JPS6235003Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a small electric furnace used for heat treatment of wire rods, etc.

Annealing treatment of welded joints of steel wire is a heat treatment method performed after welding for the purpose of improving the mechanical and physical properties of the structure, such as softening and removing internal strain. , refers to the operation of cooling at a required relatively slow rate.

Conventionally, as a method of annealing this steel wire, there is a method in which both ends of a welded joint 1a of a steel wire 1 are gripped by electrodes 2 and 3 and heated with electricity for a certain period of time, as shown in FIG.

However, in this method, it is extremely difficult to control the current heating temperature to be kept constant by turning the current on and off, and the desired annealing effect cannot be obtained.

Additionally, there is a conventional method of directly heating the welded joint 1a with a burner 4, etc., as shown in Fig. 2, but this also makes it difficult to maintain a constant temperature by adjusting the flame, and the temperature changes each time. Therefore, it is not possible to obtain uniform and consistent annealing treatment.

Therefore, in the present invention, electrodes are provided at both ends of a heating pipe into which a material is loosely inserted, the heating pipe is covered with a heat insulating material, and a current is applied to the heating pipe through the electrodes to generate heat, thereby increasing the internal temperature. The present invention provides a small electric furnace suitable for, for example, annealing wire rods, which is configured to indirectly heat a material and can heat the material to a constant temperature without variation.

Hereinafter, the present invention will be explained with reference to examples and drawings.

This electric furnace is mainly composed of a heating pipe 5 made of a relatively high-resistance conductive material such as molybdenum, tungsten, or stainless steel, which generates heat by itself due to internal resistance when energized. An electric furnace 9 is constructed by fitting electrodes 7 and 8 so as to enclose the heating pipe 5 at both ends, and covering the outer periphery with a heat insulating material 6. The heating pipe 5 may be either a circular pipe or a square pipe, and it is preferable that the cross section has a uniform thickness and the diameter is the same over the entire length of the heat generating portion. Moreover, the electric furnace 9 is shown in FIGS. 4 to 6.
As shown in the figure, it is of a split type to facilitate the setting of the long wire rod 1.

T is a step-up transformer connected to the electrodes 7 and 8, and is configured to apply a current to the heating pipe 5.

The wire 1 is then inserted and held in the heating pipe 5 of the electric furnace 9, and a current is applied from the electrodes 7 and 8 via the step-up transformer T. The entire heating pipe 5 uniformly self-heats and reaches a predetermined temperature.
Further, the heat insulating material 6 prevents the temperature of the heating pipe 5 from decreasing and promotes the heat retention effect, and the wire 1 is indirectly and uniformly heated by the amount of heat of the heating pipe 5.

Therefore, the small electric furnace according to the present invention can be used, for example, in the annealing treatment of wire rods, using the heating pipe 5 at a constant temperature.
The welded joint 1a of the wire rod 1 is held inside for a certain period of time,
It is possible to heat the weld indirectly, and instead of directly heating the weld as in the conventional method, the outer periphery of the weld is heated evenly and indirectly at the heating temperature of the heating pipe 5, resulting in sufficient annealing to the inside of the structure. It has the advantage of being effective.

In particular, compared to the conventional direct heating method using burners or electrodes, it is easier to control the heating temperature using a heating pipe, and it is possible to maintain a constant temperature and always perform uniform annealing without variation. .

As mentioned above, the small electric furnace of the present invention is most suitable for heating a wire having a circular or square cross section.

[Brief explanation of the drawing]

1 and 2 are side views illustrating a conventional example of wire annealing, FIG. 3 is a longitudinal sectional view illustrating an embodiment of a small electric furnace according to the present invention, and FIG. 4 is a cross sectional view thereof;
FIG. 5 is a longitudinal cross-sectional view showing the divided state, and FIG. 6 is a cross-sectional view thereof. DESCRIPTION OF SYMBOLS 1... Steel wire rod, 1a... Welding connection part, 5... Heating pipe, 6... Heat insulation material, 7, 8... Electrode, 9...
…Electric furnace.

Claims (1)

[Scope of utility model registration request] A configuration in which electrodes are provided at both ends of a heating pipe into which the material is loosely inserted, the heating pipe is covered with a heat insulating material, and a current is applied to the heating pipe through the electrodes to generate heat, thereby heating the material inserted inside. A small electric furnace characterized by the following.