Corrosion of iron buried in clay

Sumiyama, Morio*

JNC TJ8400 2000-009, 138 Pages, 2000/02

JNC-TJ8400-2000-009.pdf:3.0MB

To evaluate corrosion behavior of carbon steel, a candidate materials of overpack, buried in soil for a long time, the water pipes buried in freshwater clay for a long time we digged out and the soil environment and the corrosion weight loss of pipes have been researched. From the results, a corrosion model (an empirical equation), an oxygen reduction reaction rate-determing step type, of carbon steel buried in soil was introduced. The corrosion data of under ground pipe collected by the Japan Community Gas Associations was used to increase reliability of the corrosion model equation. These data are one of researches of corrosion behavior of carbon steel buried in soil for a long time studied by at home and abroad. 38 samples buried freshwater clay were selected in 171 samples. With estimating the corrosion velocities and the soil environment factors of the above data, the maximum depth of pit corrosion was calculated by the statistical method of the extreme values using the area of overpack as the recurrent time. The correlation between the soil environment factors and the corrosion weight loss was obtained by the correlation analysis. The corrosion model of the maximum depth of pit corrosion at 0.99 of cumulative probability was compared between the under ground pipe data and the above data. On the reference data and the above data, the corrosion model equation; H = aY was compared with the maximum depth of pit corrosion at 0.99 cumulative probability. The data of water pipes and community gas pipes at 0.99 cumulative probability showed the reasonable values when these data were compared with the reference data. So that the model was proved as a good corrosion model m the neutral low dissolved oxygen environment.

The basic experiment on the high-temperature chemical reaction between sodium compound and iron-base material; Part 2 Structure observations

; Yoshida, Eiichi; Furukawa, Tomohiro; Aoto, Kazumi

PNC TN9410 97-092, 87 Pages, 1997/07

PNC-TN9410-97-092.pdf:3.14MB

This experiment is carried out in the series of the investigation on the damage mechanism of carbon steel. In this paper, the damage situation is considered by structure observations. The test were carried out in 600C-1200C temperature range, in blowing an argon gas. The reagents are NaO, NaO and NaOH. From structure observations, the holes are observed on the surface of iron-base material in some test conditions. This result is indicated that the selective reaction occurs. The selective reaction is more obvious as the time exposed to the high temperature is longer. It is considered that the selective reaction occurs after the chemical reaction between iron-base material and sodium compound. The areas, in which Mn-concentration is higher, are observed in products on the surface of specimen.

None

Sumiyama, Morio*

PNC TJ1451 96-001, 121 Pages, 1996/02

PNC-TJ1451-96-001.pdf:17.3MB

None

None

PNC TJ1150 95-004, 123 Pages, 1995/03

PNC-TJ1150-95-004.pdf:11.72MB

None

None

Ikeda, Shintaro*; Sumiyama, Morio*

PNC TJ1451 94-002, 103 Pages, 1994/02

PNC-TJ1451-94-002.pdf:13.94MB

None

None

PNC TN8420 93-016, 63 Pages, 1993/10

PNC-TN8420-93-016.pdf:1.41MB

None

None

PNC TJ1150 92-002, 403 Pages, 1992/02

PNC-TJ1150-92-002.pdf:0.53MB

None

None

*; *

PNC TJ1369 91-001, 133 Pages, 1991/03

PNC-TJ1369-91-001.pdf:48.99MB

None