Metal founding – Means to shape metallic material – Continuous or semicontinuous casting
Reexamination Certificate
1999-06-10
2001-01-23
Lin, Kuang Y. (Department: 1722)
Metal founding
Means to shape metallic material
Continuous or semicontinuous casting
C164S138000
Reexamination Certificate
active
06176298
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to continuous casting moulds and to the use of such moulds.
Moulds which are employed in the continuous casting of steel have a mould passage extending from the inlet end to the outlet end. The shape of the mould passage is arranged to produce at the outlet end a casting of the required dimensions, and a slight taper may extend along the length of the mould passage, in the direction of casting, to counteract shrinkage of the casting during soldification.
The wall of the mould passage may be defined by one metal body of tubular form or in the case of square and rectangular sections the wall of the mould passage may be defined by four copper cooling plates which are clamped together.
In use, molten metal is introduced into the inlet end of the mould passage at such a rate as to form a liquid metal meniscus in the mould passage, and cooling is arranged so that a solid metal shell containing a liquid or “mushy” core is withdrawn from the outlet end of the mould passage.
If care is not taken, the casting can contain defects such as surface cracks and non-metallic particles and these can cause the casting to be rejected. Furthermore, bulging is a frequent defect caused by mould wear and this leads to internal cracking of the casting and rupture of the shell can occur.
It is known from EP-A-448773 to line a continuous casting mould with pieces of tiles of ceramics having resistance to wear, heat and thermal shock, heat conductivity and lubricating property, and of progressively reducing thickness to prevent the formation of air gaps between the surface of the lining and the solidifying shell, and cool the steel being cast according to a desired pattern, and/or to start solidification of the molten metal below the molten metal surface level.
Variations on this are to be found in JP-A-04123846 and JP-A-02220736 (and see also FR-A-812802).
SUMMARY OF THE INVENTION
In contrast and according to the present invention, the lining comprises a continuous coating the maximum thickness of which is 5 mm, and the thickness of the coating is different at first and third regions from that at a second region of the mould passage, said first and third regions being closer to the inlet end and the outlet end respectively than is the second region, and the thickness of the third region being greater than the thickness of the second region.
It is an object of the present invention to provide a continuous casting mould in which these difficulties are at least partially overcome.
According to the present invention a continuous casting mould has a mould passage extending from the inlet end to the outlet end of the mould and which is defined by at least one metal body, and wherein the wall of the mould passage has a non-metallic coating thereon and the thickness of the coating is different at first and third regions from that at a second region of the mould passage, said first and third regions being closer to the inlet end and the outlet end respectively than is the second region. In use the meniscus of molten metal is intended to be present at the first region and solidification of the molten metal may commence in contact with the first or second regions of the mould passage.
By providing the non-metallic coating in varying thickness the heat transfer in the mould can be designed such that the meniscus can be further separated from the region where solidification commences.
The non-metallic coating is conveniently a metal carbide ceramic composite, which in addition to reducing the heat transfer in the mould also reduces wear of the mould, and this means that the accurate mould dimensions are maintained for longer periods than has been the case hitherto.
The thickness of the coating can be greatest in the first region where it is intended that the meniscus will be present, and at this region it may be between 0.3 mm and 5 mm on the wall of the mould passage.
Electric heating elements may be positioned in the wall of the mould passage at the region where the meniscus is to be present, and the coating is applied to the wall to overlie the heating elements.
At the second region, where solidification may commence, the thickness of the coating, which is less than at the first region, may be of the order of 0.03 mm to 0.75 mm.
At the third region, i.e. near the mould outlet, the thickness of the coating, which may be greater than at the second region, can be say 0.25 mm to 1 mm in order to reduce wear.
REFERENCES:
patent: 5499672 (1996-03-01), Nakashima et al.
patent: 1217314 (1987-02-01), None
patent: 833394 (1952-03-01), None
patent: 846900 (1952-08-01), None
patent: 3427756 (1985-03-01), None
patent: 3336373 (1985-04-01), None
patent: 0228335 (1987-07-01), None
patent: 0383934 (1990-08-01), None
patent: 0448773 (1991-10-01), None
patent: 812802 (1937-05-01), None
patent: 2073634 (1981-10-01), None
patent: 2174320 (1986-11-01), None
patent: 56-080356 (1981-07-01), None
patent: 59-073153 (1984-04-01), None
patent: 63-180347 (1988-07-01), None
patent: 02220736 (1990-09-01), None
patent: 04123846 (1992-04-01), None
Search Report relating to corresponding PCT application No. PCT/GB 97/02808.
Search Report relating to corresponding British application No. GB 9721452.2.
Davy (Distington) Limited
Lin Kuang Y.
Trexler, Bushnell Giangiorgi, Blackstone & Marr, Ltd.
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