超高頻感應加熱於鋼料表面披覆鈷基合金的應用

Abstract

本實驗以304不銹鋼、S45C中碳鋼及SK3高碳鋼為母材，配合不同的製程參數做高週波表面Stellite 6鈷基合金披覆處理，分析其加熱功率、加熱時間對披覆層顯微組織、硬度分佈及化學組成的影響。 實驗結果發現，利用高週波感應加熱，以304不銹鋼為母材做鈷基合金披覆處理時，由於加熱功率或是加熱時間的不同，披覆層的組織主要可以分為胞狀晶及柱狀晶二大類。在硬度方面，隨著高週波功率提高或是加熱時間增長，披覆層的硬度有降低的趨勢。成份分析方面，各種披覆條件均顯示晶粒內的Co、Fe含量會高於晶界附近，而Cr、W則相反，在晶界附近的含量較多。 利用高週波感應加熱，以S45C中碳鋼及SK3高碳鋼為母材做鈷基合金披覆處理時，由於加熱功率或是加熱時間的不同，披覆層的凝固組織可以分為胞狀晶、柱狀晶及針狀組織三大類。在硬度方面，披覆層若為胞狀晶、柱狀晶組織時，則隨著功率提高或是加熱時間增長，硬度有降低的趨勢。但若出現針狀組織以後，披覆層的硬度會隨著加熱時間的增加而有上升的趨勢，這是因為基地中有碳化物均勻散佈所致。在成份分析方面，無論組織為胞狀晶、柱狀晶或針狀組織，其晶粒內的Co、Fe含量均高於晶界附近，而Cr、W則相反，在晶界附近的含量較多。

SUS304, S45C, and SK3 are cladded with cobalt-based Stellite 6 alloy by means of high frequency induction heating. The influence of heating power and heating time on the microstructure, hardness and chemical compositions of the caldded layer has been studied. The results show that there are two types of microstructure in the cladded layer depending on the heating power and heating time if SUS304 is used as base metal. They are cellular dendrite and columnar dendrite. When the heating power or the heating time increases, the hardness of the cladded layer will decrease. The content of Co and Fe within the grain is much more than that at the grain boundary, but the content of Cr and W is more at the grain boundary. If S45C or SK3 is used as base metal, there are three types of microstructure in the cladded layer depending on the heating power and heating time. They are cellular dendrite, columnar dendrite and needle structure. If the microstructure of the cladded layer is cellular dendrite or column dendrite, the hardness of the cladded layer will decrease with increasing the heating power or heating time. If the needle structure appears, the hardness of the cladded layer will increase with increasing the heating power or heating time owing to the precipitation of carbide in the matrix. No matter what the microstructure is, the content of Co and Fe within the grain is much more than that at the grain boundary, but the content of Cr and W is more at the grain boundary.