JPH0691352A - Mold for continuous casting - Google Patents

Abstract

PURPOSE:To obtain a high quality cast slab by applying Ni base alloy plating having a specific composition on the inner surface of a mold main body for continuous casting. CONSTITUTION:Ni plating is applied all the inner surface of the mold main body for continuous casting made of copper or copper alloy. On the surface of recessed part in lower part of this Ni plating, in the range of 300mm from the lower edge Ni base alloy plating 7, which has a composition consisting of 1-15wt% Fe, 0.03-0.1wt.% and the balance Ni and a hardness of >=Hv400, is formed with a thickness of 0.5-3.00mm. By this method, mold dimensions are not impaired in a short term, there is no exposure of a base body of the mold main body 1, maintaining high quality of a cast slab, further, it obtains the mold for continuous casting, which unlikely has the damage resulted from generation of heat crack.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold used for continuous casting of steel.

[0002]

2. Description of the Related Art Since molten steel is poured into a continuous casting mold by a nozzle, heat resistance is required on the inner surface of the mold, and wear resistance is lower at the bottom of the mold where solidified slabs come into contact. Is required.

The conventional continuous casting mold has Ni plating or Ni on the inner surface of the mold body made of copper or copper alloy in order to obtain the above heat resistance and wear resistance and to improve the quality of the cast slab.
-Ni-based alloy plating such as -Fe alloy is applied. Examples of cross sections of conventional continuous casting molds are shown in FIGS. In the figure, 1 is a copper base material mold body, 2 is a Ni plating layer, and 3 is a conventional Ni-based alloy plating layer.

[0004]

In the prior art continuous casting molds only plated with Ni shown in FIGS. 4 to 6, the Ni plating is severely worn due to severe casting operating conditions and long-term use of the molds, and especially solidification. The lower part of the mold that comes into contact with the cast slab deteriorates the mold size early due to wear as shown in 4 of FIG. 9, or exposes the copper as the base material as shown in 5 of FIG. 9, which adversely affects the quality. Was there.

To prevent this, hardness Hv 350-60
Ni-Fe alloy or other high hardness Ni-based alloy plating layer 3
Is applied to the lower half or the entire surface of the mold body as shown in FIGS. However, this high hardness N
In the case where the i-based alloy plating layer 3 is applied, the ductility of the coating is inferior to that in the Ni plating, and when the entire surface is coated, the meniscus portion is discharged. Heat cracks were generated in the hit portions, as shown by 6 in FIG. This heat crack causes cracking or seizure of the slab, and therefore must be avoided for the mold.

The problem to be solved by the present invention is to solve the problems of the conventional continuous casting mold, to prevent the mold size from being deteriorated early, to prevent the base material of the mold body from being exposed, and to maintain the high quality of the slab. Another object of the present invention is to provide an excellent continuous casting mold that can be produced and is not damaged by the occurrence of heat cracks.

[0007]

Means for Solving the Problems The gist of the present invention, which has solved the above problems, is to provide Fe 1 to 15 within a range of 300 mm from the lower end of the inner surface of a continuous casting mold body made of copper or a copper alloy.
wt%, C 0.003 to 0.1 wt%, Ni based alloy plating with hardness of Hv 400 or more consisting of residual Ni 0.5 to
A continuous casting mold characterized by being formed with a thickness of 3.0 mm.

[0008]

According to the present invention, the inner surface of the mold body is placed at a position 3
Fe1 to 15 wt%, C0.00 within the range of 00 mm
Since the Ni-based alloy plating layer having a hardness of Hv 400 or more and having a hardness of 3 to 0.1 wt% and residual Ni is provided, wear of the lower part of the mold is reduced and exposure of the base material copper / copper alloy is prevented.
In addition, this Ni-based alloy plating has a C content of 0.0
Since it is contained in an amount of 03 to 0.1 wt%, the ductility of the film is excellent and damage to the mold due to heat cracks can be prevented.

[0009]

EXAMPLES Examples 1, 2 and 3 of the present invention will be described below.

Example 1 (see FIG. 1) In Example 1 shown in FIG. 1, the entire inner surface of a mold body 1 made of a copper base material is plated with Ni to form a Ni plating layer 2.
The upper half of the Ni plating layer 2 has a thickness of 0.5 mm, the central portion has a thickness of 3.0 mm, and the lower portion has a recess,
The thickness of Ni plating is 1.5 mm. This Ni
The surface of the recess below the plating layer 2 is 300
Within the mm, a Ni-based alloy plating layer 7 having excellent ductility obtained from a plating solution containing an organic compound having an enediol group is applied. The hardness of this plating layer 7 is from Hv 400 to
450, the composition of the film is 5.40 wt% Fe, C
0.024 wt% and residual Ni. The composition of the plating solution and the plating conditions for the Ni-based alloy plating layer 7 are as follows.

Metallic Ni 70 to 110 g / l Organic compound having an endiol group 5 g / l or less Boric acid 30 to 40 g / l Fe ²⁺ 5 g / l or less pH 3.5 to 4.5 Temperature 45 to 55 ° C. Current density 1-5A / dm ² plating thickness 1.5mm

In the continuous casting mold of this example, no crack was observed even when used, and the plating layer underneath was small in wear and could have a long life.

Example 2 (Refer to FIG. 2) In Example 2 shown in FIG. 2, the Ni plating layer is a region of about half from the bottom of the mold body 1, and the upper half is copper of the base material of the mold body 1. It is exposed. Others are the same as those in the first embodiment.
It is an electroforming condition.

In this example, good results close to those in Example 1 were obtained. In the second embodiment, the area for Ni plating can be reduced and the cost can be reduced. In the case of Example 2, instead of the Ni plating layer (2 in FIG. 2), a Ni-based alloy of Hv 250 to 300 obtained from a plating solution to which an organic compound having an enediol group is added may be applied.

Example 3 (see FIG. 3) As Example 3, as shown in FIG. 3, an organic compound having an enediol group was added within 300 mm from the lower end of the inner surface of the mold without Ni plating. In some cases, only a Ni-based alloy plating layer having an Hv of 400 or more obtained from the plating solution is applied. In Examples 1 to 3, Cr plating may be performed in the range of 1 to 100 μm for the purpose of preventing seizure of molten steel at the initial stage of casting or reducing the initial wear in whole or in part.

[0016]

As described above, according to the present invention, Fe1 to 15w is within a range of 300 mm from the lower end of the inner surface of the mold.
t%, C 0.003 to 0.1 wt%, and a Ni-based alloy plating layer having a hardness of Hv 400 or more, which consists of residual Ni, reduces wear on the lower part of the mold, suppresses the occurrence of cracks, and It could be used as a mold for longevity. This also improved the quality of the slab.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a first embodiment of the present invention.

FIG. 2 is a vertical sectional view showing a second embodiment of the present invention.

FIG. 3 is a vertical sectional view showing a third embodiment of the present invention.

FIG. 4 is a vertical cross-sectional view showing a conventional continuous casting mold.

FIG. 5 is a vertical sectional view showing a conventional continuous casting mold.

FIG. 6 is a vertical sectional view showing a conventional continuous casting mold.

FIG. 7 is a vertical sectional view showing a conventional continuous casting mold.

FIG. 8 is a vertical sectional view showing a conventional continuous casting mold.

FIG. 9 is an explanatory view showing a state of an inner surface of a conventional continuous casting mold.

[Explanation of symbols]

1 Mold body 2 Ni plating layer 3 Conventional Ni-based alloy plating layer 4 Lower wear part 5 Copper exposed part 6 Heat crack part 7 Fe1 to 15 wt%, C 0.003 to 0.1 wt
%, Ni-based alloy plating layer of Hv> 400 consisting of residual Ni

Claims (1)

[Claims] 1. Fe 1 to 15 within a range of 300 mm from the lower end of the inner surface of a continuous casting mold body made of copper or copper alloy.
wt%, C 0.003 to 0.1 wt%, Ni based alloy plating with hardness of Hv 400 or more consisting of residual Ni 0.5 to
A continuous casting mold characterized by being formed with a thickness of 3.0 mm.