Determination of crack growth rate and threshold for caustic cracking (KIscc) of a cast iron using small circumferential notched tensile (CNT) specimens

✍ Scribed by R. Rihan; R.K. Singh Raman; R.N. Ibrahim

• Publisher: Elsevier Science
• Year: 2006
• Tongue: English
• Weight: 495 KB
• Volume: 425
• Category: Article
• ISSN: 0921-5093
• DOI: 10.1016/j.msea.2006.03.095

✦ Synopsis

A novel fracture mechanics technique has been employed for the determination of crack growth rate and threshold stress intensity factor (K Iscc ) for stress corrosion cracking (SCC) using small circumferential notch tensile (CNT) specimens. The technique was applied successfully for testing SCC susceptibility of spheroidal graphite (SG) cast iron in 5 M NaOH at 100 and 120 • C. Crack growth rate of SG cast iron in 5 M NaOH solution at 100 and 120 • C has been determined at different stress intensity factors (K I ), and the K Iscc have been determined to be 11.2 and 9 MPa m 1/2 , respectively. The surfaces of fractured specimens have been examined by scanning electron microscopy (SEM) in order to establish intergranular propagation of stress corrosion cracks. CNT testing is a simple, relatively fast and cost-advantageous approach for generating crack growth rate and K Iscc data.