Latest Developments in Coating Technologies for Molds and Rolls

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• 作者：Thomas MaarDaniel Pl(a)tzerChad DonovanUwe Schroeter
• 会议时间：2013-10-22
• 关键词：HVOF ; plasma ; furnace rolls CGL/CAL ; molds ; coating
• 作者单位：Thomas Maar(SMS Siemag AG Düsseldorf,Germany)Daniel Pl(a)tzer(Duma Bandzink,Langenfeld,Germany)Chad Donovan(SMS Millcraft,Oil City,USA)Uwe Schroeter(Service China,Beijing,P.R. of China)
• 母体文献：第九届中国钢铁年会论文集
• 会议名称：第九届中国钢铁年会
• 会议地点：北京
• 主办单位：中国金属学会
• 语种：chi

摘要

Today,the service life of core components is playing an ever more decisive role whenever it becomes necessary to save costs while at the same time increasing plant availability.Technological coatings are a tried and tested yet up-to-date means to extend service lives.Against this background,the coating of components has become more and more important.In comparison with uncoated components,the right coating for the right application can help to multiply the service life of core components.SMS Siemag has recognized this trend early on and therefore has significantly promoted both the development and the application of new coating methods.In addition to a large variety of possible applications,this paper focusses on the rollers of annealing and electroplating plants as well as the molds of continuous casters.This decision was based on the fact that in such plants these components suffer much wear but,at the same time,have a decisive effect on the quality of the final product.The automotive industry for example requires steel grades of high strength and good formability.The AHSS steel grades used for this purpose have high manganese and silicon contents,which in the furnace atmosphere of annealing plants adversely affect the installed furnace rollers.Chemical reactions taking place between the furnace rollers and the AHSS strip can lead to so-called manganese or silicon pick-up on the roller surface.This pick-up in turn can damage the strip surface,rendering the final product useless.In addition,a damaged furnace roller causes high costs due to the unscheduled opening of the furnace.SMS Siemag and its partners have developed a special carbide coating,the chemical composition of which prevents the formation of pick-up and furthermore ensures an extremely long service life of the rollers.In the steelmaking process,the mold of the continuous caster is the first component to come into contact with the surface of what is to become the final product.At the same time,this is where the most wear-inducing conditions prevail.The copper molds are very cost-intensive components.That is why they are at the center of attention when it comes to coating possibilities.In addition to increasing the service life,the coating also aims at preventing copper pick-up and improving the temperature control at the mold.Therefore,in addition to the classic nickel-coating method by means of dip plating or box plating,SMS Siemag uses the UniGardTM coating method.Here,a protective carbide coating is applied to the nickel layer by means of the HVOF process.This coating prevents premature abrasion of the nickel layer on the copper plates and protects the meniscus of the mold against damage due to friction of the solidifying strand and aggressive zinc deposits.In addition to the improved heat dissipation,the service life was able to be increased by a factor of 3 to 5 compared to conventional coatings.