Effect of jumping current on corrosion behaviors of stainless-steel and steel water pipeline separated by insulating joint

Corrosion behaviors of intrinsic jumping current in “pipe-in-pipe method”, a trenchless pipeline renewal techniques, were studied. Laboratory demonstration clearly showed that the current was generated by an electromotive force derived from environmental difference at joint section among soil and water, and that the amount of current was determined by sum of various resistance components involved in electrochemical current pathway. Value of the current decreased as the coupling distance increased. In the case of using stainless steel new pipe, almost no distance dependence was observed and the current was considerably small because of its high corrosion resistance.