Abstract: A welded joint with a cross crack in a hard weld or HAZ is simplified to be a model of the strip with a longitudinal sandwiched hard layer containing a crack perpendicular to interfaccs,The J-intergral, COD at the centre of the crack and load-point-displacement in models containing a hard layer of different width are calculated by means of the elastoplastic FEM under plane stress condition. The effects of mechanical heterogeneity are described by a comparison of the results obtained by the FEM with those estimated by the EPRI engineering approach for homogeneous material. The results of our study show that in the nonlinear stage, the effects of heterogeneity are similar to those in the models with a transverse sandwiched hard layer containing a crack parallel to the interfaces. The ratios of the values calcuted by the FEM for heterogeneous models to those by the EPRI approach can be regarded as modifying coefficients.