Patent ID: 7922484

Claim:
A rotary hearth furnace in which a rotary hearth being arranged between an outer circumference wall and an inner circumference wall includes an annular hearth frame, a hearth heat insulating material arranged on the hearth frame, a plurality of refractories arranged on the hearth heat insulating material, an outer circumference side corner refractory arranged to an outer circumference part of the rotary hearth through a first hearth curb casting, and an inner circumference side corner refractory arranged to an inner circumference part of the rotary hearth through a second hearth curb casting; wherein between the corner refractory of the outer circumference side or the inner circumference side and an outermost or innermost refractory, respectively, or between each of the plurality of refractories, a radius direction thermal expansion margin X defined by the following equation 2 is set, and if a width of the outer circumference side corner refractory is given as A and a height of the first hearth curb casting of the outer circumference side corner refractory is given as B, the following equation 1 is satisfied: X+A <√( A 2 +B 2 ) Equation 1 X =([ X 0=] a distance between an outer end part of the first hearth curb casting and an inner end part of the second hearth curb casting at an operation temperature)−([ X 1=] a total of lengths of the plurality of refractories and both corner refractories in a radius direction at a room temperature) Equation 2.