METHODS FOR PREVENTING CORROSION OF MATING SURFACES OF HINGES AND A BODY FRAME IN AUTOMOBILES

摘要

Bolted hinges are an integral part of the automotive closures. Hinges are usually metallic materials typically made of steel or iron. They are bolted to body frame and door inner in body shop. As a result, when the BIW assembly with closures is taken through paint process (including phosphating, electro deposition and top coat), protective coat does not reach mating surfaces between hinge and body frame. Due to that, these mating surfaces will start corroding over a period of time. This paper reviews an innovative method to prevent such corrosion using a very economical technology using corrosion protection sticker. Idea is to seal moisture entry in to mating surfaces by placing a sticker, which is impregnated with an anaerobic acrylic adhesive. Balance between material costs and ease of application with 75% lesser cost as compared to the existing technology was achieved. Adhesive performance was analysed by measuring the most crucial parameters - corrosion resistance, and its compatibility with pre-treatment (PT) and cathodic electro deposition (CED) coating, and ability to withstand oven temperature which is more than 190°C. Laboratory tests were conducted at both component level as well as vehicle level. In laboratory trial, it passed both the tests. In component level trial, no corrosion was found in the covered area. The proposed technology is first time in the automotive industry.