The non-uniform shrinkage and matrix strength of coke during coal carbonization have a great influence on the size of metallurgical coke. The influence of coal properties and carbonization conditions on the thermal stress and deformation of coke layer were evaluated by the carbonization test and a mathematical simulation model. The deformation was defined by the curvature of coke layer. The coke-fissure formation behavior in coke layer was investigated by the carbonization test using thin coal layer. The fissure distributions and curvature of coke layer were measured by X-ray computerized tomography. The thermal tensile stress leads to cause the curvature and coke fissure of coke layer. There is a good relationship between the curvature, fissures and size distribution of coke and the curvature and thermal stress distributions calculated by the mathematical simulation model. The contraction coefficient and Young's modulus of coal have a great influence on the thermal stress and deformation of coke layer. As the thermal stress in coke layer increases along with increase of the heating rate and transverse temperature gradient of coal layer, the size of coke is decreased. It was clarified that the thermal stress and deformation of coke layer are controlled by coal properties and carbonization conditions.
