Hydrogen Embrittlement of Boron-Modified Supermartensitic Stainless Steel
Arthur de Bribean Guerra1,2,3, Daniel Brito Bertoldi1,2, Guilherme Zepon1,2
1Department of Materials Science and Engineering, Federal University of São Carlos, Rod. Washington Luís, São Carlos, SP CEP 13565-905, Brazil.
Abstract:
Supermartensitic stainless steels (SMSS) reinforced with a percolated boride network offer exceptional corrosion and wear resistance, making them well-suited for oil and gas applications. However, hydrogen embrittlement (HE) poses significant challenges in offshore environments. This study examines HE in SMSS with boron additions ranging from 0.3 to 0.7 wt %. Samples were subjected to hydrogen charging at -1.3 VSCE, 43 mA/cm2 for 168 h in a 3.5 wt % NaCl solution, followed by slow strain rate tensile testing. While boron additions improved tensile strength, they severely reduced ductility. After hydrogen charging, mechanical degradation intensified, with SMSS-0.7%B experiencing >55% reduction in tensile strength and elongation. All boron-rich alloys displayed brittle intergranular fractures caused by M2B borides at the grain boundaries. HE impacted both the martensitic matrices and borides, with fractures initiating in boride-rich regions and propagating via secondary cracks. These results underscore a synergistic embrittlement mechanism and emphasize the importance of optimizing microstructures to enhance hydrogen resistance in boron-reinforced SMSS.
Related Concept Videos
01:18Mechanical Characteristics of Steel
The tension test is fundamental for determining tensile strength. In this test, a steel specimen is stretched using a gripping device until it breaks. The data collected during this test are used...
03:08Hydroboration-Oxidation of Alkenes
02:36Regioselectivity and Stereochemistry of Hydroboration
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn...
02:15Preparation of Alcohols via Addition Reactions
The acid-catalyzed addition of water to the double bond of alkenes is a large-scale industrial method used to synthesize low-molecular-weight alcohols. An acidic atmosphere is required to allow the hydrogen in the water molecule to act as an electrophile and attack the double bond in an alkene. The addition of a proton to the double bond creates a carbocation intermediate. The proton preferentially bonds to the less substituted end of the double bond to create a more stable carbocation...
01:27Corrosion of Reinforcement
However, over time and under certain conditions like carbonation, chloride ingress, and cracking this protective state can be compromised. Steel has areas with...
01:12Temperature Dependent Deformation