Abstract: In order to reduce the residual stresses which occur in the region of a fusion weld of two rail ends (1,2), in order to reduce, in particular to make uniform, the cooling-down rate and--associated with this--the crystallization process within the solidifying weld material, a casting mold is proposed which is equipped with a system of risers (9) and air vents (10) which are designed symmetrically with respect to a longitudinal center plane (5) and a transverse center plane (3) of the welded joint, the risers (9) and the air vents (10) being physically distributed as a function of geometric parameters of the rail foot (8) and of the weld bead (4), and the cross sections of the air vents (10) being dimensioned as a function of the cross sections of the risers (9).

Abstract: A self-opening closure for casting crucibles used in aluminothermic reactions and made of a high mechanical-strength, high boiling point inorganic material producing no gases when heated, the closure being composed of one or more sealing disk(s) made of a fibrous aluminum silicate, the ratio of the total thickness of the sealing disk(s) to its (their) diameter being 1:5 to 1:1, the melting point of the aluminum silicate being equal to or exceeding 1650.degree. C., and a metal plate between 0.1 and 3 mm thick mounted on the sealing disk(s).

Abstract: This invention relates to a prefabricated casting mold for aluminothermically welding rail ends spaced apart by a gap while simultaneously welding shut a fishplate hole in the region of each rail end, comprising two mold halves which, when assembled, form a cavity adapted to enclose the rail ends and being so widened in the region of the rail web and in the longitudinal direction of the rails that the two fishplate holes are located within the cavity, a pair of riser channels in each mold half, at least one of the riser channels in each half issuing centrally into the rail base region of the casting mold cavity and having at least one means of communication with the casting mold cavity in the rail web region, and the other of the riser channels in each mold half communicating with the casting mold cavity in the vicinity of a fishplate hole.