Effect of Austenite Grain Size and Cooling Rate on the Formation of Acicular Ferrite in SM570 Steel
碩士 === 國立成功大學 === 材料科學及工程學系 === 102 === The study is divided into two parts experiment, first one is simulation of the heat affected zone of welding process and calculate the equation of austenite grain size and holding time. Second, simulate the different cooling rate and observe the acicular ferri...
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| Format: | Others |
| Language: | zh-TW |
| Published: |
2014
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| Online Access: | http://ndltd.ncl.edu.tw/handle/37033585784391403993 |
| Summary: | 碩士 === 國立成功大學 === 材料科學及工程學系 === 102 === The study is divided into two parts experiment, first one is simulation of the heat affected zone of welding process and calculate the equation of austenite grain size and holding time. Second, simulate the different cooling rate and observe the acicular ferrite and calculate the volume proportion of each phase. The heat treatment process was designed to get the proper microstructure. OM analysis was checked the AF structure. EDS analysis identify the inclusion type. EBSD reconfirm the AF structure. By heat treatment experiment to simulate HAZ and observe growth of austenite grain size, we can construct the austenite grain growth equation of austenite grain size v.s holding time. Simulating various cooling rates, we can find that most appropriate cooling rate for the formation of acicular ferrite is air cooling. AF has a characteristic that the value of KAM will be relatively large, and the peak value at around 0.4.
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