Investigation were carried out to study the corrosion behaviour of heat treated rolled medium carbon steel and as-rolled medium carbon steel in sodium chloride medium. The as-rolled medium carbon steel was heated to a...Investigation were carried out to study the corrosion behaviour of heat treated rolled medium carbon steel and as-rolled medium carbon steel in sodium chloride medium. The as-rolled medium carbon steel was heated to a temperature of 830℃ to completely austenize it and water quenched;it was reheated to the ferrite-austenite dual phase region at a temperature of 745℃ below the effective Ac3 point. The steel was then rapidly quenched in water and tempered at a temperature of 480℃. The corrosion behaviour of the steel in marine medium (NaCl) was studied by weight loss measurement. The weight loss is between 0.02g-0.11g for the as-rolled steel and 0.01g – 0.013g for the heat treated steel. The results obtained showed that the as-rolled medium carbon steel is more susceptible to corrosion than the heat treated rolled medium carbon steel.展开更多
Pulverised stem fibres of the natural sponge plant, SP, (Acanthus montanus) and stranded coconut fibre, CF, (Cocos nucifera) from the coir tree were used as reinforcements for thin cement sheets in this research work....Pulverised stem fibres of the natural sponge plant, SP, (Acanthus montanus) and stranded coconut fibre, CF, (Cocos nucifera) from the coir tree were used as reinforcements for thin cement sheets in this research work. The mixture of cement and pulverised waste paper, which formed the matrix, was maintained constant while the fibre mass concentration of both fibres were varied. The slurry formed by adding water to the mixture of the matrix materials and the reinforcement fibres, was poured into rectangular mould and consequently pressed to eject excess water. De-moulded samples were allowed to cure in the laboratory for twenty-eight days before flexural and compressive tests were carried out. The analysis of the experimental results established that sample coded as S4, with 30% CF and 70% SP, showed the most promising result. This implied that particulate reinforcement in cement matrix composite contributed to higher and improved flexural load bearing capacity and ductility when utilised in a higher proportion than long fibres.展开更多
The effect of ageing temperature on the mechanical properties of Al-Mg-Si alloy has been studied. The material was machined into different shapes of the tests to be carried out: tensile, impact and hardness. The test ...The effect of ageing temperature on the mechanical properties of Al-Mg-Si alloy has been studied. The material was machined into different shapes of the tests to be carried out: tensile, impact and hardness. The test specimens were divided into two and, some sets were solution treated at 500℃ for one hour and peak aged at 160℃ for eight hours while the other sets were solution treated at 500℃ for one hour and peak aged at 180℃ for eight hours. The abovementioned tests were carried out on the specimens. The results show that at low ageing temperature of 160℃, the ductility and impact were high while at 180℃, the ultimate tensile strength and hardness are higher compared to the value obtained at 160℃.展开更多
文摘Investigation were carried out to study the corrosion behaviour of heat treated rolled medium carbon steel and as-rolled medium carbon steel in sodium chloride medium. The as-rolled medium carbon steel was heated to a temperature of 830℃ to completely austenize it and water quenched;it was reheated to the ferrite-austenite dual phase region at a temperature of 745℃ below the effective Ac3 point. The steel was then rapidly quenched in water and tempered at a temperature of 480℃. The corrosion behaviour of the steel in marine medium (NaCl) was studied by weight loss measurement. The weight loss is between 0.02g-0.11g for the as-rolled steel and 0.01g – 0.013g for the heat treated steel. The results obtained showed that the as-rolled medium carbon steel is more susceptible to corrosion than the heat treated rolled medium carbon steel.
文摘Pulverised stem fibres of the natural sponge plant, SP, (Acanthus montanus) and stranded coconut fibre, CF, (Cocos nucifera) from the coir tree were used as reinforcements for thin cement sheets in this research work. The mixture of cement and pulverised waste paper, which formed the matrix, was maintained constant while the fibre mass concentration of both fibres were varied. The slurry formed by adding water to the mixture of the matrix materials and the reinforcement fibres, was poured into rectangular mould and consequently pressed to eject excess water. De-moulded samples were allowed to cure in the laboratory for twenty-eight days before flexural and compressive tests were carried out. The analysis of the experimental results established that sample coded as S4, with 30% CF and 70% SP, showed the most promising result. This implied that particulate reinforcement in cement matrix composite contributed to higher and improved flexural load bearing capacity and ductility when utilised in a higher proportion than long fibres.
文摘The effect of ageing temperature on the mechanical properties of Al-Mg-Si alloy has been studied. The material was machined into different shapes of the tests to be carried out: tensile, impact and hardness. The test specimens were divided into two and, some sets were solution treated at 500℃ for one hour and peak aged at 160℃ for eight hours while the other sets were solution treated at 500℃ for one hour and peak aged at 180℃ for eight hours. The abovementioned tests were carried out on the specimens. The results show that at low ageing temperature of 160℃, the ductility and impact were high while at 180℃, the ultimate tensile strength and hardness are higher compared to the value obtained at 160℃.
