Protective Coating for Steel Parts in the Automotive Industry
Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Hot stamping is a process developed in 1977 by Plannja Hardtech, now owned by Gestamp Hardtech. Through the use of high strength boron steel, it allows the formation of particularly light and strong parts that are used as structural elements in the automotive industry.However, during the process, undesirable oxides needing to be removed from the surface of the hot stamped parts appear. Until now, a variety of coatings on boron alloyed steels are used to reduce or eliminate the apparition of those oxides in the industry. However, Gestamp Hardtech is currently studying a new solution, i.e. controlling the adhesion of the iron oxide coating by tailoring the hot stamping parameters.The aim of this study was to provide further knowledge on the impact of different specific pre-treatments on boron steel surface parameters, specifically surface roughness, in order to obtain clear process parameters for future trials at Gestamp Hardtech. Moreover, another goal was to design at lab scale a setup allowing the reproduction of the apparition of an oxide layer similar to that created at Gestamp Hardtech during the industrial process with respect to surface roughness and adhesion to the steel substrate.In order to achieve these objectives, different analysis methods were used. Scanning Electron Microscopy (SEM) was used for microstructural observations on the surface of the steel samples. Contact and optical profilometry were performed in order to gather surface roughness data. Tape adherence testing was used as a way to evaluate the adherence of the controlled iron oxide layer.The study clearly shows how to obtain repeatable results using the different specific pre-treatments. Also, oxidation results in line with those produced at Gestamp Hardtech were obtained at laboratory scale. The conditions necessary to obtain good oxide adherence are given in the study.
Place, publisher, year, edition, pages
2014. , 70 p.
Technology, Boron steel, Hot stamping, Oxidation
IdentifiersURN: urn:nbn:se:ltu:diva-51680Local ID: 8e03cf49-7161-4f0f-bf5b-e14840c0b4a2OAI: oai:DiVA.org:ltu-51680DiVA: diva2:1025044
Subject / course
Student thesis, at least 30 credits
Materials Engineering, master's level
Validerat; 20140922 (global_studentproject_submitter)2016-10-042016-10-04Bibliographically approved