This paper reports investigations made on the tempering heat treatment effects on steel welds. The properties of the weld investigated were hardness value and toughness. Micro examination of the samples was also done ...This paper reports investigations made on the tempering heat treatment effects on steel welds. The properties of the weld investigated were hardness value and toughness. Micro examination of the samples was also done with optical microscopy. Four (4) different grades of steel rods in 10mm diameter were obtained. The range of the carbon contents of the steel rods was from 0.16 wt% C to 0.33 wt % C. From each grade of the steel materials, grooved specimen of about 150 mm were prepared. The grooves were then filled to create welds using arc welding. A set of the resulting welds were then subjected to tempering heat treatment. The hardness values and toughness of the welds were determined. The microstructural analyses of the welds were carried out as well. The results show that hardness and toughness were dependent on the carbon content. There was also significant microstructural modification due to heat treatment.展开更多
Thermomechanical treatment on cast Al-Si-Cu alloy (LM4) was carried out. The aim is to determine effects of degree of cold work, slurry thermal treatment and soaking time on the tensile strength, ductility, hardness a...Thermomechanical treatment on cast Al-Si-Cu alloy (LM4) was carried out. The aim is to determine effects of degree of cold work, slurry thermal treatment and soaking time on the tensile strength, ductility, hardness and microstructure of the alloy. LM4 was prepared and cast in sand mould into rods of Φ50 mm and 200 mm in length. The prepared rods were then thermally treated at 635°C which fall within the slurry region of the alloy. The heated samples were soaked at this temperature for various times of: 5, 10, 15 and 20 min. A none-treated sample was also kept as control specimen. The thermally treated rods were subjected to various degrees of cold work. 10 %, 15%, 20%, 30% degrees of cold work were used. Hardness, tensile strength and elongation of the samples were determined. The metallographic examination of the samples was also carried out. Results of mechanical property test show sensitivity to degree of cold work, thermal treatment soaking time. The microstructures of the alloy also show significant modifications as a result of thermal treatment.展开更多
文摘This paper reports investigations made on the tempering heat treatment effects on steel welds. The properties of the weld investigated were hardness value and toughness. Micro examination of the samples was also done with optical microscopy. Four (4) different grades of steel rods in 10mm diameter were obtained. The range of the carbon contents of the steel rods was from 0.16 wt% C to 0.33 wt % C. From each grade of the steel materials, grooved specimen of about 150 mm were prepared. The grooves were then filled to create welds using arc welding. A set of the resulting welds were then subjected to tempering heat treatment. The hardness values and toughness of the welds were determined. The microstructural analyses of the welds were carried out as well. The results show that hardness and toughness were dependent on the carbon content. There was also significant microstructural modification due to heat treatment.
文摘Thermomechanical treatment on cast Al-Si-Cu alloy (LM4) was carried out. The aim is to determine effects of degree of cold work, slurry thermal treatment and soaking time on the tensile strength, ductility, hardness and microstructure of the alloy. LM4 was prepared and cast in sand mould into rods of Φ50 mm and 200 mm in length. The prepared rods were then thermally treated at 635°C which fall within the slurry region of the alloy. The heated samples were soaked at this temperature for various times of: 5, 10, 15 and 20 min. A none-treated sample was also kept as control specimen. The thermally treated rods were subjected to various degrees of cold work. 10 %, 15%, 20%, 30% degrees of cold work were used. Hardness, tensile strength and elongation of the samples were determined. The metallographic examination of the samples was also carried out. Results of mechanical property test show sensitivity to degree of cold work, thermal treatment soaking time. The microstructures of the alloy also show significant modifications as a result of thermal treatment.
