اثر تغيير فرآيند توليد و عمليات حرارتي بر ريزساختار، خواص و رفتار روغنكاري سمبه از جنس همبسته LM13

Effect of Process Variation and Heat Treatment on Microstructure and Tribological Behavior of Piston of LM13 Alloy

LM13 alloy is widely used in piston industry due to its low coefficient of thermal expansion, excellent castability and hot tear resistance. In this research, effect ofcasting process on wear behavior ofLM13 alloy was investigated. First , samples were produced using two casting processes and heat treatment. Then wear behavior of these samples under dry sliding condition was examined. Results of hardness and strength tests indicated that squeeze cast specimens exhibited high er mechanical properties . Wear experimental results showed that in both squeeze and gravity cast specimens, the amount of weight los s increases with increase in sliding distan ce which is accompanied by reduction in wear rate and fricti on coefficient. A comparison between two samples demonstrated that squeeze sample had better tribological behavior. Casting proce ss variation causes decrease in friction coefficient from 0.4 to 0.2 for squeeze cast samples and decrease in weight loss of these samples. Squeeze cast samples had better surface quality and in these samples abrasive, adhe sive and delamination are dominant wear mechanisms, while in gravity cast samples abra sive, adhe sive and surface fatigue are the dominant wear mechanisms.