Control of Warpage During Machining

The increased use of large aluminum-alloy forgings for structural components of the jumbo jet air transport brought attention to bear on the costly distortion problem associated with machining these forgings.

This paper discusses one warpage problem-the floor beam-and its solution. Investigation showed that distortion is due primarily to the relief of residual quenching stresses by machining, and that the amount of distortion depends upon the magnitude, distribution, and locations of these stresses within the part. Control of this condition and improved packing and storage methods resulted in a greatly reduced distortion incidence.