ﺷﺒﯿﻪ ﺳﺎزي رﻓﺘﺎر ﺧﻮردﮔﯽ ﺣﻔﺮهدار ﺷﺪن ﻓﻮﻻد زﻧﮓ ﻧﺰن 450 CUSTOM ﺑﺎ ﻧﺮم اﻓﺰار ﮐﺎﻣﺴﻮل و روش ﻫﻤﺒﺴﺘﮕﯽ ﺗﺼﺎوﯾﺮ دﯾﺠﯿﺘﺎل

Simulation of pitting corrosion behavior of CUSTOM 450 stainless steel by COMSOL software and DIC method

ﭘﺮهﻫﺎي ﮐﻤﭙﺮﺳﻮر ﺗﻮرﺑﯿﻦ ﮔﺎزي از ﺟﻨﺲ 450 CUSTOM در ﻣﺤﯿﻂﻫﺎي ﮐﻠﺮﯾﺪي دﭼﺎر ﺧﻮردﮔﯽ ﺣﻔﺮهدار ﺷﺪن ﻣﯽﺷﻮﻧﺪ. اﯾﺠﺎد ﺣﻔﺮه و ﺗﺮك در ﭘﺮه و رﺷﺪ آنﻫﺎ ﻣﻨﺠﺮ ﺑﻪ واﻣﺎﻧﺪﮔﯽ و ﺷﮑﺴﺖ ﻣﯽﮔﺮدد. در اﯾﻦ ﻣﻘﺎﻟﻪ ﺑﻪ ﭘﯿﺶﺑﯿﻨﯽ رﻓﺘﺎر ﺧﻮردﮔﯽ ﺣﻔﺮهدار ﺷﺪن در آﻟﯿﺎژ ﻣﻮرد اﺳﺘﻔﺎده در ﭘﺮهﻫﺎي ردﯾﻒ اول ﮐﻤﭙﺮﺳﻮر ﺗﻮرﺑﯿﻦ ﮔﺎزي 6-GEF ﭘﺮداﺧﺘﻪ ﻣﯽﺷﻮد. در اﯾﻦ راﺳﺘﺎ، در ﺑﺨﺶ آزﻣﺎﯾﺸﮕﺎﻫﯽ اﺑﺘﺪا ﻧﻤﻮﻧﻪي ﺧﻤﺶ دو ﻧﻘﻄﻪاي ﺗﺤﺖ ﭘﺘﺎﻧﺴﯿﻞﻫﺎي ﻣﺨﺘﻠﻒ در ﻣﺤﻠﻮل 3/5 درﺻﺪ وزﻧﯽ ﺳﺪﯾﻢ ﮐﻠﺮﯾﺪ ﻗﺮار ﻣﯽﮔﯿﺮد ﺗﺎ در ﻣﺤﻞ ﺧﻤﺶ ﺑﯿﺸﯿﻨﻪ دﭼﺎر ﺧﻮردﮔﯽ ﺣﻔﺮهدار ﺷﺪن و در ﻧﻬﺎﯾﺖ واﻣﺎﻧﺪﮔﯽ ﺷﻮد. ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ آزﻣﻮنﻫﺎي ﻣﺨﺘﻠﻒ ﭘﺘﺎﻧﺴﯿﻮ اﺳﺘﺎﺗﯿﮏ راﺑﻄﻪاي ﺑﺮاي ﭘﯿﺶﺑﯿﻨﯽ زﻣﺎن ﺣﻔﺮهدار ﺷﺪن و ﺗﺨﻤﯿﻦ ﻋﻤﺮ ﻧﻤﻮﻧﻪي ﺗﺤﺖ ﺗﻨﺶ در ﭘﺘﺎﻧﺴﯿﻞﻫﺎي ﻣﺨﺘﻠﻒ اراﺋﻪ ﻣﯽﺷﻮد. در ﻧﻬﺎﯾﺖ ﺑﺎ ﺑﻬﺮهﮔﯿﺮي از روش ﻫﻤﺒﺴﺘﮕﯽ ﺗﺼﺎوﯾﺮ دﯾﺠﯿﺘﺎل، ﮐﺮﻧﺶ در ﺣﻔﺮهﻫﺎي رﺷﺪ ﯾﺎﻓﺘﻪ، ﻣﺤﺎﺳﺒﻪ ﺷﺪه اﺳﺖ. در ﺑﺨﺶ ﻋﺪدي، ﺑﺎ ﺷﺒﯿﻪﺳﺎزي ﺣﻔﺮهﻫﺎي رﺷﺪ ﯾﺎﻓﺘﻪ در ﺑﺨﺶ آزﻣﺎﯾﺸﮕﺎﻫﯽ در ﻧﺮماﻓﺰار ﮐﺎﻣﺴﻮل، ﺗﻮزﯾﻊ ﮐﺮﻧﺶ اﻃﺮاف ﺣﻔﺮه-ﻫﺎ ﺑﻪدﺳﺖ ﻣﯽآﯾﺪ. ﻣﺤﻞ ﮐﺮﻧﺶ ﺑﯿﺸﯿﻨﻪي ﻣﻮﺿﻌﯽ ﺣﺎﺻﻞ از ﺷﺒﯿﻪﺳﺎزي در ﮐﺎﻣﺴﻮل و روش ﻫﻤﺒﺴﺘﮕﯽ ﺗﺼﺎوﯾﺮ دﯾﺠﯿﺘﺎل ﻣﻄﺎﺑﻘﺖ ﺧﻮﺑﯽ ﺑﺎ ﺟﻬﺖ رﺷﺪ ﺣﻔﺮهي ﺧﻮردﮔﯽ در آزﻣﺎﯾﺶﻫﺎي اﻟﮑﺘﺮوﺷﯿﻤﯿﺎﯾﯽ دارد. ﺑﺪﯾﻦ ﺗﺮﺗﯿﺐ ﺑﺪون ﻧﯿﺎز ﺑﻪ آزﻣﺎﯾﺶﻫﺎي ﺗﺠﺮﺑﯽ، ﻣﯽﺗﻮان ﺟﻬﺖ رﺷﺪ ﺣﻔﺮه را ﺷﺒﯿﻪﺳﺎزي ﮐﺮد.

The CUSTOM 450 gas turbine compressor blades are corroded in chlorine environments. The initiation and growth of pits and cracks lead to failure. In this paper, prediction of the pitting corrosion behavior of the alloy is studied. In this regard, in the laboratory section, two-point bending specimen is first subjected to different potentials in a 3.5 wt.% sodium chloride solution to cause pitting corrosion and finally leads to failure at the maximum bending region. According to different potentiostatic tests, an equation is proposed to predict the pitting and life time of stressed sample at different potentials. In the numerical section, the strain in the grown pits is calculated by using digital image correlation method and also the COMSOL Multiphysics software. The location of the localized maximum strain obtained from these two methods is in good agreement with growth of the corrosion pits in the electrochemical experiments. Thus, without needs of experiments, the growth direction of the pit can be simulated.