MEASUREMENT OF HYDROGEN PERMEATION INTO STEEL BY USING HOLLOW BOLT AND SNO2 GAS SENSOR

A method using an SnO2 gas sensor and a specially designed hollow stee l bolt was proposed for evaluating hydrogen permeation into steel, whi ch is considered to be responsible for delayed fracture of steel. As m easured with the gas sensor, the concentration of hydrogen in the cavi ty of the hollow bolt after weathering tests increased in different ma nners depending on the weathering conditions and the kinds of steel. T his method was also applied to the dynamic measurement of hydrogen pen etration through the steel wall of the hollow bolt by continuously mon itoring the hydrogen coming into the cavity. Hydrogen diffusion coeffi cients estimated from this measurement were well consistent with the h ydrogen permeation data in the weathering tests, and showed reasonable dependence on phosphorus, silicon and vanadium contents in steel. (C) 1997 Elsevier Science S.A.