In addition to extrinsic modification of a surface with coatings, processes can be performed which intrinsically change the surface characteristics.
The performance of manufactured steel is strongly dependent on process-induced structural changes. In the case of razor blades, mechanical processes such as punching and sharpening can induce tensile residual stresses, while heat treatments can be used to mitigate relieve the stress. X-ray Diffraction is an industry standard method for residual stress measurement.