me als
Communica ion
Remo e Cooling o Rolls in Ho Rolling; Applicabili y o
O he P ocesses
Jan Bohacek *, Mi osla Raudensky and Pe Ko bacek


Ci a ion: Bohacek, J.; Raudensky, M.;
Ko bacek, P. Remo e Cooling o Rolls
in Ho Rolling; Applicabili y o O he
P ocesses. Me als 2021,11, 1061.
h ps://doi.o g/10.3390/
me 11071061
Recei ed: 27 May 2021
Accep ed: 28 June 2021
Published: 30 June 2021
Publishe ’s No e: MDPI s ays neu al
wi h ega d o ju isdic ional claims in
published maps and ins i u ional a il-
ia ions.
Copy igh : © 2021 by he au ho s.
Licensee MDPI, Basel, Swi ze land.
This a icle is an open access a icle
dis ibu ed unde he e ms and
condi ions o he C ea i e Commons
A ibu ion (CC BY) license (h ps://
c ea i ecommons.o g/licenses/by/
4.0/).
Hea T ans e and Fluid Flow Labo a o y, Facul y o Mechanical Enginee ing, B no Uni e si y o Technology,
Technicka 2, 61669 B no, Czech Republic; mi osla [email p o ec ed] (M.R.); pe [email p o ec ed] (P.K.)
*Co espondence: [email p o ec ed]
Abs ac :
A no el me hod o cooling olls in ho olling is p oposed. This me hod uses a combina ion
o solid je nozzles and specially shaped de lec ing anes. The anes ans o m he incoming
cylind ical wa e je in o a la an. The eby, he coolan can be di ec ed in o ha dly accessible
loca ions whils main aining he op imal angle o impingemen . The anes allow o e ec i ely
cooling he oll su ace nea he olling gap, which is o he wise no possible wi h classical la an
nozzles. The je impac is angen ial due o he limi ed oom o nozzle moun s o a coolan supply.
The de eloped me hod was labo a o y es ed. A simila cooling e iciency was ound be ween he
ane and he la an nozzle. The la e was howe e moun ed in a posi ion impossible in he plan .
The po en ial o he p oposed cooling is, he e o e, eminen . Apa om ho olling, i could be
exploi ed in o he echnological p ocesses such as high p essu e die cas ing, machining, u ning, ho
s amping, e c.
Keywo ds:
sp ay cooling; ho olling; high p essu e die cas ing; u ning; s amping; c yogenics;
nozzle; hea ans e coe icien
1. In oduc ion
Ope a ional condi ions and many s udies con i med ha he sp ay cooling in he ho
olling p ocess has a signi ican impac on damage and se ice li e o wo k olls. I he
cooling is no app op ia e, he p o ile and shape o he olled ma e ial can be ad e sely
in luenced. Typical cooling p ac ice is based on he use o heade s wi h ows o wa e
nozzles. Cooling is usually loca ed on bo h sides (exi and en ance) o he oll. An example
o dis ibu ion o empe a u e along ci cum e ence o he oll is shown in Figu e 1. I is
ob ious ha he high su ace empe a u e d ops apidly a e he exi om he olling
gap due o hea conduc ion o he oll. The cooling in ensi y depends on hea lux a he
sp ayed su aces. Hea lux can be ob ained as a p oduc o hea ans e coe icien (HTC)
and a di e ence be ween he su ace empe a u e and he empe a u e o wa e . Hea
ans e coe icien is dominan ly dependen on he sp ay cha ac e is ics such as wa e
impingemen densi y, d ople sizes and eloci ies he eo , and p ope ies o he su ace
being cooled.
The main subjec o his wo k is ocused on shi ing he in ensi e cooling close o he
olling gap. The high su ace empe a u e o he oll could po en ially yield a high cooling
in ensi y he ein.
The ques ion o how o inc ease he wo k olls’ li e has been he subjec o con inuous
in e es . The pape o S e ens was published in 1971 bu i is s ill e y li e [
1
]. The
published esul s o he plan measu emen a e unique e en hese days. The mos equen
demand o oll cooling designe s is o hold he oll empe a u e low. Some oll p oduce s
e en ecommend a maximum ope a ing empe a u e o olls. Solu ion can be o shi he
cooling close o he olling gap. The op imal cooling depends on he oll ma e ial and is
ob ious ha ension s ess in oll su ace laye g ows wi h in ensi y o cooling.
Me als 2021,11, 1061. h ps://doi.o g/10.3390/me 11071061 h ps://www.mdpi.com/jou nal/me als
Me als 2021,11, 1061 2 o 7
Me als 2021, 11, 1061 2 o 8
Figu e 1. Typical example o oll empe a u e in ho olling.
The main subjec o his wo k is ocused on shi ing he in ensi e cooling close o
he olling gap. The high su ace empe a u e o he oll could po en ially yield a high
cooling in ensi y he ein.
The ques ion o how o inc ease he wo k olls’ li e has been he subjec o con inuous
in e es . The pape o S e ens was published in 1971 bu i is s ill e y li e [1]. The pub-
lished esul s o he plan measu emen a e unique e en hese days. The mos equen
demand o oll cooling designe s is o hold he oll empe a u e low. Some oll p oduce s
e en ecommend a maximum ope a ing empe a u e o olls. Solu ion can be o shi he
cooling close o he olling gap. The op imal cooling depends on he oll ma e ial and is
ob ious ha ension s ess in oll su ace laye g ows wi h in ensi y o cooling.
As he plan measu emen o cooling in ensi y is a e he in es iga o s use mos ly
esul s o labo a o y measu emen s. De ailed in o ma ion abou he measu ed HTC is
gi en in [2]. A hollow oll diame e 352 mm, he leng h o 900 mm and he hickness o
he wall o 16 mm is used as a es su ace. The o a ing es oll is hea ed by lame on one
side and is cooled by ow o la an nozzles on he opposi e side. Embedded he mocou-
ples a e used o empe a u e measu emen nea he oll su ace. Hea ans e coe icien s
a e e alua ed om he empe a u e measu emen s by he in e se hea conduc ion ask.
The esul s show he HTC dis ibu ion bo h a ound and along he oll.
A simila labo a o y es me hod wi h a hea ed d um was used by Tseng [3,4].
The
measu ed da a is used in nume ical simula ions o s ess–s ain condi ions in he oll. and
sugges ions a e d awn o cooling o ex end he oll li e. Mode a e cooling is ecom-
mended wi h a la ge oll su ace. On he con a y o ecommenda ions o mo e ecen
wo ks, Tseng does no ecommend in ensi e cooling nea he olling gap. As he eason
he gi es he inc eased he mal cyclic s ess educing he oll li e.
Publica ion [5] ela es o he cold olling, ye in e es ing esul s e eal he in luence
o oil in cooling wa e . I is shown ha e en small amoun o oil can signi ican ly educe
cooling in ensi y and his ac is alid o ho olling as well. This no equen ly men-
ioned e ec can be he sou ce o a cooling mal unc ion.
Clea esul s desc ibing he in luence o posi ion o cooling on he s ess in he su ace
laye is gi en in [6]. Se e al nume ical simula ions show cooling dis ibu ion dependen
on he su ace empe a u e and i s e ec on s ess condi ions. Cooling applied close o he
olling gap is conside ed as a o able.
Pape s [7,8] s udy he mal s esses in bime allic olls. Ad anced echnology o p o-
duc ion and hea ea men o hese olls allow o p epa e a o able dis ibu ion o esid-
ual s esses. Bo h pape s use nume ical me hods o e alua ion o he in luence o cooling
s a egy on s ess-s ain condi ions in bo h he su ace laye and he oll co e. S anda d
Figu e 1. Typical example o oll empe a u e in ho olling.
As he plan measu emen o cooling in ensi y is a e he in es iga o s use mos ly
esul s o labo a o y measu emen s. De ailed in o ma ion abou he measu ed HTC is
gi en in [
2
]. A hollow oll diame e 352 mm, he leng h o 900 mm and he hickness o he
wall o 16 mm is used as a es su ace. The o a ing es oll is hea ed by lame on one side
and is cooled by ow o la an nozzles on he opposi e side. Embedded he mocouples
a e used o empe a u e measu emen nea he oll su ace. Hea ans e coe icien s a e
e alua ed om he empe a u e measu emen s by he in e se hea conduc ion ask. The
esul s show he HTC dis ibu ion bo h a ound and along he oll.
A simila labo a o y es me hod wi h a hea ed d um was used by Tseng [
3
,
4
]. The
measu ed da a is used in nume ical simula ions o s ess–s ain condi ions in he oll. and
sugges ions a e d awn o cooling o ex end he oll li e. Mode a e cooling is ecommended
wi h a la ge oll su ace. On he con a y o ecommenda ions o mo e ecen wo ks, Tseng
does no ecommend in ensi e cooling nea he olling gap. As he eason he gi es he
inc eased he mal cyclic s ess educing he oll li e.
Publica ion [
5
] ela es o he cold olling, ye in e es ing esul s e eal he in luence
o oil in cooling wa e . I is shown ha e en small amoun o oil can signi ican ly educe
cooling in ensi y and his ac is alid o ho olling as well. This no equen ly men ioned
e ec can be he sou ce o a cooling mal unc ion.
Clea esul s desc ibing he in luence o posi ion o cooling on he s ess in he su ace
laye is gi en in [
6
]. Se e al nume ical simula ions show cooling dis ibu ion dependen
on he su ace empe a u e and i s e ec on s ess condi ions. Cooling applied close o he
olling gap is conside ed as a o able.
Pape s [
7
,
8
] s udy he mal s esses in bime allic olls. Ad anced echnology o p o-
duc ion and hea ea men o hese olls allow o p epa e a o able dis ibu ion o esidual
s esses. Bo h pape s use nume ical me hods o e alua ion o he in luence o cooling
s a egy on s ess-s ain condi ions in bo h he su ace laye and he oll co e. S anda d
cooling is compa ed o he si ua ion o a cooling ailu e and he si ua ion o a mill s op
when he oll is in a long con ac wi h he ho ma e ial. I is shown ha abno mali y
in cooling can cause undesi able inc eases o he s ess in he oll co e ha can cause a
oll b eakdown. Bo h pape s p esen a gene al ecommenda ion o keep he a e age oll
empe a u e as low as possible. I should be no iced ha in [
8
] i y yea s old plan measu e-
men s o E en s [
1
] we e used as an inpu . Plan measu emen s o his kind a e aluable
and a e. Pape [
9
] shows an expe imen al echnique o empe a u e measu emen s in ho
olling in which empe a u e senso s a e embedded in inse s, whose su ace is aligned
pe ec ly wi h he oll su ace. Two ypes o senso we e used. The ho olling esul s we e
compa ed o each o he . The es s we e done wi h h ee le els o slab educ ion 10%, 30%,
Me als 2021,11, 1061 3 o 7
and 50%. The esul s show he hea lux in he cooling a ea. Signi ican ly di e en hea
luxes we e obse ed wi h each educ ion. The cooling sec ion was iden ical in all h ee
cases conside ed. A cons an wa e p essu e was used. The di e ence in he hea lux was
caused by a di e en su ace empe a u e a he en ance o he cooling sec ion.
The p esen pape concen a es on in ensi ying cooling du ing he ho olling. In
p inciple, he p oposed me hod can be employed in o he echnological p ocesses as
well. E.g., in machining namely u ning o hea esis an supe alloys equi es in ensi e
cooling [
10
]. Al hough he mains eam o ecen de elopmen s is owa ds he use o he
CO
2
c yogenic cooling, a window emains o app op ia e in ensi e sp ay cooling. The
MQL migh see he po en ial o he p oposed me hod also wi h he ho s amping [
11
,
12
]
and he olle bu nishing [
13
]. Ano he p ocess ecei ing much a en ion la ely is he sp ay
cooling du ing he high p essu e die cas ing [
14
]. The empe a u e o he die mus be
swi ly lowe ed o a uni o m p ede ined alue be ween wo consecu i e cas ings, which is
ealized by a nozzle a ay moun ed on a single compu e -con olled obo ic a m. Cooling
o he die is poo on ace s aligned wi h he je di ec ion. Such ace s could be e icien ly
cooled by he me hod desc ibed below.
The main opic o he p esen pape is o edesign he sp ay cooling o he oll in
ho olling. The wa e sp ay is b ough close o he olling gap while he nea - o-no mal
o ien a ion o he wa e sp ay o he su ace o he oll is main ained. The eby, high in ensi y
cooling is achie ed.
The in oduc ion sec ion is ollowed by he sec ion Remo e cooling design, in which
he new sp ay cooling me hod is explained. In he subsequen sec ion Cooling e iciency,
he me hod is subjec ed o labo a o y es s and he ob ained cooling in ensi y is compa ed
wi h ha o a s anda d la - an nozzle. The e iciency o he newly p oposed me hod is
con i med. The CZ pa en has been app o ed by he Czech Pa en and T adema k O ice.
The pa en claims a e summa ized in he sec ion Conclusions.
2. Remo e Cooling Design
The high su ace empe a u e a he exi om he olling gap d ops as due o hea
conduc ion in o he oll co e. The ein, he high empe a u e g adien is e iden om
Figu e 1. I is ad an ageous o ex ac hea om he ho hin su ace laye and a oid hea
pene a ion in o he oll co e.
Figu e 2shows a ypical posi ioning o he i s ow o he cooling je s (a). The je
impac is oblique and hus hea ans e coe icien is low. The con igu a ion (b) is no
easible because he cooling heade would collide wi h he wipe blade o ano he essen ial
echnology. The p oposed solu ion uses solid je nozzles loca ed in he posi ion o s anda d
cooling heade s and de lec ion su aces– anes– o ans o m he solid je in o a la an. The
de lec ed la an is o ien ed in a a o able angle and posi ion. The ow o he anes can be
moun ed di ec ly on he wipe . The shape o he anes is shown in Figu e 3. The complex
3D shape o he ane is designed o he op imal con e sion o he solid je in o a la an.
The ailing edge o he ane can be s aigh o cu ed. Fu he , i can be ho izon al o
il ed depending on equi emen s o o e lapped sp ay pa e ns.
Me als 2021, 11, 1061 4 o 8
Figu e 2. A cooling sec ion con igu a ion: (a) ypical posi ion o he sp ay, (b) he op imal posi ion,
and (c) he new design.
Figu e 3. An example o di e en anes used o a con e sion o solid je s in o la ans ( he size o
he g ay ane is 50 × 50 × 24 mm
3
).
3. Cooling E iciency
The labo a o y es s we e used o compa e he cooling e iciency o he p oposed
anes (Figu e 2c) and s anda d la an nozzles (Figu e 2b) in he espec i e con igu a ions
depic ed. A single ow o i e anes was conside ed, as shown a he op o Figu e 3. Solid
je nozzles wi h he o i ice diame e o 4 mm and la an nozzles we e selec ed o ha e an
iden ical low a e a a gi en p essu e. Fu he mo e, he sp ay angle o he la an nozzle
was nea ly iden ical o ha p oduced by he ane (30°). The dis ance be ween he solid je
o i ice and he anes was 215 mm. The sp ay heigh was 170 mm. The sp ay heigh is
de ined as dis ance be ween he o i ice o he nozzle/ ane and he oll su ace. I is no a
no mal dis ance, bu dis ance aligned wi h he je axis. The es s we e done wi h he eed-
ing p essu e o 0.3, 0.5 and 0.8 MPa. The angen ial eloci y o he oll was 1 m/s. The
labo a o y con igu a ion o he solid je nozzles, he de lec ing anes and he oll su ace
is shown in Figu e 4. The pho o in Figu e 4 (le ) was aken wi h a low wa e p essu e
because he iew is o he wise obscu ed by he e lec ed wa e . The CAD pe spec i e iew
on he igh in Figu e 4 explains wha is seen in he pho o on he le .
Figu e 2.
A cooling sec ion con igu a ion: (
a
) ypical posi ion o he sp ay, (
b
) he op imal posi ion,
and (c) he new design.
Me als 2021,11, 1061 4 o 7
Me als 2021, 11, 1061 4 o 8
Figu e 2. A cooling sec ion con igu a ion: (a) ypical posi ion o he sp ay, (b) he op imal posi ion,
and (c) he new design.
Figu e 3. An example o di e en anes used o a con e sion o solid je s in o la ans ( he size o
he g ay ane is 50 × 50 × 24 mm
3
).
3. Cooling E iciency
The labo a o y es s we e used o compa e he cooling e iciency o he p oposed
anes (Figu e 2c) and s anda d la an nozzles (Figu e 2b) in he espec i e con igu a ions
depic ed. A single ow o i e anes was conside ed, as shown a he op o Figu e 3. Solid
je nozzles wi h he o i ice diame e o 4 mm and la an nozzles we e selec ed o ha e an
iden ical low a e a a gi en p essu e. Fu he mo e, he sp ay angle o he la an nozzle
was nea ly iden ical o ha p oduced by he ane (30°). The dis ance be ween he solid je
o i ice and he anes was 215 mm. The sp ay heigh was 170 mm. The sp ay heigh is
de ined as dis ance be ween he o i ice o he nozzle/ ane and he oll su ace. I is no a
no mal dis ance, bu dis ance aligned wi h he je axis. The es s we e done wi h he eed-
ing p essu e o 0.3, 0.5 and 0.8 MPa. The angen ial eloci y o he oll was 1 m/s. The
labo a o y con igu a ion o he solid je nozzles, he de lec ing anes and he oll su ace
is shown in Figu e 4. The pho o in Figu e 4 (le ) was aken wi h a low wa e p essu e
because he iew is o he wise obscu ed by he e lec ed wa e . The CAD pe spec i e iew
on he igh in Figu e 4 explains wha is seen in he pho o on he le .
Figu e 3.
An example o di e en anes used o a con e sion o solid je s in o la ans ( he size o
he g ay ane is 50 ×50 ×24 mm3).
3. Cooling E iciency
The labo a o y es s we e used o compa e he cooling e iciency o he p oposed
anes (Figu e 2c) and s anda d la an nozzles (Figu e 2b) in he espec i e con igu a ions
depic ed. A single ow o i e anes was conside ed, as shown a he op o Figu e 3. Solid
je nozzles wi h he o i ice diame e o 4 mm and la an nozzles we e selec ed o ha e an
iden ical low a e a a gi en p essu e. Fu he mo e, he sp ay angle o he la an nozzle
was nea ly iden ical o ha p oduced by he ane (30
◦
). The dis ance be ween he solid
je o i ice and he anes was 215 mm. The sp ay heigh was 170 mm. The sp ay heigh is
de ined as dis ance be ween he o i ice o he nozzle/ ane and he oll su ace. I is no
a no mal dis ance, bu dis ance aligned wi h he je axis. The es s we e done wi h he
eeding p essu e o 0.3, 0.5 and 0.8 MPa. The angen ial eloci y o he oll was 1 m/s. The
labo a o y con igu a ion o he solid je nozzles, he de lec ing anes and he oll su ace
is shown in Figu e 4. The pho o in Figu e 4(le ) was aken wi h a low wa e p essu e
because he iew is o he wise obscu ed by he e lec ed wa e . The CAD pe spec i e iew
on he igh in Figu e 4explains wha is seen in he pho o on he le .
Me als 2021, 11, 1061 5 o 8
Figu e 4. A pho o o he labo a o y es (le ) and he co esponding CAD iew ( igh ); a ho izon al
ow o he solid je nozzles a he op; he solid je s eaching i e anes; he e lec ed la ans exi ing
om anes impinging on o he oll su ace nea he olling gap.
The expe imen al equipmen used is shown in Figu e 5. The essen ial pa is he in-
s umen ed segmen o he oll wi h he mocouples (g ey in-line spo s) eco ding empe -
a u e in dep h o 0.4 mm unde he su ace. The segmen is made o aus eni ic s eel 20 mm
hick, he emaining su ace o he oll is o med by a hin s eel shee . The segmen is
ini ially hea ed up o a uni o m empe a u e. Then, he oll s a s o a ing. Once he p e-
sc ibed speed o 1 m/s is eached, he sp ay cooling is ac i a ed. Tempe a u es om all
he mocouples and he ins an aneous angen ial posi ion o he oll a e con inuously ec-
o ded in o he da alogge H 800. The expe imen is ollowed by sol ing he in e se hea
conduc ion p oblem (IHCP), which ou pu s he econs uc ed he mal bounda y condi-
ion namely su ace empe a u es and hea ans e coe icien s (HTC). The calcula ed
HTC can be plo ed as a unc ion o ime, he angen ial posi ion (de ined in Figu e 5) and
he su ace empe a u e. The expe imen and he IHCP a e de ailed in [9] and [10,15] e-
spec i ely.
Figu e 5. The oll es bench wi h wa e sp ays in blue, he segmen in o ange, he da alogge in
b own and he hea e in he back. Ins umen ed segmen is ho , and hea e is mo ed ou o he ea
posi ion.
A compa ison o da a om he expe imen wi h he la an nozzle and he ane is
shown in Figu e 6. The su ace empe a u e and HTC a e plo ed as a unc ion o he ime.
Only i e e olu ions o he oll a e shown o make he plo eadable. The cooling in en-
si ies a e e iden ly e y simila . To show he HTC as a unc ion o he angen ial posi ion,
he HTC mus be a e aged o e a ange o su ace empe a u es. Figu e 7 shows HTC
Figu e 4.
A pho o o he labo a o y es (
le
) and he co esponding CAD iew (
igh
); a ho izon al
ow o he solid je nozzles a he op; he solid je s eaching i e anes; he e lec ed la ans exi ing
om anes impinging on o he oll su ace nea he olling gap.
The expe imen al equipmen used is shown in Figu e 5. The essen ial pa is he
ins umen ed segmen o he oll wi h he mocouples (g ey in-line spo s) eco ding em-
pe a u e in dep h o 0.4 mm unde he su ace. The segmen is made o aus eni ic s eel
20 mm hick, he emaining su ace o he oll is o med by a hin s eel shee . The segmen
Me als 2021,11, 1061 5 o 7
is ini ially hea ed up o a uni o m empe a u e. Then, he oll s a s o a ing. Once he
p esc ibed speed o 1 m/s is eached, he sp ay cooling is ac i a ed. Tempe a u es om
all he mocouples and he ins an aneous angen ial posi ion o he oll a e con inuously
eco ded in o he da alogge H 800. The expe imen is ollowed by sol ing he in e se hea
conduc ion p oblem (IHCP), which ou pu s he econs uc ed he mal bounda y condi ion
namely su ace empe a u es and hea ans e coe icien s (HTC). The calcula ed HTC
can be plo ed as a unc ion o ime, he angen ial posi ion (de ined in Figu e 5) and he
su ace empe a u e. The expe imen and he IHCP a e de ailed in [9,10,15] espec i ely.
Me als 2021, 11, 1061 5 o 8
Figu e 4. A pho o o he labo a o y es (le ) and he co esponding CAD iew ( igh ); a ho izon al
ow o he solid je nozzles a he op; he solid je s eaching i e anes; he e lec ed la ans exi ing
om anes impinging on o he oll su ace nea he olling gap.
The expe imen al equipmen used is shown in Figu e 5. The essen ial pa is he in-
s umen ed segmen o he oll wi h he mocouples (g ey in-line spo s) eco ding empe -
a u e in dep h o 0.4 mm unde he su ace. The segmen is made o aus eni ic s eel 20 mm
hick, he emaining su ace o he oll is o med by a hin s eel shee . The segmen is
ini ially hea ed up o a uni o m empe a u e. Then, he oll s a s o a ing. Once he p e-
sc ibed speed o 1 m/s is eached, he sp ay cooling is ac i a ed. Tempe a u es om all
he mocouples and he ins an aneous angen ial posi ion o he oll a e con inuously ec-
o ded in o he da alogge H 800. The expe imen is ollowed by sol ing he in e se hea
conduc ion p oblem (IHCP), which ou pu s he econs uc ed he mal bounda y condi-
ion namely su ace empe a u es and hea ans e coe icien s (HTC). The calcula ed
HTC can be plo ed as a unc ion o ime, he angen ial posi ion (de ined in Figu e 5) and
he su ace empe a u e. The expe imen and he IHCP a e de ailed in [9] and [10,15] e-
spec i ely.
Figu e 5. The oll es bench wi h wa e sp ays in blue, he segmen in o ange, he da alogge in
b own and he hea e in he back. Ins umen ed segmen is ho , and hea e is mo ed ou o he ea
posi ion.
A compa ison o da a om he expe imen wi h he la an nozzle and he ane is
shown in Figu e 6. The su ace empe a u e and HTC a e plo ed as a unc ion o he ime.
Only i e e olu ions o he oll a e shown o make he plo eadable. The cooling in en-
si ies a e e iden ly e y simila . To show he HTC as a unc ion o he angen ial posi ion,
he HTC mus be a e aged o e a ange o su ace empe a u es. Figu e 7 shows HTC
Figu e 5.
The oll es bench wi h wa e sp ays in blue, he segmen in o ange, he da alogge in
b own and he hea e in he back. Ins umen ed segmen is ho , and hea e is mo ed ou o he
ea posi ion.
A compa ison o da a om he expe imen wi h he la an nozzle and he ane is
shown in Figu e 6. The su ace empe a u e and HTC a e plo ed as a unc ion o he
ime. Only i e e olu ions o he oll a e shown o make he plo eadable. The cooling
in ensi ies a e e iden ly e y simila . To show he HTC as a unc ion o he angen ial
posi ion, he HTC mus be a e aged o e a ange o su ace empe a u es. Figu e 7shows
HTC dis ibu ion a e aged in he ange o su ace empe a u e be ween 220
◦
C and 50
◦
C.
A e aged alues o su ace in e al
±
100 mm om he impac poin a e summa ized in
Table 1.
Me als 2021, 11, 1061 6 o 8
dis ibu ion a e aged in he ange o su ace empe a u e be ween 220 °C and 50 °C. A -
e aged alues o su ace in e al ± 100 mm om he impac poin a e summa ized in
Table 1.
Table 1. HTC alues, a e aged be ween su ace empe a u es o 220 °C and 50 °C.
P essu e (MPa) Flow Ra e Pe One Noz-
zle (l min−1)
A g. HTC o De lec ing Vanes
(W m−2 K−1)
A g. HTC o Fla Fan Noz-
zles (W m−2 K−1)
0.3 24.5 9002 9774
0.5 31.6 9541 10,008
0.8 40.0 10,841 10,752
Figu e 6. Su ace empe a u es and hea ans e coe icien (HTC) o expe imen s wi h la an
nozzles and wi h de lec ed je s by anes, es s wi h 0.5 MPa eeding p essu e.
Figu e 7. An a e age HTC dis ibu ion o compa ed con igu a ions, es p essu e 0.5 MPa.
4. Conclusions
The new me hod o cooling o olls in he ho olling is in oduced wi h he applica-
bili y o o he p ocesses. By using specially shaped anes, he sp aying je is eme ging
om loca ions ha a e o he wise un hinkable wi h he s anda d cooling ins umen s. I
allows he cooling je o hi he oll su ace a he op imal angle nea he olling gap so ha
he cooling in ensi y is maximized.
The p oposed me hod consis s o solid je nozzles moun ed o a common wa e sup-
ply in as uc u e and he anes. The la e con e s he cylind ical je in o a la an, which
is edi ec ed o he op imal spo on he oll su ace. The labo a o y expe imen s con i med
ha cooling in ensi y o he e lec ed je is simila o ha o he la an nozzle. Howe e ,
he la e is moun ed in he posi ion impossible in he plan . Nex , he e lec ed je does
Figu e 6.
Su ace empe a u es and hea ans e coe icien (HTC) o expe imen s wi h la an
nozzles and wi h de lec ed je s by anes, es s wi h 0.5 MPa eeding p essu e.

Me als 2021,11, 1061 6 o 7
Me als 2021, 11, 1061 6 o 8
dis ibu ion a e aged in he ange o su ace empe a u e be ween 220 °C and 50 °C. A -
e aged alues o su ace in e al ± 100 mm om he impac poin a e summa ized in
Table 1.
Table 1. HTC alues, a e aged be ween su ace empe a u es o 220 °C and 50 °C.
P essu e (MPa) Flow Ra e Pe One Noz-
zle (l min−1)
A g. HTC o De lec ing Vanes
(W m−2 K−1)
A g. HTC o Fla Fan Noz-
zles (W m−2 K−1)
0.3 24.5 9002 9774
0.5 31.6 9541 10,008
0.8 40.0 10,841 10,752
Figu e 6. Su ace empe a u es and hea ans e coe icien (HTC) o expe imen s wi h la an
nozzles and wi h de lec ed je s by anes, es s wi h 0.5 MPa eeding p essu e.
Figu e 7. An a e age HTC dis ibu ion o compa ed con igu a ions, es p essu e 0.5 MPa.
4. Conclusions
The new me hod o cooling o olls in he ho olling is in oduced wi h he applica-
bili y o o he p ocesses. By using specially shaped anes, he sp aying je is eme ging
om loca ions ha a e o he wise un hinkable wi h he s anda d cooling ins umen s. I
allows he cooling je o hi he oll su ace a he op imal angle nea he olling gap so ha
he cooling in ensi y is maximized.
The p oposed me hod consis s o solid je nozzles moun ed o a common wa e sup-
ply in as uc u e and he anes. The la e con e s he cylind ical je in o a la an, which
is edi ec ed o he op imal spo on he oll su ace. The labo a o y expe imen s con i med
ha cooling in ensi y o he e lec ed je is simila o ha o he la an nozzle. Howe e ,
he la e is moun ed in he posi ion impossible in he plan . Nex , he e lec ed je does
Figu e 7. An a e age HTC dis ibu ion o compa ed con igu a ions, es p essu e 0.5 MPa.
Table 1. HTC alues, a e aged be ween su ace empe a u es o 220 ◦C and 50 ◦C.
P essu e
(MPa)
Flow Ra e Pe One
Nozzle (L min−1)
A g. HTC o De lec ing
Vanes (W m−2K−1)
A g. HTC o Fla Fan
Nozzles (W m−2K−1)
0.3 24.5 9002 9774
0.5 31.6 9541 10,008
0.8 40.0 10,841 10,752
4. Conclusions
The new me hod o cooling o olls in he ho olling is in oduced wi h he applicabil-
i y o o he p ocesses. By using specially shaped anes, he sp aying je is eme ging om
loca ions ha a e o he wise un hinkable wi h he s anda d cooling ins umen s. I allows
he cooling je o hi he oll su ace a he op imal angle nea he olling gap so ha he
cooling in ensi y is maximized.
The p oposed me hod consis s o solid je nozzles moun ed o a common wa e supply
in as uc u e and he anes. The la e con e s he cylind ical je in o a la an, which is
edi ec ed o he op imal spo on he oll su ace. The labo a o y expe imen s con i med
ha cooling in ensi y o he e lec ed je is simila o ha o he la an nozzle. Howe e ,
he la e is moun ed in he posi ion impossible in he plan . Nex , he e lec ed je does
no lose he kine ic ene gy in compa ison o he je p oduced by he la nozzle wi h he
iden ical eeding p essu e and low a e. The di e ences in he cooling in ensi ies a e small.
The a e age HTC o he e lec ed je is lowe by 8% wi h he wa e p essu e o 0.3 MPa. I
becomes nea ly iden ical wi h he wa e p essu e o 0.8 MPa I is es ima ed by nume ical
me hods ha shi ing he cooled a ea om a ci cum e en ial posi ion o 90
◦
close o he
olling gap o he posi ion 45
◦
can inc ease he cooling in ensi y by 27%. This conclusion is
alid o iden ical HTC and app op ia e su ace empe a u es behind he olling gap.
The au ho s o his communica ion gi e labo a o y- e i ied in o ma ion o he plan
expe s and designe s. The e ec i e cooling can be shi ed close o he olling gap. One
ow o solid je nozzles can be added o he exis ing cooling heade . The anes can be
ixed o he wipe a he exi side o a olling mill. Thus, a collision wi h s anda d cooling
ins umen s is p e en ed.
5. Pa en s
The na ional pa en has been app o ed in he Czech Republic.
Me als 2021,11, 1061 7 o 7
Au ho Con ibu ions:
Concep ualiza ion, M.R. and J.B.; me hodology, P.K.; so wa e, J.B.; alida ion,
M.R., J.B. and P.K.; o mal analysis, M.R.; in es iga ion, J.B.; esou ces, M.R.; da a cu a ion, J.B.;
w i ing—o iginal d a p epa a ion, M.R. and J.B.; w i ing— e iew and edi ing, M.R.; isualiza ion,
J.B.; supe ision, M.R.; p ojec adminis a ion, P.K.; unding acquisi ion, M.R. All au ho s ha e ead
and ag eed o he published e sion o he manusc ip .
Funding: This esea ch ecei ed no ex e nal unding.
Ins i u ional Re iew Boa d S a emen : No applicable.
In o med Consen S a emen : No applicable.
Da a A ailabili y S a emen : No applicable.
Acknowledgmen s:
Labo a o y wo k p esen ed in his pape was suppo ed by he in e nal g an o
he B no Uni e si y o Technology ocused on speci ic esea ch and de elopmen No. FSI-S-20-6478.
Con lic s o In e es : The au ho s decla e no con lic o in e es .
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