Intergranular penetration of liquid 18 K gold into a superaustenitic stainless steel, which occurs during laser welding of these two materials, has been studied using a C-ring device which can be put under tensile stresses by a screw. It is shown that liquid gold at 1000 degrees C penetrates the immersed stainless steel C-ring at grain boundaries, but only when tensile stresses are applied. Based on the thickness of the peritectic phase that forms all along the liquid crack and on the transverse gold diffusion profile in steel, penetration velocities on the order of 10 mu m s(-1) are deduced. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.