scholarly journals The Effect of the pH of Ammonum Nitrate Solution on the Susceptability of Mild Steel to Stress Corrosion Cracking (SCC) and General Corrosion

2010 ◽  
Vol 01 (04) ◽  
pp. 191-198
Author(s):  
Fathia S. Mohammed ◽  
Alyaa G. Elramady ◽  
Salheddin E. Abu Yahya
Keyword(s):  
Mild Steel ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Nitrate Solution ◽  
Corrosion Cracking ◽  
General Corrosion

Intergranular microchemistry and stress corrosion cracking

1981 ◽  
Vol 377 (1771) ◽  
pp. 477-501 ◽  
Keyword(s):  
Grain Boundary ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Nitrate Solution ◽  
Corrosion Cracking ◽  
Low Alloy Steels ◽  
Intergranular Stress Corrosion ◽  
Oxidation Potentials ◽  
Alloy Steels ◽  
Impurity Elements

An important contributory role of grain boundary segregation of residual impurities in the intergranular stress-corrosion cracking of carbon and low alloy steels is proposed. Experimental results are presented of the stress corrosion susceptibility of mild steel in nitrate solution, and in relation to varying grain boundary composition as monitored by Auger electron spectroscopy. The harmfulness of a particular impurity element depends on three factors: its bulk level; its segregation thermodynamics and kinetics resulting in an equilibrium enrichment at the grain boundaries; and its ability to promote electrochemical dissolution of the grain boundary. A hierarchy of impurity elements that exacerbate stress corrosion cracking is presented and correlated with equilibrium oxidation potentials. The results and simple model allow the prediction of the relative harmfulness of impurity elements with respect to intergranular stress corrosion in commercial carbon and low alloy steels from a knowledge of the bulk concentration only. This enables significant improvements in performance to be designed in the alloy by respecifying lower levels of only the one or two highly detrimental impurities.

Surface Chemical Factors in the Stress-Corrosion Cracking off Alpha Brass

CORROSION ◽  
1966 ◽  
Vol 22 (6) ◽  
pp. 178-179 ◽  
Author(s):  
H. E. JOHNSON ◽  
J. LEJA
Keyword(s):  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Absolute Temperature ◽  
Corrosion Cracking ◽  
General Corrosion ◽  
Linear Relationships ◽  
Energy Lowering ◽  
Cracking Mechanisms ◽  
Ph Range ◽  
Alpha Brass

Abstract Stress corrosion cracking of alpha brass in ammonia solutions containing copper-ammonia complexes is most rapid in the pH range 6 to 7, where weight loss corrosion is insignificant, Linear relationships were found for (a) log 1/tc (tc = cracking time) vS log Cu++ (initial copper concentration) and (b) l/tc vs 1/T (T = absolute temperature). Oxygen appears necessary for general corrosion and cracking at pH values above 8. Rapid cracking is interpreted in terms of a drastic surface free energy decrease caused by the adsorption of an intermediate copper-zinc- ammonia complex (not yet identified) which is catalytically formed at the brass/solution interface and is surface active. It is suggested also that linear relationships like (a) and (b) above may be distinguishing features of stress corrosion cracking mechanisms which involve surface energy lowering.

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