel or any metal undergo some newlinechanges during the welding process. Consequently, adequate precautions must be taken to newlineavoid or prevent unfavourable effects that may occur during welding to ensure the level of newlinecorrosion resistance and strength in the weld zone, which is an important aspect of the welded newlinejoint. In welding, micro-segregation, secondary phase formation, solidification newlinecracking causes poor mechanical properties and inferior corrosion resistance. UNS S32750 newlineis a SDSS (super duplex stainless steel) grade, it is widely used in gas industry and newlinepetrochemical processing plant due to its remarkable combination of mechanical characteristics newlineand corrosion resistance. It contains a substantial quantity of chromium, which results in solid newlinesolution strengthening and better corrosion resistance. Even in chloride and sulphur-rich newlineconditions, this alloy shows resistance to severe destructive corrosion forms like pitting. As newlinewelding is used as main fabrication technique for many of the UNS S32750 applications, the newlinemicrostructural changes occur during welding cause the properties of the weldment to differ newlinefrom those of the parent metal. Due to the highly weldable nature of stainless steels, it is newlinepossible to obtain the optimal combination of corrosion resistance and strength of welds. newlineDifferences in metallurgi