The article aims at presenting a study into disruptions in a network supply chain of metallurgic products. The research was carried out in the years 2011-2013. Network supply chains include key chain links for building the resistance. These chain links affect material flows of the whole supply chain through silencing disruptions. Those predisposed to form a strategy strengthening the resistance of the whole network supply chain are organizations fulfilling the assumptions of flagship enterprise. The research is carried out in two stages: the stage of identification of disruptions (risk factors) and the stage of identification of strengthening disruptions zones. The authors carried out simulation experiments based on three models built in the management system dynamics technique (VensimDSS). The proposed methodology required constructing original tools for measuring disruptions and zones strengthening the disruptions in the form of cards for measuring disruptions. The value added is grouping of disruptions in risk factors distinguished in terms of the frequency of the occurrence of disruptions and their results. The authors proposed and defined the notion of zones of strengthening disruptions. The zones are formed from sets of factors strengthening disruptions with similar influence on disruptions. The IT system composed of a module for identification of disruptions in material flows and a simulation model is a proposal dedicated to organizations controlling material flows in a network supply chain in the conditions of disruptions.