Method of casting steel strip in which molten steel solidifies as a shell on a chilled casting surface (100). The casting surface (100) has a texture (101) formed by a regular pattern of surface projections (103) and depressions (102) and the steel chemistry is selected to generate in the casting pool deoxidation products which form on the casting surface (100) a layer of less than 5 microns thickness a major proportion of which is liquid during cooling of the steel to below its liquidus temperature in the formation of said solidified shell. The substantially liquid layer suppresses the formation of surface defects in the solidifying metal surface due to early deposition of solid oxides on the casting surface.

Method of casting steel strip in which molten steel solidifies as a shell on a chilled casting surface (100). The casting surface (100) has a texture (101) formed by a regular pattern of surface projections (103) and depressions (102) and the steel chemistry is selected to generate in the casting pool deoxidation products which form on the casting surface (100) a layer of less than 5 microns thickness a major proportion of which is liquid during cooling of the steel to below its liquidus temperature in the formation of said solidified shell. The substantially liquid layer suppresses the formation of surface defects in the solidifying metal surface due to early deposition of solid oxides on the casting surface.

A process for the continuous production of a thin steel strip, in which a steel melt from a melt reservoir is introduced onto one or more, in particular two, cooled shaping wall surfaces which move synchronously with a casting strip, in particular rotate in the form of casting rolls and at least partially solidifies at the shaping wall surface to form the casting strip. The steel melt, in terms of the crucial alloying constituents, contains less than 1% by weight of Ni and less than 1% by weight of Cr and less than 0.8% by weight, in particular less than 0.4% by weight, of C and at least 0.55% by weight of Mn. In the process, recesses are arranged on the shaping wall surface in a random pattern, distributed uniformly over the shaping wall surface, and the roll separating force (RSF) at the shaping wall surface is set to a value of between 5 and 150 N/mm, in particular between 5 and 100 N/mm.

In twin roll casting of steel strip, molten steel is introduced into the nip between parallel casting rolls to create a casting pool supported on casting surfaces of the rolls and the rolls are rotated to deliver solidified strip downwardly from the nip. Casting surfaces are textured by a random pattern of discrete projections at least some of which include peaks having a surface distribution of between 5 and 200 projections per mm.sup.2 and an average height of at least 10 microns. The random texture may be produced by grit blasting the casting surfaces on a substrate covered by a protective coating. Alternatively the texture may be produced by chemical deposition or electrodeposition of a coating onto a substrate to form the casting surfaces.

Disclosed are a method and an apparatus for producing a uranium foil with fine crystalline granules by forming the foil by the gravitational dropping of molten uranium or uranium alloy and rapidly cooling the foil by the contact with cooling rolls, and a foil produced thereby. In accordance with the present invention, a high-purity and high-quality uranium foil with an isotropic structure and fine crystalline granules is easily produced via a simple process without requiring hot rolling and heat treatment processes. The surface of the foil is prevented from oxidizing and residual stress is not imparted to the foil. The productivity and the economic efficiency of the foil are improved.