The Relation between In-mold Process Inoculation Treatment Used Reaction Chamber Design and Furan Resin Mold Ductile Cast Iron Quality

• Main Authors: Huang Shiu-Chen, 陳皇旭
• Other Authors: none
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/08535913292607542150

碩士 === 逢甲大學 === 機械工程學所 === 95 === The objective of this research is to focus on the manufacturing of furan resin mold ductile cast iron by using the In-mold Process. The effect of inoculation treatment used reaction chamber design (position, inlet to outlet cross section area ratio, inoculant and reaction chamber height ratio, shape etc.,) and casting parameters (addition amount and grain size of inoculant, pouring temperature etc.,) on the mechanical properties (tensile property, toughness, hardness, etc.,) and metallographic microstructures (nodularity, nodule count, matrix etc.,) of the ductile cast iron will be investigated in this research. The results of this study indicate in two ways： A. In the reaction chamber design of In-mold Process inoculation treatment： (1)When the inoculation treatment used reaction chamber position from the nodulation treatment used reaction chamber position is 60 mm, the mechanical properties are the best. The nodularity is 93%, the nodule counts are 320 counts/mm2, the tensile strength is 406MPa. (2)When the reaction chamber inlet and outlet cross section area ratio is 1：1, the casting quality of the ductile cast iron casting is the best. The nodularity is 92%, the nodule counts is 302 counts/mm2, the tensile strength is 476MPa, and the elongation is 23%. (3)When the inoculant to the reaction chamber height ratio is 3/4, the nodularity and the tensile strength of casting are better than the other two height ratios. The nodularity is 92% and the tensile strength is 436MPa. (4)When the shape of the reaction chamber is designed as a cubic, the nodularity(93%) and the tensile strength(456MPa) are the best. Either the modulus increased (cylindric) or decreased (rectangular), the metallographic microstructure and the mechanical properties were toward to worse. B. In the casting parameters： (1)When the addition amount of inoculant is 0.3%, the tensile strength and the ductile are better. The results of tensile strength and ductility variation are matched with the metallographic microstructure results of nodularity and matrix. (2)When the grain size of inoculant is coarse ( 3.62~2.42mm), the metallographic microstructure and tensile strength are the best for the ductile iron casting. (3)When pouring temperature is 1500℃, the metallographic microstructure and tensile strength are better for the ductile iron casting. (4)Use and with finer filter ( 1.5mm) to make inclusion content reduce, and the metallographic microstructures and mechanical properties will be improved to some extent. So it is good to propose using the filter and with finer filter ( 1.5mm). SEM-EDS analyses show that oxide and carbide are major compositions of the inclusion in ductile iron casting. (5)Use the statistic method of coefficient of variation to analyze the repeatability of casting quality, the results show the coefficient of variation is smaller than 5%. So it can be concluded that the repeatability of casting quality with optimum inoculation treatment used reaction chamber design condition is good. (6)When the nodularity, nodule count, diameter of graphite, ferrite content of the ductile cast iron with inoculation obviously improved, also increase the ductility, toughness and reduce the hardness. SEM analyses show that Inoculation treatment can thin pearlite structures and increase ferritic grains. All these can be proved from the improvement of mechanical properties.