Thin section high cooling rate solidification, thermomechanical processing and characterization of AISI DC53 cold work tool steel

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2019
Çardaklı, İsmail Seçkin
In this study, firstly, the solidification behaviour of AISI DC53 cold work tool steel was investigated by means of a cooling curve and its first derivative. Copper and sand wedge-shaped moulds were used to obtain various solidification rates. To reveal the cooling rate degree during solidification, the secondary dendrite arm spacing of the steel alloy was examined by scanning electron microscopy (SEM). The solidification rates of each section for both wedge steel samples were calculated by means of the secondary dendrite arm spacing using a research-based empirical relation from the literature. Secondly, as alternative method to conventional production methods involving thin section copper permanent mould casting (fast solidification) and water atomization (rapid solidification) of AISI DC53 cold work tool steel have been investigated. Thin slabs obtained by copper mould casting was homogenized at 1150°C for one hour and then hot rolling was be applied. After hot rolling, conventional heat treatment has been applied to thin slabs. The same heat treatment procedure has been performed for a commercially available AISI DC53 which is manufactured by thick section ingot casting and rolling. In order to investigate also the effect of rapid solidification on AISI DC53 tool steel, steel powder was produced by water atomization technique. Experimental results revealed that at the tip region of the cast specimen in the copper wedge shaped mould, the carbide size was 7–8 μm, where the solidification rate was approximately 4,830 °C·s-1. Thin steel slabs in permanent copper mould and rapidly solidified tool steel powder by water atomization have a more refined primary M7C3 carbides than commercially available steel.

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Citation Formats
İ. S. Çardaklı, “Thin section high cooling rate solidification, thermomechanical processing and characterization of AISI DC53 cold work tool steel,” Thesis (Ph.D.) -- Graduate School of Natural and Applied Sciences. Metallurgical and Materials Engineering., Middle East Technical University, 2019.