Fabrication of High Aluminum Content Mg alloys using a Horizontal Twin Roll Caster
This study was aimed for investigating of manufacturing high aluminum content Mg alloys using a horizontal twin roll caster. Recently, weight saving has been key issues for lighter transport equipments as well as electronic componen t parts. As alternative materials to aluminum alloys, developin g magnesium alloy with higher strength has been expected. Normally hi gh Aluminum content Mg alloy has poor ductility and is difficul t to be rolled because of its high strength. However, twin roll casting pr ocess is suitable for manufacturing wrought Mg alloys because materials can be cast directly from molten metal. In this study, manufact uring of high aluminum content magnesium alloy sheet using the roll casting process has been carried out. Effects of manufactur ing parameter, such as roll velocity, pouring temperature and roll gap, on casting was investigated. A microscopic observation of the crys tals of cross section of as cast strip as well as rolled strip was conduc ted. Keywords—AZ91, AZ111, AZ121, Magnesium alloys, Twin roll casting
Mathematical Modeling of the Twin Roll Casting Process for Magnesium Alloy AZ31
.................................................................................................................................. iii Acknowledgements ................................................................................................................. v Dedication ............................................................................................................................... vi Table of
Effects of production parameters on characteristics of magnesium alloy sheets manufactured by twin-roll casting
Purpose: : The purpose of the work is to establish a manufacturing process and technology to facilitate the economical manufacture of high-quality magnesium sheet alloys. Design/methodology/approach: Magnesium alloy AZ31B was used to investigate the appropriate manufacturing conditions for use in twin-roll strip casting. Temperatures of the molten materials and roll speeds were varied to find the appropriate manufacturing conditions. The effects of manufacturing conditions on possible forming were clarified in terms of roll speeds and roll gaps between upper and lower rolls. Findings: In the hot-rolling process, a temperature exceeding 200°C was chosen to keep cast products from cracking. An appropriate annealing temperature was effective for homogenizing the microstructure of the rolled cast sheets after the strip casting process. The grain size of the manufactured wrought magnesium alloys sheet was less than 10 micrometers. The obtained magnesium alloy sheet exhibited an equivalent limiting drawing ratio in a warm-drawing test. Research limitations/implications: AZ31 were used to investigate the appropriate manufacturing conditions for use in twin-roll strip casting. Casting temperatures were varied from 630°C to 670°C to find the best casting conditions. Roll casting speeds were varied from 5m/min to 30 m/min in order to examine which roll speed was appropriate for solidifying the molten magnesium. Practical implications: It was found that the cast magnesium sheet manufactured by roll strip casting could be used for plastic forming if the appropriate magnesium sheets were produced after the roll casting process. Originality/value: This paper showed the effectiveness of twin roll casting for magnesium alloys by a