- 學位論文
中碳鋼S45C感應熱處理製程之研究
Induction Heat Treatment of Medium Carbon Steels
摘要
在金屬材料中，鋼材的應用一直是最廣泛的，中碳鋼材S45C常使用在汽車零件、齒輪、軸承等部位，需要高表面硬度、韌性以及耐磨耗。高周波感應爐加熱淬火後，可使鋼材產生局部表面硬化作用，達到上述所要求。一般傳統高周波爐感應熱處理對於其頻率、功率、溫度、時間、尺寸等參數皆由經驗做為判斷依據，造成每次熱處理工件品質無法控制，須再經過後處理做調整，使得成本上的增加。本實驗藉由調整不同尺寸(直徑10、20與30mm)功率(12.5、15、17.5和20kW)以及時間(15、20秒)之參數，使用高周波爐設備頻率為50KHz，得到最適合熱處理之尺寸為20mm。在功率12.5kW加熱15秒及20秒有加熱不足之情形發生，使表面無法達到要求之硬度；功率17.5 kW加熱20秒與功率20kW加熱20秒可達到相同之表面硬度，但功率20kW加熱20秒之硬化層較深，不符合表皮硬化效果，由熱量對硬化深度的分佈圖可以得到不同功率與時間所得到的硬化深度。接著分別以未熱處理、功率15kW加熱20秒以及功率17.5kW加熱20秒做磨耗試驗，可發現在功率17.5kW加熱20秒時硬化層組織比功率15kW均勻，可得到較好的耐磨耗性質。
並列摘要
High frequency induction heating and quenching is often used to surface harden steels. The process parameters of induction heating are greatly dependent on experience. This study intends to vary specimen size (diameter 10,20 and 30mm), power (12.5,15,17.5 and 20kW), and time (15,20 seconds) for induction heat treatments using 50KHz high-frequency furnace . It is found that the most appropriate size for heat treatment is 20mm diameter bar. At power 12.5kW, surface exhibits large amount of ferrite indicating insufficient heating. Whilst at power 17.5 kW and 20kW, surface structure are mixed with bainite and martensite, they can all achieve similar surface hardness. The depth of hardened layer is over 5mm using 20kW power which does not meet surface hardening requirement. Through the diagram of hardening depth versus entering heat , a good rule of thumb for selecting induction heating parameters may be obtained. Wear tests are also performed on the untreated, 15kW treated, and 17.5kW treated specimens. It is found that the specimen treated using 17.5kW power for 20 seconds obtain an optimal wear resistance because of uniform microstructure formation in the hardened layer.