摘 要 為了對不同斷面沃斯回火球墨鑄鐵的機械性質作一更深入
的探討，本研究即利用三種不同斷面的Y型鑄件( 25 mm、50 mm 和100 mm
)、兩種化學成份材料( Ni-Cu-Mo和Ni-Cu-Mo-Bi )、三種不同的接種處理
方式以及四種不同的熱處理方式來作徹底的研究。 本實驗係根據三種
不同斷面的不同位置上切取不同的試棒，以便做機械性質的測試。機械性
質的測試包括抗拉強度、降伏強度、硬度以及衝擊韌性的測試。由實驗可
知，沃斯回火球墨鑄鐵的機械性質，受基地中的球墨數、球化率、殘留沃
斯田鐵的量與分佈以及肥粒鐵板條的型態所影響。 實驗結果顯示，在
最薄斷面Y型鑄件的根部( 25 mm )為機械性質最佳的位置；而在最厚斷面
Y型鑄件( 100 mm )中，靠近熱凝固中心之最慢凝固位置的機械性質為最
差。 研究結果同時顯示，在做拉伸試驗時，沃斯回火球墨鑄鐵的伸長
率不僅受基地組織的影響，同時也受拉伸試棒的量規區直徑大小的影響。
即拉伸試棒的量規區直徑愈大，試棒的伸長率會愈大。關鍵詞：不同斷面
、厚斷面、沃斯回火球墨鑄鐵、機械性質、微結構。

Abstract The mechanical properties of various-section
austempered ductile irons ( various-section ADIs ) were fully
investigated in this study. Three section sizes of Y-block
castings ( 25, 50 and 100 mm widths ), two chemical compositions
( Ni-Cu-Mo , Ni-Cu-Mo-Bi ), three different inoculations and
four different austempering heat treatments of ductile irons
were prepared and tested the mechanical properties of heat
treated ADIs. The specimens were taken from different
locations of Y-block castings. Mechanical properties included
UTS, YS, elongation, hardness and impact toughness. The
developed mechanical properties were in relation with the
amounts of nodule counts, nodularity, distribution of residual
austenite and the types of ausferrite in the matrix of various-
section ADIs. The nodule counts and nodularity decreased with
the increased of the section size of heavy-section ductile
irons. Experimental results showed that the optimum
mechanical properties obtained from the bottom of thin Y-block
casting ( 25 mm ). The inferior mechanical properties occured
near the hot spot of thick Y-block casting ( 100 mm ).
Research results also showed that not only the percent
elongations affected by the matrix of ADIs, but also the gage
diameter of tensile specimens. i.e. the bigger the gage
diameter of tensile specimens , the longer the percent
elongations. Keywords : various-sections, heavy-section, ADIs,
mechanical properties, microstructures.