Suspect Stays

There's a post from Dampfbahn-Verein Zürcher Oberland (DVZO) in Switzerland on Facebook about the stays (or standing bolts as Google Translate calls them!) needing replacement on a 10 year old boiler due to unsuitable steel used by a now defunct Czech company.

https://m.facebook.com/story.php?st...4938&id=294298207308477&fs=0&focus_composer=0

I remember there was a dodgy batch a few years ago used over here, but I didn't think it was 10/12 years ago. I recall it affected quite a few locos. Interesting to see other countries having similar issues.

 

I was under the impression that the dodgy stay material used over here was copper. but on reflection its about the same timescale so could have been steel.

 

You're correct, it was copper.

Bob.

 

It was dodgy steel rivets in the U.K. IIRC one could knock the heads off with a glancing blow from a hammer - can't remember where they came from.
Ray.

 

Dodgy materials are a far bigger issue than the heritage sector. I know of a few horror stories of higher strength stainless bolts in big civil engineering projects that simply didn't meet spec; they weren't the material claimed on the certificate and they didn't meet the specified tensile properties. Fundamentally, unless you can trust every link in the supply chain, you can't trust the paperwork, but sometimes the vendors don't think disclosing their entire supply chain is in their interests (probably correct, in a short-sighted kind of way).

Locomotive boilers aren't actually too bad in one sense, materials are generally being used in the soft state, so provided the chemical composition is within spec you're off to a good start. If I was sourcing materials for boiler work I'd be awfully tempted to get either independent verification of composition, or get a trusted supplier to provide their own test reports. If the composition doesn't plausibly match the certificate supplied, even if it's within spec, you know somebody's QA isn't up to scratch. But of course all that adds cost, and all to cover risks that a reassuring trail of paperwork is meant to eliminate.

 

The link says "unsuitable" which may

Perhaps we are talking about different things, i.e. there were problems with both steel and copper stays/fasteners, but one of the better known incidents was with 80072, this from the owing company's 2014 annual report:
"On 15th May [2014] during a routine firebox examination it was found that two stay heads had parted company with the main part of the stay giving considerable concern for the remainder of the copper stays. Resultant PMI tests and metallurgy analysis proved that the copper stay material which had been used did not meet with the required specification. Full details were provided to the specialist supplier which had carried out the boiler refurbishment some 6 years earlier. A temporary repair was carried out by the Llangollen Railway Plc and the locomotive returned to traffic on 12th June. The locomotive successfully operated through June, July and August without further problems until 3rd September when a further routine firebox examination revealed that another copper stay had failed. As a direct result of this the boiler insurance inspector instructed that the locomotive be immediately removed from traffic. At once the company which had carried out the boiler refurbishment were again advised and an urgent meeting with them took place. It was made clear that they would be held financially responsible for replacing all of the out of specification copper stays. Due to the supplier's inability to commence this work within a reasonable time all the copper stays are being replaced at the workshops of the Llangollen Railway and legal proceedings will be started to recover this cost unless a satisfactory agreement on cost is reached with the original contractor.

The Directors anticipate that the total cost for this work will be in the region of £70,000. Preliminary costs of £4,639 have been written off as repairs in this year’s accounts and the Directors are satisfied that the company has access to sufficient funds to complete the work. The expected date for completion is late July 2015, but taking an option to reduce part of this cost by utilising volunteer labour to re-assemble the locomotive after the boiler work is completed could extend this period until September/October."

I think though this is a slight drift from "unsuitable" (in the original link) to "not in accordance with specification", as the former could imply that the specification was wrong.

 

I think you may be reading too much. Not according to specification is presumably defined in the contract and difficult to argue about, unsuitable could mean lawyers arguing expensively for years.

 

Steel boiler stay material is usually EN3B, a fairly soft carbon steel commonly used all over the engineering world. It's cheap and plentiful, therefore suppliers have little incentive to tamper with the paperwork. Whilst there have been odd issues with incorrect materials, particularly with rivets, this is usually limited to genuine mistakes by people in the supply chain rather than intentional fraud. It's not feasible to send samples from every steel stay bar for analysis - you're talking about adding a cost of north of £100 to a lemgh of steel costing ££30.

Copper stay bar is a different ball game. Unfortunately C107 (arsenal copper) is a comparatively expensive and hard to obtain grade, and there have been several instances of supply chain fraud where C101 (electrical buzz bar material) or simi have been substituted for the genuine article. This means that the mill certs aren't worth the paper they are written on, and you have to either go to a supplier who has had the material batch tested by a UK lab, and is willing to give you the cert, or get the material tested yourself.

Unfortunately exactly nobody will give proper guarantees that if the copper material they supply is defective, they will pay the resultant costs - almost invariably, liability is limited to the cost of refunding or replacing the material. By the time its in a boiler, the £10 lump of copper bar in each stay will also represent about £30-50 in machining and fitting!

 

Autocorrect has much to answer for.

 

London based supplier

Keith

 

N5 1BU

 

Good Evening,

I hope you do not mind me writing this on here.
I am a Raw Material Account Manager for Smiths Advanced Metals in Biggleswade.
We stock C107 Arsenical Copper for supply purposely into the steam locomotive industry.
The material is sourced from a reputable mill supplier. But is also individually batch tested in our UKAS Lab and these certs are provided with the mill cert on every occasion.

I would welcome the opportunity to discuss this further on here or feel free to email me: rhodesj@smithsadvanced.com.

Regards

Jordan Rhodes
07710107987