CA1075434A

CA1075434A - Marking metal articles

Info

Publication number: CA1075434A
Application number: CA256,093A
Authority: CA
Inventors: Rafael Hierro Minguez
Original assignee: Foseco International Ltd
Current assignee: Foseco International Ltd
Priority date: 1975-07-02
Filing date: 1976-06-30
Publication date: 1980-04-15
Also published as: JPS527327A; ES449511A1; FR2316020B1; FR2316020A1; GB1538858A; JPS5415256B2; DE2629627A1

Abstract

A B S T R A C T
A method of marking an ingot cast in an ingot mould having a hot top lining which comprises locating, extending from the bottom periphery of the lining and in the thickness thereof, one or more marking bearing sections, casting molten metal into the mould and allowing the molten metal to solidify in the mould.

Description

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~his invention relates to marking metal articles, particularly ingots, billets and analogous bodies.
Whilst the method may be used to apply markings to many different kinds of articles it will be described for -the sake of simplicity only with reference to the marking of ingots. Analogous methods may be used for marking other articles.
In the past, hot ingots have been marked after the ingot has been stripped from the mould by means of marking pencils, comprising a refractory pigment in a suitable vehicle.
However, this method suffers from the drawback that this type of marking is not particularly durable due to the effects of abrasion, scaling or high temperature chemical attack.
Accordingly, it is necessary to check the marking carefully at various intervals.
It has been suggested to provide permanent relief markings on ingot moulds themselves. This is also disadvan-tageous, however, since although the marking can be success-fully transferred to the cast ingot, problems may arise in strip~
ping the ingot from the mould and in any case, since the same ingot mould may be used for casting different types and grades of metal, confusion is still possible.
Another approach which has been tried is to locate in an ingot mould, prior to pouring molten metal therein, some sort of marking means which, on casting, became incorporated in the ingot and which remained on the ingot surface when the ingot was removed from the mould. A disadvantage of such a system which sometimes occurs is that the marking itself tends .
'' ' . . "' '~ ; ' ~ ' . . ' . ~ , ~(~75434 to leave defects in the rolled metal and to require quantities of the rolled metal to be scrapped.
Nevertheless, it remains that in the casting of in-gots in steelworks it is often desired to apply to the ingot some identification during casting which will remain visible up to and following further processing. This is particularly necessary in large steelworks where ingots are moved from one site to another with the result that ingots or groups of ingots may receive incorrect treatment or processing if not correctly identified.
It is particularly important that the grade of metal receives the appropriate processing since if the incorrect treatment is effected large quantities of metal may have to be scrapped or are only fit for a purpose inferior to that originally intended.
In the casting of ingots of killed steel it is common-place to provide at the top of the ingot mould a heat-insulating lining to delay the solidification of the head metal after pouring and so allow feed of the head metal to the body of the ingot to compensate for shrinkage on solidification.
However, a proportion of the resulting head of metal will usually exhibit a small depression or cavity referred to as "pipe" which is normally removed, i.e. "cropped" prior to subsequent processing; if an identifying insert is located in or on such a lining, it is found that remnants of the lining often obscure the marking after the ingot has been stripped from the mould, thus rendering the marking ineffective.
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A still greater difficulty with this method is where the marking is situated in or on a hot top lining in such a place that it is actually above the line where cropping occurs.
In such cases the marking is totally ineffective inasmuch as it is removed before serving any practical purpose.
We have now found that if a marking insert is used in place of a portion of the lower periphery of such a hot top lining, these difficulties can be avoided and effective mark-ing of ingots obtained without adverse effect on the yield of usable metal after cropping or rolling.
Thus according to the present invention there is provided a method of marking an ingot cast in an ingot mould having a hot top lining which comprises locating in the bottom periphery of the lining one or more marking bearing sections, casting molten metal into the mould and allowing ;~ the molten metal to solidify in the mould.
After stripping the ingot cast in this way from the mould the majority of the original hot top lining is removed while the marker insert is retained. Because the marker in-sert in the area concerned wholly replaces the hot top lining, there is no question of the hot top lining obscuring the marker insert. Preferably, the marking bearing section is made from the same composition as the remainder of the hot top lining material. However, this is not essential as it may be made from other compositions providing that the composition chosen is sufficiently refractory to withstand the metallostatic pressure and high temperatures involved in ingot casting.

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Numerous particular ways of putting the invention into effect can be easily envisaged. The accompanying drawings illustrate by way of example three ways of putting the invention into eEfect.
In the drawings:
Figure l shows a hot top lining tile l having a cut-out portion 2 in its base into which a dovetail marker unit 3 may be inserted;
Figure 2 shows an alternative system in which a marker insert 5 may be inserted in a hot top lining slab 6 by means of two fixing pegs 7;
Figure 3 shows the system of Figure 2 in situ in the head of an ingot mould which is shown partially, and In Flgure 4, a marker insert 9 is held in a recess formed at the bottom edge of a hot top lining slab 8 by means of a staple 10.

Claims

The embodiments of the invention, in which an exclusive privilege or property is claimed, are defined as follows:

1. In a method of marking an ingot cast in an ingot mould having a hot top lining the improvement which comprises locating, extending from the bottom periphery of the lining and in the thickness thereof, one or more marking bearing sections, casting molten metal into the mould and allowing the molten metal to solidify in the mould.

2. The method of claim 1 wherein the marking is on a section of hot top lining material which is fitted into an aperture provided in the lower periphery of the hot top lining.

3. The method of claim 1 wherein the section bears at least one relief indicium.

4. A hot top lining slab having secured therein a preformed discrete marking section extending in the thickness of the slab from the lower edge of the slab.