What Kind/grade of steel is used in the boiler of a steam loco?

Doing a Physics presentation on use of steel in the boiler of a steam loco, just wondering, what grade or type of steel is used in a standard boiler?

 

Boiler Plate

 

Probably well out of date, but the Locomotive Manufacturers Handbook of 1949 gives the following information:-

British Standard Report 24 : Part 6, No.16 of 1942 -

Plates for fireboxes (steel). Acid open hearth or electric process, max sulpher 0.03%, max phosphorous 0.03%. Ultimate tensile stress 23 - 28 tons per sq. in. A yield stress of not less than 55% of the UTS is specified. Minimum elongation 25%.

For other than firebox (steel) plate. Open hearth (acid or basic) or electric process, max sulpher or phosphorous 0.05%. UTS 25 - 30 tons per sq. in. Minimum elongation 23%.

 

Thank you very much, this is the sort of answer i had hoped for. Should go well in my presentation.

 

No problem

 

Hope you are going to change the units to SI!

Cheers
Alan (Retired physics teacher among other roles)

 

Some of the later designs of boiler were made from a nickel steel alloy to save on weight. I've tried to find a reference but have failed, sorry. The addition of a little copper also helped to prevent corrosion, but again I can't find a reference.

Regards

 

What do you mean Enterprise by changing units to SI? You have me worried.

Also, just been writing it into the presentation, but what does 'minimum elongation mean?

 

How far the steel will stretch. so a 25% elongation on a 4 inch length would result in a 5 inch length.

 

SI means Standard International, basically units like length are defined in metres, mass in kilograms, weight in Newtons etc.

So in your case tons per sq. inch needs to be converted into the equivalent Newtons per square metre.

(someone correct me if I have got that wrong!)

Regards,

Dan

 

Have a look at Appendix 8 of the ORR Document 'The Management of Steam Locomotive Boilers' found at:
http://www.rail-reg.gov.uk/upload/pdf/RSP6-locoblrs.pdf

It gives BS 1501 151-400A for most boiler plates but the modern requirements for boiler materials generally are given in this appendix.

 

I was always lead to believe that SI was Systeme International, which gives the lie to it being FRENCH. No self respecting BRITISH loco engineer would want to do anything about converting the measurements that our loco's were built to, into something that Napoleonic.

Minimum elongation relates to test samples which are used to test the tensile strength of materials. Specimens are prepared to defined dimensions and then stretched in a tensometer until they break, when the yield point and Ultimate Tensile stress (UTS) are recorded. Elongation is the additional length between two specified points on the sample expressed as a percentage of the original length between the points.

With regard to materials, there were a considerable number of varying types of boiler plate which were available in the days when we actually made lots of boilers in the UK. The common one used nowadays for loco boiler repairs is steel to British Standard BS1501-151-Grade 430B.

 

Cook in "Swindon Steam" mentions the use of higher tensile steel (nickel steel) in the 1930s to enable GWR Large Prairies to be rebuilt with 225 psi boilers (instead of 200psi) without increase in weight.

 

The LMS used Nickel steel on the boilers for some of the Stanier-designed locomotives. I've read the Coronation and Princess Royal pacifics' boilers were as such. The reason was Nickel steel's better resistance to pitting and corrosion.

Richard.

 

In an earlier post I mentioned that some loco boilers where made from nickel steel. Looking through 'LMS Locomotive Profile No 11, The Coronation Pacifics' (Wild Swan) I find that the boiler and outer firebox were made of '2% nickel steel'. This is from a reproduction of LMS drawing number D36-14639 in the book. There no spec for the material on the drawing

HTH

 

Quite so and there is no need for LN850 to be worried. If the audience is sufficiently scientifically or technologically literate, they will understand either Imperial or SI units. If not, the numbers will be meaningless anyway!

Joking aside, there is an ongoing problem with units in international projects. Failures great and small occur daily across the world because of mistaken units. Eg there have been two spacecraft disasters due to a mix-up of metric and imperial units (the Mars Climate Orbiter Probe in 1999 and the DART spacecraft in 2006.

In railway engineering, the Tornado project had to work with historic and contemporary units, and the other new builds such as 82045, also do.

Eurostars in service use metric throughout but the 395s have to switch between systems as they enter or leave the high speed line.

There's a thread here about units in the aviation industry:
http://www.airliners.net/aviation-forums/tech_ops/read.main/263334/

and from the New Scientist about NASA

http://www.newscientist.com/article/dn17350-nasa-criticised-for-sticking-to-imperial-units.html

and the well known (?) Gimli Glider story - http://www.damninteresting.com/the-gimli-glider

Cheers
Alan

PS LN850 who will be in your audience?

 

The use of 2% nickel steel was all to do with saving weight rather than reduction of corrosion and pitting, and did in fact bring other problems with it not least the continued belief right up to the end of steam that reliable structural welding could not be undertaken in this material, mainly due to hardening and cracking in the heat affected zone of the parent meatl adjacent to welds, although seal welding was permitted, given adequate precautions
.
The material concerned was actually Colville's 2% Acid Nickel steel boiler plate, to give it its correct title.

Composition was Carbon 0.2/0.25 %, Silicon 0.1/0.15 %,Manganese 0.5/0.7 %,Nickel 1.75/2.0 %, Sulphur and phosphorus 0.04% max. Ultimate tensile stress was 34/38 tons per sq in, yield point 17/19 tons per sq in, elongation 22/24% on an 8 inch gauge length, Reduction in area 50% min, Ratio of yield/UTS 50% min.

This is the same material which was used by the GWR in the 225lbs pressure No 2 boilers for the 61xx tanks as a means of increasing the strength of the boiler plates without an increase in weight, due to the Nickel steel being considerably stronger than conventional boiler plate. Stanier would have been well aware of this, if in fact he was not one of the originators of the idea, and there can be no doubt that it was solely his influence which brought about the use of this plate on the LMS. The use of this material in the Coronation's diagram 1X boilers gave an overall weight saving of almost 2 tons 4cwt compared to the weight of plate which would have been required employing conventional boiler plate. This included weight savings of 12 cwt on the first barrel ring, 14cwt on the second barrel ring, and 9 cwt on the firebox wrapper plate.

The use of this plate was basically discontinued for new builds in later years due to experience of problems with this material, together with the difficulties in sourcing materials such as nickel in the post war era, and the development of more effective manganese steel boiler plate such as that used in the Br standard loco's. This trend had already started in the 1930's when it was found that the weight saving in Staniers 5X's was not needed, leading to all of the sloping throat 5X's being built with mild steel boilers.

 

With regard to audience of the presentation, a hard copy gets sent to the exam
board, but the audience for the spoken presentation is a class of 16/17 year olds
and my Physics A level teacher.

So I had probably better change the units for the presentation, modern exam boards are a pain like that. Thanks for all of this info though guys, it has proved invaluable!

 

Hope it goes well!
Alan

 

BS1501-151-430A/B with material certification