Les Cables De Lyon

Jean-Claude Bourget

A method of sequentially annealing and then hardening long metal components (1,2,3,4) made of fine or special steel with an austenitic structure, said method including at least one annealing operation by supplying heat from the outside in a reducing or neutral atmosphere and one quenching operation by contact with a flow of cooling fluid and an apparatus for putting said method into practice. The flow rate and the temperature of the cooling fluid are adjusted so that the components undergo no transformation of their austenitic structure during hardening. Application to annealing and hardening armoured electric components with conductor cores, inorganic insulant coatings and outer sheaths made of austenitic steel.

Apparatus for sequentially annealing and then hardening long metal

A method of manufacturing electric cable having compressed mineral insulation and a titanium sheath and at least one titanium inner conductor, said method including preparing a titanium sheath preform whose diameter is very much greater than that of the cable, then lengtening the preform by successive hammering and/or laminating operations between which the preform is annealed, wherein the titanium used contains not more than: 0.03% nitrogen; 0.25% oxygen; 0.015% hydrogen; 0.10% carbon and 0.30% iron; wherein its tensile strength is not more than 5.40 N/mm.sup.2 wherein its breaking strain is at least 22%, and wherein annealing operations are performed in a rare gas atmosphere at a temperature lying between 600.degree. C. and 640.degree. C.

Method of manufacturing electric cable having compressed mineral

Method for sequentially annealing and then hardening long metal

The mineral substance is mixed (2) with an organic binder, a cylindrical structure is extruded (4), said cylindrical structure having at least one internal duct, and being cut (9) to portions of determined length before undergoing (10) heat treatment to cause the organic binder to burn, then being inserted (12) while hot in a metal sheath-forming tube, then the conductor(s) is (are) passed through the internal duct(s). Application to manufacturing heating elements or thermocouples.

Method of manufacturing a preform for mineral-insulated electric cable

Cable ends (1 and 2) are to be joined. The cables are armored by stainless steel sheaths, and have two conductors (9 & 11, and 8 & 10 respectively) insulated by means of compressed mineral insulation (14). The cables are typically for thermocouples and have an outside diameter of a few millimeters. Joining proceeds as follows: The cable ends are reduced in diameter by swaging, e.g. with initial conical portions (5,4) followed by smaller diameter portions (7,6). The ends of the swaged portions are stripped to reveal the conductors which are joined end-to-end by welding. A longitudinally slotted length of tubing (3) is placed around the join, and the tubing is filled, via its slot, with powdered mineral insulation. The length of tubing 3 is then closed by welding, and the entire join is drawn down around the join to ensure that the entire joined cable is of uniform outside diameter.

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Issy les Moulineaux, France

Jean-Claude Bourget