Semi-geschmolzenes Thixogieß-Gießmaterial und Verfahren zu dessen Herstellung

摘要

A thixocasting semi-molten casting material has solid and liquid phases coexisting and a plurality of composite-solid phases having liquid and solid phase regions and a plurality of single-solid phases exist as the solid phases in an outer layer portion of the semi-molten casting material. If the sectional area of the solid phase region is represented by A, and the sectional area of the solid phase region is represented by B in one of the composite-solid phase, the liquid enclosure rate P of the composite-solid phase is defined as being represented by P = {B/(A + B)} x 100 (%). The liquid enclosure rate P of the single-solid phase is equal to 0 (%). When two groups are selected from a class of the solid phases, for example, by first and second straight lines so as to include a plurality of the solid phases, average values M1 and M2 of liquid enclosure rates of, for example, six solid phases in the first and second groups are represented by M1 = ( P1 + P2 --- + P5 + P6)/6 and M2 = ( P4 + P7 --- + P10 + P11)/6, and an average value MM of the average values M1 and M2 is set in a range of MM >/= 20 %. Thus, it is possible to inhibit the flow-out of the liquid phases from the outer layer portion in the thixocasting semi-molten casting material. This material is produced by raising the temperature of the outer layer portion preferentially to said main body portion to bring said outer layer portion into a semi-molten state.