’ Patented’
2,104,169
4,‘ 1938
' UNITED STATES
PATENT OFFICE .
2,104,189
NONAGING FLAT SILICON STEEL STRIP AND
METHOD' OF PRODUCING THE SAME
Charles A. samba, Brackenridge, Pa, assignor
to'Alleiheny Steel Company, a corporation of
Penmy yania
No Drawing. Application August 3', 1933,
‘ Serial No. ‘683,476
_
,
_
( Cl. 148-12)
A still further object is to subject cold rolled
14 claim.
My present invention relates to a method of
annealing cold rolled silicon steel strip to make it a
silicon steel strip to a ?nal anneal at ‘1000 to
flat and non-aging.
1300° F. in the manner of a continuous anneal
The ‘general practice has been to box anneal
for a suitable length of time and suitably cool
the ?nished cold rolled silicon steel strip at tem
peratures between 1400° and 2000“ F. in coils‘
ing the so annealed strip.
'
_ Other and further objects and advantages will '5
and slowly cool to obtain good magnetic proper
be understood by those skilled in the handling
of silicon steel or will be apparent or pointed out
hereinafter.
ties and a product which is non-aging. Strip of
this nature which has been given a-?nal anneal
in coils unavoidably takes the"‘set” of the coil ,
‘In general, my present invention comprises
0 and such strip will not thereafter lie flat so that the subjection of cold rolled silicon steel strip 10
punchings 'or laminations made from coils an
which has been either box annealed or continu
nealed in this manner will be curved or non» ously annealed at a temperaturebetween 1400
?at, thus having a low space factor which makes
it difficult and sometimes impossible to get the
1 in proper weight of punchings or laminations into
a core, and even when the prescribed weight can’
be obtained considerable ‘strain is introduced into
the punchings themselves, when thecores are _‘
tightened, which adversely a?ectsthe magnetic
20. qualities. Again, ?nished strip which has been
annealed continuously in strip form wherein the
strip is'subjected to the above annealing tem
peratures for a comparatively short time and
cooled at a fairly rapid rate may be ?at, if the
25 rolling and annealing operations have been con
ducted in a proper manner, but in such case
the magnetic propertiesv are. not permanent.
Consequently, in service, it has been found that
the watt loss values will increase and the perme
30 ability will decrease and hence electrical ap
paratus built up from strip which has been so'
treated will lose a considerable part of its ef
ficiency. In addition, strip which has been so
treated does not possess the well known non-_
35 aging properties which are characteristic of sili
con steels and tests have shown that the watt
loss values of steel so treated will increase from
25 to 50% when subjected to a temperature of
~2100 F. for 600 hours. _
40
‘
It is accordingly one of.the objects of the
present invention to provide cold'rolled silicon
steel strip which is not subject to the defects
and disadvantages above outlined. and to provide
a method of producing such silicon steel.
45
It is another object of the invention to provide
cold rolled silicon steel strip which is character
ized by having been subjected to a ?nal'anneal
' of the character to be set forth‘ whereby the
50
indicated properties are'provid'ed
in such steel
"
'
s rip.
A further object of theinvention is to subject
and 2000” F. to a ?nal annealing operation. My
annealing operation is carried out at 1000 to
1300’
preferably at about 1100° F., in the 1
manner of a continuous anneal for two to three
minutes or for a length of time necessary to pro
duce ?at and non-aging characteristics in the
precise material undergoing treatment and then
20
either rapidly or slowly cooling the same. _
In order‘that my invention might be better
understood it might be wellto describe the proc
ess by which the cold rolled silicon steel strip
is produced. I
'_ ~
'
_ The silicon steel ingots are heated to a suit-.- 25
able temperature and hot rolled into strip of
as light a gauge as possible, that is, to a thick;
ness which is generally from .100 inch to .045
inch depending upon the silicon content, the
kind and type of mill used, and the size of the 30
reducing rolls of the mill. ’ The hot rolled strip is
generally coiled and then annealed and pickled.
The annealed and pickled strip is then reduced
by cold rolling to the ?nished gauge. Usually
the cold rolled strip is annealed before the ?ne 35
ished gauge is reached, in order to obtain the
best magnetic properties. When the strip has
been cold rolled to the ?nished gauge it is again
coiled and the coil is then either box annealed
at a temperature between 1400 to 2000" F. and 40
then slowly cooled, or the strip is uncoiled and
continuously passed while ?at through a furnace
maintained at a temperature within the above
temperature range. It is well known that strip
which has been box annealed is non-aging, but
will take the set of the coils, and when reeled
from the coil will not be ?at, and has the disad
vantages which have already been pointed out.
It has been found that exceptionally good mag- '50
netic results may be obtained by the method of
fully annealed cold rolled silicon steel strip to a
continuous annealing, but when the strip has been
?nal annealing operation under such “conditions
annealed in this manner it is aging, and when '
as will ensure production of such steel with the
55 desired ?at and non-aging properties.
used in electrical apparatus the watt loss will in
crease and the'permeability decrease to such an 55 ‘_
‘2,104,109
extent that the apparatus is no longer eillcient.
while ?at-at about 1100' for about two to three
In order to render such material non-aging it is
minutes and then rapidly cooled while still ?at.
After this anneal, the strip was perfectly ?at and
had a watt loss of 1.098 watts per pound at 10,000
customary to anneal the strip tor a long time
within the temperature range given above'and
to slowly cool. However, when this annealing is
carried out in the coil the strip will no longer be
?at ‘and when used ‘in electrical apparatus in
ferior resulm will be obtained as described above.
B and 60 cycles. Alter aging 1150 hours at 210“
F. the watt loss value was 1.108 watts per pound
at 10,000 13 and 60 cycles indicating that no aging
had resulted, -
-
I have accordingly discovered that by subject
The above is descriptive of the methods which
10 are commercially used‘ to produce silicon steel " ingsilicon steel strip of the character set forth 10
strip of a‘ commercial ‘grade, and in no way re
lates to my invention.
'
-
to‘ a ?nal anneal, subsequent tcthe no al ?nal ‘
anneal, under the conditions speci? , E can
I have discovered that‘ when silicon steel strip ' produce ?at non-aging cold rolled silicon steel
which has been her: annealed in coils within the
-15 temperature rouge given above is oncoiled and
strip of reduced watt loss and permanent mag
netic
at a temperature between 1000 to i300" F. and
properties;
,
v
ll
‘
> Such strip is far more valuable and has much
_ subjected to o continuous anneol while ?at and
greater utility and uniformity in electrical ep
then rapidly cooled such strip will be perfectly ' paratus, than cold rolled silicon steel strip made
?at and will have‘ magnetic properties equal to
20 or slightly better their the box annealed strip, end
that these values will he permanent. \Such strip
can thenbe coiled without taking, coll set.,- In
other words, the strip when uncoilecl is flat and
is non-aging. I have also found thot when sili
hos been continuously an
?nealed within the temperature range oi 1400 to
2000.a R, is then silhlecte'd'to a, continuous anneal
between loco and 1300 F. for e, few minutes and
rapidly cooled, it will be flat end managing, and
"so have magnetic properties eouol to or slightly bet
ter than those cbtoioed in the ?rst onheel. Such
strip may also he coiled without ‘taking e coll set.
The silicon steel‘ol’ the present invention may
contain'i’rom “hoot to ohout coco, silicon and
,30 more broadly ted cootoins less thorn shoot 5%
silicon; In
the strip steel is intended for
use in’ electrical oooorotos such so troosiomners,
motors and other electricsll equipment making
use of so=colled electrical steels cool is pcztlcu“
larly suitable ifor minorities or lorrimtioos for use
by the ‘present methods known tome.
It is understood that the foregoing is intended
more in an illustrative manner than ihalimitatlve
manner and that suitable additions, omissions,
variations and substitutions may he made without
departing from the spirit and scope of the in—
25 con steel strip
therein.
' Since the
vention.
'
Letters Patent is:
1. In a method oi‘ making magnetic-materiel
in the ‘term of silicon steel strip, the steps which
consist in casting o, steel ingot loosing a silicon
content of from about 5% to 0%, in reducing the
ingot by hot rolling to o stoic oi‘ intermediate
gauge, in annealing the
rolled strip, in.
pickling the annealed strip,’ in ‘cold rolling the
pickled strip to ?mhocl gauge, in annealing the
strip or ?nished gauge rcriltfoiczv o temperature range
oi from 1400-2000", lit, in then cooling the strip,
dot at o temperature
Eliai oi
00
03% sili
con and .0315 inch thick otter ‘cox annealing in
the regular mariner heel e, watt loss oi‘ 3.1.000 watts
per pound et roots is and co cycles. lifter such
box anneal the vstrip
very wow Fond would
not lie flat. The strip was then imcoiled and
while ?st woe annealed continuously at about
1100“ F. for about two to three minutes and then
rapidly cooled While still ?st. when cooled otter
this latter ermeal the strip was perfectly flat and
60 did not take s set when recoile'd. Tests showed
that it hook it watt loss oi only .0533 watt per
pound at lililllil B end E30 cycles Alter coins;
i150 hours
210°
the
value was _
about 1.01s watts goerooimd at will?’ B end to
cycles indicating; thot cocaine
Zimmcle- ll’
Silicon steel strip oi’ o
A
t
I
-
_
, consist in casting e, steel ingot herring a‘ silicon
cedures, the rcllings both hot
cold ore cor
45 ried on in the usuel simmer of producing strip
material ‘shot is, oil of the rolli
carried on
in one direction, the direction
which the ingot
is rolled.
Ecomyole .1?
Silicon steel strip containing
.
.2. In o. method of melting magnetic materiel
in the form of silicon steel strip, ‘the steps which
invention is ‘strip
hot and cold rolling ‘pro
iro-
and then in cooling the stop.
' ‘
materiel produced
.
What I claim 'as new and desire to secure by
content of from about .5%,
5%, in reducing
the ingot by hot rolling to at strip of intermediote
gauge. in annealing the hot rolled strip, in
pickling the annealed strip, io- cold rolling the
pickled strip to ?nished collate, in o'onealing: the
strip of ?nished gauge Within temperature rouge
of from 1400-2000” El, in then cooling the strip,
then in continuously canceling the strip while
to
?at at a temperature of shoot ll00° F" and then
in coolingthe strip.
,
3. In a method of melting mccnetlc material
in the form of silicon steel strip, the steps which
consist in casting a steel ingot having a silicon
content of from about 5% to 5%, in reducing the
ingot by hot rolling to a, strip of intermediate
gauge, in pickling the strip, in cold rolling the’
pickled strip to ?nished gouge, in box anneolioc ‘
the strip of ?nished cause
o temperature
range of from 1400-2000” K, in slowly cooling
the ‘strip, then vin continuously annealing the
strip while not at to temperature oi’ from he
tween 1000 and l300°- Fl. end-then cooling the »
strip while ?at.
_
,
i. In a method of making; magnetic-materiel
the form oi silicon steel strip, the steps which
cl’
inch . consist in casting o steel ingot-having a silicon
70 vend having 's silicon‘ content oi’ scoot com
silicon alter
concealing in
regular mon
ner had to loss oi i228 watts
ground at iocco
B and 80 cycles. Alter this treatment the strip
was very wavy and would not lie
‘when un
coiled. The strip ‘was then annealed continuously
content of from about 5% to 5%, in reducing the 70
ingot by hot rolling to o strip of intermediate
gouoc, in cold rolling to ?nished gauge. in box
annealing the strip of ?nished more within at
temperature range oi’ from l-itMilOt“ 21"., in cool
‘ ing the strip slowly, then in continuously anneal-v (s
3 .
.
9,104,100
by hot and cold rolling operations to‘a strip oil;
ing the strip while ?at at a temperature of about
1100° F., and then in cooling the strip while
that gauge, in coiling the strip or ?nal gauge, in
5; In a method of making magnetic material box annealing the coiled strip, .in cooling the
in the form of silicon steel strip, the steps which - coiled strip, in uncoiling the strip. in continuously
a temper- _
consist in casting a steel ingot having a silicon annealing the strip while ?at within in cooling
_
ature
range
01
irom
1000
to
1300°
It,
content or from about .5% to 5%. in reducing the
. ingot by hot rolling to a, strip of intermediate the strip while ?at and then in re-coilins the
gauge, in cold rolling to ?nished gauge, in an ’ strip.
healing the strip ‘of ?nished gauge within a tem-‘ ' 11. In the art’ot making a coil of magnetic 10
perature range of from 1400-2000" It. in cooling ' material in the form of silicon steel strip which
10- the
strip, and then in continuously‘ annealing the ' is non-aging and free from coil set, the steps
strip ‘while ?at at a temperature of about 1100° I". which consist in reducing ‘suitable silicon-steel
6. In a method of making magnetic material by hot and cold rolling operations to a strip of
?nal gauge, in then annealing such strip of final ,
in the form of silicon steel strip, the steps which
consist in casting a steel ingot having a silicon
content of from about .5% to 5%, in reducing the
gauge, in cold rolling to ?nished gauge, in box
gauge within a temperature range of from 1400
to 2000" F., in cooling thestrip, in continuously
annealing the strip while flat at about 1100. F.,
in then cooling the strip while ?at and then in.
annealing the strip of ?nished gauge within a
coilingthe same.
' ingot by hot rolling to-a strip of intermediate
-
_
12. Inthe art of making a coil' or magnetic
ing the strip slowly, then in continuously anneal
material in the form of silicon steel strip which
ing the strip while ?at at a temperature of from ‘ is non-aging and free from cell set, the steps
temperature range of from 1400-2000" F., in 0001- -
1000 to 1300° F., and then in rapidly cooling the~
'
which consist in reducing suitable silicon steel by
' hot and cold rolling operations to a strip ‘01' ?nal .
'7. In ‘a method oi’ making magnetic material gauge, in coiling the strip of ?nal gauge, in box
_ in the form oi'.silicon steel strip, the steps which annealing the coiled, strip, in cooling the coiled
strip while ?at. ' >
consist in e?ecting a heavy reduction by cold
work, heating the strip to a temperature of from
about 1400 to about 2000" 1"., in cooling the strip,
'30 then subjecting the strip while ?at to a-continu
ous anneal of from about 1000' to about 1300' 1".,
and then cooling the strip vwhile ?at. .
-
strip, in uncoiling the strip, in- continuously an
healing the strip while ?at at aboutj1100° F., in
cooling the strip while ?at and then in recoiling 30
the strip.
,
i
~
13. As a new article of manufacture, a coil of
v
magnetic material in the form of cold rolled sili- _ I
8. In a method of making magnetic material
.in the form of silicon steel strip, the steps which
can steel strip having a silicon content between
approximately -.5% and 5% which is nonéaging' 85
consist in electing a heavy reduction by cold
work, heating the strip to a temperature or from
and free from coil set and produced from a strip
of silicon steel having a silicon‘ content within‘the
limits set forth which has been annealed at a
- about 1400 to about 2000° 1"., in then cooling the
strip, then subjecting the strip while _ilat to a
temperature between approximately 1400° 1"..and
7 continuous anneal at about 1100° 1“., and then in
2000° E, cooled, then subjected to a continuous 40
40 cooling the strip while ?at.
anneal at a temperature of approximately 1100" _
I". and again cooled.
_
14. As a new article of manufacture, non-aging
9. In the art of making a coil of magnetic me
~ terial'in the form of silicon steel strip which is
non-aging and tree from-coil set, the steps which magnetic material in the form of silicon steel strip
consist in reducing suitable silicon steel by hot ,free from coll set and having, a silicon content
and cold rolling operations to a strip '0! ?nal
gauge, in then annealing such strip of ?nal gauge between approximately .5%‘ and 4.5% and pro
within a temperature range of from 1400 to 2000°
F., in cooling the strip, in continuously annealins
the strip while ?at within a temperature range
of from 1000 to 1309’ E, in then cooling the strip
‘while ?at ‘and then in coiling the same.
-
-
duced from silicon steel strip having a silicon
content within said range which has been sub
iected to hot and cold roll reductions, then an
,nealed at a temperature between approximately 50
1400° F. and 2000’ F., cooled, then given a con-.
tinuous anneal while ?at at a temperature be
10. In the art of making a coil of magnetic.
material in the form oi-silicon steel strip which tween approximateiy 1000° F.‘ and 1300" I". and
I
‘is non-aging'and tree from coil set. the steps then again cooled.
- which consist. in’reducing suitable silicon steel
45
~
, CHARLES A.
as