Effect of K-rate and cathodic protection potential on fracture toughness of the super duplex stainless steel UNS S32750. (15th October 2017)

• Record Type: Journal Article
• Authors: Scheid, Adriano; Sartori, Marcelo; Renck, Tiago; dos Santos, Fabrício Pinheiro; Borges, Marcelo Favaro; Kwietniewski, Carlos Eduardo Fortis
• Is Part Of: Engineering fracture mechanics. Volume 184(2017)
• Page Start: 296
• Page End: 306
• Publication Date: 2017-10-15
• Subjects: K-rate -- Super Duplex Stainless Steel (SDSS) -- UNS S32750 -- Hydrogen Induced Stress Cracking (HISC); Fracture mechanics -- Periodicals; Rupture, Mécanique de la -- Périodiques; Fracture mechanics; Periodicals; 620.112605
• DOI: 10.1016/j.engfracmech.2017.09.019
• Languages: English
• ISSNs: 0013-7944

Abstract

Highlights: Fracture toughness of super duplex stainless steel is largely affected by cathodic potential. Cathodic potential dictates the fracture micromechanism. k-rate influences toughness especially for less cathodic potentials. k-rate alters the intensity of a particular brittle micromechanism. Ferrite is promptly embrittled by hydrogen while austenite is more resistant and it controls the overall fracture behavior. Abstract: Super duplex stainless steels (SDSS) have emerged in the last decade or so as a candidate material to withstand harsh oil and gas production environments. However, documented cases of failure due to hydrogen induced stress cracking (HISC) have raised some concerns. The aim of this investigation is to evaluate the effect of the cathodic protection potential and K-rate on the susceptibility of SDSS to HISC. The results indicated that although the susceptibility to HISC might appear unequivocal, the tests parameters should be carefully considered since they influence dramatically on the results produced. Indeed, for more cathodic electrode potentials stronger is the detrimental effect on fracture toughness while the influence of K-rate is rather weak. However, the influence of this latter parameter becomes more relevant when the applied electrode potential is less negative.