Research On The Crack Of The Continuous Temperature Sensor Made Of Aluminum And Carbon In Firing Process Based On The Thermal Stress

The continuous temperature sensor made of aluminum and carbon is the major elements to achieve the continuous temperature measurement of molten steel, but in firing process, the sensor in the bell type furnace will engender a large stress because of the uneven heating and locality temperature difference, there will be a head breakage in the sensor. In this paper, a research on the thermal stress and fracture in the firing process, combined with the firing temperature and the sensor strength of materials, is to improve the firing temperature, and increase the rate of finished firing sensor and it’s life.The main research contents are as follows:(1) The measurement of sensor strength of materials and the bell type furnace temperature on different locations during firing process. Simulate different firing temperature for three-point bending flexural strength test, and ensure it’s relationship between temperature; Measure the porosity and volume density in different temperatures, and ensure it’s relationship between temperature. Measure the temperatures at different locations of the bell type furnace in firing process, Analysis the furnace temperature distribution.(2) Establish the sensor thermal stress model using the ABAQUS finite element software. According to the characteristics of the sensor, in accordance with the ratio of the actual materials, research and identify material changes with temperature thermal parameters. Apply the different positions of the measured temperature as a thermal stress load to the model of the sensor, Find the maximum thermal stresses of the sensor and ensure it’s position and draw stress, strain and temperature versus time curve, determine the maximum stress position where may break and find the temperature of the segments.(3) Research the stability of the fracture using the ABAQUS finite element software. Take a numerical analysis the stability of the Fracture by solving the crack tip stress intensity factor, study the relevant factors affecting crack propagation at the same time, optimize the firing temperature in the bell type furnace sensor at last.The results show that the maximum stress point of the sensor models appears between400-500℃in the firing process, the cracked structure is also easy to extend in this temperature range, the actual production results also proved the correctness of this conclusion.