Stress corrosion cracking of high strength steels. Crack propagation mechanism and fracture toughness

Title: Stress corrosion cracking of high strength steels. Crack propagation mechanism and fracture toughness
Author(s): J. Sanchez, J. Fullea, C. Andrade
Paper category : conference
Book title: International RILEM Conference on Advances in Construction Materials Through Science and Engineering
Editor(s): Christopher Leung and K.T. WAN
ISBN: 978-2-35158-116-2
e-ISBN: 978-2-35158-117-9
Publisher: RILEM Publications SARL
Publication year: 2011
Pages: 938 - 944
Total Pages: 7
Nb references: 24
Language: English

Abstract: The stress corrosion cracking (SCC) process is at present a not fully elucidated mechanism of deterioration. It is a surface process that implies a corrosion and stress synergy, but the most practical consequence is that stress corrosion cracking can modify the mechanical characteristics of the metal causing brittle failure. Previously, we present some results about stress corrosion cracking, crack propagation rate or, even, crack arrest conditions in High Strength Steels. This kind of steels is usually used in prestressed and postensioned structures.
These wires are of eutectoid composition and cold drawn. It is well established that failures occur when the wires are in contact with electrolytes of specific compositions while under stress. In the case of concrete, the electrolyte is its pore solution and the stress levels result from the different loads applied due to structural requirements.
In this work we suggest some improvements of the Mechanism of SCC based in the Surface Mobility of vacancies on the crack surface proposed by Galvele. Improvements consist in incorporating the electrochemical corrosion as one of the sources for the creation of vacancies and some mechanical effects, both produce synergic effect in the crack propagation rate and they are important for a more comprehensive explanation of the process.
On the other hand, the Fracture Toughness change when the steel corrodes, questioning the idea that is an intrinsic characteristic of the material. The reduction in the fracture toughness of steel wires when they are in contact to aggressive media involve that the material becomes less damage tolerant, which implies that it is necessary to detect defects of smaller size, as for example, small notch, pits or superficial cracks.

Online publication: 2011-10-31
Publication type : full_text
Public price (Euros): 0.00