Stress Corrosion Cracking of Carbon Steel in Carbonate Solutions

Abstract

From observations of the characteristics of nitrate and hydroxide solutions, known to promote stress corrosion cracking (SCC) in carbon steels, and from the form of potentiodynamic polarization curves and the structural dependence of the corrosive attack, it was predicted that carbonate solutions would also produce intergranular stress corrosion in carbon steels. Constant strain rate stress corrosion tests, with some supplementary constant strain and constant load tests, have shown that intergranular cracking can be made to occur in certain ranges of electrode potential in carbonate solutions over a wide range of concentrations and temperatures with NH4, Na, or K as the cation. The range of potentials for cracking, which varies with solution composition and temperature, is shown to coincide with that range in which polarization curves obtained at different sweep rates indicated marked anodic activity and strong passivating tendencies. At more negative potentials than those that promote intergranular cracking, superficial transgranular fissuring is first detected and then, as the potential is moved toward even more negative values, a progressive loss in ductility is observed due to hydrogen entry into the steel.

Mg and Its Alloys for Biomedical Applications: Exploring Corrosion and Its Interplay with Mechanical Failure

“…From the middle of the 20th century, several metallic materials have been reported susceptible to the synergistic effect of mechanical loads and corrosive medium, leading to corrosion assisted cracking phenomena, i.e., SCC and CF [61][62][63]. These mechanisms result from a simultaneous combination of three factors, susceptible material, corrosive environment and tensile stress.…”

“…Moreover, hydrogen as a corrosion product together with the generation of respective hydrogen pockets can influence the healing process or, if the pockets are large, they may cause death of patients through blocking of the blood stream. Finally, the simultaneous action of the corrosive human-body-fluid and the mechanical loading can cause the further complication of sudden fracture of implants due to corrosion-assisted cracking, such as stress corrosion cracking (SCC) and corrosion fatigue (CF) [61][62][63].…”

Untersuchungen zur interkristallinen Spannungsrißkorrosion unlegierter Stähle in Ammoniumcarbonatlösungen

“…Die interkristalline SpannungsriDkorrosion (SRK) unlegierter Stahle konnte auber in den seit langer Zeit bekannten aggressiven Medien, wie Natronlauge und Nitratlosungen ( 1 -3), in den letzten Jahren in einem erweiterten Kreis von Angriffsmitteln nachgewiesen werden (4)(5)(6). In Nitratlosungen (1,7,8) tritt im gesamten Bereich der Deckschichtbildung SRK auf, wahrend sich in Natronlauge ( 2 , 7 , 9) die SRK nur auf den Bereich der unvollstandigen Bedeckung durch Magnetit beschrankt.…”

“…Die schwarze Deckschicht auf der Stahloberflache selbst konnte rontgenographisch als Fe3 0 4 mit eingelagertem FeC03 identifiziert werden. Erste Untersuchungen von Sutcliffe (4) …”

“…Es ist also durchaus legitim. die Anrisse als einen kerhartigen LochfraR anzusehen, wie auch schon von Su tcliffe( 4 ) angedeu t et wurde. Die von Sutcliffe ( 4 ) und Schwenk ( 10) unter konstanter Dehngeschwindigkeit gefundene SRK-Anfilligkeit von unlegierten Stihlen in Carbonat losungen wird hestiitigt.…”