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Automatic Measurement of a Crack Propagation Rate in Stress Corrosion Cracking of Type 304 Stainless Steel

1984; Volume: 33; Issue: 11 Linguagem: Inglês

10.3323/jcorr1974.33.11_623

1884-1155

Michinori Takano,

Ultrasonics and Acoustic Wave Propagation

An automatic measuring system of SCC crack propagation rate was developed. Crack length was obtained as a variation of an electric resistance of the specimen, in which the electric resistance was obtained from the voltage measurement under the constane current of 1A. Whole system for the measurement is composed of a personal computer system (PC-8801, PC-8049N, PC-80S 31, PC-8023C), interface system (8255, ADC) and test machines (4 slow strain rate machines). A variation of electric resistance of an 1mm thick Type 304 stainless steel exposed in air at room temperature without stress was within 0.5 micro-ohm. This corresponds to 30-40 micro meter of crack length of the specimen. Stress corrosion test of Type 304 stainless steel was carried out in boilling 42% MgCl2 solution by using a slow strain rate technique. The results showed a good agreement with those obtained in previous studies.