The mechanical behavior of metal loss, localized in the heat affected zone of welded joints in low carbon steel pipes, was analyzed by mean of the finite element method, considering the non linear material behavior (plasticity). The numerical experimentation was done for metal losses of different length and depth, considering the kinematic hardening rule and pressurizing internally the pipe monotonically until the ultimate tensile strength was reached, to determine the limit load than it can support before the failure. Furthermore, hydrostatic testing with measuring of the deformation using strain gages placed in different locations of interest was realized, to verify the results obtained by mean of numerical experimentation, founding that is possible to operate a pipe with metal loss than generate stress near to yield stress, without to affect its global operation.