Mass Effects, Mn Addition and Heat Treatment on Mechanical Properties of Ductile Cast Iron

• Main Authors: Chiu, Mau-Chan, 邱茂展
• Other Authors: Shen-Chih Lee
• Format: Others
• Language: zh-TW
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/60879297938712036863

碩士 === 大同工學院 === 材料工程學系 === 84 === Mn element can increase and refine pearlite thus enhances strength in cast iron. However, matrix of cast iron would become embrittled when intercellular carbides formed due to excess amount of Mn (>0.7%)[40]. In this study, the effects of different Mn amount (0.31%, 0.35%, 0.56%, 0.97%) on mechanical properties of ductile iron of various thickness in as-cast state and after full annealing / sub- critical annealing were investigated. The results indicated that the strength and hardness increased with amount of Mn, but the ductility and impact values decreased. Strength and hardness decreased with increasing section thickness, but the effects on ductility and impact values were indefinite. After heat treatment , strength and ductility of the sub-criticaly annealed was superior to those after full annealing ,but hardness was worse off. For both full annealing and sub-critical annealing , the strength increased and ductility decreased with section size ,but the effects on impact values and hardness have no definite correlation. Attempts were made to explain the mechanical behavior based on microstructural features.