Effect of Ferrite Grain Size on Tensile Behaviour of a Hydrogenated Low Alloy Steel

摘要

A low alloy steel containing 0.10C, 0.25Ci, 0.87Mn, 0.56Cr, 0.47Ni, 0.21Mo, 0.023S and 0.01P (mass was reduced by cold rolling to 1.6 mm in thickness and recrystallised at 700 deg C for 24, 72 and 120 h to get ferrite grains of 8, 21.5 and 32.5 um respectively along with a random distribution of some spheroidal carbide particles and a few inclusions. Tensile specimens prepared from these sheets were cathodically charged in 1 N NaOH, 0.1 N H_2SO_4 and 1.4 N H_2SO_4 solutions for periods varying from 2 to 24 h, with the current density of 50 mA/cm~2. Tensile test were carried out with the cross-head velocity of 1.2 mm/min and fracture surfaces were examined in SEM.