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Патент USA US2129683

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‘2,129,683
Patented Sept. 13, 1938'
UNITED STATE S. PATENT OFFICE
.
2,129,683 .
MANUFACTURING‘ COMPOUND ROLLS
Hans Gontermann and Ferdinand Kiihn,
~
Siegen, Germany
No Drawing. Application January 14, 1936, Se?
rial No. 59,158. In Germany January ' 16,
1935
_
13 Claims. (01. 80-58)
It,- for example,the material for the sleeve con
In compound rolls it is known to. weld a hard sists of an alloy containing
,
outer sleeve which solidi?es white and has a pre
l
ponderantly' martensitic‘ structure, special cast
ing _methods such, for example, as disclosed in
5 Germant ‘Patent 602,060, being used, to a softer
\
a
Percent
Carbon ____________ __'___..'_ ______________ __ 3.6
Manganese
.. 4.5
core having pearlitic structure and which'solidi
Nickel _______________________________ -._-__ 2.5
?es grey. It has not been found possible so far
Chromium _________________ Q. ___________ __ 1.5
in the-manufacture. of these rolls to avoid the
very ?ne cracks which appear after cooling and
10 which have usually been assumed to be due to
tension effects These cracks still appear even
when it is sought to adapt the shrinkage of the
sleeve to that of the core.
Extensive researches have now proved that not
15 only should the total expansion of the core, after
the cooling of the roll from the casting tempera
ture to the room temperature, be adapted to the
total expansion of the sleeve, but that the‘ varia
tions in volume of the core and of the sleeve
20
v
should-be adapted to‘, each other throughout the
‘
' _ ‘whole cooling
process and throughout each cool
ing stage; This can be achieved by so selecting
the materials as to subject approximately equal
portions of the substance of the core, and of the
25 sleeve to the same critical transformations at‘ the
same intervals of time throughout the cooling.
This is effected in accordance with the inven
tio‘n by casting compound rolls having a sleeve
of white martensitic structure and a core of cast
30 iron alloy and aiming by suitable choice and pro
portioning of the constituents of the alloy to ob
tain a graphitic structure for the core which
contains niartensitid mixed crystals in an amount
corresponding to that in the sleeve structure.
35 ‘ The term “corresponding” is to be construed as
indicating that the amounts of martensitic mixed
crystals in the core .and in the sleeve are such
that-on microscopic observation of the two parts,
an approximately similar total impression of the
40 two grain structures is obtained. The existence
of such correspondence in the cooled roll is evi-'
dence of such inherent relation between the shell
and core metals of the roll‘that the expansions
occurring ‘on cooling which are bound ,up with the
45 transformation‘ in the solid state take place to
approximately the same extent and at approxi
50
Remainder iron and the usual impurities,
then the core will preferably contain _
' Percent
Carbon? ____ _; _________________________ .__
3.3
l.\£ang'anese____v ________ __- _____ __- ________ __'._. .10
Silicon _________ u, __________ __' _____ __' ____ __
3.5
Remainder iron and the usual impurities;
When a roll is cast with use of two suitable‘
formulae such as those given above for the sleeve
and the core of the roll, the sleeve structure then
cools martensitically. The core alloy has mar 20
tensitic mixed crystals in an amount correspond
ing to that in the sleeve structure. It’ is, how
ever, sui?ciently tough because, owing to the high .
silicon content, the carbon is not combined as
iron carbide but is deposited as ?nely divided 25
graphite. _ A suitable alloy which ful?lls the
above mentioned requirements may, for example,
' have the following composition:-_-
‘
‘
‘
Percent
Carbon
2- 3.5
30
Silicon____’____\_______________________ __ 2- 5
’
Manganese
-_
‘
'5-15
_
Remainder iron and the usual impurities.
They can be run successfully on to practically '
all martensitic sleeve alloys. In addition to the ‘
characteristic content of carbon, silicon and
manganese, the core alloy may also, however,
contain 0.1 to 8% of nickel. An example of a
composition suitable for a core alloy containing 40
manganese and nickel is:
Percent
Carbon-
_.__._ 3.3
Manganese _______________ -_- _____________ __ 9
Nickel ____________ -'. _____________ .._ _____ __ 0.8
Silicon“; _____ __,__; ______ _~_ _____________ .._
3.0
Remainder iron and the usual impurities.
mately the same time,‘ so- that tension stresses
We claim‘:
‘between the core and the sleeve are avoided dur
1'. A compound roll having a martensitic white 50
ingv the cooling or, at any rate, are so small that
they can be borne by the sleeve without difficulty.
The described corestructure which is neces
sary for the manufacture of compound rolls can
be made up in a known manner trom the most
55 varied alloy materials by suitable proportioning.
:
sleeve structure, and a softer core, comprising ‘a
core of cast iron alloy, the elements of which pro
duce a casting which has a graphitic structure
which contains martensitic mixed crystals in an
amount substantially corresponding to that in 55
the sleeve structure.
2
2,129,683
‘ 2. A compound roll having a‘ martensitic white '
sleeve structure and‘a softer core, comprising a
core made of an alloy containing‘
1
~
Carbon
Percent
_____
Silicon
Manganese
2- 3.5
2- 5 .
5-15
____
Remainder iron with the usual impurities
3. A compound roll having a martensitic white
10
sleeve structure and a softer core, comprising a
core made of' an alloy containing
Percent
Carbon
15
___._
I
2
'- 3.5
Silicon _____________ __' ______________ __ 2
- 5
Manganese_________________________ __ 5
-15'
Nickel ______ __- ______________________ __
0.1- 8
structure which contains martensitic mixed' crys
tals in an amount corresponding to that in the
sleeve structure.
9. A method of manufacturing compound rolls
having a martensitic white sleeve structure and
a softer core, comprising castingfthe core of the
roll as an alloy containing
-
Percent,
Carbon ____________________ _.._\______v__ ___ 2- 3.5
Silicon"-
____
<
____ __
._-
2— 5
10
Manganese _________________ __' _______ .. 5-15
Remainder iron with the usual impurities.
- 10.v A method of manufacturing compound
rolls' having a martensitic white sleeve structure '
and a softer core, comprising casting the core 15
-
of the roll as analloy containing
Percent
Remainder iron with the usual impurities.
4. A compound ferrous roll cast as a sleeve and
20 core of diverse alloys, in which roll the sleeve
alloy possesses in relative degree the character
Carbon
-
2
Silicon__.____,_ ______________________ __ 2
- 3.5
- 5
Manganese____-_ ________________ _‘____.. 5 '-15
20
Nickel ______________________________ __' 0.1- 8
istic of hardness and in which roll the core alloy
possesses with relation to the roll sleeve the char
Remainder iron with the usual impurities.
acteristic of machinability, the. two diverse fer
11. A cast iron compound roll comprising a
sleeve of white martensitic structure, a softer 25
cast iron'core containing graphitic carbon and
rous constituents of the roll having in common
martensitic grain structure of such correspond
ence that in the form of a ‘one-piece roll-casting
having a‘metallographic structure approximating
there is a minimum of tensile stresses in the zone
that of the sleeve in martensitic content, whereby
the sleeve and core exhibit similar critical trans
of uni?cation between'\the diverse ferrous con
80 stituents of the roll.
5. A composite unitary roll 'casting as de?ned
in claim 4, in which the softer roll core is sub
formation phenomena, and a welded bond be 80
tween the sleeve and core formed between the
metals by solidi?cation from the molten state in
stantially graphitic, that is, has substantially its
contact with each other; the roll being approxi
entire carbon content in graphitic state.
6. A composite cast roll having a sleeve and
mately free from cracks by virtue of said corre
spondence in the critical transformation phe
nomena in thessleeve and core.
12. A cast iron compound roll comprising a
a core of diverse ferrous alloys the uni?cation
between the roll sleeve and the roll core being
that incident to the casting and solidi?cation of
the roll sleeve and core and subsequent simulta
40 neous cooling each in the presence of the other
and the uni?cation between the roll sleeve and
the roll core being approximately free from ten
sile stresses by virtue of the characteristic of their
sleeve of white martensitic structure, a softer
cast iron core containing graphitic carbon.
,manganese, and silicon, and vhaving a metallo 40
‘graphic structure approximating that of the
alloys to develop similar metallographic struc
45 tures in cooling with corresponding approxi
mately simultaneous expansion in both during
phenomena, and a welded bond between the
sleeve and core formed between the metals by
solidi?cation from the molten state in contact 45
passage through their critical transformation
temperatures.
7. A composite roll which is made from a sleeve
50 and a core of di?erent iron alloys which have
sleeve in martensitic content, whereby the sleeve
and core exhibit similar critical transformation
with each other; the roll beingapproximately free
from cracks by virtue of said correspondence in
the critical transformation phenomena in the.
sleeve and core.
I
I
A
13. A cast iron- compoundroll’comprising a 50
similar critical thermal charcteristics and which
form a unitary body as a result of casting and ‘ sleeve of white martensitic structure, a softer
congealing of the core and sleeve in contact with cast iron core containing graphitic carbon, man
one another, the region of transition betweenthe g'anese, silicon and nickel, whereby the sleeve
55 sleeve. and core being substantially free from and core exhibit similar critical transformation
phenomena,- and a welded bond between the 55
tensile stresses which otherwise would-be pro
sleeve.
and core formed between‘ the metals by
duced from diverse critical thermal character
istics of the metals forming the core and the solidi?cation from the molten state in contact
sleeveduring the pouring, the congealing, and
60 the subsequent cooling of the roll.
_
8. A method of manufacturing compound rolls
having a martensitic white sleeve'structure and
a softer core, comprising casting the core from
cast iron alloy, the elements of which are‘chosen
65 and proportioned so that the core hasa’graphitic
with each other; the roll being approximately
free from cracks by virtue of said correspond
ence in the critical transformation phenomena
in the sleeve and core.
HANS GONTERMANN.
FERDINAND KI'iHN.
65
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