Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
2~
I ' 93 31~17 121 al 2: 1 212 972 5~7 C;IHEN PONTRNI 03
lid th~Inv~ntion
Thy ~rJot3nt inv~ntl~n fit to a ~0thod ox
suf P,~uring hlgh ~trQngth let steel t~4~$ by jot oiling
~ollo wed by accs~ler~ cao~ E rrO~ tha rolllng h¢~t. Thy
tubosl art ~ultllblo or Ulil6 a oil ld nnd ~orlduit pip and
compl y at l~aot lo A~I-gr~de X70.
or 93 5 3
'~9 eB~I~ 12~ 02 2; 1 2 12 972 5~1137 C[)HEH PC~R~JI ~4
EI~Q~t~U7~ .~ the ~Qa
eaml~3s~ tubo~ are ~uotor~rlly m~m~actur~d i:~y thy hot
rollin ox otoel ingot whlch have bran heo'c~d 'co abeut 1200-
1250'C . Tho maln sh~plng oLr thy rolllng proce~i tax place ~UE~t
below the lngot dr~wlng 'compnraturo and th~r~or~ it Vory hl~7h
t~npor ~tur~, The rParylttalll2~tlon Or the ~tructUr4 cAua~d my
thy 8h lping l r bct cull ox th~3e high tump~ratur~o~ to ~tronq
grlin ;rowth an, ~;aaordlngly, to corr~pon~llng impAirz~nt ox
tho to llghnoa~ ox th0 mat~-rlal. There~4rs~, up to now lt ha
a1WAY~ beon con~lde~ed nec:2~ary to rollow tho rolllng proce~ by
sop~ate ht3at treatmc:nt ln tho fo~3 Or lo norm ation or age-
h&rdhn~ng process tht3rt~y abtalnl~q a miner ~truc~ur~ and
lmprov Lng the toughno~ proportlos by re-grnnulation.
8uch a heat tre~ltment roq~roa a c~n~idorablc
expenrg Itur~ ox timo and monny 80 thnt it npp~arsd deslrablo to
avc,ld this additional tro~tmnnt. It prlnc~ple, lt 16 po~ibl~ by
a targ Ted cooling alter tha hot rollin9~ lo produae a br~initic
~truct pro ln tho tubc and, thare~ore~ to sub~otantially avold botl
~errit ~ormatlon end m~rtanslte ~ormatlon. A bainitic
etruct lro, in nddltion to providing hirJh strangth value,
exhlbi to good toughnees properti00. Thls ~tho~ has, hoover
6c:~rc~ y ban po~l~lbla up to now on a lnrgt lnciu6tri~1 scalt3
since k ~on~xol Or thy t~mpornturo during thy ~cc~lr3r~t*d
abolin J :~t~p could nct bo oe~t3ctod ln such A mannor JIB 1::o 2~ urea
the ye lahing ox to oainitc roglon.
53
' 9a ~1~17 12-0~ 212 972 54137 COHEH F'O~:rFlNI
hi lo duo to the raot that tha lndlvldu~ oel tube
lnv~rlab ly havo t-mp~raturns whloh not only er prom eAch
other it thy ond Or thy last rclllng step jut lo show
conoldor ablu ~l~r-rens-o ln importune o'er the l-ngth ox the
tubo and ~v-n over th- circumr-r-nc~ by k tub. Th~oe
dl~feren ~oc in t-mp-rature amount typlc~lly to up to about lOO'C
and aan Do m~nsur~d at thy ~n4 thy acc-lorated aoollng asp in
~pproxim ~tely unchnng-d amount. TherefOro, in Actual practlce, a
flxed co in temperat~ro cannot be achl~ved.
Thls, however, meat that, duo to tho coollng,
bol~lt- ~eglon i4 obtalned ln the d~lrod mann-r only in
indlvldu Al zonks ox the tubo, whlls in the other zonoa ~errlte it
proved by exoo~lvoly olow or ln~u~lclontly doep coollng) or
01Be mar tenslte due to oxco~olv~ly deop coollng). Aa whole,
such tub it havo toughnuas end strength propertl-n whl~h dl~er
greatly Erom oach othor folly and thoy f thu4 not oultable
or thy lnt-nd-d u--.
From Foder~l R~publia or Germany 33 11 62g C2 method
it known , however, whlch permit the ~anuracturo ox hl~h-~trength
8~amle~ oll-rlol4 tubo~ Or good toughness proporti~Y rrOm
led ha v~ng the ~ollow~ng compo~ltion:
0.02 - 0.12 % C
1.30 - 2.20 Mn
mAx. 0.30 Mo
max. 0.50 % Ni
0.01 -- O.D4 % Tl
0.02 - 0.06 % Nb
0.003 - 0.008 N
0.03 - 0.05 Al
o 001 - 0.003 B
0 001 - O.010 i g
_3_
~3~C~
pa 01~17 l 1 212 972 5~67 I:OHEN F'ONTCINI ~6
the bhlan~ :e kelng lron and ordlnsry lmpuritl0~.
In order to obtain a ~inoly gr~n~lar ~tru~tur~, thy
prlor nrt method provide or ~ontrolls~ ~lnnl r~llln~ it low
t~mper~tu~ rid (700-850-C), wh~ro~y n ~o~ t-ly unlfor~ ~tartln~
t~mp~ratu ^~ 18 curd by previoualy old equalizing
~nn~llng ~vor who length ot thy tu~o nit it ho been pr~rollod
ln thy ho .,
Actor the final rolllng, ths tub ool~d wlth watnr
and/or al r to room tomper~ture end ~Lnally A~Co te~er~d in ordqr
to im~rov the strength prop~rtlo~. The lnter~dl~t~ or
~ube~qu~n : heDt treatment mans An ad~l~ional ~xponoo with
r~p~ot t tuchnLo~l plant md unorgy con~umptlon~
, f ?,
' ~3 ~1~17 121 ~4 ;~ 212 972 5~7 CI~HEN PONT;I~`II q7
gu~m~Y 0~ thy InvQ~.$~n
An ob~oct Oe th in~entlon l ther~or~, to pro~id~ a
mathod ox ma~ur~cturlng ~eaml~ t¢el tube huvlng high yl~l~
point nd high t~llo ~tr~ngthD ~lth~ at thy Ba~O tlma, Good
~oughn By prop2~ti~ tAV+20~c~ 6QJ) g~ude X70 or hlgh~r)
wlthou havlng to ~ub~ oct tho tub~u to an a~dition~l heat
troatm nt after ~ollln~. Accordlng to thl~ method, tomp0~tu~e
dl~f~r ~oe~ ln the rollud lube dirdctly borore thy ooollng of
the tu ox butwe~n Qbout 100-15~ K nr~ pc~ml~lblo wlthout
~ao~cr living thy dealred propurti~a. who tub can lo ye
produo at low p~lce and thoreror- do not reguiro l~rg~
qyanti iQa 0~ ~xpun~lve alloy elements,
Thla oh~ect l ~chlevu~ by method ox m~nu~oturln~
hlgh 8 rongth ~o~tnless staal tu~e~ by hot rolllng ~ollow~d by
ado atcd tooling, whlch oo~pri60~ (a provi~lng rod ingots Or
a stow annealn~ with alumlnu~ and/or ~lllcon h~vlng the
hollow no ~o~posltlon in wcight per cent
o.o~ - 0.13 C
1.40 - 1.90 % Mn
D.20 - D.5D Cr
o - 0.5D Mo
o - 0,70 Ni
0 - 0.40
0,04 - 0.13 V
mix. ~.020 P
max. O.Olo % S
tho ba ance bolng iron and or~in~ry impuri~ie~, the sum ox tha
conton 8 of or and Mo lying withltl thy r~ng~ of tout 0.20 to
bout .70~ and the Out quant~y ratio ln a ox thæ prn~enoa
~5-
2~ so
20337-377
Of both elements being limited to at most l; (b) heating said
feed ingots to a temperature of about 1150 to about 1280C and
hot-rolling said ingots into tubes in multiple stages; and tc)
after leaving the last hot-rolling stage, quenching said tubes
having a temperature above AC3 directly from the rolling heat in
about 5 to about 50 seconds preferably substantially avoiding
formation of ferrite down to a temperature range of about 340-
560C and thereafter further cooling said tubes in air. By
"substantially" avoiding formation of ferrite is meant that the
formation of ferrite does not exceed about lo by weight. The
steel composition of the present invention does not contain more
than about 0.04~ by weight of Nb and Ti .
In preferred embodiments: at most about 0.04~ by
weight of Nb is added to said steel; at most about 0.04% by weight
of Ti is added to said steel; the ferrite formation does not
exceed 10~ by weight.
35~
'90 01~17 12~ Do 1 212 972 5~a7 OOHIIN l'ONT~NI _~_
.
F~ a graph lllu~tr~ting the benerlel~l
Prop rt~e3 ~a~leved ~lth thy ~thod ox thy prevent lnventlon, thy
bet OVA indicting ~tr~ngth v~l~oo in N~Z and tb- ordln~te
lndlc ~tlng tonolle ~tr-ngth (R~) end ylold palnt Rto.5s
Fig. 2 lo graph lllu~t~tl"g ~urthelr b-n-P~
promo: rtl~s echlQvod wlth the method Or thy pre-ent lnven~lon, the
l 1-4 ln~lantlng n~toh~d so lmp~ct work ao-c ln ~AV+3O~C)
end to lo o~rdlnnt- lndlcotlng tha catoh te~p~r~ture ln c.
-7-
Æ~0~35-~
pa 7 121û6 Z~ 1 212 97~ 54137 CO~IEN ~OI~TR~II l0
Thy glutton in ~ccordanco with thy inventlons con~lst~
scent ally or A dl~tinot ~eleotion ox a ot- d mat-rl~l with
narrow llmlts or the ~ndlvldual alloy ento and pre-
det~rm ned dlmon~ionin~ rules or thy contcnt Or indivldu~l
~l~m~ 4 wlth ro~p-ct to earh oth-r, a well ox co"trolled
quench ng traat~nt which it ape~i~io~lly adapted to thls
~At-rl l. it his, aeoordingly, teen po~lble to ~lnd a steel
whlch knot on1y ha pro4uccd at low cot ~inae lt ~o~ not
r-qulr 1argo amount ox oxp~naiv~ alloy la~ant~, but whloh
a1eD rprlalngly cure the torm~tlon Or b~l~lte over n wide
tom~er tura range for ln~tAnse, 105 K) or the ooolln~ (chtsh
tq~pcr~ ture). who productlon ox ~orrlt- awn 4a~ily bs tilted to
noncrl~ loal value Or leoo thin ~40ut lo per wright 4~ the
~trUctu re. It haa beon tound that tho ratio ox the 012mentn
copper and nickel to etch other aY well aa thy v sr thy
oontent (weight Der cant) ox Cr an Mo are ot extremo imp~rtancq
rOr k COOling ~havlor wlth ref~renoa to tho obtaining ox
unlrorm atrength ~n~ toughn~s valve This alto true ot thy
norrowl r llmlt-d eontont ox earbon, Unto othorwlsa indicted
all par and p~raent~gee oro by welght. Whon the ~rodnter~ined
compocl loh i- m~int4in~, a steal ia obt~lned which ~xhibltR
prAetlo lly equnlly good valuae wlth respect to thc hat
tempera or- ox the quenching treat~nt wlthin a brood temp~r~turQ
r~nga. In thle aonnactlon lt io i~m~terial undar what conditionn
2~ s~3
' ~0 01~ I 7 12 Do 2 12 ~72 3~ ~7 ~:OHIill lot
the told lngotl- f cent or ~x~mpl~, CAlilt ingot round
co" lnuou~ catting ruundbd l-qu~r cont$nuou~ a n~J4, folio
rou steel).
ho otl1r~no-~ Or thy ~ç~thod Or 'cho pi nt
lnve tlon la ~urthor demonstr~tod by th- ~/elu0- of thy tenslll~
it . a g~h R", and the ye ld polnt Rt~, 5 or notchod bay lmp~ct work
Av~ O ag a ~unctl~n Or the catoh temp~ra~u~l ox ohs ~ocol~ratud
cool ng shown, rOr exempt ln ~lq-. 1 and I. Thy value wound
rnre to a ~t~nl havlng the ~ollowln~ co~pooltiont
o.os c
1. 5 Mn
0.2~ " Cr
0.06 % V
0.04 Nb
o. 016
0. 003 t g
thy b lancs ~olng lron J.nd ordinary ixpuritla~.
can by note rro~ Flg. 1, the m-~urod ~olue~ Or t]
yl-ld polnt and ox th- ten-lle ~t~ngth ar- a~proxlm~tely at a
con~t nt lov-l with a catch torlperature rango Or 350-520~. Thc
yield polnt ratio Xto,~/R~ ore, ln all Cab4U, than B0~.
pit the aoarY0 initial ~tr~ct~re, the Eteel whl~h ha beon
oubjo od to the ooollng treatment ox tho pr~sont lnvontlon haJ
good n tch~d bnr lmpact worX values jig. 2). It the r~ng3 ox
thy ca ch temporature no 350-520~c, lt it ln all ace olearly
r- t nn 50 J qt a tout t-mperaturO of +20-c.
ho method ox thy pre~o~t ln~ention render po~sl~le,
wlth t us ox low-c~et alloy and desplto thy dl~penslng with
a coil y end ~epA~atn heft trontm~n~, to m~nuSacture hlg~-
_9_
Z~ S~3
' 93 of 7 !21 1~7 æ 1 2 2 972 5~ OHE11 f'ONTRNI 12
utren~ h lest tub-- such as oil-Xl~ld end ~ondult pip my thy
aC~8le at coolln~ no who rolling heat, b41nlto ~tructur~
h~vlng good toug~ne~e propertle~ ovor toe entlre lahgth ox thy
tub i do~lnltely produced, oven on tubee whlch exhlbit n non-
unlro~ t~m~er~ture dlstrlbutlon Dlr~eronce~ l tha nigh
topper turn Or us to nbout lOS and, depending on tho
co~pO~ tlon ox th- alloy, ~bbvo thl~ te~parature, do not hav- n
orltlc 1 er~6ct on th- Ltrength or toughn~c proportie~ oP the
tubea o produc-d
Wh 11- thorn hns been do~arl~od ~n~ lllustrated n preforred
~mbodl~ nt ox the prevent inv-ntlon, lt l apparent that nu~rou~
~lternt on, oml6alon~ and addltlon- Jay bo m~¢ without
dopartl g m the splrlt end scope ox the lnv~ntion tenor
t should nl o be ~nd-r~tood that the pr-r~rr~d
ombo41~ nt nn4 exarple d~acribed boo art rOr llluotrntlvo
purpo~ only a"d ~rs not to by con~truad nD llmltlng th- COP
Or thy nv~ntlon which 1J properly delin~n~od only in the
nppende cl~lrs
-10-
