中低合金鋼球化處理對塑性加工的影響

Effects of Spheroidization on Cold Working by Low Alloying Carbon Steel

黃煒盛(Wesley Huang) ； 李宜鴻(Lileo Li) ； 傅兆章(Tsow-Chang Fu) ； 李國維(Guo-Wei Li)

《鍛造》 23卷2期 (2014/07) Pp. 30-35

摘要

中低合金鋼常應用於較高強度需求的零件。本文討論中低合金鋼應用於盤元線材或運輸工具零組件時，其球化處理對塑性加工性質的影響。球化退火處理影響後續工程品質甚鉅，中低合金鋼係屬中碳鋼的亞共析鋼球化退火，在退火完成後，波來鐵組織中所包含碳化物組織，包含鐵及其他合金碳化物，因受熱能作用而產生球化。影響塑性加工的主要因素包含材料硬度、抽線減面率以及線材球化率。其中，線材球化率即表示線材中球狀碳化物的球化情形。低合金中碳鋼線材球化率可以標準照片比對及數位化判定等兩種方式檢測。在標準圖片比對中常用到的為JIS G3509－2:2003、JB／T 5074－2007以及ASTM A892－88等三種標準；而在數位化判定部分，一般公認使用球狀碳化物的長寬比比例計算之並以標準檢測圖片進行人工比對，其結果精確度有待商榷，且較易受個人主觀判定影響，本文以電腦進行自動掃描判定的數位化判定方式之結果則相對較為精確且客觀。

並列摘要

The low allying carbon steel is usually applied in high toughness requirement component. This paper discusses the effects of spheroidization treatments on cold working operations. The quality of spheroidization treatment has a great influence on later forming operation. The spheroidization treatmentof low allying carbon steelis belong to hypo-eutectoid steel treatment. After spheroidization process, the carbides of steel include FeC_3 and M_xC_yarespheroidized with absorbed enough heat energy. To investigateplastic formation of low allying carbon steelincludes measuring the material hardness, reduction of cross-sectional area and spheroidization rate (sphericity). And, sphericity measurement is to investigate the spheroidization condition of carbides. The classification of sphericity is approached by two ways. One is to compare the metallographic with the related standards manually, including JIS G3509-2, JB/T 5074-2007 and ASTM A892-88. Another way is to calculate the length-width ratio in the metallographic by a computer program which carries on the image recognizing automatically. This method has more efficiency and accuracy than comparing the metallographic with standards manually. This paper also discusses the efficiency and accuracy about these two measurement methods.