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A Kurdziel		#1 Posted : 14 January 2015 12:36:54(UTC)
Rank: Super forum user		See http://www.bbc.co.uk/new...-england-london-30811889 Interesting to see that the owners main concern is not the bolts falling on people’s heads but the ‘building’s structural integrity’. Can someone explain how hydrogen can corrode a steel bolt several stories up a skyscraper?
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David Bannister		#2 Posted : 14 January 2015 12:52:27(UTC)
Rank: Super forum user		A bolt falling off and being caught by an additional control is newsworthy for a short while. The collapse of a major building would be somewhat more concerning to a large number of people, not least the owners.
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peter gotch		#3 Posted : 14 January 2015 12:52:44(UTC)
Rank: Super forum user		I'd be interesting to hear why there would be highly explosible gas beside the bolts?
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ExDeeps		#4 Posted : 14 January 2015 13:04:54(UTC)
Rank: Super forum user		I don't think it's as simple as the story makes out - the most probable cause from what I can glean from the link is that there is a quality issue leading to Hydrogen Stress Corrosion Cracking. The hydrogen may have been inadvertantly introduced a long time before the steel was made into a bolt and has been sitting hapily in the steels crystaline lattice waiting for a bit of stress to be applied. As I say, quality issue and going out on a limb one of the effects of someone feeding sub standard materials into the supply chain for profit?
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Ian Bell		#5 Posted : 14 January 2015 13:10:55(UTC)
Rank: Super forum user		Exdeeps is on the right lines. Hydrogen is introduced during the steel manufacture. http://en.wikipedia.org/...i/Hydrogen_embrittlement
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chris42		#6 Posted : 14 January 2015 13:29:49(UTC)
Rank: Super forum user		Hydrogen embrittlement can also be an issue with welded joints in steel if you do not control the process. Chris
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teh_boy		#7 Posted : 14 January 2015 13:38:51(UTC)
Rank: Super forum user		A Kurdziel wrote: Can someone explain how hydrogen can corrode a steel bolt several stories up a skyscraper? http://en.wikipedia.org/...i/Hydrogen_embrittlement
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teh_boy		#8 Posted : 14 January 2015 13:40:08(UTC)
Rank: Super forum user		DOh I took so long to reply I answered an already answered question - must be fatigue...
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A Kurdziel		#9 Posted : 14 January 2015 14:18:05(UTC)
Rank: Super forum user		So a manufacturing issue then... Which according to the wikipedia article can be tested for...so why was this not done especially after 2 bolts had come off last year?
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Jane Blunt		#10 Posted : 14 January 2015 21:07:59(UTC)
Rank: Super forum user		We only have a press article to go on - accurate? While many instances of hydrogen cracking are easily predictable, this is not always the case. Let's wait and see whether a proper report becomes available. A limited quantity of hydrogen can dissolve in steel, but it diffuses out, so it generally only manifests itself early on.
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paul.skyrme		#11 Posted : 14 January 2015 21:21:18(UTC)
Rank: Super forum user		Stress corrosion cracking facilitated by minor hydrogen embrittlement cracking during manufacture? You would know more than I Jane, but that is my off the cuff gut thought, thinking out loud, kind of idea?
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johnmurray		#12 Posted : 15 January 2015 06:52:11(UTC)
Rank: Super forum user		Hydrogen induced delayed brittle failure. "Hydrogen is exceptionally mobile and quickly penetrates into any recently formed cracks, lesions or material surface discontinuities, which become high stress areas. Cracks will promulgate through the component surface, weakening the component due to the loss of cross-section area. The failure is usually completed by a ductile fracture. The tougher the material, the more it is capable of resisting the above phenomenon" http://www.fera.org.uk/p...gen%20-%20march%2006.pdf
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bob youel		#13 Posted : 15 January 2015 08:03:44(UTC)
Rank: Super forum user		this is probably another bankers [via a procurement department] issue as all that those up the stairs want is excess profit so the procurement department bought cheap steal - whats new then?
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johnmurray		#14 Posted : 15 January 2015 09:42:29(UTC)
Rank: Super forum user		bob youel wrote: this is probably another bankers [via a procurement department] issue as all that those up the stairs want is excess profit so the procurement department bought cheap steal - whats new then? Or even cheap steel? It's a fixings problem. The material doesn't even have to be cheap, bad or low-standard. The problem can be induced in good fixings by the anodising/plating process. Who/what/where the blame attaches is, however, a political problem (even if only business politics)
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