JPS6035035Y2 - graphite crucible - Google Patents

Description

[Detailed description of the invention] This invention relates to graphite crucibles used for melting and refining non-ferrous metals, and is aimed at improving durability and stable use.

Traditionally, graphite crucibles have been discarded due to chemical erosion of the molten metal, erosion by additives such as flux, which thins the crucible, and eventually causes holes, and disposal due to temperature increase due to the burner in the catalytic furnace. Depending on the thermal effect at the time and the position of the burner, the flame rays may directly hit the graphite crucible, and the graphite crucible may crack due to thermal spalling due to the temperature difference.

The former object occurs at the top, and the latter object occurs at the bottom or bottom.

In response to this phenomenon, material improvement in the conventional single-material structure lowers the content of C component in order to improve corrosion resistance.

This will weaken the cracking resistance. On the other hand, if the content of the C component is increased in order to improve the side-closing property, the corrosion resistance will naturally deteriorate, and due to contradictory properties, one has to be sacrificed, and sufficient durability cannot be obtained.

Moreover, there are over 1,000 companies nationwide who use graphite crucibles.
A single configuration was extremely unsuitable for different usage conditions such as crucible size, furnace body, burner usage, melting metal, and melting time.

Therefore, the inventors of the present invention constructed the lower part, which is strongly affected by the burner wire entry, using a crack-resistant material, and the so-called slag line part (upper part), where reactions with molten metal and flux occur, using a material with excellent corrosion resistance. This solved the problem mentioned above.

To explain this invention with reference to a drawing example, in a graphite crucible for non-ferrous metals, a corrosion-resistant material part 1 with excellent corrosion resistance is placed on the upper part of the side wall at any horizontal position, and a crack-resistant material part 1 with excellent crack resistance is placed on the lower part. Table 1
The materials shown in can be applied.

Incidentally, as in the embodiment shown in FIG. 1, an intermediate material part 3 having an intermediate C component may be interposed between the corrosion-resistant material part 1 and the crack-resistant material part 2.

Next, we will discuss the materials used in this idea.

In short, a material with excellent corrosion resistance is mainly composed of SiC with a C content of 35% or less, and as a material for improving corrosion resistance, it is preferable to use Al.
It is made by adding 2O3, MgO, etc.

Further, as a material with excellent crack resistance, it is necessary that the material is mainly composed of SiC and contains 35% or more of C.

This idea seems to have been described above, and with this idea, it is possible to appropriately select the crack-resistant material for the lower part and the corrosion-resistant material for the upper part, depending on the usage conditions of the graphite crucible, especially the height position of the burner flame line and the position of the slag line. This eliminates the need for cracking and waste, fully exhibits corrosion resistance, and improves durability and ensures stable use.

By the way, when I put it into practical use with a #4 hammered shape and a two-layer structure with the upper part made of the material marked ■ in Table 1 and the lower part made of the material marked ■, out of 100 pieces, none were discarded due to cracking, and the service life was 100 to 12. (
It had a long life and was stable.

In addition, with the conventional single product, 20 pieces out of 100 were broken and discarded.
There were ~25 pieces, and the average service life was as low as 30-60.

[Brief explanation of the drawing]

The drawings show an embodiment of this invention; FIG. 1 is a longitudinal sectional front view, and FIG. 2 is a longitudinal sectional front view of another embodiment. 1...Corrosion-resistant material part, 2...Crack-resistant material part, 3...Intermediate material part.

Claims (1)

[Scope of utility model registration request] A graphite crucible for non-ferrous metals, characterized in that the upper part of the side wall is made of a material having excellent corrosion resistance and the lower part thereof is made of a material having excellent crack resistance at any horizontal position.