In this work, direct potential measurements during cold rolling of zinc and X20Cr13
stainless steel were carried out in the rolling slit to follow the tribologic and galvanic
mechanisms of hydrogen formation and absorption on the surface of the working rolls made
of DHQ1 grade steel. An Ag/AgCl in 3.5 M KCl reference microelectrode was used to record
the open circuit potential of the electrochemical system roller-product immersed into
commercially relevant electrolyte (rolling emulsion) with a pH value of 4.5 and an
electric conductivity 46 mS cm-1. The potential shift into either negative or positive
direction of the rolls-product system gives information on the processes taking place at
the surface in the course of the friction. A detailed discussion of the in-situ
potentiometry experiments reveals a stationary situation established between the
destruction and repassivation of the surface structures during continuous cold rolling
accompanied with intensive hydrogen evolution. Galvanic coupling of the working rolls with
the product significantly intensifies the hydrogen embrittlement related problems of the
rolls. Atomic hydrogen is adsorbed on the surface and exhibits a pressure supported
absorption into the rolls during their whole lifetime.