摘要
研究了砂型冷却、金属型冷却和水冷冷却条件下,冷却速率对Cr23高铬铸铁凝固组织的影响,以及各试样在热碱(Na OH,80℃)溶液中的腐蚀行为。结果表明:随冷却速度的增加,Cr23中的碳化物和共晶团细化,碳化物分布更加均匀。在不同的冷却速度下,腐蚀速率均先增加后趋于平稳。在碱溶液中的腐蚀初期,在电化学腐蚀作用下形成腐蚀产物,导致腐蚀速率增加。当腐蚀产物聚集在Cr23表面达到一定厚度时,有效地降低了腐蚀速率。冷却速度的提高改善了Cr23的凝固组织,降低了两相(奥氏体与渗碳体)的电位差,减小了腐蚀电流。因而,水冷试样的腐蚀速率最低,砂型试样的腐蚀速率最高。
The influence of cooling rate on the solidified structure of Cr23 high chromium cast iron under cooling conditions of sand mold cooling, metal mold cooling and water cooling was studied, and the corrosion behavior of different samples in hot alkali NaOH solution （80 ℃ ） was investigated. The results show that with the increase of cooling rate, the carbides and eutectic colonies are refmed and the carbides distribution is more uniform＇. The corrosion rate firstly increases and then tends to be stabe under different cooling rates. At initial corrosion in hot alkali solution, the corrosion rate increases because of the formation of corrosion products under the effect of electrochemical corrosion. When the thickness of corrosion product aggregated on the surface of Cr23 cast iron reaches certain value, the corrosion rate is effectively decreased. The increase of cooling rate improves solidified structure of Cr23 cast iron, reduces potential difference between austenite and cementite, and decreases the corrosion current. Therefore, the corrosion rate of water cooling sample is the smallest and the corrosion rate of sand mold cooling sample is the highest.
出处
《热加工工艺》
CSCD
北大核心
2017年第21期68-71,79,共5页
Hot Working Technology
基金
国家自然科学基金项目青年基金(51301115)
材料腐蚀与防护四川省重点试验室开放基金科研项目(2015CL06)
2015年省级大学生创新创业训练计划项目(201510622007)
关键词
高铬铸铁
冷却速率
热碱
NAOH
腐蚀
high chromium cast iron
cooling rate
hot alkali solution
NaOH
corrosion
