Hisaki Watari

Hot forging of roll-cast high aluminum content magnesium alloys

This paper reports on hot forging of high aluminum content magnesium alloy sheets manufactured using horizontal twin-roll casting. AZ111 and AZ131 were applied for twin-roll casting, and a hot-forging test was performed to manufacture high-strength magnesium alloy components economically. For twin-roll casting, the casting conditions of a thick sheet for hot forging were investigated. It was found that twin-roll casting of a 10mm-thick magnesium alloy sheet was possible at a roll speed of 2.5m/min. The grain size of the cast strip was 50 to 70µm. In the hot-forging test, blank material was obtained from as-cast strip. A servo press machine with a servo die cushion was used to investigate appropriate forging conditions (e.g., temperature, forging load, and back pressure) for twin-roll casts (TRCs) AZ111 and AZ131. It was determined that high aluminum content magnesium alloy sheets manufactured using twin-roll casting could be forged with a forging load of 150t and a back pressure of 3t at 420 to 430°C. App...

An Unequal Diameter Twin Roll Caster for Aluminum Alloys Casting

An unequal diameter twin roll caster was adopted for the strip casting of the aluminum alloys. The diameter of the upper roll was 250 mm, and that of the lower roll was 1000 mm. The width of the rolls was 100 mm. 6111 aluminum alloy strip was-cast at speeds of 5, 10 and 20 m/min. This caster could cast the strip at the speeds higher than the conventional twin roll caster. The start of casting was very easy. The strip did not stick to the roll without the lubricant. This was the effect of the low separating force. The microstructure of the 6111 was not a columnar structure but near to the equiaxed structure. This caster was adopted with closed top nozzle and side dam plate and cooling slope. Lower superheat casting was carried out using the cooling slope.