High energy synchrotron X-ray diffraction is widely used for residual stress evaluation. Rapid and accurate conversion of 2D diffraction patterns to 1D intensity plots is an essential step used to prepare the data for subsequent analysis, particularly strain evaluation. The conventional multi-step conversion process based on radial binning of diffraction patterns ('caking') is somewhat time consuming. A new method is proposed here that relies on the direct 'polar transformation' of 2D X-ray diffraction patterns. As an example of using this approach, residual strain values in an Al alloy bar containing a Friction Stir Weld (FSW) and subjected to in situ bending were calculated by using both 'polar transformation' and 'caking'. The results by the new approach show good agreement with 'caking' microstrain evaluation. However, the 'polar transformation' technique simplifies the analysis process by skipping 2D to 1D conversion and opens new possibilities for robust 2D diffraction data analysis for strain evaluation.