Metal injection mold with injection channel and cold plug, used for magnesium-based melt, has specified composition avoiding undesired interactions

摘要

The section of a mold coming into contact with magnesium melt comprises one of the following materials: tool steel, molybdenum, cobalt, tantalum, niobium, molybdenum-, cobalt-, tantalum-, niobium based alloy. The section is part of a mold lining constructed as a removable insert. In locations other than the lining, the mold is made from the same tool steel, a different tool steel, or a nickel-based superalloy. The mold is a metal injection mold. A heated (4) injection channel (3) is connected to the mold cavity (9). Between channel and cavity, a cooled (10) channel section (11) intervenes. This has a controller, to set the local channel temperature. The channel is shut-off by forming a cold plug of solidified metal. In a further channel section leading from the cooled section to the cavity, a pocket (15) intercepts the plug. The cooling device (10) is a cavity (13) around the channel, which carries a liquid coolant. The controller has a temperature sensor for the channel section (11) and/or the liquid coolant. Fluid flow and/or temperature are controlled. Control is automatic and is related to a given temperature of the channel section and/or the coolant temperature. Thermal insulation (12) intervenes between the cooling unit and the heating unit. This comprises a metal with a thermal conductivity less than 20 W/mK. The further channel section (14) is part of a mold insert (1) which includes the cavity (9).