There are four types of load

namely medium pressure

bending moment

axial force

and shearing force

acting on small diameter tubes in the reheater's header of boiler equiped for 200 MW units in operation.Through calculation model of numerical solution

the influence of load property borne by the welded joints of small diameter tubes upon their stress concentration has been studied.Results show that the values of stress acting on three studied key points are as follows:the highest value is on the first point;the influence of bending moment upon stress concentration at the most dangerous points is most remarkable;and the effect of shearing force

axial force

and medium pressure ranks in the next.