| 摘要 |
PROBLEM TO BE SOLVED: To provide stainless steel in which the effect of suppressing stress corrosion cracks can be maintained over a long period in a radiation exposure environment, and which has increased corrosion resistance. SOLUTION: Cooling conditions after heat treatment are controlled by utilizing liquid sodium, so that a segregated layer in which chromium or molybdenum is concentrated on the grain boundaries of stainless steel is made to improve the corrosion resistance of the stainless steel. Namely, liquid sodium 3 is poured into a vat 1 for sodium, and stainless steel 4 as an object of treatment is immersed into the liquid sodium 3, so that the stainless steel 4 as an object of treatment is quenched with the liquid sodium. Cooling temperature after the quenching is controlled within a temperature-controlled vessel 2. Thus, a segregated layer of chromium or molybdenum can be made in the thickness direction of the grain boundaries of the stainless steel. COPYRIGHT: (C)2003,JPO
|
