Strength and Microstructural Features in ausextruded H13 Steel
강찬형Chan Hyoung Kang, 맹선재Sun Chae Maeng
Abstract
Mechanical properties and microstructures in the ausextruded AISI H13 steel have been studied. Carbon extraction replicas were examined to find the evidence for a fine carbide dispersion after ausfoming. The carbides in as-ausformed specimens were observed to be about 0.05㎛ of average size, whereas those in conventionally as-quenched ones were 0.22㎛. The ausformed specimens showed higher hardness and bending strength than the conventional ones. Upon tempering, the ausformed specimens maintained the same strength level with increasing temperature up to 500℃, in spite of the marked increase in carbide size. This result is interpreted as being attributed to the formation of cell substructures, which has been verified by thin film transmission electron microscope.