MgO-C bricks are widely used as converter refractory lining in the steel industry,meanwhile,the use of patching materials can improve work efficiency of converter and service life of lining.During using service,the refractories used in converter suffer mechanical stress of weight of lining,thermal expansion stress,and thermal stress due to uneven temperature distribution.Among them,mechanical stress takes a small part.Thermal stress is one of the important factors causing damage of lining refractories of steelmaking converter,and if the thermal stress of interface between MgO-C bricks and patching materials is large,it is not good for the patching materials bonding on the surface of MgO-C bricks,which does harm to service life of converter.Thermal stress simulations by the finite element method ( FEM) are widely used to analyze refractory damage caused by mechanical factors.In previous studies,it focuses on thermal stress of the furnace shell and MgO-C bricks,few reports have discussed the interface stress of MgO-C bricks and patching materials.The stress field of MgO-C bricks and patching materials used in the converter was simulated by finite element method.The effects of property parameters ( thermal conductivity,thermal expansion coefficient and elastic modulus) of MgO-C bricks on thermal stress of interface between MgO-C bricks and patching materials were researched.The results show that there is a exponential relationship between thermal stress and the thermal conductivity of MgO-C bricks,when thermal conductivity of MgO-C bricks ranges from 11W/( m·K) to 13W/(m·K),the reduction of thermal stress is large.The greater the thermal conductivity of the materials is,the faster heat transfers,temperature can be easily stabilized,the tensile stress is smaller,the crack growth rate is shortened.Thermal stress of interface between MgO-C bricks and patching materials has linear relationship with elastic modulus and thermal expansion coefficient of MgO-C bricks,which increases with the increase of elastic modulus and thermal expansion coefficient.This is bacause the elastic modulus and thermal expansion coefficient of MgO-C bricks are larger,the deformation shape is laeger.Use a slightly lower purity magnesia to make MgO-C bricks,impurity phase in the grain boundary has a large proportion,the width of the grain boundary is large,it can reduce thermal expansion coefficient of MgO-C bricks in order to reduce thermal stress.