Liquid Metal Embrittlement after Hot Dip Galvanizing of Dirty Beams 4

[Guest102023]

I have a situation where the cope area of fabricated WF beams is experiencing LME in many parts. The complicating factor is that the beams are full of big long inclusions at the web/flange junction. Can anyone comment on possible interaction of these inclusions with LME?

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

 

[metengr]

If you are observing liquid metal embrittlement after hot dip galvanizing, it is from contaminants in the molten zinc bath irrespective of the inclusion content or orientation in the structural steel.

 

[metengr]

Also, check the coped area to determine if it was left in a flame cut condition. Galvanizing over flame cut, coped edges, can result in locally hardened material with tensile residual stresses that may induce cracking during HDG.

 

[Guest102023]

Thanks, Metengr.

In my research I became aware that zinc contaminants are a significant risk. How would you rate the probability of cracking in contaminated zinc?

The client has made this product many times before without many issues. However, there is also evidence in the zinc layer metallurgy that the material was overheated. I also observed numerous surface microcracks that have been linked to flame cutting of electric furnace remelted steel and the attendant high residual alloy content. Unusually there was not much of a HAZ at the flame cut surface, either microstructurally or by HV testing. Another result is that the zinc layer flakes off easily, consistent with the micro attached.

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

 

[Guest102023]

Second micro

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

 

[BAretired]

The two images appear identical.

BA

 

[Guest102023]

That should fix it.

I believe flaking happened because of brittleness of the layer just above the interface.

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

 

[Guest102023]

Metengr,
What are potentially harmful contaminants?

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

 

[SJones]

Did you get these two in your research:

https://www.google.com.qa/url?sa=t&...e=web&cd=1&cad=rja&ved=0CCoQFjAA&url=https://

http://www.steelconstruction.org/co...=9iIV21_hBLZiG1PXen9q5g&bvm=bv.47534661,d.bmk

http://elsa.jrc.ec.europa.eu/publications/JRC56810.pdf

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.

 

[Guest102023]

Yes and no. Thanks very much.

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

 

[metengr]

You might as well add one more to the mix;

http://www.aisc.org/uploadedFiles/Research/Research_Reports/Kinstler - Cracks During Galvanizing.pdf

 

[Guest102023]

Metengr,
Fabulous resource; you've saved me a bunch of hours of futile googling.

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

 

[Rich2001]

The AISC paper above was written to combat the publicity caused by the failures attributed to the Galveco process. The Galveco process introduced other low melting point elements into the galvanizing alloy. Umicore withdrew Galveco from the market in March 2007.

Below are some additional information

http://reddogalaska.com/tc/gg/pdf/presentations/AGA_2003_Paper.pdf

Galvanizing Structural Steelwork - An approach to the management of Liquid Metal Assisted Cracking

https://www.steelconstruction.org/component/documents/?task=downloadDocument&doc=3475&file=3475

http://www.aws.org/itrends/2004/07/it0704-29.pdf‎

http://www.aws.org/itrends/2005/10/023/‎

http://www.fim.usv.ro/conf_1/tehnomusjournal/pagini/journal2011/files/21.pdf

From Nyrstar Annual Report 08

Legal actions
Galveco is patent-protected zinc alloy used for galvanising steel. Between June 2000 and March 2007, Umicore produced and supplied (approximately) 45Kt of Galveco to galvanisers in various countries (corresponding to approx 3.5Mt of steel that has been galvanised with Galveco).
Umicore withdrew Galveco from the market in March 2007 as a precautionary measure following the discovery of cracking in steel that had been hot dip galvanised. It is alleged that a cause of this cracking is the use of Galveco.
The production and supply of Galveco in certain countries was part of the zinc alloys activities of Umicore, which through contributions of business branches, were transferred to Nyrstar. However, nothwithstanding these contributions, Umicore remains a party to certain Galveco proceedings.
There are a number of legal proceedings in Germany, Belgium and France related to Galveco that directly or indirectly involve Nyrstar.
• Germany: Four legal proceedings are pending before the Regional Court (Landgericht) in Kaiserslautern, Mannheim and Zweibrücken and concern
evidence hearing proceedings to determine the causes of cracks discovered in the steel construction of a football stadium roof in Kaiserslautern,
a freight cargo hall in Ramstein, a parking facility in Ramstein and a roof in Bruchmühlbach-Meisau. These proceedings are still ongoing and the
experts’ final findings and conclusions are not yet known. Umicore/Nyrstar are involved in these proceedings through demands for intervention
from the German galvaniser Verzinkerel Rhein-Main GmbH and Co KG (VRM).
Another legal proceeding in Germany is a € 50,000 damages claim, which was initiated by another galvaniser, Rietbergwerke GmbH and Co KG
on 29 December 2006, before Regional Court in Bielefeld and which involves Umicore/Nyrstar. This proceeding was dismissed by the Court
on 10 December 2008 for Rietbergwerke’s lack of legal interest and as its claims are time-barred.
The remaining legal proceeding in Germany is a € 950,000 damages claim, which was initiated on 19 December 2007 by VRM and four other
galvanisers belonging to the VRM group before Regional Court in Essen and which involves Umicore/Nyrstar. On 22 October 2008, the Court
ordered that this proceeding be divided into five separate proceedings and referred these proceedings to the Regional Courts in Darmstadt,
Siegen, Bochum, Würzburg and Saarbrücken.
• Belgium: The legal proceeding in Belgium was initiated on 27 December 2007 by VRM and four other galvanisers belonging to the VRM group
before the Brussels Commercial Court and which involves Umicore/Nyrstar. The claimed damages are provisionally estimated at (approximately)
€ 5.8 million. This proceeding is currently inactive.
• France: On 22 January 2009 Nyrstar was summoned to appear on 6 February 2009 before the President of the Commercial Court in Douai
(France) to intervene in a pending expert investigation between a number of French galvanisers, a galvanising kettle manufacturer and a steel
manufacturer to determine the cause of cracks discovered in a steel galvanising kettle. This proceeding is ongoing and the experts’ final findings
and conclusions are not yet known.
A number of other claims have been received in relation to cracks that have been discovered in steel constructions in Germany and France.
In two of these cases, the claimed damages are (respectively) € 725,053 and € 532,563. The amounts for the other claims have not been quantified.

Richard

http://www.6sproductivitycom.com