Effect of Water Vapor Pressure on Environment Embrittlement of Spheroidal Graphite Cast Iron.
Grant-in-Aid for Scientific Research (C).
|Research Institution||Muroran Institute of Technology|
田中 雄一 室蘭工大, 工学部, 教授 (20002892)
OSAFUNE Yasuhiro Dept. of Eng., Research Associate, 工学部, 助手 (30241409)
|Project Fiscal Year
1998 – 1999
Completed(Fiscal Year 1999)
|Budget Amount *help
¥3,500,000 (Direct Cost : ¥3,500,000)
Fiscal Year 1999 : ¥1,000,000 (Direct Cost : ¥1,000,000)
Fiscal Year 1998 : ¥2,500,000 (Direct Cost : ¥2,500,000)
|Keywords||Spheroidal graphite cast iron / Hydrogen embrittlement / Environment embrittlement / Water vapor / ADI / Water embrittlement / 球状黒鉛鋳鉄 / 水素脆性 / 環境脆化 / 水蒸気 / オーステンパ球状黒鉛鋳鉄 / 水脆化 / 水蒸気分圧 / 破壊靭性 / 疲労試験|
"Water embattlement" phenomenon under the steam circumstance in the high strength nodular graphite cast iron was examined. The following results were obtained.
The embattlement phenomenon by the water was remarkable with the high strength nodular graphite cast iron (pearlite, martensite, austempering nodular graphite cast iron).
After plastic deformation is done in the water adhesion condition, increase in hydrogen volume is confirmed as a result of doing hydrogen analysis, and it is considered that this embattlement is attributable to the hydrogen brittleness.
(1) Tensile characteristics in the vacuum are higher value than the atmosphere inside of the drying condition (humidity of 0%).
(2) Tensile characteristics decline in accordance with the rise in the steam pressure. But, that decline volume is small in comparison with the water adhesion condition.
(3) The critical steam pressure which the embattlement of the grade which was the same as the water adhesion condition evaluated didn't exist.
Tensile strength in the drying and wet (more than humidity of 95%) hydrogen gas atmosphere was examined. The following results were obtained.
(1) Wet hydrogen gas atmosphere embattles more remarkably than dry hydrogen gas.
(2) The effect to the embattlement of the strain rate is small.
(3) There is critical exposure time in the inside of the atmosphere which evolutes embattlement.
(4) Graphite in the cast iron affects in the remarkable embattlement phenomenon in wet hydrogen gas.
Research Output (18results)