TENSIONED BODY PANELS PREVENT DISTORTION AFTER WELDING

Ripples that result from welding distortion when thin sheets are attached to a structure cannot be tolerated in the case of rail passenger vehicles. The problem is particularly acute in the case of aluminum or stainless-steel rolling stock which is not painted after assembly. Kawaski Heavy Industries has succeeded in developing fabrication methods which can virtually eliminate post-welding distoration, procedures applied in the construction of stainless-steel rapid transit cars for the New York City Transit Authority. To introduce residual tensile stress which cancels out the compressive stresses normally produced by welding, Kawasaki uses a combination of stretching and heating of plate before it is welded to framing members. Having applied the process successfully to carbodies, it is now expected to be used in other areas where thin sheets are welded to structures.