Abstract: A semi-solid metal forming process using a cast billet and having the following steps: 1. heating the cast billet to a temperature above its recrystallization temperature and below its solidus temperature; 2. extruding the cast billet into an extruded column; 3. cutting the extruded column into at least one billet; 4. heating the billet from step 3 to a semi-solid state; and 5. squeezing the billet from step 4 into a cavity in a metal forming die set to form a part.

Abstract: A system is presented for monitoring, measuring and controlling tie bars in, for example, a die casting machine. In this system, an ultrasonic device is used to monitor stress, strain, load, bending and temperature changes in each of the tie bars (typically four). This ultrasonic system will sound an alarm and/or shut down the die cast machine if bending in individual tie bars exceeds a predetermined limit, or if the variance in the combined tie bar loads exceeds a predetermined critical limit. The system of the present invention is comprised of an ultrasonic device that monitors changes in tie bar length with applied load, transducers that send and receive the ultrasonic signals to and from the tie bars, a microprocessor to select the proper transducer and log the data, and a multiplexer that switches the transducer signals on command from the controlling microprocesor. Preferably, the tie bars are instrumented with four equally spaced transducers.