Abstract: A device for heating components of tools and machines has another ring and an annular or tubular part which is surrounded by the outer ring. The annular or tubular part has a heatable surface and may constitute a tool or machine component or, alternatively, may be designed to be slipped onto such a component. The outer ring and the annular or tubular part cooperate to define a space and an electrical resistance heating element is received in this space with no play. The outer ring and the annular or tubular part have one or more pairs of abutting surfaces and the abutting surfaces of each pair are joined at their outer margins by a continuous weld seam. The weld seam or seams join the outer ring and the annular or tubular part to one another and provide gastight and liquidtight seals between the space containing the heating element and the atmosphere. The outer ring has a coefficient of thermal expansion less than or equal to that of the annular or tubular part.