Furukawa-Sky Review No.9 (April 2013)
技術論文
ろう付加熱後に180℃熱処理したAI-Mn-Cu系合金の粒界腐食感受性
Intergranular Corrosion Susceptibility for AI-Mn-Cu Alloys Subjected to Heat Treatment at 180℃ after Brazing Process
- 大谷 良行
Yoshiyuki Oya - 田中 哲
Satoshi Tanaka - 二宮 淳司
Junji Ninomiya - 土公 武宣
Takeyoshi Doko - 兒島 洋一
Yoichi Kojima
カーエアコンの熱交換器の冷媒がフロン系からCO2へと切り替わると言われている。CO2冷媒の熱交換サイクルにおける温度は最大180℃に達するとされており,Al がこのような熱を受けた場合,粒界腐食の発生が危惧される。前報(本誌,2(2006),35.)において,ろう付後に180℃の熱処理を施したAl-Mn-Cu系合金の粒界腐食感受性に及ぼすCu,Mn添加量の影響および粒界腐食発現機構について報告した。本報では,これに腐食深さの経時変化のデータを追加し再考察するとともに,Al-Mn-Cu系合金の粒界腐食感受性に及ぼす均質化処理条件の影響についても報告する。
The alternation of an air-coditioner refrigerant from a freon-based refrigerant to CO2 is proposed. A maximum temperature in the CO2 heat-exchange cycle approaches to 180℃ after brazing, which might affect susceptibility to intergranular corrosion. In this work, the intergranular corrosion susceptibility of Al-Mn-Cu alloys heat treated at 180℃ after brazing was investigated. In both of the heat treated and non-treated Al-Mn-Cu alloys, Al-Cu intermetallic compounds were observed at grain boundaries, while in the non-treated Al-Mn-Cu alloys, Al-Mn intermetallic compounds also existed at the grain boundaries, being in contact with the Al-Cu compounds. The observation indicates that the Al-Mn compounds promote precipitation of the Al-Cu compounds at the grain boundaries. It also means development of Cu depleted zone along the grain boundaries. However, the intergranular corrosion susceptibility was decreased when the heat-treatment time become longer because Cu solid solubility in the grains decreased down to the same level of the Cu depleted zone. With the Mn concentration, the decreasing rate is accelerated and the time needed to show no susceptibility is shortened.
技術論文 / Technology Articles
- High Strain Rate Blow Formability of Newly Developed Al-Mg-High-Mn Alloy
- Al-Mg-Si系合金の再結晶集合組織形成に及ぼす冷間圧延率の影響
Effect of Cold Rolling Reduction on Development of Recrystallization Textures in an Al-Mg-Si Alloy - ろう付加熱後に180℃熱処理したAI-Mn-Cu系合金の粒界腐食感受性
Intergranular Corrosion Susceptibility for AI-Mn-Cu Alloys Subjected to Heat Treatment at 180℃ after Brazing Process - アルミニウム合金の腐食試験における酢酸の孔食促進効果
Effects of Acetic Acid on Pitting Corrosion Acceleration in Corrosion Tests of Aluminum Alloys - Al-Mn系合金のしきい応力に及ぼすマグネシウム添加の影響
Effects of Magnesium Addition on Threshold Stress of Al-Mn Alloys