Corrosion inspection of the water circulation cooling system of injection molding machines

Cooling systems (CO) are used in various industries. Often, they are a structure of different metals that are subject to contact corrosion. For this reason, aluminum alloys used in CO may lose their corrosion resistance. In this regard, it is important to conduct timely examination of CO. In this work, the water circulation cooling system of injection molding machines of the Swiss company Netstal Maschinen AG PetLine was studied. Determination of the causes, nature and rate of corrosion of CO through a visual examination, familiarization with the history of operation of CO, recommendations of service organizations, anti-corrosion measures and identified damage was carried out. The effectiveness of the inhibitor used in relation to the aluminum, copper and steel that makes up the CO parts was determined using linear polarization resistance and microscopy methods. It has been shown that the main reason for the increased corrosion rates of CO parts is the high content of oxygen and copper ions in the water used. In this case, a short-term increase in temperature in the system can lead to a significant acceleration of the corrosion rates of aluminum and copper, while the corrosion inhibitor used is primarily intended to reduce the corrosion rate of steel parts.