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Патент USA US2379434

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Patented 1.1, a, 1945
' v _'
. “ 2,379,434.
UNITED STATES PATENT lorries Franskllensehlnlialapolk,
man-user to we a
P. I; Mall." l (10., 130-, litilllnlpolb, Incl, a
corporation of Delaware _-" ~\
Application December 20, 1941,
Serial No. 428,101
0 Claims. (01. see-m)
will have the highest strength-and are especially
This invention relates to bearings.
An object of the present invention is to improve ‘ useful where the bearing is not provided with a
steelbsokingshell. Buchallmmbeproduced
copper base" bearings.
Other objects of the-invention will be apparent
by ?rst melting the copper, then adding the thal
iiuin to the melt. In some cases a small propor
' from the following description taken in connec
tlonofother ingredientswillalsobeusedtoim~
tion with the appended claims.
prove the properties of the alloy either during
The present invention comprises the combina
melting or during. use. In any event. the melt
tion of elements. and the product thereof brought
should be thoroughly stirred before pouring. The
out and exempli?ed in the disclosure hereinafter
slloycan be used in'the formlof castings or in
set forth, the scope of the-invention being indi 10‘ somecasesthecastmaterialmaybeforgedtothe
cated in the appended claims.
desired form. Photomicrographs of the material
While a preferred embodiment of the invention
show relatively small globules of thallium uni
is described herein, it is contemplated that'con
formly distributed throughout the casting at the
siderable variation may be made in the method
of procedure and the combination of elements
Bearings having this lower thallium content
without departing from the spirit of the inven
have su?lcient strength to withstand fairly heavy
loadswithoutsteelbackingsandmay alsobesub
In the prior art, bearings have been formed of
lected to impact loads when used with or without
> copper or bronze containing various percentages
of lead. While such bearings have performed
with considerable satisfaction and have relatively
high strength combined with low friction quali
ties, such bearings have not always been satis
factory in‘all-j particulars. For example, it has
been di?icult to ‘obtain uniform distribution. of
lead throughout'the copper matrix and this has
Another class of copper-thallium bearings com- '
prises the group having the composition:
Per cent
Thalllum '-
resulted in some non-unifo'mity of bearing prop-‘
10 to 20
oeppearahnlhi. Substantially the balance
haoklngshells to which the! may be integrally
attachedby fusion welding. casting, centrifugally
Bearings of the type described are frequently
bonded to a steel backing for additional strength 30 esstinmbra?nscr-cthsrmesns. sincethese com
and support. Such bonding requires the appli
cation of relatively high temperatures‘for a com
paratively long period of time. Such prolonged
m suneapplies'tiths
' , heating, however, interferes with the proper dis
tributlon of leadand promotes the accumulationv 85 of thallium
of the lead in relatively large globules. Such large
size lead inclusionsare not as effective in promot
ingabearing ofuniformlylowfrictionas areuni
Copper........... _- substan?allythehalanoe
formly distributed ?ne particles ' of lead.
Lead is also subject to‘ a certain‘ amount of oil; 40
corrosion when used in bearings.
- The present invention contemplates a copper
‘ "base bearing of improved characteristics. Accord- -
made by several manufaetm'ing
as ing to the present invention, the bearing‘ is formed
of a copper base metal composition containing - by the melting. mixing-and
scribedabove. Theycanalsohaymadebysimul
thallium instead of lead. It is contemplated that
’ the bearing may be formed of metal compositions
taneously electroplating
within the following fame of proportions:
ins themixture'.
The proportion of thallium used will be varied
of the
is required‘to be subiected. The lower'per 65. ‘recreation
In casting, a
thismethodissmtable forv
the entire composition rangedisclosedlit is par- ,
ticularly advantageous
percentages .'
,oi' thallium are
is‘easier to prevent
Copper---_..-.. ..... -
bymi'iingthemetalpowders, mmdlll'im
Copper.... -_'. ..... .. Substantially the balance
centagesof thallium such as:_
from a suitable...
‘taking vplaice. I,
of thallium segre-t
gaticn may
thorough misinggis
achievedfollowed by afairlyrapid cooling.
another methodof manufacture comprises "
the balance so spraying mixed molten partielssof copper-and.‘
' 2
thallium onto the surface to ‘be provided with a
bearing using either a Schoop gun wherein the
(2) Thallium --_-___; _________________ .._ 22.42
raw materials are used in the form of wire, or
'a Shori gun wherein metal powders are used.
‘It is of advantage in some cases to improve the 5
-characteristics 01' the copper by the addition of
relatively small quantities oi materials which act
In order to still further improve the corrosion
_ resistance of the alloy it has been found of ad~ ‘I
vantage in some cases to apply a coating of in-'
either as grain re?ners or hardening ingredients
or both. One of the most useful materials is tin ‘. dium preferably by electroplating the surface of
which may be present in proportions varying from 10 the ?nished bearing and then heat treating the
.1 to 10% by weight of the composition. The tin
bearing ‘to di?use the indium into the surface.
increases the hardness and strength of the cop
Indium and thallium form a series of solid solu
per base and increases the resistance of the bear
tions which are highly corrosion resistant. The
ing to fatigue.
indium plating can be di?used into the thallium
Instead of tin, silver may also be used to in
at slightly elevated temperatures such as 300° F.
In some cases the indium can be added di-.
crease the strength of the copper base and it does
so without greatly decreasing the thermal con-'
rectly to the copper~thallium alloy prior to cast
ductivity of the‘ bearing. Silver also appears to
ing. One such bearing alloy which was found to‘
provide a nucleus-forming ingredient which pro
show a very pronounced segregation of thallium
motes ‘the ?ne and homogeneous distribution-of so globules in the grain boundaries had the-composi
the free thallium phase. Nickel and manganese
also act as grain re?ners and improve the physi-.
Per cent
cal properties of the bearing.
Thallium and copper do not form solid solu
Indium _
tions and hence the thallium is distributed in the
bearing in the form of small particles interspersed
with the grains of the copper matrix. These small .
thallium particles or globules are very ductile and '
It may also be of advantage in preparing the ,
bearing alloy to add small amounts of alkali or
earth metals as deoxidizers. These me
soft. Moreover. cold working, such as is always - 1
grain re?nementand may increase
present at a bearing surface, ‘does not harden the 80
the" hardness of the thallium somewhat.
thallium particles. It is believed that this is one
‘application is'a continuation-in-part of
factor which renders copper-thallium composi
myco-pending application for Bearings, serial.
tions so well suited for bearing purposes.
No. ssasoamed September 16. 1938.
since the thallium particles will melt at-a tem
perature of approximately 578'’ 1''. they will a?ord 3,5 ' While the present invention, as to its objects
and advantages. has been described herein as car
liquid lubrication if the oil supply should be tem
porarily cut off and the bearings become over- > ried out in speci?c embodiments thereof,v it is not
desired to be limited thereby but it is intended to
cover the invention broadly within the spirit and
The hardness or the copper-thallium alloys at
room temperature and at elevated temperaturesv 40 scope of the appended claims.
> ‘What is claimedis:
is low. For instance, a bearing of: ‘
.1. A’ hearing formed‘of a. metal composition of
Per cent ’ .2‘to 35% thallium'and‘ the balance substantially
- 20 ~
all copper.
Balance .
2. A hearing formed of a metal composition of
had a Brinell hardness of 36 at 80‘? F. and the 45 s to 10% thallium and‘ the balance substantially -
hardness was reduced to 27 at 355° F. The bear7 ‘all copper.
ing was found to have excellent anti-friction 1
3. A bearing formed of a metal composition of.
10 to 20% thallium and the balance substantially
Another bearing formed of:
all copper.
Per cent
was also found to have high anti-friction char
Alloys of the following compositions, when
melted, thoroughly stirred and chill cast showed
a uniform ?ne dispersion of the thallium at the
rain boundariesof the copper matrix:
Per cent
(1) Thallillm -'._-...... ............ -s ____ __ 11.11'
Copper .._. .... _-..__._--_..-__-..._ 3.181106
4. A bearing formed of a metal composition of
20 to 35% thallium and the balance substantially
all copper.
- 5. A copper base bearing formed of. a copper.
base matrix and small particlessi'pf' thallium dis
tributed in the bearing at the grain boundaries
of the copper base matrix, said thallium forming
2 to 35% by weight of the bearing composition.
6. A copper base bearing formed of a copper
base matrix and small particles of thallium dis
00 tributed in the'bearing in the found small par
ticles interspersed with the grains ‘of the copper
matrix, said thallium forming 2 to 35% by weight
of the bearing composition,
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