Among the zinc and zinc alloy coated steels used in automotive bodies, galvannealed (GA) sheets are the most widely accepted due to their superior spot weldability, paintability, corrosion resistance after painting and improved scratch resistance. Though galvannealed layers have the preceding advantages, they suffer from an inherent drawback in the form of poor powdering resistance due to presence of hard and brittle intermetallic phases. This powdering resistance mainly depends on the distribution and orientation of different phases in the coating. Since, almost 75% of the coating is covered by the delta phase; the powdering behaviour of the galvannealed coating is expected to be primarily governed by the texture or crystal orientation of the above phase. The present research deals with the effect of galvannealing temperature on texture and its subsequent effect on powdering behaviour of galvannealed coatings on High Strength Interstitial Free (HIF), Dual Phase (DP) and Transformation Induced Plasticity (TRIP) aided steels. It has been found that in galvannealed coating on HIP steel a (01.3) pyramidal type of fiber texture is formed in the delta phase, whereas (01.3) along with (01.2) type of fiber textures are formed in the delta phase over the DP and TRIP steels. The powdering resistance behaviour of coatings is enhanced with increasing continuity of the above fibers.
Effect of galvannealing temperature on texture and powdering behaviour of galvannealed coating on different grades of steel
Einfluss der Galvannealingstemperatur auf die Textur und das Pulverisierungsverhalten der Galvannealing-Beschichtung bei verschiedenen Stählen
2011
8 Seiten, 3 Bilder, 4 Tabellen, 14 Quellen
Aufsatz (Konferenz)
Datenträger
Englisch
IF-Stahl , TRIP-Stahl , Dualphasenstahl , hochfester Stahl , chemische Zusammensetzung , Beschichtungsverfahren , Temperatur , metallischer Überzug , Zink , Zinklegierung , Mikrostruktur , Textur , Pulverisierung , Korrosionsbeständigkeit , Schweißbarkeit , Kratzfestigkeit , Fahrzeugbauteil , Karosserieanbauteil , Manganstahl
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