Abstract: In a method of fitting a top or a bottom to the body of a can, the top or bottom is placed inside a die having a rolling surface. The top or bottom has an inwardly rolled edge defining a support surface adapted to be substantially mated with at least part of the rolling surface. An end portion of the can body is inserted between this rolling surface and this support surface. Thrust is then applied to the can body until it causes the end portion to roll around and envelop the support surface. The corresponding machine comprises at least one rolling die incorporating a bush defining a first rolling surface facing radially inwards and a plurality of jaws disposed along a perimeter corresponding to the shape of the can. The jaws are movable towards an inside wall of this bush and are shaped to define at least part of a second rolling surface which faces radially outwards.

Abstract: The invention relates to a tool for opening a can with a top which is easy to open whereby the tool is directly connected to the top. Cans of this type can be opened easily with the tool according to the invention, as once the breaking of the weak line of the top has been initiated by an incision with the pointed end of the tool, the tool is turned sideways through the point of connection with the top, after which the ringed end portion of the tool is rotated like a key for opening cans until the weakened area of the top has been completely detached.

Abstract: The process relates to the welding of the cylindrical bodies of food cans in which the body is rolled with edges overlapping along a longitudinal welding line between resistance welding electrodes. The ratio of the radius of curvature of a first electrode with respect to the second is at least equal to 1.2. The material constituting the body is mild steel sheet having on one face at least, a protective conductive coating whose contact resistivity with respect to copper is at least 10.sup.-5 ohm/cm.sup.2. A material is selected having a ratio of the contact resistivity of a first face to that of the second at least equal to 1.2, and the material is rolled in such a way that the first face is in contact with the first electrode. The preferred materials have on each face a layer of tin of at the most 1.05 g/m.sup.2 and a composite layer of metallic chromium (5-140 mg/m.sup.2) and of chromium in oxidized form (1-30 mg/m.sup.

Abstract: The invention relates to mild steel sheet, having deposited on at least one of its major faces a sub-layer of tin in an amount of 0.1 to 1.05 g/l and a composite coating containing chronmium and chronmium oxide. The content of chromium in the composite coating is more than 5 .mu.g/cm.sup.2 while the content of chromium oxide in the coating, expressed in terms of chromium, is less than 2.5 .mu.g/cm.sup.2.The resultant sheets give improved welds when joined by electric welding and are particularly suited for making can bodies for food cans.