The thermophysical properties of API 5L X80 steel were experimentally measured, in order to use these in computational models to determine the temperature field in welded joints. In this work, values of thermal expans...The thermophysical properties of API 5L X80 steel were experimentally measured, in order to use these in computational models to determine the temperature field in welded joints. In this work, values of thermal expansion coefficient, specific heat, thermal diffusivity and thermal conductivity were experimentally obtained as a function of temperature. The thermal expansion coefficient was determined at temperatures of 20°C to 1200°C in a dilatometer DIL 402 PC. The specific heat was determined on a differential scanning calorimeter at temperatures between 300°C and 1200°C. The diffusivity and thermal conductivity were determined in the temperature range 100°C to 800°C in a 457 LFA diffusivimeter using laser flash technique. The thermal expansion coefficient remained approximately with constant value of 8.5 × 10-6 K-1 and suffered two falls reaching values -25 × 10-6 K-1 and -50 × 10-6 K-1 in the stages of heating and cooling respectively. It was observed for this material, minimum and maximum values of specific heat equal to 0.571 J/gK and 1.084 J/gK at temperatures of 300°C and 720°C, respectively. The behavior of thermal diffusivity and thermal conductivity in the temperature range 100°C to 800°C tends to decrease with increasing temperature. Based on the measured properties, computational modeling of the temperature field can be numerically obtained with better accuracy.展开更多
The Jahn-Teller distortion of C80 (D5 , C2 ) singlet was studied by ZINDO method. n ...The Jahn-Teller distortion of C80 (D5 , C2 ) singlet was studied by ZINDO method. n d v C80(D5 ) is more stable than C80(C2 ), which agrees with the experimental results. Jahn-Teller d v distortion happens in some ions for the C80 (D5d) singlet. Total energy of C80 singlet is affected by n n the increase of electric charges. Electronic spectra of C80 singlet were calculated and the reasons for n the red-shift of UV bands for some ions of C80 (D5 ) singlet compared with that of C80(D5 ) and the n d d blue-shift of UV bands for C80 (C2 ) singlet relative to that of C80(C2 ) were discussed. n v v展开更多
文摘The thermophysical properties of API 5L X80 steel were experimentally measured, in order to use these in computational models to determine the temperature field in welded joints. In this work, values of thermal expansion coefficient, specific heat, thermal diffusivity and thermal conductivity were experimentally obtained as a function of temperature. The thermal expansion coefficient was determined at temperatures of 20°C to 1200°C in a dilatometer DIL 402 PC. The specific heat was determined on a differential scanning calorimeter at temperatures between 300°C and 1200°C. The diffusivity and thermal conductivity were determined in the temperature range 100°C to 800°C in a 457 LFA diffusivimeter using laser flash technique. The thermal expansion coefficient remained approximately with constant value of 8.5 × 10-6 K-1 and suffered two falls reaching values -25 × 10-6 K-1 and -50 × 10-6 K-1 in the stages of heating and cooling respectively. It was observed for this material, minimum and maximum values of specific heat equal to 0.571 J/gK and 1.084 J/gK at temperatures of 300°C and 720°C, respectively. The behavior of thermal diffusivity and thermal conductivity in the temperature range 100°C to 800°C tends to decrease with increasing temperature. Based on the measured properties, computational modeling of the temperature field can be numerically obtained with better accuracy.
文摘The Jahn-Teller distortion of C80 (D5 , C2 ) singlet was studied by ZINDO method. n d v C80(D5 ) is more stable than C80(C2 ), which agrees with the experimental results. Jahn-Teller d v distortion happens in some ions for the C80 (D5d) singlet. Total energy of C80 singlet is affected by n n the increase of electric charges. Electronic spectra of C80 singlet were calculated and the reasons for n the red-shift of UV bands for some ions of C80 (D5 ) singlet compared with that of C80(D5 ) and the n d d blue-shift of UV bands for C80 (C2 ) singlet relative to that of C80(C2 ) were discussed. n v v
