全系列烘烤硬化鋼開發

Development of High Strength Bake Hardening Steels

10.30069/MM.201512_59(4).0002

蔣龍仁(L.J. Chiang)；涂睿帆(J.F. Tu)；蔡科賢(K.S. Tsay)；鄭暉志(H.C. Cheng)

烘烤硬化性 ； 極低碳鋼 ； 碳化物回溶 ； bake hardening ； ultra-low carbon steels ； carbide redissolution

鑛冶：中國鑛冶工程學會會刊

59卷4期（2015 / 12 / 01）

25 - 37

繁體中文

本研究致力烘烤硬化性的冶金機制研究，探討各式碳化物在極低碳鋼中的演變，以及在各製程中的回溶再析出行為，研究結果顯示高溫碳化物Ti_4C_2S_2的析出是影響極低碳鋼烘烤硬化性的關鍵。而低碳鋼可藉由控制波來鐵、變韌鐵及雪明碳鐵回溶及再析出程度來得到適當的固溶碳濃度及烘烤硬化性，本研究透過控制碳化物尺寸及析出位置有效提升鋼材強度及烘烤硬化性，完成中鋼公司產線全系列烘烤硬化鋼產品開發，包含世界最高強度等級烘烤硬化鋼EN HX340BD。

This paper investigated the mechanism of bake hardening (BH) by studying the evolution of carbides in ultra-low carbon steels. Results showed that the precipitation of Ti4C2S2 during high temperature critically affected the BH ability. Proper control of redissolution and reprecipitation of pearlite, bainite and cementite during annealing process can maintain low-carbon steel solute carbon content and stable BH property. A technique of controlling the size and site of carbide precipitation enhanced both steel strength and bake hardening ability. All high strength cold-rolled and GI BH steels, including En HX340BD, were successfully produced in CSC production lines.