Stress corrosion cracking testing techniques

R.B. Diegle and W.K. Boyd, The Role of Film Rupture during Slow Strain-Rate Stress Corrosion Cracking Testing, Stress Corrosion Cracking—The Slow Strain Rate Technique, STP 665, G.M. Ugainsky and J.H. Payer, Ed., ASTM, 1979, p 26-46... 

Kim, C.D., Wilde, B.E. A review of constant strain-rate stress corrosion cracking test. In Ugianski, GAl., Payer, J.H. (ed.) Stress Corrosion Cracking—The Slow Strain Rate Technique. American Society for Testing and Materials ASTM STP vol. 665, pp. 97-112 (1979)... 

Although not commonly listed as a weld defect, high-welding stress nevertheless provides an essential ingredient to stress-corrosion cracking and other failures. It differs in an important respect from other types of weld defects in that stresses cannot be visually identified or revealed by conventional nondestructive testing techniques. 

Fig. 9.8 Effect of strain rate ductility in SSRT testing for HIC and SCC [20]. Reprinted, with permission, from ASTM STP 665, Stress corrosion cracking - the slow strain rate technique, Copyright ASTM International, West Conshohocken, PA [20],...

R. N. Parkins, Development of strain-rate testing and its imphcations, in G.M. Ugiansky, J.H. Payer (Eds.), Stress Corrosion Cracking— The Slow Strain Rate Technique, ASTM STP 665, ASTM International, West Conshohocken, PA, 1979, pp. 5-25. 

The non-electrochemical techniques include direct immersion of materials samples in the test fluid in either the laboratory or plant. These s lmples sometimes have an artificial crevice generated with a serrated washer. They may be welded to determine the effects of welds and weld heat affected zones. Real-time information can be obtained using electrical resistance probes. Heat transfer effects can be evaluated by having a test sample that is exposed to the corrodent on one side and the other side heated or cooled. Stressed samples are used to evaluate stress corrosion cracking tendencies [33]. 

Even with effective corrosion test programs, many unexpected failures occur in chemical processes. There are several reasons. The corrosion behavior of a material is a combination of the property of the metal (composition and condition) and of the environment. Corrosion can take many forms, from general to localized. An acceptable rate of general corrosion may not translate into successful performance if there is also localized corrosion, such as pitting or stress corrosion cracking. There is no universal corrosion test for all situations, and sometimes a combination of corrosion test techniques may be required to raise one s level of confidence. 

Standard Test Method for Determining Stress-Corrosion Cracking Resistance of Heat-Treatable Aluminum Alloy Products Using Breaking Load Method Standard Practice for Evaluation of Hydrogen UptEike, Permeation, and Transport in Metals by an Electrochemical Technique... 

An experimental technique for evaluating susceptibility to stress-corrosion cracking. It involves pulling the specimen to failure in uniaxial tension at a controlled slow strain rate while the specimen is in the test enviromnent and examining the specimen for evidence of stress-corrosion cracking. 

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