SEDL / STP / STP770-EB / STP32439S

Fatigue Crack Initiation of Cr-Mo-V Steel in High-Temperature Environment

Wada, K
Mitsubishi Heavy Industries Ltd., Sagamihara Machinery Works, Sagamihara,

Iino, Y
Associate Professor, Toyota Technological Institute, Nagoya,

Suzuki, M
Professor, Toyota Technological Institute, Nagoya,

Pages: 14    Published: Jan 1982

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Abstract

The fatigue crack initiation behavior of chromium-molybdenumvanadium steel in high-temperature air and steam was studied in respect with the cyclic frequency and oxygen concentration in the surrounding atmosphere. Fatigue tests were conducted at 565°C in air and steam at frequencies of 10, 1, and 0.1 cpm. The number of cycles to crack initiation was determined by the potential drop technique. It was found that the fatigue life to crack initiation is significantly reduced by decreasing frequency. At a low cycling frequency, the oxygen concentration determines the reduction of cycles to crack initiation. In the case of crack initiation related to inclusions, the reduction of number of cycles to crack initiation is remarkable.