ALUMINUM ALLOYS _____
-. - .I___.
K.H. BRORX 1x1) E. 1). \ EHINK, JK. Aluminicric Contpciny of 4nwricri. VPWherisington, P n .
ONSIDERABLE aluniiriuiii vtieiiiical aquipiiirrit lrax used in industry. I n addition to its resistmce t o the attack of a wide variety of chemicals, aluminum offers to the desigrlt,i, the advantages of light weight, with its effect on cost of t,he equi1)merit : ease of fabrication; high thermal ronduct,ivity; and reflcct'ivity of radiant energy. I t s compounds are colorless; this influences its choice for equipmerit in the textile and varnish industries. It is nonsparking and thus reduccs explosion hazardh. pi'opc~rtics.:(11. The chemical compositions and typival rnechaiii~~nl ttluminiim alloys are given in T a h l ~I and IT. ~N~ILII
I
ILCL~L). Tht. Alclad prcducts aie characterized by their supelor resistance to perforation (17,18). These products consist of II
Yurface layer of one aluminum alloy metallurgically bonded to mother alloy possessing thr desired nii~chanicalproperties. The Yurface coating, mhich is applied to either one or both sides of &et products but only on thr inqide of tubular products, is I hosen so that it will he anodic to the core in many solutions (Figure 1). In this mannei cathodic protection is provided at rhe metal surface. This meam that, in a mrdium which might induce pitting, B pit mill not progress beyond the surface layer into the core. I s a result the Ytiuctural integrity of the core iLLOYk niaterial is maintained. The Alclad products now available arr .llclad 35, LIlclad 14s. A HOUGHT. The wrought ah^) of nluiiiiiiuni &it: of I N IJ g ~ ~ i i llclad 24S, and .illclad 768 plat? and aheet: ilclad 35 tubing, rral types: those in which highri itiengths ale developed IJ\ .ind Alclad 56s wire for screen cloth. Although Alclad 17s-T \train hardening and those which respond to lieat treatmcsni .ind W a d 14s-W sheet, because of their evcellent resistance to With the exception of alloys 538, 615, and 635, 1%-hichare heat t.1 Brrosion and high mechanical properties, have been used fo1 weatable, most of the alloys used for chemical proces4 equipnieiit vquipment to handle chemicals, Alclad 35 is the most widely used la11 into the nonheat treatable group. These three heat tledtUclad product for chemic.al applications. hlclad 175 sheet is no able alloys and all of those in the nonheat treatahlr longer manufactured. having h w n replaced hy the higher strength group have excellent resistance to corrosion and moderatel\ ilclad 24s or 145 high strength, whereas the remainder of the heat treatable groul I have very high strength and somenhat lower resistance to POI(:ONUEYSEH TITBE'i rosion. tltw twhanger tubes of 2s and 3Y have been used for many apCASTING.The casting alloy- a r divided ~ t)t.t\\ ctAn heat t i t w able and nonheat treatable allow. -\lloy 43, €3214, and 406 :if( ihcations in contact with a variety of rhemicals. Ordinarily, iintural maters having n p I 1 ranging from about 5 to 8 do not cmnheat trentable, whereas 220 aiid %ti itrr heal t i tswtithlc* 5
T w o Types of Large Tanks Being Constructed of Aluminum i l l o y s , with Ehtensive Use of Welded Constrnc-tion for Handling Organic. Chemirals
1198
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
October 1947 TABLE I.
1199
XOMINAL c O > l P O S I T I O S O F A i L t 3 1 1 X t - M .iLI.OY-"
(Aluminum a n d normal impurities constitute remainder) .Way Copper, Silicon, Manganese, Magnesium, Chrocmium. ? 1-0, 7% 7c R
T r o u g h t Alloys
wrfdce have hwn miaunieti. Figure 1. Phu:omicrograph of Cross The t.fiective Section of Alclad 3s Sheet Etched to life of this ,urface Di*tinguiih hetween Coating a t d Core la\ er 15 dependent a Heat treatment symbols are omitted *ince cotlipusition d:,e> n o t vurj011 manv factoic, Iightrr band. on rach side of 3s Tore are725 for different heat treatment practices. coating. b Impurities are closely controlled. Special foundry terhniqur is rr. .uch a3 c0nduc~quired t o produce castings of 214 a n d B214 alloys. tivity of t h e -01ution, teniperatuie, dissiniilai metal contact, etc. One striking ex:imple of the effertiveness of this piotection was observed in a large c vchanger located in a Texas plant in which water from the Gulf cause general attack of aluminurn; hov ever, occasionally certain passed through .4lclatl35 rondenwr tubes 2 5/8 inches in diameter waters may induce a localized or pitting type of attack. Within The headers and tube bheets iii this case were cast iron, consethe last few years a ~ C Rtype of condenser tube has become availquently, the added cumplication of dissimilar metal contact war able which has special resistance to perforation even in thekc! introducrd A%ftera period of iiirir ntonths the 7 2 s surface material Raters. This development followed many successful applicahad been cori,-unied foi a tliatarice of about 10 inches back from tions of Alclad 3s sheet (16). The Alclad 3s condenser tube i. composed of a 3s tube having an interior coating of 72s ( 2 4 ) the erids of the tubes, arid yet, despite the electrical contact beThis alloy coating, applird onli- nil the i i i ~ i d cof thew tuheq, hR* a I ~ I V J I tI l i r , i t I I I iiriitig 3s ( o r ( ' nidTerial and the cast iron, negligible ittack nf the 3 s had resulted. Satuially such adverse condition* had resulted in considerable con.uinption of the coating alloy, but it 'Ir n 4 on .I I t.niarkable that the protective curreiit . . HnrdElongation, To in 2 I n . ness, _____.___ v a* vffective for nearly 10 inches down Br?nell Yield Sheet Round tht, iritcrior of a 25/&1ch pipe. Under strength Ultiiiiate ypecimen. .pecimen, 500-Kg. * Shearing set at 0.274, atrength. l/ls-in. ]/?-in. 10-3Im. Strength, .Uloy and rii wii-tances R here dissimilar metal lb./sq. in. Ib./.q. 111 thick diameter Temper Rnl1 Lb./Sq. T n c m t a c t iq eliminated, greatly improved \Vrought Alloys liit' is rtdizrd. Other data are cited in ~~
~~
13,000 15,000 17,000 20,000 24,000 16,000 18,000
3s-0 3 S- 1/4 H 3S-1/2H 3S-3/4H 3s-H Alclad 149-0 Alclad 14s-W Alclad 145-T Alclad 24.3-T Alclad 245-RT 525-0 62S-','rH 52S-'/2H 5 ~ s - a ; ~ ~ 52s-H 53s-0 535-R53s-T 618-0 61s-W 615-T 635 63s-T3
21,000
25,000 29,000 25,000 59,000 65,000 61,000
67,000
19,000 34,000
37,000
39,000 41,000 16,000 33,000 39,000 18,000 35,000 45,000 23.000 31,000
43 214 220-T4 355-T6 356-TB
35 12 9
9 30 10 8 3
4 21 18 '3 18 11 2.5
12 10
s
22
22 12
45
25 20 17
15 40 20 16 14
10 ,.
,.
.. 30 18 11 10
8 35 30 20 30 28 li 17 11
25,000 46,000
6 0 9 0 14 0
35,000
2 5
33,000
4 0
19,000
I .?
62 67
74 85 26 65 80 30 65 93
40
50
75 80 iO
9,500 10,000 11,000 12,000 13,000 11,000 12,000 14,000 15,000 IH.OOO 18,000 39,000 61,000 10,000 41,000 18,000 20,000 21,000 23,000 24,000 11,000 20,000 24,000 12.500 24,000 80,000 14,000 19.00(3
14,000
po,ono 33,000 30,000 27.000
3,000
q,ooo
,,000 I,OOO
8,000 9,000 9,500 10,000
9,000
27,000 27,000
24,000 43,000
soon
9 0 4 0 .j 0
' l ' i ~ i , 111. ~
F:I.F(
lib
1::600
17,500
18.000 18,500 19,000 8,000 13,000 13,000 9,000 I :3,500 i 3 , m
Elrctrolyrr b C-lf
.Lf NazS04 .If HCI
I\. "01
.\INaOH .\f "4OH Satd. soln. Ca(0H)r Satd. s o h . Ba(0H)r .if Ka&Oa .\f SaaPO4 Satd. s o h . CaCOi Satd. CaSOa
.. ti,500
5,500 7,000 8,5011 8.000
90 90
18,000 30,000
u.ii10ci
dlCla
If YaCl
Potential b (0.1 N Calomel Scale). Volts -2.11 -1.11 -0.85 -0.50 -0.71 -0.88 -1.47 -0.80 -1.54
- 1.53 -1.35
-1.32 1.04 -0.77
-
U a t a from Aluminum Research Laborn-
lories on alloy 25-0.
Reversible potential calculated from heat data f o r aluminum ion concentration of one molal activity. C .VI indicates one gram molecular weight of the compound per liter of solution. b
1;.
EFFECTOF COMPOSITION O N POTESTIAL OF
TROLYTE
~T,1711XlJ.Ila
Periiinnent Alold-('n*ting hlloj
43 355-T6 356-T6
t tip litrlstiirt. iS0)
8,500 8,500
INDUSTRIAL AND ENGINEERING CHEMISTRY
1200
Vol. 39, No. 10
POTENTIALS OF VARIOUS ALLOYS' TABLE IV. ELECTRODE
Alloy b Magnesium Zinc 72S, Alclad 3S, Alclad 755 220-T4 566, 214
525, aluminum (99.95% min.) 45, B214
Potential (0.1 A' Calomel Scale c), Volt
Alloy
-1.73 -1.00
108, C113 85, A108
-0 96 -0.92 -0.87
195-T6 B195-T4 , 4 s - ~ ~,7s-T, -, 24S-T, 2 5 s - W
Potential (0 1 N Calomel qcalet), Volt 29,39,1819.539, 61S-T, 639. 406, Alclad 149. Alclad 249 i3, 43 75%" 360 356 24S-Tb1, 26S-T, 61s-Tv 355-T6 149-T. 113, 355-T4
-0.77 -0.75 -0.73 - 0-0 6871t o -0 7 0 d
-0.85
Ateel
- 0 68
- 0 04
Lead
-0.5.5
-0.83
Tin
-0.82 -0.81
Cppper Bismuth Stainless steel Silver Nickel
-0.80
-0.79 -0.78
Acetic acid
JOINING OF ALUMIhbIM SUCCESSFULLk Condensers, receivers, storage tanks, tank cars, piping, oxidizing kettles Piping, storage tanks, tank cars Ih. S E R T ICE
BY
1 9 U . 9 X D SMALL SC.4I.E SERVICE TESTS Diitillation columns, drume
ALLOY 25, 33, 525, 619-TI Alclad 3S, 43, 214. B214,356, 406 Same
Ammonium hydroxide Cellulose acetate
Heat exchangers, reaction \ essels. drums Ammonia tanka, evaporators, crys- Reartion vessels. tanks, pip- Same ing, drums tallizeru. tank rars. piping Same Condensers, dephlegmato?. piping Abwrbers Tanks, acetylators, precipitators, Aging tanks. sollent stnrage Game tnnke washing equipment, driers, dephlegmators, stills, condensers, evaporators, piping
Edible oils and fats
Deodorieerfi. #-nndensorfi, tanks. piping
llleachers, winterizing equipment (stills, separators, traps, bleachers, hlters, pumps:, drums. tank cars
Ssnit.
F a t t y acide
Condensers, storage tanks, melting vessels
Trays, filter presses, receiverr, drunip
Yame
Food processing
Kettles, conveyers, trucks, stock pots and pans, piping, miscellaneOUB packaging. refrigerating equipment Receivers, storage tanks. tank pars. Srrubbers, drums piping, pump-
Acetic anhydride immonium nitrate
Formaldehyde
Glue and edible gelatin
Evaporatorr. ranks, pipinp
Same
condensers,
iais. heat exchangers; cool-
Ing towers, pumps, chutes, screens, spread-
29, 38, 525. 61S-T, Alclad 39, 43, 214. B214, 366, 406 Same
ers, molds. filters
Hydrogen peroxide
-0.Oi
Data from Aluminum Research Laboratories. b Potential of all tempers the same unless temper is designated. hleasured in an aqueous solution of 53 g r a m h'aC1 -I- 3 g r a m HAOI per liter. d Potential varies with quenching rate.
INDICATED
CHEMICAL
-0.20 -0.18 -0.09 -0.08
Q
TABLE V. PROCEB0 O R
Poteni ia' (0.1 N ) Calomel calec), Voli -0.48
Stills, storage tankn, piping, druirts. tank cars
Microbiological proc- Fermenting tank3, soiution tanka, esses piping Stills, condensers, storage tanks. Naval stores piping, drums, tank car8 Nitroglycerine, guncotton, and dynamite
Hoods, ducts packaging Pquiprnrnr
Refrigerants Ammonia Carbon dioxide Freons (11, 12, 21, 22. 113, 114) hlethyl formate Sulfur dioxide
Compressors, heat exchanghrs. evaporators, rereivers. tubing
receivers, 99 % .6 AI, 2b. 525 43, 356
Cundeuserr. pumps
Same K r r P i ~ e rciayoratore ~
25, 38. 525, 615-T Alclad 35, 43, 214 356, 406
ZIixing
26 35 .4lclad b2S. 818-T
TP.PI
fears, R. B.,and Fahrney, H. J., Trans. Am. Inst. Chem. Engrs., 37, 911 (1941). \29) Mearb, R. B., and Freche, H. R., Pioc. 15th Annual State are not greatly different, to minimize an important cause of College Wash. Inst. Dairying (March 1946). electrochemical corrosion (14). The solution potential of aluminum, as is the case also with other metals, varies with the solu(30) PerWman, J. kf.9 J . Am. Water works Assoc., 38, 1327 (1946). (31) Relchert, J. S., and Pete, R. H., Chem. Eng.,54, 213 (1947). tion (Table 111). A b ' ComPosition also influences ;32) Sawyer, D. W., and Brown, R. H., Corrosion, to be published. potentials (Table IV). '33) Stefanlak, J. J., Gailey, F. B., Brown, C. S., and Johnson, &l.J.. IND.ENG.CHEM.,38, 666 (1946). (34) 1-erink, E. D., Jr., Chem. Eng., 53, 253 (1946). ARCH~TECTURALAND STRUCTURAL APPLICATIONS (35) West, J. R., Ibid., 53,225 (1946). In many chemical p l a n b the use of aluminum alloys for struc(36) W1llard, J. R.7 and blears, R. B., Refrig. Eng., 40, 381 (1940). '37) Ziels, X . W., and Schmidt. I\-. H., Oil & Soap, 22,327 (1945). tural and architectural applications permits substantial in maintenance costs because of the inherent resistance of these alloys to weathering, even in atmospheres contaminated by a number of corrosive substances (19, 20). For example, handrailings, walkways, tread plates, roofing and siding sheet, window frames, and doors are available in aluminum alloys.
TRANSPORTED IN ALUMINUJI TANK TABLE VI. CREMICAW CARS
I"' (g)
i%'
.4PPLlCATIONS IN CHEMICAL INDUSTRIES
Table \r summarizes briefly some of the many applications for which aluminum equipment has been successfully used together with the alloys which are normally recommended for these aervices. Aluminum tank cars have been successfully used for a number of years for many chemical commodities. Table VI liets several of the commodities now being transported in aluminum tank cars. Table VI1 refers to some articles where more detailed information is given regarding the use of aluminum in the chemical process industries. BIBLIOGRAPHY
(1) Anonyxnoua, Light Metals, 1, 205 (1938). (2) Ibid., 1, 223 (1938). (3) I b i d . , 2,36 (1939).
(4) I b i d . , 7, 267 (1944). (5) Ibid., 7, 352 (1944). (6) IbM., 7, 483 (1944). (7) Ibid., 7, 537 (1944). (8) Ibid.,8,42 (1945). (9) Ibid., 8, 520 (1945). (10) Ibid., 8,528 (1945). (11) Ibid., 9,236 (1946).
Figure 2.
Cross Section of Alclad 3s Tube
The 72s coating, which is on t h e inaide of t h e tube only, ham been m a d e visible by the use of proper etohing.
