JPH02133146A - Horizontal continuous casting method - Google Patents

Abstract

PURPOSE:To cast a good cast slab without developing casting defect of segregation, etc., on surface of the cast slab by specifying thickness of the cast slab and casting velocity at the time of casting the cast slab with horizontal continuous casting method. CONSTITUTION:By using a mold arranged at one side of a holding furnace, the cast slab having >=2000mm<2> cross sectional area is continuously cast to horizontal direction. In this case, the thickness of the cast slab is made to >=6mm and <13mm and further, the product t.v of the thickness (t) of the cast slab and the casting velocity (v) is made to >=2400 and <=3600. That is, by thinning the cast slab, temp. inclination of molten metal in a mold is increased, and by increasing solidified velocity of the molten metal, the casting structure is made to fine, and in this result, shifting of segregation elements is made to difficult, and the development of the segregation is restrained and the effect of this phenomenon is increased by increasing the casting velocity.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for casting slabs by a horizontal continuous casting method using a mold provided on one side of a holding furnace. This invention relates to a horizontal continuous casting method for stably casting slabs of good copper-based alloy without causing casting defects such as segregation in the slabs.

[Conventional technology]

The horizontal continuous casting method uses a cooling mold with one central hole through which molten metal air is supplied from one end of the mold.

This is a method in which molten metal is solidified in a mold, and slabs are continuously pulled out horizontally from the other end. This method allows for miniaturization of the equipment and allows slabs to be shaped more closely to the product. It is widely used in the production of ferrous and non-ferrous alloys because the processing costs after the casting process are low.

Conventionally, when casting slabs by the horizontal continuous casting method to manufacture strips of copper-based alloys, the slabs had a plate thickness of 13 to 18+n.
It is cast in m.

[Problem to be solved by the invention]

However, among copper-based alloys, phosphor bronze in particular is an alloy with a wide range of solid-liquid coexistence during solidification, and as is well known, a so-called reverse segregation phenomenon occurs in which tin segregates on the surface of the slab during solidification of the molten metal. Therefore, in order to remove this reverse segregation layer, the surface of the slab or the surface of the blank after the slab has been rolled must be subjected to face milling by a certain amount, which is one of the causes of a decrease in yield.

The present invention has been made in view of the above circumstances, and provides a horizontal continuous casting method for stably producing good quality slabs without causing casting defects such as segregation in slabs of copper-based alloys. The purpose is to

[Means to solve the problem]

For the above purpose, the present inventor conducted extensive research on the thickness of the slab, casting speed, cooling conditions of the mold, and castability, especially the occurrence of segregation, when casting a copper-based alloy using the horizontal continuous casting method. layered.

As a result, it was found that when the thickness of the slab was reduced, the columnar crystals developed well, the dendrite arms basing became smaller, and the formation of a reverse segregation layer on the slab surface was suppressed.

In other words, as the slab becomes thinner, the temperature gradient of the molten metal in the mold increases, and the solidification rate of the molten metal increases, making the casting structure finer.As a result, it becomes difficult for the segregated elements to move, and segregation occurs. Furthermore, it has become clear that the above phenomenon becomes more pronounced as the casting speed increases.

Therefore, when casting a copper-based alloy by the horizontal continuous casting method, it is possible to produce a good slab without causing casting defects such as segregation on the surface of the slab.

Based on the above knowledge, the present invention makes the plate thickness of the slab 6 m or more and less than 13 on when manufacturing the slab having a cross-sectional area of 2000 as'' or more by the horizontal continuous casting method.

Furthermore, the plate thickness t (on+) of the slab and the casting speed V (mm/a
This horizontal continuous casting method is characterized in that the product t·v of kin, ) is 2400 or more and 3600 or less.

Next, the reasons for limiting the slab thickness and casting speed of the present invention will be explained.

The reason why the plate thickness of the slab is set to 61 or more and less than 13 nn is because 61
This is because if it is less than 1111, the flow of the molten metal in the mold will be poor and there is a high probability that the slab will break during casting, and if it is more than 13 nn, the effect of suppressing reverse segregation will not appear.

Thickness t (Im) of slab and casting speed v (mm/win,
) is set to 2,400 or more and 3,600 or less because if it is less than 2,400, the effect of suppressing reverse segregation is small, and the productivity in the casting process is greatly reduced compared to conventional technology. This is because if it exceeds 3600, there is a high risk of breakout occurring.

〔Example〕

Examples of the present invention will be described below in comparison with comparative examples.

A graphite mold is installed in the holding furnace of a horizontal continuous casting machine, and the first
Three types of phosphor bronze were cast using the combinations of slab thicknesses and casting speeds shown in the table, and the castability, such as the occurrence of cracks and breaks during g-molding, and the occurrence of segregation of the slabs were evaluated. In addition, Na 1~
3 is the case according to the present example, and Nα4 to Nα6 are the comparative examples.

These results are shown in Table 1 along with comparative examples.

In Table 1, Nα4 is the conventional condition, Nα5 and 6 are examples where the slab plate thickness is 1011111 and the casting speed is drastically changed.

As shown in Table 1, it was found that Nα1 to Nα3 according to this example could stably cast slabs with good castability and no porcelain segregation on the slab surface by the horizontal continuous casting method. did.

Table 1 [Effects of the Invention] As described above, according to the present invention, good copper-based alloy slabs can be stably produced without causing casting defects such as segregation in the slabs drawn from the mold. It becomes possible to do so.

Claims (1)

[Claims] (1) Using a mold installed on one side of the holding furnace, a cross-sectional area of 2
When continuously casting slabs of 000 mm^2 or more in the horizontal direction, the thickness of the slab should be 6 mm or more and less than 13 mm, and the slab thickness t (mm) and casting speed v (mm/min
．． ) product t·v is 2400 or more and 3600 or less.