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oririnally Prepared by subcommittee 405.10 on Embrittlcmcnt Lnvcstigation ofQemmin6 aQJ es Corrosion of hon ad Stocl and ba$d on an invcstigatiin madcby Battcllc Mcmorial Instiotc utr&r Amcdcal society ftr Tcsting and Matcrirls'sponsorship. Set, Pruceedings,Am. Soc. Testing Mats., Vol 31. part I, 1931, p. 2ll;also papcr by Samucl Epstcin, 'Embrittlcmcm of tlot-Dip Galvanizcd StrucnrralSt€cl," scc Pmceedings, Am. Soc. Testing Mats., Vol 32, part II, L932, p.293-

Cunrnt cdition appoved April 10, 2003. pub|ished May 2003. b.iginafyapprovcd h 1932. Last previous cdition apptovcd in 2001 as A 143 _ Ol.

Deslgnation: A 143/A 14gM - 0g

Standard Practice forsafeguarding Against Embrittlement of Hot-Dip Galvanizedstructural steel Products and Procedure for D'etectingEmbrittlementl

This standard is issued under the fi.xed designation A 143/A l43M: the number immediately following the rlesignation indicares the yearof original adoption or, in the case of revision, the year of last rcvision. A numbcr in parentheses indi"ates thi year of last reapproval.A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.

This starulard has been approved for use by agencies of the Departmenr of Defense.

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3. Terninolory3.1 Definition:3.1.1 embrinlement, n-the loss or partial loss of ductility in

a steel where an embrittled product characteristically fails byfracture without appreciable deformation; types of embrittle-ment usually encountered in galvanizsd steel are related toaging phenomena, cold workjng, and absorption ofhydrogen.

4. Factors in Embrittlement4.1 Embrittlement or loss of ductility in steel is often

associated with strain-aging. Strain-aging refers to the delayedincrease in hardness and strength, and loss of ductility andimpact resistance which occur in susceptible steels as a resultof the strains induced by cold worting. The aging changesproceed slowly at room temperaturc, but proceed at an accel-erated rate as the aging temperature is raised and may occurrapidly at the galvanizing temperature of approximately g50.F[455'C].

4.2 Hydrogen embrittlement may also occur due to thepossibility of atomic hydrogen being absorbed by the steel. Thesusceptibility to hydrogen emb,rittlement is infusased by thetype of steel, its previous heat treafment, and degree ofprevious cold work. In the case of galvanizrd steel, the acidpickling reaction prior to galvanizing presents a potentialsource of hydrogen. However, the heat of the galvanizing bathpartially expels hydrogen that may have been absorbed. Inpractice hydrogen embrittlement of galvanized steel is usuallyof concern only if the steel exceeds approximarcly 150 ksi[100 MPa] in ultimate 0ensile stnength, or if it has beenseverely cold worked pnor to pickling.

4.3 Loss of ductility of cold-worked steels is dependent onmany factors including the type of steel (strength level, agingcharacteristics), thickness of steel, and degree of cold work,and is accentuated by areas of stess concentration such ascaused by notches, holes, fillets of small radii, sharp bends, etc.

2 Amual Book of ASTM Sundads, Vol 15.0E.

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l. Scope

l.l This practice covers procedures that can be followed tosafeguard against the possible embrittlement of steel hot-dipgalvanized after fabncation, and outlines test procedures fordetecting embrittlement. Conditions of fabrication may inducea susceptibility to embrittlement in certain steels that can beaccelerated by galvanizing. Embrittlement is not a comrnonoccurrence, however, and this discussion does not imply thatgalvaniziqg increases embrittlement where good fabricatingand galvanizing procedures are employed. Where history hasshown that for specific steels, processes and galvanizingprocedures have been satisfactory this history will serve as anindication that no embrittlement problem is to be expected forthose steels, processes, and galvanizing procedures.

1.2 This practice is applicable in either inch-pounds or SIunits. Inch-pounds and SI units are not necessarily exactequivalents. Within the text of this practice and where apprG.priate, SI units are shown in brackets.

1.3 This standard does not purport to oddress all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-piate safety and health practices and determine the applica-bility of regulatory limitations prior to use.

2. Refercnced Documents

2.1 ASTM Standards:F 606 Test Methods for Determining the Mechanical prop-

erties of Externally and Intemally Tbreaded Fasteners,

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4.4 Low temperatures increase the risk of brittle failure ofall plain carbon steels including steel that has been galvanized.

The rate at which this temperature loss of ductility occursvaries for di-fferent steels. The expected service temperatureshould thus be taken into account when selecting the steel.

5. Steels

5.1 Open-hearth, basic-oxygen, and electric-furnace steels

shall be used for galvanizing. Other materials that can begalvanized include continuous cast slabs, steel or iron castings,and wrought iron.

6. Cold Working and Thermal Treatment

6.1 For intermediate and heavy shapes, plates, and hard-

ware, cold bend radii should not be less than that which isproven satisfactory by practice or by the recommendations of*re steel manufacturer. These criteria generally depend on the

direction of grain, strength, and type of steel. A cold bending

radius of rhrec Limes (3X) thc scctioo thickness, or aD recom-mended ny'./tSC Manwt of Steet Construction 3 will ordinarilyensure satisfactory properties in the final product. Althoughsharper bending sa thin sections can usually be tolerate4embrittlement may occur if cold bending is especially severc.

If the design requires sharper bending than discussed herein,

the bending should be done hot, or if done cold the marerialshould be subsequently annealed or stress relieved as noted in6.3.

6.2 Smaller shapes, including thickness ap to V+ in. [6.4mml may be cold worked by punching without subsequent

annealing or sEess-relieving. Shapes %o to LVrc in. [8 to 18

mml in thickness are not seriously affected as to serviceabilityby cold punching or if the punching is done under good shoppractice. The heavier shapes, % n. ll9 mml and over, shall be

reamed with at least %c in. t1.6 mml of metal removed fromthe periphery ofthe hole after punching, or shall be drilled orthermally treated prior to galvanizing as noted in 6.3.

6.3 Fabrication in accordance with the principles outlined in6.1 and 6.2 will normally obviate the need for thermaltreament. However, if rcquired, ProPer thermal tneatuent shallprecede galvanizing of the steel. For heavy cold deformationexemplified by cotd rolling, sheared edges, punched holes, orcold_formed rods and bolts, subcrilisal annsaling at tempera_

tures from 1200 to 1300'F [650 to 705'C] should be employed.

For less severe cold deformation typified by cold bending, rollforming, etc., it is advisable to limit the thermal treament tostress rglieving at a maximum of 1100'F [595'C] to avoidexcessive grain growth or alternatively to fully normalize the

steel at temperatures from 160O to 1700'F [870 to 925'Cl. Thetime at t€mp€rature should be approximately I Wlln. [24min/cml of section thickness.

6.4 Flame cut copes on structural beams shall have aminimum radius of I in. [2.5 cm]. After cuning, the cut surface

shall be ground to remove notches, Srooves, and irregular

surface features to leave the surface smooth.

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7. Preparation for Galvanizing

7.1 Hydrogen can be absorbed during pickling and in some

instances, as noted tn 4.2, may contribute to embrittlement of ,

the galvanized product. The likelihood sf this, or of surface

cracHng occurring, is increased by excessive pickling tempera-

ture, prolonged pickling time, and poor inhibition of thepickling acid. Heating to 300"F [150'C] after pickling and

before galvanizing in most cases results in expulsion ofhydrogen absorbed during pickling.

7.2 Abrasive blast cleaning followed by flash pickling mayalso be employed when over-pickling is of concern or whenvery high strength steel, ultimate tensile strenglh higher than150 ksi [1100 MPal, must be galvanized. The abrasive blastcleaning does not generate hydrogen while it is cleaning the

surface of the steel. The flash pickling after abrasive blastcleaning is used to remove any final traces of blast media

before hot-dip galvanizing.

E. Responsibility for Avoiding Embrittlement

8.1 Design of the product and selection of the proper steel

for its suitability to be fabricated and to withstand normalgalvanizing operations without embrittlement is the responsi-

bility of the designer and fabricator. The galvanizer shallemploy proper pickling and galvanizing procedures.

9. Ibsting for Embrittlement of Steel Shapes' StcelCastings, Threaded Articles' and Ilardware ltems

9.1 Subject to base material and dimensional limitations, the

tests given in 9.2, 9.3, 9.4, or 9.5, or a combination thereof,shall apply. [f one test specimen should be found embrittled bythese tests, two additional specimens should be tested. Failureof either the second or the third specimen shall be cause forrejection of the lot (see Note 1) that the samples rePresent.

Ncrm l-A lot is a unit of production from which a sample may be

taken for testing. Unless otherwise agreed upon by the manufacturer and

the purchaser, or established within this practice, the lot shall be as

follows: For t€st u a manufacturer's facility, a lot is one or more articles

of the same type and size comprising a single order or a single deliveryloaA whichever is the smaller, c a smaller number of articles identi6ed as

a lot by the menufachrer, when these have been galvanized within a single

production shift. For test by purchaser after delivery, the lot consists of the

single order or the single delivery loa4 whichever is the smaller, unless

the lot identity, established in accordance with the above, is naintaircdaad clearly indicated in the shipment by the manufacurer.

9.2 A convenient bend test for embrittlement of galvanized

steel hardware such as bolts, lnle and tower steps, braces, rods,

reinforcing bats, etc., consists of bending the article and

comparing the degree of bending to that which is obtained on

a similar ungalvanized article. The article, before and aftergalvanizing, may be clamped in a vise and using a lever ifnecessary, bent uniil crasking ofthe base steel occurs, or to 90"

whichever is less. In the case ofpreviously bent articles such as

reinforcing bars, the test shall be accomplished by revenie

bending the previously bent section. The galvanized article

should withstand a degrce of bending substantially the same as

the ungalvanized article. plnking or spalling ofthe galvanized

coating is not to be construed as an embrittlement failure. Forth€aded articles, the test shall be made on the unthreaded

portion.

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{ffi a 1€/A 14sM - 039.3 Small steel castings and steel hardware of such shape or

size that do not permit bending may be struck a strarp Llowwith a 2-lb [l-kg] hammer and the results for both gavanizeaand ungalvanized sarnples comparcd. If the article witnstanassuch a b-low in the ungalvanized condition, but after galvaniz_ing cracks under the btow, it shall be considered embrittled.

9.4 A test for embrittlement of galvanized steel angles isdetailed as follows:

.9.4.1 Test Specimen-Atest specimen with a length deter_mined by the table in9.4.2.1and by Fig. I shall be cuifrom thesteel angle before galvanizing. A hole shall be made in the testspecimen at its midlengtl, using the same procedure as will beemployed in the fabricated material which the specimenrepresents, whether this be by punching, punching and ream_ing, or drilling. The dirnensional values, diameter, and locationof hole shall be not less than those empioyed in the strucfuraidetails. Care should be taken not to place the hole near stampedor rolled-in identification marks. The specimen shall then begalvanized. For determining the elongation after fracture, a2-iri. [5]-mm] gage length (Frg. i) shall be prick_punched inthe middle of the edge of the vertical leg of the galvanizedanqle algng a line parallel to its length and cenrercd directlyunder the hole. For specimens under Vz in. tl3 nnl ;thickness, or those in which the distance from the edge of the_h9le

to the edge of the angle is less than % in. tlO mmj, a l-in.[25-mm] gage length shall be used.

9.4.2 Procedurc:9.4.2.1 The test shall be made in a universal testing ma_

chine, or by other means such as a press with the load afpliedslowly, until fracture of the galvanized test specimen o"curs.The length of the rcst specimen and the distance between thesupports are shown in the following table:

9.4.2.2 After the test, the distance along the gage lengthfrom each punch mark to the corre.pondiog eAgi of lrefracure shall be measured to 0.01 in. t0.t5 mml with a flexiblescale and the percentage of elongation calculated from the sumof these distances.

9.4.2.3 For determining the percentage reduction of thick_ness after fracture, the reduction shall be measured with aball-point micrometer at the tfuee locations indicated in Fie. 2:namely d. outer side of hole; b. inner side of hole: *i ..middle of leg. The percentage reduction of rhickness shall becalculated on the basis of the original thickness of the angleand the average of the three values at a, b, and c.

9.4.2.4 The test shall be made upon galvanized specimenshaving a temperahre not below 60"F U6'Cl and not over 9O.F[32C] when tested.

9.4.3 Requirements-T\e elongation measurcd in accor-dance with 9.4.2.2 shall be not less thans % with the followinge:.ception: when the specimen does not show 5 % elongationlthe reduction in thickness shall be measured in accordanci with9.4.2.3. J[s srrm of the percentage of elongation plus theaverage percentage reduction of thickness shall not be less than10.

- 9.5 For hot-dip galvanized externally threaded fasteners, an

alternate test to section 9.2 for embrittlement is detailed in TestMethod F 606.

10. Keywords

l0.l coatings-zinc; galvanized coatings; steel products_metallic coated; zinc coatings-steel products

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Asw lntemationa! takes rc.poeitlon rcsp€r,ling the valiclity of any Ftent rbhg assefted in @nnrr'ion with any item mentton"din this san&td' us€B ol thls standan ara expresitv aau"a"n t *iiii"i"i ii i" iii,ty or any such Ntant dghg, artr, t te dskof inftingement of stnh tighH, arc mdrcly their orri, ,"p"Ultw. --)

Thls sbdad is suqd b rcvision.at any ame ry the re'{r,nsibta tachnknl ammittee aN must be reviawed every rNe years andit nottevlsed' eidDr rcapprcved or witMra*r. vouri^^i,{i "re

invited eitherf,r revision olthisstancf|' orfor aili60natstanclardsand should be addressd to AsrM lntematio*t u.quii"o. Your rxrlnmen9 witt rccdve canfut a:nsi&nfpn at a meeting of therawtsxue technical @mm,ttee' which You maf att"i. tt ii l€€l that your @mmffiE haw td r&eivd a fair heatlng you shoutdmaka your views known to ne asru cfonmnip * sanii,a", at the add*ss shown berow.

This stanturcl is @pyrigttted lv llru namationa!, loo Ban Harfur Driva, po Box c7oo, west conshoheken, pA 19428-2959,united states' lndividual repnnb,(:inct? oy,yultiqte copieqTt this standad may oa ioainea by contacting Asru at the aboveadctrcss or at 610&32-95A5 (phone), etO-Ag2-gSSb 6ax1, or ""*'ane"sh.irg- t"-iitl; ot through tha ASTM websit€(www.asffi.org).

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