Round Corner - or best fatigue performance and best value

We recommend the round corner design for all applications. This design results in the lowest corner stress if fit up and welding of the corner seams are carefully controlled.

Single Miter Corner - conventional design

We also recommend the single miter design for corner construction. If a corner preference is not specified, we will use the single miter design for all convolution profiles for lowest cost. This design allows for maximum amount of motion possible for a given convolution profile. The corner is a simple "picture frame" construction.

Double Miter Corner - value added - low corner fatigue

The double miter corner design offers lower corner fatigue than the conventional single miter corner or camera corner designs. Welds are positioned away from the centerline of the corner and the highest stressed area of the bellows.

Camera Corner - not recommended

We do not recommend the use of camera corner construction for rectangular metal expansion joints of any convolution profile. This is a method of assembly that allows all corner seam welding to be performed on the outside of the corner in a very accessible area with welders of lower skill level than would be required for a single miter corner. However, this style corner results in deep crevices at the corner that are corrosion initiators in certain flue gas conditions. The design also results in a reduction in movement capability.