Twin stand cold reversing mill

A cold rolling mill and method for cold rolling is disclosed. The cold rolling mill includes at least two tandem four-high reversing mills with at least one tension reel on each side of the tandem mills. Bridle roll units may be positioned on each side of the tandem, reversing mills to allow the cold rolling mill to be utilized as a temper mill.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a method and apparatus for cold rolling 
metal. Specifically, the present invention provides a twin stand tandem, 
reversing cold rolling and temper mill and a method for utilizing the same 
to achieve high production capacity, improved yield and the ability to 
handle a variable product mix. 
2. Prior Art 
The cold reduction mills commercially available and/or in use are of 
several types. Historically, the bulk of cold reduced steel is rolled on 
continuous three to six stand four-high tandem mills. Conventionally, in 
each mill stand of a continuous multistand mill, the work roll and back 
roll diameters are on the order of 20 inches and 50 inches, respectively. 
Such continuous mills are nonreversing with the working rolls being driven 
and the requisite back tension being created by each preceding mill stand. 
These types of continuous, nonreversing mills require a significant amount 
of capital investment and additionally take up a significant amount of 
floor space. 
In contrast to the continuous multistand nonreversing tandem mills, a 
single stand reversing cold mill is known in the art. The first example of 
such a mill is the Steckel mill which includes a four-high reversing mill 
employing working rolls which vary in diameter from 2-5 inches with backup 
rolls about six to eight times the working roll diameter. The Steckel mill 
utilizes two separately driven tension reels through which all of the 
power is provided. U.S. Pat. No. 2,025,002 to McIlvried discloses a single 
stand cold rolling reversing mill in which the roll diameter between the 
working roll and the backup roll is preferably 3:1. A significant 
difficulty in the operation of the known reversing mills is the amount of 
scrap material which is produced. In a single stand reversing cold mill, a 
significant amount of the strip at each end of the coil must be retained 
on the tension reel to supply the appropriate amount of back tension 
sufficient for cold rolling. This can result in scrap corresponding to 
about 20 feet per strip per coil at the product's original gauge. This 
limitation becomes significant where particularly costly materials are 
involved. A further limitation of the single stand reversing cold mill is 
the slower rolling rate as compared to a multistand continuous mill. 
The cost of constructing a drive for a reversible mill has historically 
been higher than constructing a drive for a one-way mill. Consequently, 
the prior art has suggested the development of twin stand reversing mills 
in which one stand is configured to operate on the work in one direction 
while the other is held disengaged with the procedure reversed for the 
reversing direction. Examples of these machines can be found in U.S. Pat. 
Nos. 1,964,503 to Coryell and 3,485,077 to Wilson. In operation, these 
twin stand cold rolling mills present the same difficulties as the single 
stand cold reversing mills discussed above. 
The object of the present invention is to overcome the aforementioned 
drawbacks of the prior art. It is a further object of the present 
invention to provide a cold rolling reversing mill which provides greater 
control over back tension, minimizing material losses at either end of the 
coil. A further object of the present invention is to provide a 
cost-effective method for cold reducing and tempering a wide product mix. 
SUMMARY OF THE INVENTION 
The objects of the present invention are achieved by providing a method of 
cold rolling metal, particularly steel, which includes providing at least 
two tandem four-high reversing mills with at least one tension reel on a 
first side of the tandem mill and at least one tension reel on a second 
side of the tandem mill. The metal is passed in a first pass from a 
tension reel on the first side through the tandem mills to a tension reel 
on the second side wherein each tandem mill reduces the metal during the 
pass such that the tandem mill operates in tandem during the pass. The 
metal is then passed in a second pass from the tension reel on the second 
side through the tandem mill to a tension reel on the first side wherein 
each tandem mill again reduces the metal during a subsequent pass, thereby 
operating in tandem. Additional passes may be utilized to further reduce 
the metal to a final thickness. 
A payoff reel may be provided with the tension reel on the first side of 
the tandem mill. The provision of these two reels may be utilized to 
increase the speed of the overall cold rolling process. A payoff reel can 
be undergoing a setup procedure for working on a subsequent coil while the 
tension reel is being utilized in the reversing cold rolling operation. 
The method of cold rolling according to the present invention may reduce 
the metal by at least one-third in the first pass, preferably reducing the 
metal between one-third and 55% in the first pass. The metal may be 
reduced at least 50% in the first two passes, preferably between 55-80% in 
the first two passes. For those materials requiring a third pass, the 
method according to the present invention may reduce the material between 
80-95% in the third pass. 
The method according to the present invention may further include the step 
of passing metal through the tandem mills in a separate campaign for a 
temper pass whereby the tandem mills will reduce the strip less than 10%, 
preferably up to about 3% for the temper pass. A bridle roll unit may be 
provided on each side of the temper rolls wherein the metal is passed 
through the bridle roll units on each temper pass. 
The method of cold rolling according to the present invention can be 
repeated for a mix of metal products including, but not limited to, low 
carbon steel, medium carbon steel, high carbon steel, alloy, Si steel and 
stainless steel. The method according to the present invention can be 
utilized to cold roll and temper roll each of the products of the product 
mix whereby the tandem mills may cold roll in a given year about 240,000 
tons of the product mix in about 4,623 hours, and the tandem mills can 
temper roll about 196,800 tons of the product mix in about 2,250 hours 
resulting in a total production of about 458,000 tons of product mix cold 
rolled and temper rolled in 7,200 hours, which is roughly a full year.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 illustrates a tandem, reversing twin stand cold rolling and temper 
mill 10 schematically according to the present invention. The mill 10 
includes two four-high reversing mill stands 12. Each reversing mill stand 
12 includes two work rolls 14 positioned on either side of the pass line 
16. Each work roll is 19-21 inches in diameter, preferably 21 inches, and 
has a working face or width of 56 inches and is formed of alloyed forged 
steel. Each reversing mill stand 12 includes a backup roll 18 positioned 
behind each work roll 14. Each backup roll is preferably between 49-53 
inches in diameter, most preferably 53 inches, with a width of 56 inches 
and is also formed of alloy forged steel. It will be understood that the 
roll width is exemplary only as a product mix which includes wider cold 
rolled products which require a wider roll capability. Each reversing mill 
stand 12 is driven by a 6,000 horsepower motor assembly (not shown), 
preferably formed of two 3,000 horsepower submotors. 
The mill 10 includes a payoff tension reel 20 and tension reel 22 on a 
first side of the reversing mill stands 12 and a tension reel 24 
positioned on a second side of the reversing mill stands 12. Each 
reversing mill stand is a 20 inch diameter roll adapted to have the strip 
of material coiled thereon and paid-off to the reversing mill stands 12. 
Preferably, the payoff tension reel 20 is only utilized in the first pass 
feeding the strip of material from the payoff tension reel 20 through the 
reversing mill stands 12 to the tension reel 24 on the second side of the 
reversing mill stands. The second and subsequent passes through the 
reversing mill stands 12 will be between the tension reels 22 and 24 
allowing the payoff tension reel to be utilized for setting up the 
subsequent coil to be rolled. With this operation in mind, the tension 
reels 22 and 24 are preferably each powered by a 2,000 horsepower motor 
(not shown) while the payoff tension reel 20 is powered by a 600 
horsepower motor (not shown). 
In the first pass, the strip of material will be fed from the payoff 
tension reel 20 through pinch rolls 26, the three roll flattener 28, the 
reversing mill stands 12 and onto the tension reel 24. Each roll of the 
three roll flattener 28 is preferably an 8 inch diameter roll with a 56 
inch width made from solid steel. Each of the pinch rolls 26 is preferably 
a 10 inch diameter pinch roll with a 56 inch width formed from hardened 
alloy steel. Both the pinch rolls 26 and the three roll flattener 28 are 
preferably driven from a single 75 horsepower motor (not shown). 
A coil car 30 is provided adjacent each reel 20, 22 and 24 for conveying 
appropriate coil material to and from the mill 10. Each coil car 30 
preferably has a capacity of 60,000 pounds. 
An upcut dividing shear 32 is provided adjacent the reversing mill stands 
12 to allow for severing of the individual coils into smaller coil lengths 
as needed during rolling operations. 
To operate the mill 10 as a temper mill, a pair of bridle roll units 34 is 
provided on each side of the reversing mill stands 12 between the 
reversing mill stands 12 and the tension reels 22 and 24, respectively, as 
shown in FIG. 1. Each bridle roll utilizes a pair of 44 inch diameter 
rolls having a 56 inch width and preferably powered by a 400 horsepower 
motor (not shown). 
In operation, the mill 10 can operate as follows. The coil of metal, 
preferably steel, to be rolled is supplied to the payoff tension reel 20 
by coil car 30 and fed through pinch rolls 26, the three roll flattener 28 
and to the reversing mill stands 12 for a first pass along pass line 16. 
Each of the reversing mill stands 12 will reduce the metal during the 
first pass whereby the reversing mill stands 12 operate in tandem during 
the first pass. The controls are known multistand rolling mill 
synchronized controls now applied to a tandem stand cold mill. From the 
reversing mill stands 12, the material will be coiled on tension reel 24. 
After the first pass, the material to be cold rolled will be passed from 
the tension reel 24 through the reversing mill stands 12 along the pass 
line 16 to the tension reel 22. Each of the reversing mill stands 12 will 
again operate to cold reduce the workpiece whereby the reversing mill 
stands are operating in tandem during the second pass. Subsequent passes, 
if needed, will occur between the tension reels 22 and 24 through the 
reversing mill stands 12. While the second and subsequent passes are 
occurring between the tension reels 22 and 24, the payoff tension reel 20 
can be loaded with the next coil to be worked. After the final pass, the 
workpiece can be carried to subsequent processing or storage by the coil 
car 30 adjacent the appropriate tension reel 22 or 24. It is also 
anticipated that if the mill 10 is positioned inline with subsequent 
processing that an additional tension reel can be provided on the second 
side of the reversing mill stands 12 adjacent tension reel 24 to allow for 
simultaneous pay off to downstream processing. 
When utilizing the mill 10 for temper passes of a work product, the 
particular product will also be passed through each of the bridle roll 
units 34 to better control the tension of the thinner gauges during the 
tempering pass. Because cold reduction is carried out with rolling 
lubricants and temper rolling generally is not, the tandem mill must be 
cleaned prior to use as a temper mill. In addition, different roll 
surfaces are required for different end product; therefore, roll changes 
are required. This all necessitates that the cold reduction and temper 
rolling be carried out in separately scheduled campaigns. In other words, 
a given tonnage and product mix is cold reduced in a first campaign, the 
tandem mill is then cleaned and converted to include temper rolls and a 
second campaign of a given tonnage and product mix is scheduled for temper 
rolling. In a temper rolling mode, the two mills are not operated as 
reversing mills and, depending on the final product surface and temper 
requirements, one or both of the mills may be operated to provide the 
temper pass. Where both mills are operated in a temper pass, different 
roll surfaces may be used on each mill. 
The present mill can provide several distinct advantages over the prior 
art. The provision of two tandem, reversing mill stands 12 allows for 
greater control of the back tension required for cold rolling the steel. 
This ability to better control the back tension with the tandem rolling 
stands can allow for a decrease in the amount of scrap material previously 
provided on some reversing mills. The present mill 10 additionally 
improves the processing time of previous reversing mills. The following 
Comparison Chart utilizes a simplified product mix to compare the twin 
stand cold reversing mill of the present invention with a single stand 
cold reversing mill and a six stand nonreversing cold continuous mill of 
the prior art. The advantages of easily rolling a significant amount of 
product are illustrated; however, some of the advantages of the present 
invention are not adequately illustrated with the narrow product mix 
chosen for the comparison. 
______________________________________ 
COMISON CHART 
TONS/YEAR 
(18 TURNS .times. 
GAUGE TPH 8 HRS. .times. 50 
(INCHES) (@ WKS. = 7,200 
MILL PRODUCT IN OUT 75%) HRS./YEAR) 
______________________________________ 
Single Stand 
Sheet .100 .0393 54 TOTAL 
Reversing 
Tin Plate .070 .007 23 320,980 
Temper 
(Double Pass) 
.007 .006895 
64 
(Single Pass) 
.022 .02134 
91 
Twin Stand 
Sheet .100 .0393 83 TOTAL 
Reversing 
Tin Plate .070 .007 35 506,271 
Temper 
(Double Pass) 
.007 .006895 
68 
(Single Pass) 
.022 .02134 
91 
Six Stand 
Sheet .100 .0393 181 TOTAL 
Tandem Tin Plate .070 .007 60 926,045 
Nonre- Temper -- -- -- 
versing 
______________________________________ 
The present mill 10 provides the versatility of reversing mills over 
expensive continuous multistand nonreversing tandem cold mills. The 
present mill 10 allows for rolling of a wide product mix in both cold 
rolling and temper rolling operations. The wide mix and capabilities of 
the present mill 10 are illustrated by the following Examples. 
The following Example illustrates a more realistic, proposed product mix 
for the mill 10 utilized for both cold rolling and temper rolling of the 
products. The schedule assumes a two minute delay between temper coils and 
a 75% operating efficiency. For reference purposes, a conventional work 
year can be considered as 18 shifts per week, 8 hours per shift, 50 weeks 
per year, for a total of 7,200 hours per year. 
__________________________________________________________________________ 
ROLLING 
THICKNESS 
THICKNESS TONS/ 
SCHEDULE 
IN OUT WIDTH 
HOUR @ 75% 
TONS/ 
HOURS/ 
GRADE EXAMPLE # 
(IN.) (IN.) (IN.) 
EFFICIENCY 
YEAR YEAR 
__________________________________________________________________________ 
COLD ROLLING: 
LOW CARBON II .070 .007 40.0 
35.0 48,000 
1,371 
LOW CARBON III .077 .013 41.4 
52.0 88,800 
1,708 
MEDIUM CARBON 
IV .074 .017 36.0 
60.0 36,000 
600 
HIGH CARBON 
V .078 .022 27.8 
56.0 24,000 
428 
ALLOY VI .094 .035 30.8 
71.0 9,600 
135 
Si VII .113 .049 37.0 
98.0 4,800 
50 
STAINLESS STEEL 
VIII .113 .046 33.0 
87.0 28,800 
331 
SUBTOTAL COLD 240,000 
4,623 
ROLLING: 
TEMPER ROLLING: 
LOW CARBON IX .007 .00686 
40.0 
68.0 48,000 
706 
LOW CARBON IX .010 .0098 34.0 
75.0 14,400 
192 
DOUBLE COLD 
REDUCTION: 
DOUBLE PASS-TIN 
PLATE 
LOW CARBON X .013 3% 41.4 
100.8 74,400 
738 
MEDIUM CARBON 
X .017 3% 36.0 
102.7 36,000 
351 
HIGH CARBON 
X .022 3% 27.8 
90.9 24,000 
264 
SUBTOTAL TEMPER 196,800 
2,251 
ROLLING: 
SINGLE PASS-SHEET 
GRAND TOTAL: 436,800 
6,874 
457,515 
7,200 
__________________________________________________________________________ 
The specific rolling schedules for each of the above-listed grades follows 
hereinafter. 
For low carbon (0.10% carbon) steel beginning with an 80 inch outer 
diameter coil having a thickness of 0.07 inch and a width of 40 inches, 
the following rolling schedule is appropriate. 
__________________________________________________________________________ 
PASS NUMBER 1 1 2 2 3 3 
ROLLING STAND 
1 2 2 1 1 2 
THICKNESS ENTRY 
0.0700 
0.0455 
0.0324 
0.0221 
0.0150 
0.0102 
THICKNESS DELIVERY 
0.0455 
0.0324 
0.0221 
0.0150 
0.0102 
0.0070 
SPEED CONE MIN.-FPM 
2249. 
2249. 
2249. 
2249. 
2249. 
2249. 
SPEED CONE MAX.-FPM 
4498. 
4498. 
4498. 
4498. 
4498. 
4498. 
MAX. OPERATING FPM 
4050. 
4050. 
4050. 
4050. 
4050. 
4050. 
ROLLING FPM ENTRY 
1284. 
1976. 
1852. 
2715. 
1867. 
2745. 
ROLLING FPM 1976. 
2775. 
2715. 
4000. 
2745. 
4000. 
DELIVERY 
BITE ANGLE DEGREES 
2.77 2.03 1.80 1.49 1.23 1.00 
% REDUCTION 35.00 
28.79 
31.79 
32.13 
32.00 
31.37 
TOTAL % REDUCTION 
35.00 
53.71 
68.43 
78.57 
85.43 
90.00 
ENTRY STRIP LENGTH 
3576. 
5501. 
7725. 
11326. 
16686. 
24539. 
FT. 
DELIVERY STRIP 
5501. 
7725. 
11326. 
16686. 
24539. 
35756. 
LENGTH FT. 
PASS TIME MIN. 
2.78 2.78 4.17 4.17 8.94 8.94 
ENTRY TENSION LB. 
8800. 
25704. 
12000. 
12000. 
12000. 
8160. 
DELIVERY TENSION LB. 
25704. 
14666. 
12000. 
12000. 
8160. 
2520. 
ENTRY TENSION HP 
343. 1539. 
673. 987. 679. 679. 
DELIVERY TENSION HP 
1539. 
1233. 
987. 1455. 
679. 305. 
ENTRY STRESS PSI 
3143. 
14123. 
9259. 
13575. 
20000. 
20000. 
DELIVERY STRESS PSI 
14123. 
11316. 
13575. 
20000. 
20000. 
9000. 
LB./IN. WIDTH 
41918. 
45023. 
52324. 
50737. 
55950. 
80123. 
SEP. FORCE LB. 
1676733. 
1800934. 
2092979. 
2029488. 
2237988. 
3204907. 
WORK HP 4498. 
4946. 
4351. 
4877. 
2698. 
3384. 
TENSION HP 1197. 
-306. 
314. 467. 0. -373. 
BRG FRICTION HP 
134. 202. 230. 328. 248. 518. 
CONTACT WR-BU HP 
252. 394. 483. 679. 539. 1347. 
REQD NET HP 3687. 
5848. 
4749. 
5417. 
3485. 
5622. 
__________________________________________________________________________ 
In the above illustrated Example, the first pass can be completed in 262 
seconds, the second pass in 350 seconds and the third and final pass in 
695 seconds which, together with a 10 second delay for the reverses, 
results in a total running time of 1,317 seconds. This corresponds to the 
product rate of 47 tons per hour at 100% capacity or 35 tons per hour at 
75% capacity, as illustrated in the mill schedule discussed above. 
For low carbon (0.10% carbon) steel having a coil of 80 inch outer 
diameter, with a strip width of 41.4 and a strip thickness of 0.07 inches, 
the following rolling schedule is appropriate. 
__________________________________________________________________________ 
PASS NUMBER 1 1 2 2 3 3 
ROLLING STAND 
1 2 2 1 1 2 
THICKNESS ENTRY 
0.0770 
0.0539 
0.0425 
0.0316 
0.0235 
0.0174 
THICKNESS DELIVERY 
0.0539 
0.0425 
0.0316 
0.0235 
0.0174 
0.0130 
SPEED CONE MIN.-FPM 
2249. 
2249. 
2249. 
2249. 
2249. 
2249. 
SPEED CONE MAX.-FPM 
4498. 
4498. 
4498. 
4498. 
4498. 
4498. 
MAX. OPERATING FPM 
4050. 
4050. 
4050. 
4050. 
4050. 
4050. 
ROLLING FPM ENTRY 
1670. 
2385. 
2212. 
2975. 
2213. 
2989. 
ROLLING FPM 2385. 
3025. 
2975. 
4000. 
2989. 
4000. 
DELIVERY 
BITE ANGLE DEGREES 
2.69 1.89 1.85 1.59 1.38 1.17 
% REDUCTION 30.00 
21.15 
25.65 
25.63 
25.96 
25.29 
TOTAL % REDUCTION 
30.00 
44.81 
58.96 
69.48 
77.40 
83.12 
ENTRY STRIP LENGTH 
3251. 
4644. 
5889. 
7921. 
10651. 
14385. 
FT. 
DELIVERY STRIP 
4644. 
5889. 
7921. 
10651. 
14385. 
19253. 
LENGTH FT. 
PASS TIME MIN. 
1.95 1.95 2.66 2.66 4.81 4.81 
ENTRY TENSION LB. 
8800. 
28416 
12000. 
12000. 
12000. 
8160. 
DELIVERY TENSION LB. 
28416. 
14666. 
12000. 
12000. 
8160. 
2520. 
ENTRY TENSION HP 
445. 2054. 
804. 1082. 
805. 739. 
DELIVERY TENSION HP 
2054. 
1344. 
1082. 
1455. 
739. 305. 
ENTRY STRESS PSI 
2761. 
12734. 
6820. 
9173. 
12334. 
11328. 
DELIVERY STRESS PSI 
12734. 
8335. 
9173. 
12334. 
11328. 
4682. 
LB./IN. WIDTH 
38300. 
38923. 
48062. 
47790. 
50222. 
55300. 
SEP. FORCE LB. 
1585625. 
1611422. 
1989750. 
1978520. 
2079197. 
2289437. 
WORK HP 4987. 
4490. 
4735. 
5191. 
3293. 
3562. 
TENSION HP 1609. 
-709. 
277. 373. -66. -434. 
BRG FRICTION HP 
153. 197. 239. 320. 251. 370. 
CONTACT WR-BU HP 
275. 357. 482. 642. 517. 799. 
REQD NET HP 3806. 
5753. 
5178. 
5780. 
4127. 
5165. 
__________________________________________________________________________ 
In the above Example, the first pass can be completed in 206 seconds, the 
second in 253 seconds and the third in 442 seconds which, together with a 
10 second delay for reversing the rolling direction, results in a 911 
second total time. This corresponds to 70 tons per hour at 100% capacity 
or 52 tons per hour at 75% of capacity. 
For medium carbon (0.20% carbon) steel having a coil of 80 inch outer 
diameter, with a width of 36 inches and an entry thickness of 0.07, the 
following rolling schedule is appropriate. 
______________________________________ 
PASS NUMBER 1 1 2 2 
ROLLING STAND 
1 2 2 1 
THICKNESS ENTRY 
0.0740 0.0488 0.0354 0.0245 
THICKNESS 0.0488 0.0354 0.0245 0.0170 
DELIVERY 
SPEED CONE MIN.- 
2249. 2249. 2249. 2249. 
FMP 
SPEED CONE MAX.- 
4498. 4498. 4498. 4498. 
FPM 
MAX. OPERATING 
4050. 4050. 4050. 4050. 
FPM 
ROLLING FPM ENTRY 
1191. 1806. 1532. 2213. 
ROLLING FPM 1806. 2490. 2213. 3190. 
DELIVERY 
BITE ANGLE 2.81 2.05 1.85 1.53 
DEGREES 
% REDUCTION 34.05 27.46 30.79 30.61 
TOTAL % 34.05 52.16 66.89 77.03 
REDUCTION 
ENTRY STRIP 3382. 5129. 7070. 10216. 
LENGTH FT. 
DELIVERY STRIP 
5129. 7070. 10216. 14723. 
LENGTH FT. 
PASS TIME MIN. 
2.84 2.84 4.62 4.62 
ENTRY TENSION LB. 
8800. 22000. 12000. 12000. 
DELIVERY TENSION 
22000. 12000. 12000. 5000. 
LB. 
ENTRY TENSION HP 
318. 1204. 557. 805. 
DELIVERY TENSION 
1204. 905. 805. 483. 
HP 
ENTRY STRESS PSI 
3303. 12523. 9416. 13605. 
DELIVERY STRESS 
12523. 9416. 13605. 8170. 
PSI 
LB./IN. WIDTH 
54950. 58051. 66876. 71124. 
SEP. FORCE LB. 
1978201. 2089836. 2407545. 
2560454. 
WORK HP 4752. 4816. 3976. 4568. 
TENSION HP 887. -299. 248. -322. 
BRG FRICTION HP 
144. 210. 215. 330. 
CONTACT WR-BU HP 
311. 465. 512. 809. 
REQD NET HP 4321. 5791. 4455. 6029. 
______________________________________ 
In the above Example, the first pass can be completed in 261 seconds with 
the second pass in 431 seconds including delays which results in a 692 
second running time. This equates to 80 tons per hour at 100% capacity or 
60 tons per hour at 75% capacity, as illustrated on the milling schedule. 
A high carbon (0.35% carbon) steel coil having a strip width of 27.8 inches 
and entry thickness of 0.78 inch and an outer coil diameter of 80 inches 
is rolled as follows. 
______________________________________ 
PASS NUMBER 1 1 2 2 
ROLLING STAND 
1 2 2 1 
THICKNESS ENTRY 
0.0780 0.0568 0.0414 0.0301 
THICKNESS 0.0568 0.0414 0.0301 0.0220 
DELIVERY 
SPEED CONE MIN.- 
2249. 2249. 2249. 2249. 
FMP 
SPEED CONE MAX.- 
4498. 4498. 4498. 4498. 
FPM 
MAX. OPERATING 
4050. 4050. 4050. 4050. 
FPM 
ROLLING FPM ENTRY 
1449. 1990. 1807. 2485. 
ROLLING FPM 1990. 2730. 2485. 3400. 
DELIVERY 
BITE ANGLE 2.58 2.20 1.88 1.59 
DEGREES 
% REDUCTION 27.18 27.11 27.29 26.91 
TOTAL % 27.18 46.92 61.41 71.79 
REDUCTION 
ENTRY STRIP 3209. 4407. 6046. 8315. 
LENGTH FT. 
DELIVERY STRIP 
4407. 6046. 8315. 11377. 
LENGTH FT. 
PASS TIME MIN. 
2.21 2.21 3.35 3.35 
ENTRY TENSION LB. 
8800. 21317. 14666. 11296. 
DELIVERY TENSION 
21317. 14666. 11296. 5504. 
LB. 
ENTRY TENSION HP 
386. 1285. 803. 851. 
DELIVERY TENSION 
1285. 1213. 851. 567. 
HP 
ENTRY STRESS PSI 
4058. 13500. 12743. 13499. 
DELIVERY STRESS 
13500. 12743. 13499. 8999. 
PSI 
LB./IN. WIDTH 
59189. 69716. 78604. 86446. 
SEP. FORCE LB. 
1645448. 1938101. 2185182. 
2403209. 
WORK HP 3871. 5189. 4050. 4539. 
TENSION HP 899. -72. 48. -284. 
BRG FRICTION HP 
132. 214. 219. 330. 
CONTACT WR-BU HP 
296. 519. 565. 892. 
REQD NET HP 3400. 5994. 4786. 6044. 
______________________________________ 
In the above Example, the first pass can be completed in 221 seconds with 
the second pass completed in 352 seconds for a total running time of 573 
seconds. This results in 74 tons per hour at 100% capacity which when 
reduced to 75% capacity is 56 tons per hour, as illustrated on the milling 
schedule. 
An alloy steel (0.50% carbon) having an entrance thickness of 0.094 inch, a 
strip width of 30.8 inches and an outer diameter of coil of 80 inches will 
roll according to the following schedule. 
______________________________________ 
PASS NUMBER 1 1 2 2 
ROLLING STAND 
1 2 2 1 
THICKNESS ENTRY 
0.0940 0.0690 0.0573 0.0448 
THICKNESS 0.0690 0.0573 0.0448 0.0350 
DELIVERY 
SPEED CONE MIN.- 
2249. 2249. 2249. 2249. 
FMP 
SPEED CONE MAX.- 
4498. 4498. 4498. 4498. 
FPM 
MAX. OPERATING 
4050. 4050. 4050. 4050. 
FPM 
ROLLING FPM ENTRY 
1664. 2267. 1484. 1898. 
ROLLING FPM 2267. 2730. 1898. 2430. 
DELIVERY 
BITE ANGLE 2.80 1.91 1.98 1.75 
DEGREES 
% REDUCTION 26.60 16.96 21.82 21.87 
TOTAL % 26.60 39.04 52.34 62.77 
REDUCTION 
ENTRY STRIP 2663. 3627. 4368. 5587. 
LENGTH FT. 
DELIVERY STRIP 
3627. 4368. 5587. 7151. 
LENGTH FT. 
PASS TIME MIN. 
1.60 1.60 2.94 2.94 
ENTRY TENSION LB. 
8800. 30519. 8800. 18627. 
DELIVERY TENSION 
30519. 14666. 18627. 9702. 
LB. 
ENTRY TENSION HP 
444. 2097. 396. 1072. 
DELIVERY TENSION 
2097. 1213. 1072. 714. 
HP 
ENTRY STRESS PSI 
3040. 14361. 4986. 13499. 
DELIVERY STRESS 
14361. 8310. 13499. 9000. 
PSI 
LB./IN. WIDTH 
74247. 71959. 90795. 97182. 
SEP. FORCE LB. 
2286798. 2216350. 2796500. 
2993196. 
WORK HP 6509. 4812. 3921. 4532. 
TENSION HP 1653. -883. 676. -357. 
BRG FRICTION HP 
209. 244. 214. 294. 
CONTACT WR-BU HP 
524. 603. 594. 842. 
REQD NET HP 5590. 6542. 4054. 6025. 
______________________________________ 
In the above Example, the first pass can be completed in 180 seconds with 
the second pass completed in 319 seconds resulting in a total running time 
of 499 seconds for cold rolling of this coil. This corresponds to 94 tons 
per hour capacity at 100% or at 71 tons per hour capacity at 75%, as 
illustrated on the schedule. 
The cold rolling of a steel coil having 3.18% silicon with an 80 inch outer 
diameter, a 37 inch width and an entry thickness of 0.113 inch can be 
accomplished according to the following schedule. 
______________________________________ 
PASS NUMBER 1 1 2 2 
ROLLING STAND 
1 2 2 1 
THICKNESS ENTRY 
0.1130 0.0870 0.0744 0.0587 
THICKNESS 0.0870 0.0744 0.0587 0.0490 
DELIVERY 
SPEED CONE MIN.- 
2249. 2249. 2249. 2249. 
FMP 
SPEED CONE MAX.- 
4498. 4498. 4498. 4498. 
FPM 
MAX. OPERATING 
4050. 4050. 4050. 4050. 
FPM 
ROLLING FPM ENTRY 
1603. 2082. 1498. 1899. 
ROLLING FPM 2082. 2435. 1899. 2275. 
DELIVERY 
BITE ANGLE 2.86 1.99 2.22 1.74 
DEGREES 
% REDUCTION 23.01 14.48 21.10 16.52 
TOTAL % 23.01 34.16 48.05 56.64 
REDUCTION 
ENTRY STRIP 2215. 2877. 3364. 4264. 
LENGTH FT. 
DELIVERY STRIP 
2877. 3364. 4264. 5108. 
LENGTH FT. 
PASS TIME MIN. 
1.38 1.38 2.25 2.25 
ENTRY TENSION LB. 
8800. 25419. 14666. 26773. 
DELIVERY TENSION 
25419. 14666. 26773. 14666. 
LB. 
ENTRY TENSION HP 
428. 1604. 666. 1541. 
DELIVERY TENSION 
1604. 1082. 1541. 1011. 
HP 
ENTRY STRESS PSI 
2105. 7897. 5328. 12327. 
DELIVERY STRESS 
7897. 5328. 12327. 8089. 
PSI 
LB./IN. WIDTH 
65914. 62562. 82184. 81353. 
SEP. FORCE LB. 
2438803. 2314798. 3040797. 
3010077. 
WORK HP 6620. 4724. 5211. 4469. 
TENSION HP 1176. -522. 875. -530. 
BRG FRICTION HP 
205. 228. 233. 277. 
CONTACT WR-BU HP 
484. 523. 615. 725. 
REQD NET HP 6133. 5997. 5184. 6000. 
______________________________________ 
In the above Example, the first pass can be completed in 163 seconds while 
the second pass can be completed in 274 seconds resulting in a total 
running time for this coil of 437 seconds. This corresponds to 130 tons 
per hour of production at 100% capacity or 98 tons per hour at 75% 
capacity. 
A ferritic stainless steel having an entry thickness of 0.113 inch, a width 
of 33 inches and a coil outer diameter of 80 inches can be cold rolled 
according to the following schedule. 
______________________________________ 
PASS NUMBER 1 1 2 2 
ROLLING STAND 
1 2 2 1 
THICKNESS ENTRY 
0.1130 0.0870 0.0720 0.0575 
THICKNESS 0.0870 0.0720 0.0575 0.0460 
DELIVERY 
SPEED CONE MIN.- 
2249. 2249. 2249. 2249. 
FMP 
SPEED CONE MAX.- 
4498. 4498. 4498. 4498. 
FPM 
MAX. OPERATING 
4050. 4050. 4050. 4050. 
FPM 
ROLLING FPM ENTRY 
1552. 2015. 1661. 2080. 
ROLLING FPM 2015. 2435. 2080. 2600. 
DELIVERY 
BITE ANGLE 2.86 2.17 2.13 1.90 
DEGREES 
% REDUCTION 23.01 17.24 20.14 20.00 
TOTAL % 23.01 36.28 49.12 59.29 
REDUCTION 
ENTRY STRIP 2215. 2877. 3476. 4353. 
LENGTH FT. 
DELIVERY STRIP 
2877. 3476. 4353. 5441. 
LENGTH FT. 
PASS TIME MIN. 
1.43 1.43 2.09 2.09 
ENTRY TENSION LB. 
8800. 26789. 8800. 26789. 
DELIVERY TENSION 
26789. 14666. 26789. 14666. 
LB. 
ENTRY TENSION HP 
414. 1636. 443. 1689. 
DELIVERY TENSION 
1636. 1082. 1689. 1156. 
HP 
ENTRY STRESS PSI 
2360. 9331. 3704. 14118. 
DELIVERY STRESS 
9331. 6173. 14118. 9661. 
PSI 
LB./IN. WIDTH 
59540. 57988. 65614. 65903. 
SEP. FORCE LB. 
1964806. 1913604. 2165267. 
2174808. 
WORK HP 5256. 4564. 4004. 4553. 
TENSION HP 1222. -554. 1246. -533. 
BRG FRICTION HP 
160. 188. 182. 228. 
CONTACT WR-BU HP 
359. 417. 428. 539. 
REQD NET HP 4552. 5723. 3368. 5853. 
______________________________________ 
In the above Example, the first pass can be completed in 167 seconds while 
the second pass can be completed in 268 seconds resulting in a 435 second 
total running time. This corresponds to 116 tons per hour of production at 
100% capacity or 87 tons per hour at 75% capacity. 
The temper rolling schedules of some of the above-listed products are as 
follows, with the first Example corresponding to the listed grades of low 
carbon steel (0.10% carbon) and the second Example representing a double 
cold reduction of various products having a temper reduction of 3%. 
______________________________________ 
LOW LOW LOW LOW 
MATERIAL CARBON CARBON CARBON CARBON 
______________________________________ 
PASS NUMBER 1 1 1 1 
ROLLING STAND 
1 2 1 2 
THICKNESS ENTRY 
0.0070 0.0069 0.0100 0.0098 
THICKNESS 0.0069 0.0069 0.0098 0.0098 
DELIVERY 
SPEED CONE MIN.- 
2249. 2249. 2249. 2249. 
FMP 
SPEED CONE MAX.- 
4498. 4498. 4498. 4498. 
FPM 
MAX. OPERATING 
4050. 4050. 4050. 4050. 
FPM 
ROLLING FPM ENTRY 
3969. 4029. 3969. 4029. 
ROLLING FPM 4029. 4050. 4029. 4050. 
DELIVERY 
BITE ANGLE 0.18 0.10 0.22 0.13 
DEGREES 
% REDUCTION 1.50 0.51 1.50 0.51 
TOTAL % 1.50 2.00 1.50 2.00 
REDUCTION 
ENTRY STRIP 35756. 36301. 25029. 25411. 
LENGTH FT. 
DELIVERY STRIP 
36301. 36486. 25411. 25540. 
LENGTH FT. 
PASS TIME MIN. 
9.01 9.01 6.31 6.31 
ENTRY TENSION LB. 
2716. 3000. 2761. 3000. 
DELIVERY TENSION 
3000. 2716. 3000. 2716. 
LB. 
ENTRY TENSION HP 
327. 366. 327. 366. 
DELIVERY TENSION 
366. 333. 366. 333. 
HP 
ENTRY STRESS PSI 
9700. 10877. 7988. 8958. 
DELIVERY STRESS 
10877. 9898. 8958. 8151. 
PSI 
LB./IN. WIDTH 
2708. 2695. 3008. 2879. 
SEP. FORCE LB. 
108312. 107808. 102272. 
97883. 
WORK HP 24. 9. 28. 10. 
TENSION HP 40. -33. 40. -33. 
BRG FRICTION HP 
18. 18. 17. 16. 
CONTACT WR-BU HP 
8. 8. 8. 8. 
REQD NET HP 10. 68. 14. 67. 
______________________________________ 
__________________________________________________________________________ 
LOW MEDIUM 
HIGH 
MATERIAL CARBON 
CARBON 
CARBON 
__________________________________________________________________________ 
WORK ROLL DIAMETER (IN.) 
21.00 
21.00 
21.00 
ENTRY YIELD STRENGTH (PSI) 
35000. 
51000. 
61000. 
COEFFICIENT OF FRICTION 0.300 
0.300 
0.300 
ENTRY THICKNESS OF STRIP (IN.) 
0.01300 
0.01700 
0.02200 
DELIVERY THICKNESS OF STRIP (IN.) 
0.01261 
0.01649 
0.02134 
r REDUCTION (RATIO DRAFT TO ENTRY 
0.03000 
0.03000 
0.03000 
THICKNESS) 
REDUCTION (%) 3.00 3.00 3.00 
MATERIAL WIDTH (IN.) 41.40 
36.00 
27.80 
ENTRY STRIP SPEED (FPM) 3929. 
3929. 
3929. 
DELIVERY STRIP SPEED (FPM) 
4050. 
4050. 
4050. 
ENTRY BRIDLE TENSION (LB.) 
4655. 
7448. 
12103. 
DELIVERY BRIDLE TENSION (LB.) 
4655. 
7448. 
12103. 
ENTRY BRIDLE TENSION (PSI) 
8649. 
12170. 
19789. 
DELIVERY BRIDLE TENSION (PSI) 
8917. 
12546. 
20401. 
ARC OF CONTACT LENGTH (IN.) 
0.1260 
0.13436 
0.14297 
AVERAGE STRAIN RATE (IN./IN./SEC.) 
191.65 
180.86 
169.96 
COMPRESSIVE STRESS REQD TO DEFORM STRIP 
74619. 
90430. 
100228. 
(PSI) 
CONSTRAINED YIELD STRENGTH IN 
COMPRESSION (PSI) 86185. 
104447. 
115763. 
AVERAGE STRIP TENSION IN ROLL BITE (PSI) 
8783. 
12358. 
20095. 
SPECIFIC ROLLING FORCE (LB./IN. OF WIDTH) 
63185. 
53264. 
43979. 
SEATING FORCE (LB.) 2615854. 
1917520. 
1222622. 
SPECIFIC TOTAL TORQUE (LB.-IN.) 
51518. 
59845. 
54364. 
ROLLING HORSEPOWER REQD (HP) 
602. 700. 636. 
TENSION HORSEPOWER (HP) 17. 27. 45. 
BEARING FRICTION HORSEPOWER (HP) 
428. 314. 200. 
CONTACT LOSS WR-BU HORSEPOWER (HP) 
593. 399. 231. 
REQD NET HORSEPOWER (HP) 
1606. 
1385. 
1022. 
ENTRY DRAG BRIDLE HORSEPOWER REQD (HP) 
554. 887. 1441. 
DELIVERY BRIDLE HORSEPOWER REQD (HP) 
571. 914. 1485. 
ENTRY BRIDLE (LB. PULL/IN. OF WIDTH) 
112. 207. 435. 
DELIVERY BRIDLE (LB. PULL/IN. OF WIDTH) 
112. 207. 435. 
CYCLE TIME (MIN.) 7.86 6.70 5.85 
TONS/HOUR @ 75% EFFICIENCY 
100.8 
102.7 
90.9 
__________________________________________________________________________ 
While the preferred embodiments of the present invention has been described 
in detail, it will be obvious to those of ordinary skill in the art that 
various modifications may be made to the present invention without 
departing from the spirit and scope thereof. Consequently, the scope of 
the present invention should be defined by the following claims.