US3339588A

US3339588A - Continuous casting mold

Info

Publication number: US3339588A
Application number: US463147A
Authority: US
Inventors: Nilles Paul
Original assignee: Centre de Recherches Metallurgiques CRM ASBL
Current assignee: Centre de Recherches Metallurgiques CRM ASBL
Priority date: 1964-06-13
Filing date: 1965-06-11
Publication date: 1967-09-05
Anticipated expiration: 1984-09-05
Also published as: NL6507471A; GB1090145A; BE664575A; LU46316A1

Description

Filed June 11, 1965 United States Patent 3,339,588 CONTINUOUS CASTING MOLD Paul Nilles, Embourg, Belgium, assignor to Centre National de Recherches Metallurgiques, Brussels, Belgium, a Belgian company Filed June 11, 1965, Ser. No. 463,147 Claims priority, application g ilrembourg, June 13, 1964,

46, 6 Claims. (Cl. 138145) The present invention relates to an ingot mold used for the continuous casting of metals and more particularly for the continuous casting of steel.

In vertical continuous casting of metals, the molten metal is poured in a continuous fashion into a ingot mold which, usually, is made of copper and is open above and below. The metal solidifies superficially in this mold to form a pseudo-ingot that is to say an ingot which is not completely solidified, which is drawn out from below down through the ingot mold.

The superficial solidification of the molten metal results from the intense cooling that it undergoes on making contact with the walls of the ingot mold which are cooled by the circulation of water.

In the course of the peripheral solidification of the metal it is however noted that the thin solidified skin tends to adhere or stick to the walls of the ingot mold so as to cause tearing as the ingot is drawn downwards by the extraction mechanism placed below the mold.

Prior art workers have suggested various remedies for preventing this tearing. For instance it has been suggested that the internal walls of the ingot mold should be lubricated and/ or should be caused to reciprocate vertically. However all these suggestions appear to have substantial disadvantages. Moreover the use of copper molds for continuous casting has the disadvantage that small molten particles or copper are plucked off from the internal walls of the mold and diffuse into the steel. In consequence the steel becomes red short as is testified by the appearance of flaws. In order to overcome this disadvantage it has been suggested that the inside of the mold should be chromium plated since chromium does not dissolve in steel at least not when it is used for lining continuous casting molds. It has also been proposed to line ingot molds made of copper with other metals such as molybdenum.

One particular object of the present invention is to provide a remedy for the disadvantages enumerated above.

The present invention is essentially characterised in that the faces of the ingot mold making contact with the ingot are constituted, partially or totally, of cobalt or a cobalt alloy.

In accordance with the invention, the walls of the ingot mold can be covered with a protective coating of cobalt applied by spraying, for example by means of a metal coating gun by means of a so-called plasma torch, one or several layers being applied.

Alternatively, in accordance with the invention, the protective skin of cobalt can be applied to the walls of the ingot electrolytically.

As an example of the cobalt alloy which can be employed in my invention, it is possible to use an alloy sold under the name of UMCo 50 containing amongst other elements, 50% of cobalt and approximately 30% of chromium.

This alloy can of course be applied by metal spraying of electrolytically.

Alternatively, instead of applying the alloy to the inner walls of the ingot mold, the walls themselves can be made of the alloy, UMCo 50.

Furthermore the walls of the ingot mold can be made of cobalt.

One embodiment of the invention shown in the attached drawing which is a vertical section.

In this drawing 1 denotes the casing of the mold which is generally cylindrical and is separated from the inner part of the mold by a gap 2 serving for-the circulation of water which is supplied through annular ducts 3 and 4 respectively at the bottom and top of the ingot mold.

Inside the casing 2 there is a copper sheath 5 of annular cross section and this is coated internally, by a process known as explosive plating with UMCo 50. This coating is denoted by reference numeral 6 and reference numeral 7 is used to indicate the passage through which the solidifying ingot passes downwards through the mold.

The composition of UMCo 50 is as follows:

C 0.05-0.12 Mn 0.5-1 Si 0.5-1 P max 0.02 S max 0.02 Cr 27-29 Co 48-52 Fe Remainder Its physical properties are as follows:

Melting zone C 1380-1395 Specific gravit 8.05 Coeflicient of thermal expansion C 16.8. l0 Thermal conductivity (25 C.) 0.0215

While I have described several forms of my invention in order that those skilled in the art may put it into effect, it is to be understood that the invention is not limited to the particular forms described above but is to be delimited by the gist and scope of the following patent claims.

I claim:

1. An ingot mold for the continuous casting of metals, the ingot mold having metal-contacting faces formed of cobalt.

2. An ingot mold for the continuous casting of metals, the ingot mold having internal faces covered with a protective layer of cobalt.

3. An ingot mold for the continuous casting of metals, the ingot mold having metal-contacting faces formed of an alloy of cobalt containing 50% of cobalt and approximataely 30% of chromium.

4. An ingot mold for the continuous casting of steel having internal walls formed by a cobalt containing alloy.

5. An ingot mold for the continuous casting of steel having internal walls formed by a cobalt containing alloy containing 50% of cobalt and approximately 30% chromium.

6. An ingot mold for the continuous casting of steel having internal walls formed of an alloy consisting essentially of .05 to 12% carbon, 27% to 29% chromium, 48% to 52% cobalt and the balance essentially iron.

References Cited UNITED STATES PATENTS 2,358,171 9/ 1949 Lindemuth 2491 14 3,035,934 5/1962 Cape 117-131 X 3,055,089 9/1962 Drummond 117-131 X 3,059,325 10/1962 Taylor et al 117l31 X 3,102,044 8/1963 Joseph 11713l X 3,302,251 2/1967 Speith et al. 249-116 X LAVERNE D. GEIGER, Primary Examiner. C. L. HOUCK, Assistant Examiner.