凝固裂紋敏感度的新型評估方法｜國立中央大學博碩士論文系統

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研究生：	劉興穎 Hsing-Ying Liu
論文名稱：	凝固裂紋敏感度的新型評估方法 New-type Evaluation Method for Solidification Cracking Susceptibility
指導教授：	林志光 Chih-Kuang Lin 山本元道 Motomichi Yamamoto 崔正原 Jeong-Won Choi
口試委員:
學位類別：	碩士 Master
系所名稱：	工學院 - 機械工程學系 Department of Mechanical Engineering
論文出版年：	2022
畢業學年度：	110
語文別：	英文
論文頁數：	76
中文關鍵詞：	凝固裂紋、高溫延性曲線、高速攝影、脆性溫度區間
外文關鍵詞：	Solidification cracking, High temperature ductility curve, High-speed imaging, Brittleness temperature range (BTR)
相關次數：	點閱：15 下載：0
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凝固裂紋是焊接過程中的一個重要指標，當熔池尾部的高溫局部應變在焊接過程中，超過其凝固溫度範圍內的焊縫金屬的延性時，此時凝固裂紋便會發生。因此為了準確預測和防止凝固裂紋發生，需要對其凝固溫度範圍內的高溫延性曲線進行定量分析，以便得到高溫延性曲線。凝固裂紋是一種涉及材料和力學因素的複雜行為。如果我們想要有更精確的觀察與預測，就必須使用高速相機或其他異於傳統評估方式以進行預測與評估。

在本研究中，為了得到更高精度的高溫延性曲線來評估凝固裂紋，將使用新的凝固裂紋測試方法測量局部應變及使用4-sensors camera進行溫度測量。採用新的凝固裂紋測試方法搭配適當的拍攝條件，可以精確地計算局部應變。結合溫度測量及應變結果，可以得到更高精度的高溫延性曲線來預測凝固裂紋。根據上述實驗的結果，可以更準確地判斷凝固裂紋的預測及其極限。

Solidification cracking is an important index during welding and it occurs when a high-temperature strain at a molten pool tail exceeds the ductility of weld metal within its solidification temperature range during welding. Therefore, in order to accurately predict and prevent the solidification cracking, it is required to quantitively analyze the high-temperature ductility curve within its solidification temperature range and obtain the high-temperature ductility curves. Solidification cracking is a complicated behavior involved both material and mechanics factors. If we want to have more precise observation, using high speed camera or something different from traditional way must be carried out.

In this research, in order to get more higher-precision high temperature ductility curve to evaluate solidification cracking, new solidification cracking test method and temperature measurement which measured by 4-sensors camera will be carried on. With new solidification cracking test method and optimal shooting conditions, the local strain can be precisely calculated. Combined with temperature measurement result, higher-precision high temperature ductility curve can be gotten to predict the solidification cracking. Based on the results obtained from the mentioned experiments, the prediction of solidification cracking and their limits can be more accurately judged.

LIS OF TABLES……………………………………………………………………………………………………………………VII
LIST OF FIGURES……………………………………………………………………………………………………………VIII
INTRODUCTION……………………………………………………………………………………………………………………1
1 Background………………………………………………………………………………………………………………1
2 Classification of Solidification Cracking……………………………2
3 Mechanism of Solidification Cracking…………………………………………4
4 Purposes……………………………………………………………………………………………………………………7
LITERATURE REVIEW……………………………………………………………………………………………………10
1 Solidification Cracking Literature Review…………………………10
2 Shrinkage-Brittleness and Strain Theory………………………………10
       2.2.1 Shrinkage-Brittleness Theory……………………………………………10
2.2 Strain Theory……………………………………………………………………………………………12
3 Generalized Theory………………………………………………………………………………………13
4 Modified Generalized Theory………………………………………………………………15
5 Technological Strength Theory…………………………………………………………17
6 Commentary on Solidification Cracking Theories……………19
EXPERIMENTAL PROCEDURES……………………………………………………………………………………22
1 Experimental Equipment……………………………………………………………………………22
2 Material and Experiment Conditions……………………………………………27
3 Strain Calculation………………………………………………………………………………………33
4 Temperature Measurement…………………………………………………………………………35
       3.4.1 Temperature Measurement Conditions……………………………37
       3.4.2 Temperature Measurement Data Sorting Method……39
RESULTS AND DISCUSSION………………………………………………………………………………………41
1 Comparison of Observation Results Under Different Shooting Conditions………………………………………………………………………………………………………41
2 Specimen Appearance……………………………………………………………………………………46
3 Strain Calculation and Details of the Video……………………48
4 Fracture Observation…………………………………………………………………………………52
5 Temperature Measurement Result………………………………………………………53
6 High Temperature Ductility Curve…………………………………………………54
CONCLUSIONS……………………………………………………………………………………………………………………58
FUTURE WORKS…………………………………………………………………………………………………………………59
REFERENCES………………………………………………………………………………………………………………………………60

                                

1. F. Matsuda, “Hot Tearing and Its Dependability on Alloying Elements in Weld Metal During Solidification,” Journal of the Japan Welding Society, Vol. 36, No. 9, pp. 973-986, 1967. (in Japanese)
2. S. Yamashita and K. Saida, “Interpretation and Metallurgical Modeling of Hot Ductility Curve for Solidification Cracking,” Quarterly Journal of Japan Welding Society, Vol. 38, No. 4, pp. 275-290, 2020. (in Japanese)
3. J. C. Borland, “Suggested Explanation of Hot Cracking in Mild and Low Alloy Steel Welds,” British Welding Journal, Vol. 8, pp. 526-540, 1961.
4. K. Shinozaki, “Hot Cracking in Welding Zone,” Journal of the Japan Welding Society, Vol. 71, No. 6, pp. 455-459, 2002. (in Japanese)
5. F. Matsuda, “Hot Crack Susceptibility of Weld Metal,” 1st US-Japan Symposium on Advances in Welding Metallurgy, pp. 19-36, 1990.
6. N. N. Prokhorov, “Fundamentals of the Theory for Technological Strength of Metals While Crystallising During Welding,” Transactions of Joining and Welding Research Institute, Vol. 2, pp. 205-213, 1971.
7. F. N. Rhines and P. J. Wray, “Investigation of the Intermediate Temperature Ductility Minimum in Metals,” Transactions of American Society for Metals, Vol. 54, pp. 117-128, 1961.
8. F. Matsuda, H. Nakagawa, and K. Sorada, “Dynamic Observation of Solidification and Solidification Cracking During Welding with Optical Microscope,” Transactions of Joining and Welding Research Institute, Vol. 11, pp. 67-77, 1982.
9. F. Matsuda, “Solidification Crack Susceptibility of Weld Metal,” Recent Trends in Welding Science and Technology, pp. 127-136, 1990.
10. W. R. Apblett and W. S. Pellini, “Factors Which Influence Weld Hot Cracking,” Weld Journal, Vol. 33, pp. 83-90, 1954.
11. J. C. Lippold, Welding Metallurgy and Weldability, Wiley, New Jersey, pp. 84-85, 2015.
12. A. A. Bochvar and Z. A. Sviderskaya, Izv, Akad Nauk, Russia, pp. 349-355, 1947. (in Russian)
13. B. I. Medovar, “On the Nature of Weld Hot Cracking,” Avtomatichaskaya Svarka, Vol. 7, pp. 12-28, 1954. (in Ukrainian)
14. W. I. Pumphrey and P. H. Jennings, “A Consideration of the Nature of Brittleness and Temperature above the Solidus in Castings and Welds in Aluminum Alloys,” Journal of the Institute of Metals, Vol. 75, pp. 235-256, 1948.
15. W. S. Pellini, “Strain Theory of Hot Tearing,” Foundry, Vol. 80, pp. 124-133, 1952.
16. J. C. Borland, “Generalized Theory of Super-Solidus Cracking in Welds and Castings,” British Welding Journal, Vol. 7, pp. 508-512, 1960.
17. J. C. Lippold, Welding Metallurgy and Weldability, Wiley, New Jersey, p. 93, 2015.
18. F. Matsuda, H. Nakagawa, H. Kohmoto, Y. Honda, and Y. Matsubara, “Quantitative Evaluation of Solidiﬁcation Brittleness of Weld Metal During Solidiﬁcation by In- Situ Observation ad Measurement (Report II),” Transactions of Joining and Welding Research Institute, Vol. 12, pp. 73-80, 1983.
19. P. Wen, K. Shinozaki, M. Yamamoto, Y. Senda, T. Tamura, and N. Nemoto, “In-situ Observation of Solidiﬁcation Cracking of Laser Dissimilar Welded Joints,” Quarterly Journal of Japan Welding Society, Vol. 27, pp. 134-138, 2009.
20. K. Shinozaki, “Prediction of Solidification Cracking in Welding Metal During Welding using In-situ Observation Method,” The Japan Society of Mechanical Engineers, Vol. 9, No. 110, p. 1066, 2007. (in Japanese)
21. J. C. Lippold and W. Lin, “Weldability of Commercial Al-Cu-Li Alloys,” Proceedings of ICAA5. Aluminum Alloys-Their Physical and Mechanical Properties, pp. 1685-1690, 1996.
22. Y. Kusamoto, Investigation of Solidification Cracking Susceptibility During Hot Wire Laser Welding on the Narrow Gap Joint of Ni Base Alloy, M.S. Thesis, Hiroshima University, Hiroshima, pp. 22-23, 2021. (in Japanese)
23. K. Tomita, Evaluation of Solidification Cracking Susceptibility on Al-alloys Using Laser Welding, M.S. Thesis, Hiroshima University, Hiroshima, pp. 51-53, 2019. (in Japanese)
24. S. Yamashita, M. Yamamoto, K. Shinozaki, K. Kadoi, K. Mitsui, and H. Usui, “In-situ Temperature Measurement Using a Multi-sensor Camera During Laser Welding,” Quarterly Journal of Japan Welding Society, Vol. 33, No. 2, pp. 93-97, 2015.
25. J.-H. Lee, Y. Itasaka, S. Yamashita, T. Ogura, and K. Saida, “Prediction of Solidiﬁcation Cracking During Arc Welding of 310S Stainless Steel in U-type Hot Cracking Test,” Quarterly Journal of Japan Welding Society, Vol. 38, No. 2, pp. 68-75, 2020.
26. D. Wang, S. Sakoda, K. Kadoi, K. Shinozaki, and M. Yamamoto, “Investigation of Evaluation Method for Hot Cracking Susceptibility of 310S Stainless Steel During Laser Welding using Trans-Varestraint Test,” Quarterly Journal of Japan Welding Society, Vol. 33, No. 2, pp. 39-43, 2015.

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