### Simulation of hydrogen diffusion in welded joint of X80

2014-12-4 · gradient of the hydrogen concentration at the lattice sites CL but also by the gradient of the hydrostatic stress σh, so J is given by LLH LL h DCV D RT JC (2) where DL is the diffusion coefficient of hydrogen at the lattice sites, VH is the partial molar volume of hydrogen, R is the gas constant, i.e., 8.314 J/(mol·K), and T denotes