Note: Descriptions are shown in the official language in which they were submitted.
r~he pre~ent invention relates -to the repairing o~
~e.rrous metal bodies, egO mould components, by heat
~enexatin~ compositions.
~ in~ot mould usually con6ists of an open ended cas-t
iron bod~ eg~ o~ rectangular cross section, sligh-tly
tapered internally to facilitate removal o~ the solidified
ingot~ Tbe mould i~ set on a cas* iron ba~e which forms the
bottom of the mouldin~ cavity. ~his same base is used with
moulds of different sizes which are arranged centrall~ located
on the base. ~he molten metal poured in from the top of the
mould in castin~ the ingots thus tends always to impinge
upon the same region of the base. ~he resulting progressive
erosion eventually produces a hole o~ unacceptable depth.
~he present in~ention is based upon the discovery that
an acceptable rapair may be achieved by filling the hole to ~ -
produce a workin~ sur~ace of a wear-resisting no~-metallic
inorganic material ~ormed in situ~
In accordance with one aspect of the present invention
, ,
there is pxovided a method of repairing a body of ~errous -
metal by filling the surface forming~ a cavit~ in said bod~
which method comprises in-troducing into the ca~ity a heat
generating composition in the form o~ a ~irst metal in
particulate metallic form a~d a second metal i~ the form of
a compound reactable exothermically with the first metal to
25~ yield the second metal i~ the fused metallic ~tate a~d a
~ molten slag cont~ining the first metal in an oxidi~ed ~tate,
, ~ , .
~ exothermicall~ reacting the compositio~ in the cavity to
:
form the molten ~la~ and fused second metal therei~ also
~ introducin~ into the ca~it~-a no~-metallic re~ractor~ materail
; 3~ ~ in the form of particlesi 9 and allowing the second me-tal and
the sla~ to set to the solid s-tate with the islag bin~ing the
:
~0~;6869
: particles o~ re~rac-tory materi~l together, so thnt the cavity
is f`illed at least partially by solidified material having an
upper ~one of solid sla~ and ~ound refractory material and a
lower zone o~ solidi~ied second metal.
In accordance wi-th another aspect o~ the present invention
there is provided a compo~ition for use i.n the filling of a
hole in a ferrous metal body which compri.seæ (1) a mixture
reactable o~ i~nition to yield a molte~ ~lag containi~g a
`~ Pirst metal in an oxidised s-tate and a second metal in the
fused metallic state by reaction of the first metal pro~ided i~
: particulate metallic form with the second metal provided in the .
form of a compound reactable exothermically with the first
metal and (2) a refractory material of the ceramic type in ;
~ particulate ~orm and present in an amount such as to be bound
,~ 15 together b~ the sla~ when the slag has solidified by cooling.
,.; ~hermite has bee~ used previousl~ for the present purpose 7 ~:
j but in such a manner as to ~ill the hole with a weld button of
: mietallic iron. ~he slag produced ~y the exothermic reaction ~ ~
`, i3 aD u~wanted product which is discarded. ~he re~ult is : ~:
,'J~ 20 imperfe¢t in that the molten metal ca~ fuse with the metal of
the button so ~hat the button is pulled out of the hole when
,, the i~got is stripped from the ba~e. In contrast the present ~::
-~ compo~ition is used in such a manner that the hole is ~inished
" . ~ :
,, ~ with the refractory material bound b~ the ~lag. Underlying the
slag is a weld-button producod a~ a b~-product o~ the reaction.
Its presence is incide~tal and the working surPace i~ provided :
by the bound refrac~ory material which providos the workin~
.~ . ~ .. .
surface and has a high resistanoe to thermal shock. A~ the
3:: bound re~rac~ory material is wor~ awsy with continued use, it ~ .
ma~ be re~iaired us~ng appropriate amounts o~ the composition
1 - 3 - :
~ B :
. .
~ - .~ - . .. - .
... . . . . . . . . . . . . . . .
66~69
including the re~`rac-tory adcli-tlon, be~`ore the weld butt;on is
exposed~
~he refrac~ory material of the composition may be of the
:Eired-clay or other ceramic type. aonvenien-tly, there may be
used firebrick (e~g. reco~ered from steelwork~) which has been
reduced to particulate form, e.g~ by crushing~ Al-ter~ative
refxactory ma-terials are siliconicarbide, magnesite, alumino
silicates, burned dolomite~ alumina and mixtures o~ these
materials. Magnesite is attractive because o~ its favourablR
cowe~ficient o~ expansion. ~he particle size is not critical,
a~d for mo~ purposes a suitable finish is obtained using
particulate ~irebrick or other refractory material of coarse
grade. Good results have been obtained with firebrick sieved
to less tha~ one-eigh~h inch. Improved resul-ts have been ~-
obtained with firebrick granulss which pas~ a half inch sieve
but are retained on an eighth inch sieve, probably because of
the avoidance of fine particles ha~ing a relatively high
solubility in the slag~
~ suitable proportion of -the re~ractor~ material may be
2~ asoer~ained b~ simple experiment. Using crushed ~irsbrick in
an amount of from 15 to 30~, preferably about 20% based on the
weight o~ the composition gives satis~actor~ results with
thermite containi~g from 60 to 70~ by weigh-t o~ aluminium
calculatea at A1203
Accordin~ to a modification uf the method a~ hereinbefore
de~cribed7 the particulate r~fraGtory material or a part thereo~
i~ introduced into -the ~la~ formed in the bole whilst the slag
i~ sti11 in the molten sta~e. ~ypicall~ the re~ractor~ material
i5 mixed with the slag by stirring~
'rhe acoompanying self-explanatory drawing is given i~ order
to illustrate the invention~
~ 4 _
~, .
1~668~;~
In the drawings:
Figure 1 is a plan view of an inyot mould base haviny
an erosion hole filled with a particula-te composition
according to the invention, and
Figure 2 is a vertical cross-section along the line
2-2 of Figure 1.
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