The Study of the Steel Sheet on the Chipping Resistance in Low Temperature for Automotive Body

摘要

Due to continued customer demand for better quality and more durable coatings of car body, interest in improving the physical damage resistance of automotive coatings has intensified. Stone chip resistance remains one of the major concerns among the various mechanical durability. Stone chipping resistance can be defined as the ability of a multi-layered coating systems applied onto a substrate to withstand d impact of foreign particles without damage. Moving automobiles are often subjected to impact by lofted stones. It was caused specific damages of coating systems, such as delamination, paint loss, or fracture of interlayer. And the delamination at the metal-polymer interface can lead to corrosion. So, stone impact damage automotive paint has drawn significant attention not only automobile manufactures but also steel sheet suppliers. We study the stone impact response in low temperature of Galvannealed (GA), ElectroGalvanized (EG) steel sheets in a so-called chipping resistance and detected impact induced corrosion. After the stone chip resistance tests were carried out on various standards, we evaluated the number of hits down to the metal on steel substrate. And we analyzed chipping characteristics by using Scanning Electron Microscope(SEM), Salt Spray Tester(SST), Corrosion Cyclic Tester(CCT).