温度对不锈钢经电浆软氮化后之影响-YOKE.DOC

以三維斷層掃描顯像技術探討波來鐵組織球化機構 Investigation of spheroidization mechanism of pearlite by quantitative three-dimensional analysis 王元聰* 林守杞** 黃慶淵* Yuan-Tsung Wang* Shou-Chi Lin ** Ching-Yuan Huang* *中鋼公司-鋼鋁研究發展處-鋼鐵產品發展組 **中鋼公司-鋼鋁研究發展處-產品應用研究組 摘要 本研究利用聚焦離子束電子顯微鏡(FIB-SEM)，並結合三維電腦輔助軟體，以重建鋼經700℃靜態退火其波來鐵組織球化之立體影像，並釐清促使雪明碳鐵形成完全球狀化機制之關鍵因素。研究結果顯示，存在於雪明碳鐵中之孔洞引發雪明碳鐵三維顯示，孔洞間之孔洞結合及成長與孔洞間距及雪明碳鐵板片厚度有關。’s perturbation主導，直到球狀化完成為止。本研究經由對波來鐵球化機構之掌控，使高碳工具鋼能落實生產，並已被廣泛應用於園藝工具、鋸片、刀具及捲尺等高品級產品上。 關鍵字：孔洞、片狀雪明碳鐵、表面能、表面曲率、三維斷層掃描 Abstract We investigated the pearlite spheroidization of a 0.85 mass% C-Fe tool steels under 700℃ static annealing conditions using a combination of FIB-SEM and computer-aided three-dimensional (3D) tomography to reconstruct the 3D images and clarify the elements contributing to the mechanism of complete pearlite spheroidization. The results imply that the holes present naturally grown cementite lamella causes shape instability and induces shape evolution of the lamellar structure during spheroidization. 3D visualization demonstrated that the intrinsic holes play an important role in the initiation and development of pearlite spheroidization. Furthermore, the growth mechanism of the inter-hole coalescence is related to the ratio of half the hole distance on the lamella to the thickness of the cementite lamella. At the initial stages of pearlite spheroidization, the hole coalescence and expansion causes the breakup up of large cementite lamellae into several long narrow ribbons. The driving force for hole growth is either the difference in surface energy or the curvature between the hole edges and the adjacent flat surface of the lamella. The cementite ribbons will change their shape to cylinders or small spheres by Rayleigh’s perturbation process after long spheroidization period. Through the key point controlling of the pearlite spheroidization mechanism, CSC has successfully development the high carbon tool steels and these tool steels have broadly applied in high qu