臺灣博碩士論文加值系統

傳統刀具的選用是使用高速鋼或工具鋼，其熱處理後硬度雖可達到HRC 62∼65，但因軋鋼廠是屬於熱軋製程，刀具皆處於高溫及高磨耗等嚴苛環境下，更因剪切面剪切1050℃高溫材料，使剪切面因晶粒粗大，碳化物凝聚而軟化，造成切刀提早下線或生產線異常停機，因此在軋鋼廠提升刀具壽命是值得研究的課題。

本研究使用雷射硬面被覆法，於JIS S45C中碳鋼基材表面被覆Stellite 1鈷基合金，探討其對刀具壽命提升之影響，並探討被覆層之熱處理及其衍生之相變化。結果顯示被覆後之切刀經實際剪切使用後，壽命較SKD61刀具壽命提升6倍。因被覆後刀具之顯微組織及表面硬度，使用前後比較並無顯著改變，可維持剪切面之耐磨特性，解決SKD61刀具時壽命不佳的現象。

在本實驗中被覆層經不同熱處理溫度作均質化處理，結果在1000℃以上可大幅改善被覆層Cr偏析於晶界情形，且發現溫度在1000℃硬度值最高，為Hv700。1000℃均質化後再經650℃高溫回火後，硬度值可增加Hv100，經XRD分析顯示在均質化過程中M7C3分解成M6C的碳化物。以TEM進一步解析高溫回火後被覆層顯示M6C 相於富鈷之γ相中呈整合性析出，產生析出硬化之效果。

In general, the high-speed tool or hot tool steel was selected as the material of the cutter. The hardness is from HRC62 to HRC65 after the heat treatment. However the rolling process is conducted in rolling wires, the cutter is under the environment of hot temperature and serves wear. The hardness of the cutter was decline due to the grain size coarsening, which results in the mill line abnormally shut down. It was worth researching to improve the life of the cutter.

In this study,the Stellite 1 cobalt-based alloy was cladding on JIS S45C medium carbon steel by laser. The improvement on the life of the cutter and the phase transformation after the heat treatment of the layer are investigated. The results show that the life of the cutter is elevated 6 times than that of the conventional cutter. It was observed that the microstructure and the hardness of the used cladding cutter are little differences than before. Then the Cobalt-based layer were conducted by the different heat treatment conditions to be homogenized When the temperature is over the 1000 ℃, the Cr segregation is dramatically eliminated. The highest hardness up to Hv700 occur at 1000℃.The hardness will increase Hv100 through tempering at 650℃ following the homogenization at 1000℃. During the homogenization, it is observed that M7C3 decomposed into M6C by XRD analysis. After tempering , M6C coherently precipitates in the Co-rich γmatrix by TEM analysis and the effect of precipitates hardening will be resulted in.

中文摘要……………………………………………………………………………Ⅰ
英文摘要……………………………………………………………………………Ⅱ
致謝…………………………………………………………………………………Ⅲ
目錄…………………………………………………………………………………IV
圖目錄………………………………………………………………………………VI
表目錄………………………………………………………………………………IX

第一章、緒論
1-1 前言……………………………………………………………………………1
1-2 文獻回顧
1-2-1 雷射加工發展歷史………………………………………………………3
1-2-2 雷射加工理論背景………………………………………………………4
1-2-3 被覆合金種類……………………………………………………………9
1-2-4 鈷基被覆層之特性 ……………………………………………………12
1-2-5 熱處理後性質探討 ……………………………………………………13
1-2-6 顯微組織與稀釋率 ……………………………………………………14
1-2-7 被覆層之物理性能 ……………………………………………………14
1-2-8 被覆層的磨耗行為 ……………………………………………………14
第二章、研究動機與目的…………………………………………………………19
第三章、實驗方法與步驟
3-1實驗設計………………………………………………………………………21
3-2實驗用材料……………………………………………………………………21
3-3雷射被覆………………………………………………………………………22
3-4熱處理…………………………………………………………………………22
3-5實驗與分析設備………………………………………………………………23
3-6試片分析………………………………………………………………………24
3-7實際磨耗試驗…………………………………………………………………26
第四章、結果與討論………………………………………………………………34
4-1 SKD61刀具使用前後金相組織與硬度變化分析
4-1-1金相組織變化分析………………………………………………………35
4-1-2硬度變化分析……………………………………………………………35
4-2 被覆刀具使用前後金相組織與硬度分析
4-2-1使用前金相組織…………………………………………………………35
4-2-2使用後金相組織…………………………………………………………37
4-2-3被覆刀具使用前後硬度比較分析………………………………………37
4-3 被覆層熱處理後性質探討
4-3-1 均質化硬度變化探討……………………………………………………40
4-3-2 高溫回火後硬度變化探討………………………………………………40
4-3-3 相變態探討………………………………………………………………41
第五章、結論………………………………………………………………………71
第六章、參考文獻…………………………………………………………………72

1、Banas,C.M，1978，“High Power laser Cladding”，Optical Engineer， vol.17,No.3，pp210∼2162、La Rocca，A,V.，1982，“Laser Application Manufacture”，Scientific American，vol.246，No.3，pp.94∼1033、Mazumder，J.，1983，“Laser Heat Treatment：The State of the Art”，Journal of Metals，vol.15，pp.18∼264、Gnanamuthu，P.S.，and Shankar，V.S.，1985，“Laser Heat Treatment of Iron-Base Alloys ”，Processing Application of High Power Laser，Jacobs，R.R.，ed.，22∼23 Jan. 1985，Los Angeles，CA.SPIE，vol.527，pp56∼725、Steen，W.M.，1985，“Surface Engineer with Laser”，Metals and Materials，vol.1，No.12，pp730∼736 6、Weerasinghe，V.M. and Steen，W.M.，1987，“Laser Cladding with Blown Powder”，Metal Construction，Vol.19，No.10，pp581∼5857、K. Komvopoulos and K.Nagarathnam“Processing andCharacterization of Laser-cladded Coating Materials”，Journal of Engineering Materials and Technology，Apr.,1990, Vol.112, pp.131∼1438、John R Bradley and Sooho Kim ,“Laser Transformation Hardening of Iron-Carbon and Iron-Carbon-Chromium Steels”, Metallurgical Transactions A , Aug. , Vol.19A , pp2013∼2025 , 19889、M. Pilloz , J. M. Pelletier and A.B Vannes ,“Residual Stress Induces by Laser Coatings：Phenomenological Analysis and Predictions”, Journal of Materials Science , Vol.27 ,pp1242∼1244 , 199210、H.So，C.T. Chen，Y.A. Chen，“Wear behaviours of Laser-clad stellite alloy 6”，Wear ，1996，pp.78∼8411、John R Bradley and Sooho Kim ,“Laser Transformation Hardening of Iron-Carbon and Iron-Carbon-Chromium Steels”, Metallurgical Transactions A , Aug. , Vol.19A , pp2013∼2025 , 198812、K.C. Antony，“Wear Resistant Cobalt-base Alloys”，Journal of Materials，Feb.，1983，pp52∼6013、Andre Frenk，Nicolas Henchoz and Wilfried Kurz，“Laser Cladding of a Cobalt-based alloy ”，Processing Parameters and Microstructure，Z.Metallkd，1993，Vol.84，No.12，pp882∼89214、A Frenk and W.Kurz，“High Speed Laser Cladding：Solidification conduction and Microstructure of a Cobalt-based Alloy ”，Materials Science and Engineer，1993，A173，pp339∼34215、Xiaolei Wu , Guangnan Chen ,“Nonequilibrium microstructures and their evolution in a Fe-Cr-W-Ni-C laser clad coating”, Materials Science and Engineering ,1999 ,A270 , PP183∼18916、P.J.E Monson and W.M. Steen ,“Comparison of Laser Hardfacing with Conventional Processes”，Surface Engineering，1990，Vol.6,No.3,pp.185∼19317、S.Atamert and H.K.D.H.Bhadeshia，“Comparison of the Microstructure and Abrasive Wear Properties of Stellite Hard facing Alloys Deposited by Arc Welding and Laser Cladding”，Metallurgical Transactions A，Jun.,1989,Vol.20A,pp.1037∼105418、P.J.E Monson and W.M. Steen，“Laser Harding/Cladding”,Laser Treatment of Materials, edited by Barry L.Mordike,198619、Ming-Chang Jeng，Li-Yung Yan and ji-Liang Doong，“Wear Behavior of Cobalt-based Alloys in Laser Surface Cladding ”,Surface and coating Technology,1991,Vol.48,pp225∼23120、J. Mazumder and A Kar , “Solid solubility of laser cladding”, J. Met. ,Feb .,pp18∼23 , 198721、A.Frenk and W.Kurz，“Microstructure Effects on the Sliding Wear Resistance of a Cobalt-based Alloy”，Wear,1994,Vol.174,pp81∼9122、G.. Abbas and D.R.F. West，“Laser Surface Cladding of Stellite and Stellite-SiC Composite Deposits for Enhanced Hardness and Wear ”，Wear,1991,Vol.143,pp353∼363 23、周漢標，蘇演良,“鉬含量對鈷基合金硬面補銲之影響”, 中華民國銲接學會，83年論文集，pp.157∼16624、Jogender Singh and J.Mazumder，“Microstructure and wear Properires of Laser Clad Fe-Cr-Mn-C alloy ”，Metallurgical Transaction A,Feb.,1987,Vol.18A,pp313∼322 25、M.Riabkina-Fishman，J.Zahavi，“Laser Alloying and Cladding for improving Surface Properties”，Applied Surface Science，1996，pp.263∼26726、David A. Belforte ,“Cladding improves cutting tools”, Industrial Laser Solutions , Feb. , 200127、J.F. Lancaster，Metallurgy of welding，5th ed，1993，PP.14828、金重勳， “熱處理”，復文書局，1999。29、V. M. Desai，C. M. Rao，T. H. Kosel and N. F. Fiore，“Effect of Carbide size on the abrasion of Cobalt_base powder metallurgy alloys”，Wear，1984，vol.94，pp89∼10130、M. Murphy，C. Lee，W. M. Steen，“Studies in Rapid Prototyping by laser surface cladding”，ICALEO，1993，PP882∼892 31、關振中，“激光加工工藝手冊”，中國計量出版社，1998。32、J. L. Koch，J. Mazumder，“Rapid Prototyping by laser cladding”，ICALEO，1993，pp556∼55933、E. W. Kreutz，G. Baxkes，A. Gasser，K. Wissenbach，“Rapid Prototyping with co2 laser radiation”，Applied Surface Science， 1995，vol.86，pp310∼31634、P. Erasenthiran，R. Ball，Jungreuthmayer C.，W. O’Neill and W. M. Steen，“Laser step shapping for laminated object manufacturing parts”，section E-ICALEO，1997，pp84∼9235、Hu，Y. P. Chen，C. W.，“Laser cladding of wear-resistant tool steel”，Advanced Materials ﹠Prosesses， 1997，vol.152，pp.3136、A. Frenk and W. Kurz，“Microstructural effects on the sliding wear resistance of a cobalt-based alloy”，Wear，1994，vol.174，pp81∼9137、陳建成，“鈷基及鎳基銲覆層高溫熱疲勞後磨耗特性研究”，國立中正大學碩士論文，民國八十八年。38、劉國雄、林樹均、李聖隆、鄭晃忠、葉均蔚 , “工程材料科學”, 全華科技圖書股份有限公司 , 1992。39、簡志明，“中碳鋼雷射硬面層與相變硬化層之特性研究”，國立中正大學碩士論文，民國八十五年。40、Kenneth Easterling，Introduction to the physical Metallurgy of welding，2nd ed，199241、William M. Steen，Laser Materials Processing，Springer Verlag，1991