Babcock-hitachi Kabushiki Kaisha

Hitachi, Ltd.

Babcock-hitachi K.k.

Nippon Yakin Kogyo Kabushiki Kaisha

Kiyoshi Yamauchi

Shigeo Hattori

Yoshito Fujiwara

Takenori Shindo

Rikio Nemoto

Koichiro Osozawa

Fumio Manabe

Tomoaki Okazaki

Yasuhiro Miura

To provide a method for simply and easily causing only IGSCC to initiate and grow in a specimen, which can retain corrosion resistance through passivation, under atmospheric pressure in a short time, an aqueous solution of potassium tetrathionate is brought into contact with the specimen capable of retaining corrosion resistance through passivation. The potassium tetrathionate concentration, temperature and pH value of the aqueous solution are from 0.3 to 6 wt. %, from 5 to 60&#xb0; C., and from 3 to 6, respectively.

Method of causing intergranular stress corrosion crack to generate and grow in sample

A system of preventive maintenance for plant component parts correlates parameters for determining the transition probability distribution of degradation phenomena, selects an arbitrary influencing factor with respect to each of various influencing factors of the degradation phenomena, selects one of the parameters for the transition probability distribution as a first function, and sets the transition probability distribution when the variables of various influencing factors are reference degree values of a reference system. The system computes a ratio between the first function and the parameter value in the reference system to give a function of the subdivided index of degradation of the influencing factor, multiplies the subdivided index of degradation of various influencing factors by a unit conversion and a coefficient for reliability.

Maintenance systems for degradation of plant component parts

An alloy prepared by reducing the sulfur content of ASTM UNS N06600 (Trademark Inconel Alloy 600) to an extremely small value and adding specified amounts of Nb and N, and an alloy prepared by reducing the oxygen content of Inconel Alloy 600 and adding specified amounts of Nb, N, B and Mg show a mechanical strength equivalent or superior to that of Inconel Alloy 600 and excellent hot workability, and further has intergranular corrosion resistance and integranular stress corrosion cracking resistance which are far more excellent than those of Inconel Alloy 600.

Ni-based alloy excellent in intergranular corrosion resistance, stress

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Kure, Japan

Kiyoshi Yamauchi