การศึกษาเปรียบเทียบความแข็งแรงต่อขนาดและรูปร่างของแกรไฟต์ในเหล็กหล่อสีเทา

Abstract

At present, Gray Cast Iron is very important for industry, for example, the production of the parts mobile and machjne. The study about an influence of the size and the shape of graphite which an effect on the strength of Gray Iron. When it is completely cool in a sand mould. When we consider the mechanical qualification, if the mixture ratio of silicon (Si) is changed by 0.15 % and 0.5 % each time, the experimental object is 500 mm. long, 30 mm. เท diameter, and it takes 0.883 minute to be completely cool in the sand mould. From the experiment, increasing the silicon mixture cause the structure of the Gray Iron change the crystal shape of Graphite to a longer and bigger one. It depends on the quantity of Carbon. When we experiment mechanical quantification, we find that strength and tensile stress decrease,and the Iron, the lowest tensile stress in 98.82 N/mm2 1 is composed of (C) 2.61 %, (Si) 2117%, (P) 0.025%, and the Iron 1 the highest tensile stress in 365.84 N/mm2 and the highest strength in 220 (HB) is Gray Cast Iron that is composed of (C) 2.84%, (Si) 1.46%, (P) 0.02%, and the Iron, the lowest strength in 121. (HB), is Gray Cast Iron that is composed of (C) 3.47%, (Si) 3.79%, (P) 0.024% Therefore, it can be concluded that the Characteristic of the graphite with small, short and constantry spreading crystal will be the strongest one . on the contrary, that with big, long, inconstantly speading one will be least strong.