In this paper, we have studied hydrogen intrusion to HSLA steels during acid pickling to remove surface films before hot-dip galvanizing. For example, under certain circumstances, hydrogen introduced into steel during its manufacture, subsequent component fabrication, or in service may result in brittle failures at applied stresses far below the yield strength or the nominal design stress for the materials. However, HSLA steels may also give rise to some risks. Depending on design, the higher strength can evolve into better fatigue and crash performance, while maintaining or even reducing required material thickness. These steels have the potential to introduce weight savings while improving performance.

It is generally accepted that the transition from mild steel to HSLA steel occurs at yield strength of about 300 MPa. The number and the applications of new high-strength low-alloy (HSLA) steels with enhanced formability are constantly increasing. The penetration rate of hydrogen into the steel and exit rate from the steel were lower for higher strength steel. No protective coating, for example, palladium on the anodic side of the sample, is needed. The penetration and the permeability of hydrogen were measured using an electrochemical cell with hydrochloric acid on the one side of the steel sample and a solution of NaOH on the other side. The effect of pickling of high-strength low-alloy (HSLA) steels was investigated using a cell construction based on the Devanathan-Stachurski method with modified anodic surface treatment and hydrogen production using acid. However, in pickling of steels with higher strength, the penetration of hydrogen into the steel may cause severe damages. When normal low strength steels are pickled, hydrogen formed in pickling reactions does not have any significant harmful effect on the mechanical properties of steel. Pickling with hydrochloric acid is a standard method to clean steel surfaces before hot-dip galvanizing.

Acid pickling of martensitic steel