AN EXPERIMENTAL AND SIMULATION RESEARCH ON THE DIFFUSION BEHAVIOR OF A LOW CARBON STEEL PLATE IN A CAST IRON CASTING

摘要

In the present research, low carbon steel plates with various thicknesses, 2 mm, 5 mm and 10 mm, are inserted in a block casting of 200x200x60 mm. After pouring cast iron, the carbon and silicon contents of the plate and the block are analyzed. The results show a significant change in the carbon content of the plate as well as of the cast iron block, whereas this variation is not found in the silicon content. Although the carbon content near the surface of the 2 mm plate increases up to 1.1%, resulting in a decrease of the liquidus temperature of the steel, the liquidus temperature is still higher than the pouring temperature of the cast iron. Under these conditions, the steel plate cannot melt. The thickness of the carbon diffusion layer in the block depends on the thickness of the plate due to the chill function. At an increasing plate thickness, the thickness of the diffusion layer in the block decreases. Metallographic examination supports this conclusion. A numerical model that can simulate the diffusion between two different materials has been developed. The diffusion model is based on Fick's second law. The diffusion of carbon is calculated during solidification and cooling. Based on the experimental data, the diffusion coefficient of carbon as a function of temperature has been obtained.