CHANGE IN THE COMPOSITION AND STRUCTURE OF EUTECTIC CARBIDES DURING HEATING OF HIGH-SPEED STEELS

1. Eutectic carbides differing in composition and structure are formed in the cross section during solidification of ingots of complex alloy high-speed steels with 12% W-skeletonlike M6C in the axial zone and fanlike M2C in the peripheral zone. 2. There is a difference in the mechanism and temperature range of spheroidization of these carbides. Spheroidization of M6C carbides occurs at 1260-1280°C due to breaking up and subsequent coalescence of the platelets (rachia) of the carbide skeleton. M2C carbides undergo carbide transformation in advance of breaking up, forming carbides of the M6C and MC types. © 1979 Plenum Publishing Corporation.