Design of Ladle

7/29/2019 Design of Ladle

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LADLESHOT METAL WELDED andHOT METAL RIVETEDTRANSFER for theBESSEMER STEEL

OPEN COPPERHEARTH BRASSELECTRIC ALUMINUMFURNACE and ALLIEDFOUNDRY INDUSTRIES

TREADWELL CONSTRUCTION CO.MIDLAND, PENNSYLVANIA

208 S. LaSalle StreetCHICAGO 4, ILL.

CEntral 6-9784

SALBS Orr.CBS140 Cedar StreetNEW YORK 6, N. Y.

WOrth 4-33441217 Farmers Bank BuildingPITTSBURGH 22, PA.

ATlantic 1.2883

LS-16 IRON AND STEEL ENGINEER, MARCH, 1952


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.LADLESWELDED OR RIVETED

5 TO 300 TON CAPACITY 22 5 TON LADLEFOR

BLAST FURNACEOPEN HEARTH

ELECTRIC FURNACEBESSMER CONVERTER

FOUNDRY

LADLE TRANSFER CARSLADLE STANDSLADLE BAILSLADLE HOOKS

ALL WELDED LADLES

STRESS RELIEVED

250 TON LADLE

30 0 TON LADLE

IRON AND STEEL ENGINEER, MARCH, 1952 LS15


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LS-14

P6LL6CKSince 1863

BLAST FURNACES HOT METAL CARS AND LADLESCINDER AND SLAG CARS INGOT MOLD CARS

CHARGING BOX CARS. WELDED OPEN HEARTH LADLES

THE WILLIAM B. POLLOCK COMPANYYOUNGSTOWN, OHIO

STEEL PLATE CONSTRUCTION. ENGINEERSFABRICATORS. ERECTORS

IRON AND STEEL ENGI EER, MARCH, 1952


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22. Location- of teeming spout will be as follows: - ... _23. Diameter of tap hole will be as follows :____________________________________________________________________________________ _24. Location and number of pouring lips will be as follows: ----------------------.----25. Painting required is as follows :__________________________________________________ __

26. Protection of finished parts for s h i p ~ e n t will be as follows : _

27. IJadle will be unloaded b y _ ~ . .____________ _ _ _28. (See 3 A, a) material for bottom plate will be______ _ - .29. (See 3 A, b) ma,terial for shell plate stiffener rings, etc., will be _30. (See 3 A, f) the lining shall be composed of the following:

---------------- -------------- _.,"

81. Lining will be furnished by . . . . . _/ 32. (See 4 B) Bottom plate will be dished or flaL as checked.33. Ladle will be welded or riveted________ as checked.34. (See 4F) Are steel bushings required for trunnions? _35. (See 4 F) Are 6illess bronze bushings required on the trunnion pin? _36. (See 4 I) Are heat protection plates required around pouring nozzle? _37. (?ee 4K) Are weep holes required on side of ladles?_____________ _

SPECIAL FEATURES

ASSOCIATION OF IRON AND STEEL ENGINEERSSTANDARDS

AISE Standard No. 1 - D-C MILL MOTOR STANDARDS. . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . $0.25 eaAISE Standard No. 2 - STANDARD DIMENSIONS FOR ENCLOSED SWITCHES. 0.25 eaAISE Standard No. 3 - STANDARDS FOR MACHINED SURFACE FINISHES. . . . . . . . . . . . . . .. 0.25 eaAISE Standard No. 4 - SLING AND CRANE CHAIN STANDARDS. . . . . . . . . . . . . . 0.25 eaAISE Standard No.5-STANDARDS FOR '\TIRING DIAGRAMS. . . . . . . . . . . . . . . . . . . . . . . / 0.25 eaAISE Standard No. 6 - SPECIFICATIONS FOR ELECTRIC OVERHEAD TRAVELING

CRANES FOR STEEL MILL SERVICE 1.00 'eaAISE Standard No. 7 - SPECIFICATIONS FOR DESIGN OF LADLE HOOKS .. 0.25eaAISE Standard No. l3 - CRANE WIRING STANDARDS : . . . . . . . . . . . . . . . . . . . . . . . . . .. 0.25 eaAISE Standard No. 9 - STANDARDS FOR DESIGN OF HOT METAL LADLES (Tentative).... 0.25 eaAISE Standard No. 10 - CARBON BRUSH SIZE AND SHUNT STANDARDS (Tentative) : 0.25 eaAISE Standard No. 1 1 - D-C MILL MOTOR BRAKE STANDARDS (Tentative - In Process). . . . 0.25 ea

RECOMMENDED PRACTICESAISE Recommended Practice No. I -PLAIN BEARING RECOMMENDED PRACTICE (Tentative).. 1.00 eaQuantity prices may be obtained on request.'Minimum price for any order $1.00.IRON AND STEEL ENGINEER, MARCH, 1952 1.8-13


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l ip r ing, which may in practice be weakened by spoutsor ho t metal spills.9. DESIGN OF SIDEWALL PLATES

Minimum sidewail thicknesses are in accordance withusage requirements, and in addition it is specified thatthe sidewall thicknesses shall no t be less than 0.75 timesth e bottom plate thickness. This last requirement is setup to provide adequate restraint or fixity to the edge ofthe bottom plate. .

CONCLUSION

Simplified design and analysis procedures for open

top hot metal ladles have been presented and the resultscompared with laboratory tests and actual designpractice. Reasonably good agreement has been foundin each case. Generally accepted ru les of good practicehave been incorporated into the specification, as a resultof suggestions by the Hot Metal Ladle Committee ofthe Association of Iron and Steel Engineers. Preliminarydrafts of th e specification'} later revised by the commit tee' , were prepared by Dr . Bruce G. -Johnston,Professor of Structural Enginecring, at th e Universit.yof Michigan. The formulas for dished bottom shellthickness in Section 7 were prepared by Dr. BrunoThurlimann, former research worke r in th e field cifthin shell structures at Fritz Engineering Laboratory ofLehigh U n i v e r s i t ~ , .

AISE HOT METAL LADLE SPECIFICATIONPURCHASER'S INFORMATION SHEETS........................... -- -- -- .. -- .. -- __Coillpany... __ __ .. __ __ __ .. __ .. __ __ Works

.. .. .____________ . . Dated __.TON HOT METAL I ~ A D L E

(This information to bc furnished bidder, by purchaser)1. The following specific information, together with th e A ISE Standard No.9, Specifications for Design of Hot:M:etal Ladles, dated . __ , shall form the complete specifications of number as noted above.

Contractor shall f u r n i s h ~ _ . . ------- --_--0-------------.------... ------------------------ . -- .. -.. -..... ------------- ---------------------.. ---

Located at . ..... __ -- .... -- ------.--.------------.----.------.------.----------------.----------.------.--..Specification No ..

... -.-.----------.------ ----------.-----_.... _.-----------------

10.11.12.13.14.15.16.17.18.

as covered by these specifications.B. Ladle to be delivered F.O.B ..__ . __ . . ------------------------. ------------------------. -- ...... -- ... -------------- ------------ .. ---------- ..----.4. Number of sets of prints, etc., t.o be furnished:Specificat.ions ... .. --------.-------- .. ----------------.... ----. ----------. ------. --. -- -- . --------------.-- .... ------....--.Are prints or tracings required ?--... -------------------------- -------------------------------------- ..... -------------------------- ------.------5. Required delivery date is :.... __ .__ --.-- .. ----------. ----------------.... -- .. --. ------... --------------. ---------- '-' .-------- .. ---- .. . --GENERAL DETAILS6. Capacity of ladles is __ .. __ .. .t.ons.7. Material which ladle will handle is . __ . .. . ..... __ .. .. . ..... . .. . ... --.------------------.-- . .. -- ....8. Weight of molten metal to be handled is __ .... lb per cu ft.9. Maximum allowable weight of ladle will be. ., .lb.

Limiting height of ladle is________________ft. .... lI1.Limiting diamet.er of ladle is________________ft. .. .in.Centerline of trunnion t.o top of lining flange shall not. e x ~ e e c L - - - - - - - - - - - - - - . f L - - - - - - - - .. -- --.in.Centerline of trunnion t.o underside of bottom shall not exceed . . fL .in.Inside diameter of ladle at top shall not exceecL fL l I1.Thickness of ladle hooks is .in.Diameter of trunnions will be as follows : . ~ - - - - - - - - - - - - . - - - - - - - - - - - - - - - - - - - - - - - - - - - - . - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -Distance between centerlines of trunnions and ladle hooks is... .f L .. __ .. __ in.Side hook loops are required as follows :------------------.-"------------------.--.. ---- . . --.. ------------ ---------------- ---- . . ---------- .. ------.--.

,--------_ ... -.----------_ ... -----------------19. Ladle stand seat is required as follows:. . . . .. __ . __.----------------------- .--------_ ------_ _ _.. -_. . - . _ - .. _ . _ -.. - - _ _ _ . _ .

20. Is a heat shield required on bottom? ----.------------------------------ .. ------ ---------- ------------------.. --------. ---------- . . --21. Stopper rod rigging will be as follows :-------- .. --.----.--------------.----:--.---- --.----.--.-- .... ------------------------ .. __ . ~ . - - . : : - - - - - - . o ....

.. - _ - -- .. _._ _- .-._ _ _._ .. _ - - _ _.. - _- __ _ - _.._ _ _ _- .. - - --- _.. __ _ _._-_._-- - - _. . _-. _ _- -- _ _. .



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Tables I, II , and III show a comparison of themaximum stresses actually measured in model ladles, asreported in Reference (1), with the stresses obtained bythe procedure given in Section 8. A study of these tableswill show that reasonably good agreement exists between stresses by analysis and tes t, especial ly in thecase of the most critical maximum stresses.

The proposed analysis procedure was also tried outon five actual designs selected to cover a wide range ofladle capacity, from 70 to 270 tons. Most of the stressesso calculated, as shown in Table IV, were below the proposed allowable value of 16,000 psi, However , two ofthe ladles, designated in the table as made by "e", hadtop rib sections markedly reduced for hook clearance atthe critical section, with stresses in this location in the

neighborhood of the yield strength of structural gradesteel. I t is also of interest that this manufactuI'el' hasreported actual yielding of ladles in service' at thislocation,In Section 8G, no computation is required for the

bottom rib at the trunnion, since the ladle researchprogram showed these ,'3tresses to be less than at theother locations. In addition, the bottom rib is sometimesstrengthened here to enable the ladle to be set in a ladlestand seat, However, good practice usually dictates thatthe lower ring be as large if not larger than the topring, and that it be fully as large if no t larger at thetrunnion than at 90 degrees from the trunnion. The lipring is no t considered in the specification, since it isfelt that the ladle should be strong enough without the

TABLE IIISTRESSES IN TEST LADLE C

(Round, Welded, Sidewall Thickened Between Ribs)

Location 2Yz-in. Hook distance 7Yz-in. Hook distanceTest Formula Test Formula

I Outside - 9,150 - 9,350 -18,500 -15,430. 00 Inside ........ + 12,460 , , . . . . . +20,580Lip ring Outside + 3,540 + 5,420 + 6,020 + 8,96090 0 Inside - 5,930 - 7,230 - 9,500 -11,920- - - - - - - -Outside - 3,100 - 4,220 - 6,740 - 6,96000 Inside + 3,700 + 3,600 + 7,300 + 5,950Top rib Outsjde +,5,250 + 7,290 + 9,250 +12,03090 0 Inside - 3,400 - 3,610, - 5,700 - 5,960Outside + 4,180 + 4,140 + 4,430 + 6,840Bottom rib 90 0 Inside - 2,340 - 2,070 - 4,430 - 3,420

TABLE IVSTRESSES BY PROPOSED DESIGN METHOD FOR VARIOUS FULL SIZE LADLES

SampleActual ladle designs in service designexampleLadle mfg., , , , , , , .. , ' . . . . . , . , , .. , . . . . . C C A B A------ - - - - - - - - - - - - - - - - -Ladle capacity in tons . . . . , . ' . . . . . . . , . , , 70 140 200 225 270 150- - - - - - - - - - - - -----Outside -39,000 -36,400* ** -16,750 ** .-13,50000 - - - - - - ------- - - - - -Inside + 19,700 +19,000 ** +10,300 ** + 8,130- - - - - -At Outside . . . . . . . . . . . . . . . . -15,600 -12,100 -16,700 -15,500Top change of - - - - - -rib section Inside . . . . . . . . . . . . . . . . +10,000 + 6,500 +10,600 + 8,400- - - - - -Outside +16,000 + 5,540 + 7,800 +13,800 + 4,600 + 13,10090 0 ----- - - - - - -Inside - 9,200 - 4,010 - 5,900 - 7,550 - 3,650 - 7,950- - - - - -Outside +10,500 + 4,250 + 6,100 + 8,900 + 4,800 + 9,600Bottom 90 0 ------ - - - - -rib Inside - 6,800 - 3,230 - 4,700 - 5,500 - 3,450 - 6,700 ,-*Section was reduced for hook clearance.

IRON AND STEEL ENGINEER, MARCH, 1952

**Stress obviously greater at change of section,LS-ll


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7. DESIG:N" OF BOTTOM PLATES OFDISHED BOTTOM I , A ] ) J ~ E SThe formulas for thickness of dished bottom ladles,as given in Section 7, were obtained by a theoreticalanalysis of the local bcnding stresscs at the juncturebetween th e ladle bottom and sidewall. Since thesestresses are highly localized, and since the load iscarried no t by bending bu t by direct stress, an allowablestress of ~ 4 , 0 0 0 psi, as explained in Section 5, was

permitted.The init ial formulas result ing from this analysis werequite complex. Simplifications were introduced so that

th e result ing empirical formulas, as given in Sections 713and 7C, for circular and oval ladles respectively, wouldgive proportions on the safe side.

In Figure 8 th e thicknesses required by th e empiricalformula are compared with a number of actual ladledesigns. The dimensionless ratio 10,000 T/R is plottedas ordinate against the' dimensionless rat io appearingon the ri ght side 'of' th e proposed empirical formula(Section 7C) . Of th e fourteen designs considered, onlytwo have thicker bottom plates than would result fromth e specification formula. The remainder, however, aresti ll in reasonably good agreement and show th e sametrend the solid line plotted from th e formula.8. DESIGN OF STIFFENER BIBSThe notation used in the rib analysis and design hasbeen g iven in Figures 1 to 4, th e design procedure

illustrated inAppendix A for th e ladle shown in Figure 5.TABLE I

STRESSES IN TEST LADLE A(Round, Riveted, with Flat Stiffener Bands)

Location 2Y2-in. Hook distance, 2Y2-in. Hook distance, 7Y2-in. Hook distance,8 x 8-in. trunnion pads 8 x 16-in. trunnion pads 8 x 16-in. trunnion padsTest Formula Test Formula Test Formula

Outside -10,800 -10,900 - 6,850 --:- 8,750 -12,200 -14,30000Lip Inside +28,400 +25,900 +23,400 +20,750 +33,600 +34,000ring Outside + 4,880 + 5,400 + 4,010 + 5,400 + 7,730 + 8,90090 0 Inside -15,500 -14,200 -17,990 -14,200 -29,770 -23,400Outside - 6,450 - 7,300 - 2,180 - 5,900 - 4,360 - 9,70000 - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - -Top Inside + 3,500 + 5,600 +1,600 + 4,400 + 3,400 + 7,300rib - - - - - - -Outside + 3,740 + 3,800 + 3,450 + 3,800 + 5,570 + 6,30090 0 Inside - 1,820 - 3,000 - 2,010 - 3,000 - 3,120 - 4,900-------- - ~ ~ - - - - - - - - - -Outside + 4,600 + 3,100 + 4,220 + 3,100 + 7,570 + 5,200Bottom 90 0 - - ~ - - - -rib I Inside - 1,340 - 2,700 - 1,910 - 2,700 - 4,150 - 4,400

TABLE IISTRESSES IN TEST LADLE B

(Oval, Welded, Uniform Sidewall Thickness)

Location . 2Y2-in. Hook distance 7Y2-in. Hook distanceTest Formula Test Formula----- - - - - - - - -Outside . . . . . . . . -10,260 . . . . . . . . -17,50000

Inside + 9,160 + 13,200 +18,100 +22,600Lip ring Outside + 2,750 + 4,260 + 5,800 + 7,27090 0 - - - ~ -------- - - - - - - -Inside - 6,330 - 5,950 - 7,580 -10,130- - - - - - - - - - - - - - -Outside - 9,970 -11,000 -22,400 -18,80000 Inside + 3,620 + 5,580 + 6,900 + 9,500Top rib - - - - ----- - - - - - - - -Outside + 3,390 + 4,560 + 6,450 + 7,79090 0 ---- - - - - - - -Inside - 1,880 ~ 2,600 - 4,220 - 4,430Outside + 4,290 + 4,600 + 8,500 + 7,850Bottom rib 90 0 ---------Inside - 3,310 - 3,700 - 6,060 - 6,320

LS-l0 IRON AND STEEL ENGINEER, MARCH, 1952


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Figure 8 - Sketch shows comparison between design re quirements and a number of exist ing dished bottomladles.

G'O00 20 30 40(0.G4 D",AX - 0.04\H(0.1 +.r:)" DM'N / R.

v0 /1// 000 ~ o ob / 0V Z l/ ~~ '/L 10,000:;&-1 =0, s. 2+0I04-D ... -0.04) H 0 . 1 + ~ )M,,,,V

o OVAL L A O ~ E . S{). Roc/NO LADLESI IiO

6. DESIGN OF BOTTOM PLATES OF" .'FLAT BOTTOM LADLESThe formulas given herein for thickness of flat bottomplates have been arrived at on the basis of the bending

theory of circular plates, considering the restraint ofthe sidewalls as be ing intermediate between simplesupports and fully fixed edges.Figure 6 shows the agreement for circular bottomladles between the proposed design formulas and a

number of ladles built by various manufacturers over aperiod of many years. The design formulas give thicknesses on the safe side of existing practice.Figure 7 is similar to .Figure 6, but is for oval bottomladles, and is based on an "equivalent" diameter asgiven in Section 6F. "Oval" ladles usually have flatsides at th e minimum diameter, joined by circularsections. Their shape is not greatly different from anellipse. A study of the bending of elliptical p la tes,together \vith consideration of the fact that the flatportions of the ladle sidewalls offer much less bending

restraint than the circular sections, showed that an"equivalent" diameter equal to the average of themaximum and minimum diametcrs could be used in theempirical formulas of Sections 6B and 6D.The greatest discrepancy between the proposed design formulas and existing practice appears to be in thecase of the flat bottoms with no reinforcing plates.These are used only for relatively small capacity ladlesand only a few designs were available for this comparison. Bottom plate thicknesses in these cases would havehad to be appreciably thicker if the present specificationhad been applied.

20

s

70

D I+D I i~ I ' i iI L - - - - ' - - - - - - L - ~ J ___L_.__JI.z.o 1.100 2.00 2.40 2.BO ~ . Z OTH \ c:: K NE s: ; IN ' rNC 11 e: s

Figure 7 - Sketch shows comparison between des ign re quirements an d a number of exist ing oval flat bottomladles.

E;\OOOwa800 f-f----h''---A-----1

1 6 0 0 ~ - - - I - - _ J , , {

14001----t------,fJL-+_

12.00f-----1+----+--- ,


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Figure 6 - Sketch shows comparison between des ign re -quirements an d a n um be r o f existing circular f latbottom ladles.

APPENDIX BBASIS AND EXPLANATION OF

THE SPECIFICATIONThis specification on Design of Ho t Metal Ladles isbased on an extensive program of research sponsored

and financed by the Association of I ron and Steel Engineers at the Fritz Engineering Laboratory of LehighUniversity at Bethlehem, Pa. In this research program,model test ladles were loaded and the stresses measured.at various point s in the ladle. The ladles were thenanalyzed by mathematical methods. The ladle modelswere scale models of various types. in actual service.Primary attention in the ana lys is was given to thestiffening rings and trunnion assembly.Guiding this work was a committee c'omposed of steelmill engineers, ladle manufacturers, representatives ofLehigh University and the Association of Iron and SteelEngineers. Credit is due this ent ire group for directingthe research work into channels which have resulted ina relat ively simple, pract ical specification which is ofvalue to the steel industry.The committee to' whom this' credit is due consistsof the following men:

F. E. Kling (chairman), Tenafly, N. J.Leo J. Gould, Chief Engineer of Construction, Bethlehem Steel Co., Bethlehem, Pit.

H. A. Leermakers, Building Engineer, Construction andEngineering' Department, Bethlehem Steel Co.,Bethlehem, Pa.William H. Mursch, Staff Engineer, U. S. Steel Co.,Pittsburgh, Pa.

The recommendations in this section are based onaccepted good practice in ladle design and in large partthese are drawn verbatim from a previously proposedspecification. (2) Reference (1) also reviews these andother related recommendations.

(1) KNUDSEN, K . E. , MUNSE, 'VM. M ., and JOHNSTON, B. G., "Stress-es in Hot Metal Ladles," Iron and Steel Engineer. Vol. XXVI,No. XII, December, 1949, pp. 49-70.(2) "Tentative Specifications for Hot Metal Ladles," Carnegie-IllinoisSteel Corp., Senior Staff Engineering Bureau, No.7, Pittsburgh,

Pa., December 2, 1948.

4. DETAILS OF CONSTRUCTION

Leonard Larson, Chief Engineer, Corrigan-McKinneyPlant, Republic Steel Corp., Cleveland, Ohio.

F. L. Lindemuth, Chief Engineer, Wil liam B. PollockCo., Youngstown, Ohio. .H. L. McFeaters, Chief Engineer, Pennsylvania Engineering Corp., New Castle, Pa .W. W. Wallace, Treadwell Engineering Co., Pittsburgh,Pa.

I. E. 1\1adsen, Standards Engineer, Association of Ironand Steel Engineers, Pittsburgh, Pa .

Bruce G. Johnston, Professor of Structural Engineering,University of Michigan, Ann Arbor, Mich. , formerly. Director, Fritz Engineering Laboratory, LehighUniversity, Bethlehem, Pa.K. E. Knudsen, Research Engineer, Lehigh University,Bethlehem, Pa. .Wm. 1\1. l\1unse, Research Engineer, Lehigh University,Bethlehem, Pa.The proposed formulas wei'e based on theoreti ca lconsiderations and allowable unit stresses modifiedaccording to the s ta te of stress in the member and itsreserve strength. The goal has been to achieve the

maximum simplicity possible, consistent with safety andeconomy.The resul ts of thi s study indicate that ladles are ingeneral well-designed as they are now manufactured,irrespective of whether or no t a great amount ofanalysis was carried ou t as a preliminary. 1\1any yearsof trial and error have evolved good proportions. Thedesign formulas of the specification yield proportionssimilar to those now obtained in pract ice. One of thepurposes of this appendix is to show to what extent thisis the case. However, the design formulas were not

arrived at by working backward from existing practice,but as mentioned before are based on theoretical considerations.The procedure for calculating maximum stresses in

the stiffening ribs is a simplification and revision of themethod previously proposed as a result of the researchcarried ou t at the Fritz Engineering Laboratory ofLehigh University. (1) The agreement between the designprocedure and experimentally measured stresses is evenbetter than in the earlier more complicated procedure,especially with respect to the Blore critical stresses.The following paragraphs will be numbered to correspond to the numbering in the body of the specification. No discussion is offered with respect to Sections 1,and 3, which are self-explanatory.

o.BO. 1.2.0 loGO 2.00 Z:4o 2.GOBO"TTONI Ttl ICI


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175'000 Lb. In... -: 4 S ' ~ , 0 0 o Lb. In... - ,"00,000 lb . In.

N.A.1 ~ . 5 " I . ' 2 S ' ~ 1.1., > Top R:b, 'to .fr"'Oo"l\ +...unl'd..... 4xiS

N ' h ~ =-2I,oS-0" o . 3 . n . ~o Bo1i-o-. Rib, ')0 . f . r " o ~ + " ' I J Y I ~ i ' " 4)(;'.M5 t = - 1 . ~ , I ' 5 " o " O . ; . to':).;

f i : . _"l.?2S"o _G>oo.ooo .. -co 100 S:""Gol Sf . a, , toTop R;lo o v e V " s + . . - t ' s s e c : l . ~ 'j

- j - + - ~ - ~

'* I " ""'>e o f oV41 l.dle he Sure +0 4d.1'10,.,.".1 st.-e, s Au e f"b e ~ d i ~ j .+ .fl= 7 x'ZoZ,'oo 4 ) 2 ~ O 1'5",331 o." .5-dI 'Q'?Jbl4'S 8IJCOps;Stf"eSS = 'S -= L..o'ZI,)OO:: I,IS-0f$;,

1710.1 QIS..s.5EAVj. he.,.i"j d",sl (Sec+. SF ) 'q+ ofl'"'!"'Oro i+ 8 , 4 0 5',000 [1+ Gx ,z, zl 178" .2." 18 " 7,H, 7,IZ,: I ", 0 PSi.0.1_.N

:::

IRON AND STEEL ENGINEER, MARCH, 1952


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F W 1.27RM) f . 'b


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Figure 4 - Method of making ri b moment calculations asrequired by Section 8 F an d 8 G is illustrated by thissketch.

- - - - C a l c v l o ~ e s - \ - ~ e s s hue on bDd" o-f C'.!!!'wii-h maximum C n o r r n o r e f . h 4 n ~ .. "T. 3C.kvl.+e sfress h ~ r e on b.s:s of c=ron v"fh,cKel1ed s l ' c l e w Q P ~

t - + - - - - ; + - - ' - + - , , = - - - - f - - ~ - - - Z (90)

CtQ]lO p Rib

AT=effective area of top ribAB=effective area of bottom ribhT=vertical height of top rib stiffener centerlineabove juncture of ladle bottom and sidewallhB = vertical height of bottom rib stiffener centerlineabove juncture of ladle bottom and sidewallRT=effective radius of top ribRB= effective radius of bottom ribh:=moment of inertia of effective top ribb=Moment of inertia of effective bottom ribSTD, STI, SBO, 'Sm = section modulus for outer orinner surface of top or bottomeffective rib, as designated bysubscript 0 or I, T or B,respectivelyW = total weight of ladle, lining, and molten metalwhen filled to maximum heighta = distance between lifting hook centerlinesc= distances from vertical section through trunnionpin to sections of top rib which are being'checked for strength in region of trunnion. See

Figure 4. This a variable. distance.l=in an oval ladle, one-half the width of thestraight sideRM=mid-height radius to middle plane of sidewallE. The effective ribs develop compressive forces, with. rcsultant parallel to the trunnion pin axis, that may becomputed by the following formulas:

bhBRfe= h h T R ~ = a constant

[ Dmax . l' ]15.2 + (0.64 D . - 0.04)H(0.1 + R) Rrr mm. = 10,000D. I f the molten metal to be transported has a unit

weight "q" per cu ft that is appreciably different from430 lb per cu ft, the thickness is to be determined bythe formulas in this section modified by multiplying the

e. Oval:dished ladle bottoms (Figure 3) havinga maximum diameter not more than 1.4 times the minimumdiameter shall have a bottom plate thickness determined by the following formula:

be=:: br + 1.4vRstwhere br = width of rib stiffenerRs = sidewall radiust = sidewall thickness at stiffener

I f the sidewall thickness changes at a rib, the total widthof th e effective rib shall be taken as:be= br + b i +

where b i is the effective width of the thicker portion(thickness tI) of the sidewall and b2 the thinner portion (thickness t2) as follows:bi ~ 0.4vRs(ti + 2 t ~ )

b ~ = 0 . 7 V R s t 2D. After determining the effective width by Section8e, the area, moment'of inertia, section modulus, andeffective radius of each rib are to be calculated. Byeffective radius is meant the radius of the neutral axisof the e f f e c t i ~ e rib at the centerline of the stiffener.

These properties and other necessary information willbe designated as follows:

E. Reinforcing plates, if used, are not to be consideredeffectively adding to the strength of dished boltoms.8. DESIGN OF STIFFENER RIBS

A. The t endency of the ladle to collapse whensuspended by the ladle hooks may be resisted by twostiffener ribs or rings, one above and one below thetrunnion pad or framing, designated by the subscriptsT and B, for top and bot tom, respectively. The lipreinforcement of the ladle is not to' be considered incalculating the stresses in the ladle ribs. The strengthof each rib is to be determined on the basis of allowablestress, as calculated by the following procedure, whichstress is not to exceed 16,000 psi.B. Each "effective rib" shall consist of the stiffenerr ing toge ther with a por tion of the adjacent ladle sidewall of "effect ive width = be," provided however thatthe rib or band be welded or r iveted to the ladle sides.Welding is recommended and should be continuous. I fthe ribs and trunnion band are not riveted or welded tothe sides, no part of the sidewall shall be included incalculating the properties of the "effective rib."

e. I f the sidewall thickness is the same both aboveand below a rib, the total width of the ladle shell to beused in calculating the section p ~ o p e r t i e s of the effectiverib shall be taken as:

term "H" in the numerator by,-.-5L.430

IRON AND STEEL ENGINEER, MARCH, 1952 LS-5


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7. DESIGN OF BOTTOM PLATES OFDISHED BOTTOM LADLES

DE = D max + D min2

F. In the case of "oval" ladles, having a maximumbottom 'plate diameter no t more than 1.4 t imes thc.minimum bottom plate d iameter (see F igure 2), theforegoing formulas for b o t t o ~ plate thickness as givenin this section may be used by replacing circular bottomplate diameter "D" by an equivalent diameter for theoval ladle, "DE", determined by the following formula:

A. The notat ion used in this section is shown inFigure 3. A ladle bottom m a ~ ' be considered as "dished"providing the dishing radius "R" is less than 10 timesthe minimum radius "r" of the bot tom plate. Thedishing must be to the shape of a spherica l segment incircular ladles and in the end sections of oval ladles. Thecenter section only of an oval ladle may be dished to acylindrical shape.B. The bott om plate thickness for dished circularbottoms shall be determined by the following formula:

[15.2 + 0.60H(0.1 +i) ]R10,000T=

T = DylH625C. Reinforc ing pla tes, if used, shall be placed on theinside of the ladle bottom, and shall be r i v e t ~ d to the

bottom pla te in a row or rows around the circumference,as well as throughout the entire reinforcing plate area,so as to make the two plates act as a' unit. The diameter"d" of the reinforcing plate shall no t be less than 0.88times the diameter "D" of the bottom plate.

D. When a reinforcing pla te is used, the combinedthicknesses of the reinforcing plate (TR) and bot tomplate' (TB) shall not be less than:Dy lHT B + TR =--510

The thickness of the bott om plate (as distinguishedfrom the reinforcing plate) shall be at least 716 in. morethan one-half the combined thickness of the two plates.

E. 'Vhen the molten metal to be handled has a unitweight "q" appreciably different from 430 lb per cu ft,the required minimum thicknesses shall be those givenby the foregoing formulas, multiplied byVio

B. Circular flat bottoms with no reinforcing plateshall have a thickness no t less than

Figure 2 - Notation used in specification fo r flat bottomladles is given in this sketch., Figure 3 - Notation used in specification fo r dished bot-tom ladles is given in this sketch.

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Bo".. .,," 5 ~ c " , o t J XXo rO ..." .. L"pl.

1'0.,.,-0 ... S!c-r,.tJ xxOF CIRC.ULA.R.. L ~ o e - .

V ~ " T 1 C " l . SE.c-r,,'-'" ... OUGtf TRIoNW'ONS

'Oo"oM SEC'TIO>JXXOF OVAL LAPLE

BO',0M SEcTION Xx. F Clllcul.AlI. Ll'l>L

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mended practice for these and other similar details shallconform with good practice as ' recommended' by the1950 ASME Code for Unfired Pressure Vessels, or lateredition thereof. Details of welded ladles, or subassemblies, and welding symbols shown on drawings,and welding procedure shall conform with latest recommended practice of the American Welding Society.D. The trunnion pin where it fits in the trunnion

plate should not be reduced in diameter for this fit, butmay be increased, in which case the fillet should bemade to as large a radius as is possible.E. Trunnion pins, which are press or shrink fitted

into the block, shall prderably be installed af ter theladle has been stress relieved.F. I f specified by the purchaser, trunnions for open

hearth steel teeming ladles shall be provided with steelbushings to take the wear. Also, if specified by thepurchaser, the t runnions for ladles which are tilted forpouring shall have oil-less type bronze bushings (for700 F temperature) fixed to the trunnion pin, and cas tsteel sleeve with collar revolving on the bushing.G. Safety flanges shall preferably be provided on theend of the trunnion pin to guide the ladle hook infoproper engagement.H. Open hearth ladles shall be provided with a splashplate underneath the slag spouts, to prevent splashingslag from sticking to side plates of the ladle and buildingup on the stiffening ribs or bands. The plate shall bebolted and arranged to permit removal for inspectionof ladle. This plate shal l be a close fit around the spoutand extend down below the lower rib. Allowance shallbe made for expansion of the plate.r. I f so specified by the purchaser, teeming ladlesshall be provided with heat protection plates aroundthe pouring nozzle.J. The ladle is to be stress rel ieved by uniformlyheating in a furnace. The temperature of the furnace,when the ladle is put into it, shall not be over 300 F atstart and inereased to 1200 F at a ra te not exceeding200 F per hour, then held at that temperature for onehour per inch of thickness of ribs. I t shall then becooled in the furnace at a rate (not exceeding 200 Fper hr) to 500 F, before being taken from the furnace.K. Vent or weep holes will be provided in the bottomof the ladles. Examples of good practice in this regardare >/z-in. holes on 9-in. centers or %-in . holes on 8-in.centers. Weep holes may be provided .on side of ladle,if specified on information sheet.

5. DESIGN STRESSES AND D ~ S I G NASSUMPTIONSA. The combined center of gravity of the ladle and

the molten metal when full shall be safely below thecenterl ine of the trunnions, and t runnions shall belocated at least 65 per cent of the overall vertical heightabove the lowest point of the shell. I f trunnions must belocated lower due to crane clearance, trunnions shouldbe provided with loek bars o r othe r means to preventaccidental tilting of the ladle.B. Formula given in this specifieation are based onmolten metal which has a unit weight of 430 Ib per cu ft.C. The follo,vingstresses will no t be 'exceeded in thedesign of the ladle. These stresses are based on the useof the materials outlined in Section 3 A.a. In members where the axial stress through thethickness is nearly constant, the stress shall no t

exceed 8000 psi. (Example: Direct stress in ladle'wall or dished bottom). 'b. St resses in members which are subject to bending'or combined bending and di rect load shall notexceed 16,000 psi. (Example: Stress in stiffenerribs). An except ion is the trunnion pin. See Sect ion 5E.c. Stresses in members which do not help appreciablyin carrying load, bu t which are secondary stressesor due to stress concentrations at discontinuitiesshall not exceed 24,000 psi. (Example: Normalstress due to bending at juncture of sidewall andbottom of dished bottom ladles).

D. The maximum allowable shear stress shall be 0.6times the allowable tensile or c o m p r e s ~ i o n stress.E. The maximum normal stress in the trunnion pinsdue to bending, neglecting s tress concent ra tions infillets, shall no t exceed 8000 psi. The average shear stressin the trunnion pins shall not exceed 2400 psi, computed

by dividing the total shear by the area of the pin.(Maximum ,shear stress will be about double averageshear s tress in a circular section). In caleulating thebending moment in the trunnion pins, the lifting forceshall be assumed to ac t 1 in. in from edge of collar oftrunnion pin.F. The average bearing stress between the trunnton

pin and trunnion block in the ladle shell shall be calculated by the following formula:

fB = ~ (1 + 6e 2)2DBtT tT(See Figure 1 for notation)

but in no case shall this stress exceed 20,000 psi.G. The trunnion blocks shall be rigidly connected tothe ladle shell through ribs or other stiffening devices. 'Unit stresses in such connecting devices shall not exceed16,000 psi.6. DESIGN OF BOTTOM PLATES OF

FLAT BOTTOM LADLESA. Notation used in this section is shown in Figure 2.Slightly dished ladle bottoms shall be considered as

"flat" if the dishing radius "R" (See Figure 3) is morethan 10 times the minimum radius "r" of the bottomplate.

Figure 1-Sketchshows nota-tion used a tt runnion pin.

IRON AND STEEL ENGINEER, MARCH, 1952 \ LS3


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AISE STANDARD NO. 9SPECIFICATIONS FOR DESIGN OF HOT METAL LADLES

(TENTATIVE)

(SEPTEMBER 30, 1951)

1. GENERALA. This specification shall be known as Specificationsfor Design of Hot Metal Ladles, AISE Standard 1\0. 9,

and shall cover such open top ho t metal ladles of circularor oval cross-section as arc used in steel mills fortransporting molten metal. Insofar as applicable thesespecifications may be uscd in the design of other typcsof hot mctal ladles.B. Thcse specifications arc intcnded to covcr onlymaterials (by reference) and the more important struc

tural dcsign features, such as thickness of sidcwalls andbottom, propo rtions of stiffener rings, etc. Supplementary specifications covering special features may bcadded by purchascr.2. WORK1VL-\NSHIP, AND I ~ S P E C T I O ~

A. Workmanship and mater ia l shall be first class in

every respect, and sub jec t to the inspection of pur-chaser's rcpresentative at all times.3. }1ATERIALS

A. Matcrials for th e following parts of the ladle shallbe in accordance with the latest rcvision of thc followingspecifications:(a). Bottom plate - ASTM, Standard Specificationfor Low and Intermediate Tensile Strength

Carbon Stcel Plates of Flange and Fireboxqualities, A-285, firebox qualit,)" gradc C.(b). Shell plate, stiffener rings, S7Jlash plates, trunnionblock - ASTM, Specification for Steel for Bridges

and Buildings, A-7. I f th e A-7 steel used exceedsI-in. and does not exceed 272-in. thickncss, thesteel must also meet the requirements of AWSSpecification No.D2-0-47 Standard Specificationfor Welded Highway and Railway Bridgcs.I f specified on the information sheet, materialshall meet the requirements of A-285, gmde Cfircbox quality for thicknesses up to and includ

ing 2 in. For thicknesses over 2 in., if specifiedon the information shce t, thc material mustmect requirements of specification ASTM A-20I,Gradc A, f1angc quality.(c). Trunnion pin, miscellaneous forged fittings-:\STM, Specification for Carbon Steel Forgingsfor Genera l Industrial Use, A-235, Class C,normalized or annealed (unless integral part ofcast steel trunnion band or pad).(d). Trunnions - ASTM, Specification for Mild tol\Iedium Strength Carbon Steel Castings forGeneral Application, A-27, Grade 60-30 orAST]\!( A-2I6, WCA.(e). Rivets - ASTM A-3I, boiler rivet steel, Gracie A.

(f). Lining - As specified on information sheet.4. DETAILS OF CONSTRUCTIONA. Details of construction no t provided for in thisspecification shall be consistent with good practice inladle design.B. The bot tom pla te may bc "flat" Ol ' "dished" andshall be flanged around the edge by hot forming with

an inside radius not less than 3 and prefembly 4 01'more t imes th e thickness. Connection to thc sidewallshall be either by a full penetration double butt weld 01'by a lap riveted joint.C. Openings in th e ladle bottom for nozzles shall befully reinforced by a welded stiffener pla te. Recom-

LS-2


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S P f ~ J f t C A ~ i ; o t t s 1 0 1 t B t S I G N OFHOT METAL LADLES

FRITZ ENGINEfRINl A B O R A T O ~ L ; ~ R : A # 1

A/Sf STANDARD NO.9(TENTATIVE)

SEPTEMBER 30, 1951

PUBLISHED BY,ASS 0C IAT I 0NO " I RON AND STEE lE N GINEERS

1010 EMPIRE BUILDINGPITTSBURGH 22, . PA.

Copyright 1952 by Association of I ro n and Steel Eng in ee rs and p rint ed in USA.

Documents

Design of Ladle