Changes in toughness properties of liquid metal in the process of acid steel large ingot formation

Experimental data are given on the viscosity of molten metal answering the various structural zones of a 70-ton 34KhMAR acid steel ingot. The viscosity of molten metal increases from the periphery of the ingot towards its centre and from the bottom of the ingot towards its head. The main contributions to the variation in the viscosity of steel during solidification of the ingot are those of the segregation of chemical elements possessing different viscosity activities in binary iron melts and of the presence and the uneven distribution of nonmetallic inclusions throughout the width and the height of the ingot. A consideration of the viscosity of molten steel and of the latter's plastic properties in solid state evidences of a definite correlation between the two parameters