146:
138:
130:
122:
25:
418:
A hot-dip galvanized coating is relatively easier and cheaper to specify than an organic paint coating of equivalent corrosion protection performance. The
British, European and International standard for hot-dip galvanizing is BS EN ISO 1461, which specifies a minimum coating thickness to be applied
240:
Like other corrosion protection systems, galvanizing protects steel by acting as a barrier between steel and the atmosphere. However, zinc is a more electropositive (active) metal in comparison to steel. This is a unique characteristic for galvanizing, which means that when a galvanized coating is
345:
In some cases, it may be desirable to have designates parts of the metal as non-galvanized. This is often desired when metal will be welded after galvanization. To accomplish this, a galvanizer will typically use a masing compound to coat the areas that will not be galvanized during the hot dip
314:
easier and protect the kettle from uneven heat distribution from the burners. Environmental regulations in the United States disapprove of lead in the kettle bath. Lead is either added to primary Z1 grade zinc or already contained in used secondary zinc. A third, declining method is to use low Z5
426:
Further performance and design information for galvanizing can be found in BS EN ISO 14713-1 and BS EN ISO 14713-2. The durability performance of a galvanized coating depends solely on the corrosion rate of the environment in which it is placed. Corrosion rates for different environments can be
224:
Galvanized steel can be welded; however, one must exercise caution around the resulting toxic zinc fumes. Galvanized fumes are released when the galvanized metal reaches a certain temperature. This temperature varies by the galvanization process used. In long-term, continuous exposure, the
318:
Steel strip can be hot-dip galvanized in a continuous line. Hot-dip galvanized steel strip (also sometimes loosely referred to as galvanized iron) is extensively used for applications requiring the strength of steel combined with the resistance to corrosion of zinc, such as
225:
recommended maximum temperature for hot-dip galvanized steel is 200 °C (392 °F), according to the
American Galvanizers Association. The use of galvanized steel at temperatures above this will result in peeling of the zinc at the
236:
is often used in automotive manufacturing to enhance the corrosion performance of exterior body panels; this is, however, a completely different process which tends to achieve lower coating thicknesses of zinc.
253:
The process of hot-dip galvanizing results in a metallurgical bond between zinc and steel, with a series of distinct iron-zinc alloys. The resulting coated steel can be used in much the same way as uncoated.
293:
is applied to the steel to inhibit oxidation of the cleaned surface upon exposure to air. The flux is allowed to dry on the steel and aids in the process of the liquid zinc wetting and adhering to the steel.
419:
to steel in relation to the steels section thickness e.g. a steel fabrication with a section size thicker than 6 mm shall have a minimum galvanized coating thickness of 85
306:
is often added to the molten zinc bath to improve the fluidity of the bath (thus limiting excess zinc on the dipped product by improved drainage properties), help prevent floating
334:
gates, can be hot-dip galvanized by a process called batch galvanizing. Other modern techniques have largely replaced hot-dip for these sorts of roles. This includes
176:
in a bath of molten zinc at a temperature of around 450 °C (842 °F). When exposed to the atmosphere, the pure zinc (Zn) reacts with oxygen (
545:
427:
found in BS EN ISO 14713-1, where typical corrosion rates are given, along with a description of the environment in which the steel would be used.
299:
The steel is cooled in a quench tank to reduce its temperature and inhibit undesirable reactions of the newly formed coating with the atmosphere.
42:
369:, for whom galvanizing was named, discovered the electrochemical process that takes place between metals during an experiment with frog legs.
145:
108:
89:
296:
The steel is dipped into the molten zinc bath and held there until the temperature of the steel equilibrates with that of the bath.
61:
513:
376:
furthered the research on galvanizing when he discovered the electro-potential between two metals, creating a corrosion cell.
569:
68:
46:
589:
570:
European
Commission, Reference Document on Best Available Techniques in the Non Ferrous Metals Industries, December 2001
75:
467:
451:
446:
320:
57:
35:
549:
290:
323:, safety barriers, handrails, consumer appliances and automotive body parts. One common use is in metal
137:
436:
355:
230:
210:
82:
129:
242:
121:
201:), a usually dull grey, fairly strong material that protects the steel underneath from further
594:
487:
482:
403:
399:
286:
492:
477:
472:
373:
272:
241:
damaged and steel is exposed to the atmosphere, zinc can continue to protect steel through
380:
218:
217:, and is considered superior in terms of cost and life-cycle. It can be identified by the
214:
149:
Steel strip coming out of the zinc pot of a continuous vertical hot-dip galvanizing line
462:
339:
327:. Galvanised steel is also used in most heating and cooling duct systems in buildings
245:(often within an annulus of 5 mm, above which electron transfer rate decreases).
599:
583:
388:
366:
157:
141:
Protective effect: completely rusted letter box mounted to a hot-dip galvanized wall
520:
456:
331:
233:
195:
24:
420:
276:
262:
311:
202:
133:
Crystalline surface of a hot-dip galvanized handrail, known as "spangle"
441:
324:
177:
172:, which alloys with the surface of the base metal when immersing the
338:, which deposits the layer of zinc from an aqueous electrolyte by
307:
173:
165:
144:
136:
128:
120:
384:
359:
303:
169:
161:
514:"GalvInfoNote / The Spangle on Hot-Dip Galvanized Steel Sheet"
188:
184:
18:
358:
described a method of coating iron by dipping it in molten
257:
A typical hot-dip galvanizing line operates as follows:
221:
patterning on the surface (often called a "spangle").
383:
obtained a patent for a method of coating iron with
330:
Individual metal articles, such as steel girders or
265:
solution. This removes oil/grease, dirt, and paint.
49:. Unsourced material may be challenged and removed.
387:, after first cleaning it with 9% sulfuric acid (
16:Process of coating iron or steel with molten zinc
362:in a presentation to the French Royal Academy.
187:), which further reacts with carbon dioxide (
8:
548:. V&S Hot Dip Galvanzing. Archived from
342:, forming a thinner and much stronger bond.
268:The caustic cleaning solution is rinsed off.
109:Learn how and when to remove this message
504:
209:is widely used in applications where
7:
282:The pickling solution is rinsed off.
47:adding citations to reliable sources
573:Primary zinc grade table on page 15
14:
546:"The Hot-Dip Galvanizing Process"
275:in an acidic solution to remove
23:
160:. It is the process of coating
34:needs additional citations for
213:is needed without the cost of
1:
459:– galvanization and annealing
402:it with ammonium chloride (
616:
519:. GalvInfo. Archived from
468:Liquid metal embrittlement
452:Corrugated galvanised iron
447:Bolt manufacturing process
194:) to form zinc carbonate (
261:Steel is cleaned using a
512:GalvInfo (August 2011).
379:In 1836, French chemist
354:In 1742, French chemist
205:in many circumstances.
58:"Hot-dip galvanization"
291:zinc ammonium chloride
183:) to form zinc oxide (
150:
142:
134:
126:
154:Hot-dip galvanization
148:
140:
132:
124:
590:Corrosion prevention
437:Electrogalvanization
356:Paul Jacques Malouin
211:corrosion resistance
125:Galvanised hand rail
43:improve this article
321:roofing and walling
336:electrogalvanizing
243:galvanic corrosion
151:
143:
135:
127:
488:Surface finishing
483:Sendzimir process
231:Electrogalvanized
119:
118:
111:
93:
607:
574:
567:
561:
560:
558:
557:
542:
536:
535:
533:
531:
525:
518:
509:
493:Thermal spraying
478:Prepainted metal
473:Metal fume fever
374:Alessandro Volta
207:Galvanized steel
114:
107:
103:
100:
94:
92:
51:
27:
19:
615:
614:
610:
609:
608:
606:
605:
604:
580:
579:
578:
577:
572:
568:
564:
555:
553:
544:
543:
539:
529:
527:
526:on 2 March 2014
523:
516:
511:
510:
506:
501:
433:
416:
407:
396:
392:
381:Stanislas Sorel
352:
251:
219:crystallization
215:stainless steel
199:
192:
181:
115:
104:
98:
95:
52:
50:
40:
28:
17:
12:
11:
5:
613:
611:
603:
602:
597:
592:
582:
581:
576:
575:
562:
537:
503:
502:
500:
497:
496:
495:
490:
485:
480:
475:
470:
465:
460:
454:
449:
444:
439:
432:
429:
415:
412:
405:
394:
390:
351:
348:
340:electroplating
301:
300:
297:
294:
283:
280:
269:
266:
250:
247:
227:inter-metallic
197:
190:
179:
117:
116:
31:
29:
22:
15:
13:
10:
9:
6:
4:
3:
2:
612:
601:
598:
596:
593:
591:
588:
587:
585:
571:
566:
563:
552:on 2013-06-23
551:
547:
541:
538:
522:
515:
508:
505:
498:
494:
491:
489:
486:
484:
481:
479:
476:
474:
471:
469:
466:
464:
461:
458:
455:
453:
450:
448:
445:
443:
440:
438:
435:
434:
430:
428:
424:
422:
414:Specification
413:
411:
409:
401:
397:
386:
382:
377:
375:
370:
368:
367:Luigi Galvani
363:
361:
357:
349:
347:
343:
341:
337:
333:
328:
326:
322:
316:
313:
310:, make dross
309:
305:
298:
295:
292:
288:
284:
281:
278:
274:
271:The steel is
270:
267:
264:
260:
259:
258:
255:
248:
246:
244:
238:
235:
232:
228:
222:
220:
216:
212:
208:
204:
200:
193:
186:
182:
175:
171:
167:
163:
159:
158:galvanization
156:is a form of
155:
147:
139:
131:
123:
113:
110:
102:
99:November 2013
91:
88:
84:
81:
77:
74:
70:
67:
63:
60: –
59:
55:
54:Find sources:
48:
44:
38:
37:
32:This article
30:
26:
21:
20:
565:
554:. Retrieved
550:the original
540:
528:. Retrieved
521:the original
507:
457:Galvannealed
425:
417:
378:
371:
364:
353:
344:
335:
332:wrought iron
329:
317:
315:grade zinc.
302:
256:
252:
239:
226:
223:
206:
153:
152:
105:
96:
86:
79:
72:
65:
53:
41:Please help
36:verification
33:
530:27 February
346:process.
234:sheet steel
584:Categories
556:2012-11-30
499:References
277:mill scale
69:newspapers
463:Jewelling
372:In 1801,
365:In 1772,
312:recycling
203:corrosion
595:Coatings
431:See also
289:, often
442:Plating
400:fluxing
350:History
273:pickled
263:caustic
249:Process
229:layer.
83:scholar
398:) and
85:
78:
71:
64:
56:
524:(PDF)
517:(PDF)
325:pails
308:dross
174:metal
168:with
166:steel
90:JSTOR
76:books
600:Zinc
532:2014
385:zinc
360:zinc
304:Lead
287:flux
196:ZnCO
170:zinc
164:and
162:iron
62:news
410:).
185:ZnO
45:by
586::
423:.
421:μm
408:Cl
404:NH
393:SO
285:A
189:CO
559:.
534:.
406:4
395:4
391:2
389:H
279:.
198:3
191:2
180:2
178:O
112:)
106:(
101:)
97:(
87:·
80:·
73:·
66:·
39:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
