Ducol or "D"-steel is the name of a number of

high-strength low-alloy steel High-strength low-alloy steel (HSLA) is a type of alloy steel that provides better mechanical properties or greater resistance to corrosion than carbon steel. HSLA steels vary from other steels in that they are not made to meet a specific chemica ...

s of varying composition, first developed from the early 1920s by the Scottish firm of David Colville & Sons,

Motherwell Motherwell (, ) is a List of towns and cities in Scotland by population, town and former burgh in North Lanarkshire, Scotland, United Kingdom, south east of Glasgow. It has a population of around 32,120. Shires of Scotland, Historically in the p ...

. Applications have included warship hull construction and light armouring, road bridges, and pressure vessels including locomotive steam boilers and nuclear reactors.

History

The original Ducol, or "D"-steel, is a manganese-silicon steel, a toughened version of the new, proven standard construction steels developed by David Colville & Sons just after WW1. It was an improvement on British Admiralty "HT" (High Tensile) steel, a shipbuilding and light armour steel developed c1900 and used through the end of WWI. HT was a

carbon steel Carbon steel is a steel with carbon content from about 0.05 up to 2.1 percent by weight. The definition of carbon steel from the American Iron and Steel Institute (AISI) states: * no minimum content is specified or required for chromium, cobalt ...

with a small amount of nickel, which allowed it to be hardened to a greater level without cracking (i.e. increased "toughness"). Foreign similar steels – for example, German "Low-%" Nickel Steel and U.S. High Tensile Steel (HTS) – were more complex alloys using chromium, vanadium and molybdenum. Up until about 1945, Ducol generally contained only manganese and silicon as alloying elements. More recent weldable grades (Ducol W21, W25, W30, and W30 grades A & B) include varying amounts of nickel, chromium, copper, molybdenum and vanadium.

Composition

Weldability

Although modern grades of Ducol are termed 'weldable', this doesn't necessarily mean 'easily weldable'. A 1970 report on an explosion in a cylinder made of Ducol 30 found that in Ducol W30, embrittlement of the heat-affected zone (HAZ) occurs in welds unless post-weld heat treatment takes place at a sufficient temperature (675C). In addition, the original product from the 1920s was also weldable (ie 'capable of being welded'), but with dubious results. The

Imperial Japanese Navy The Imperial Japanese Navy (IJN; Kyūjitai: Shinjitai: ' 'Navy of the Greater Japanese Empire', or ''Nippon Kaigun'', 'Japanese Navy') was the navy of the Empire of Japan from 1868 to 1945, Potsdam Declaration, when it was dissolved followin ...

built large warships using all-welded Ducol structural elements, which swiftly led to severe problems with the Mogami-class cruisers.

Applications

Ships

Ducol has been used for bulkheads in both general construction and against torpedoes, and for light

armour Armour (Commonwealth English) or armor (American English; see American and British English spelling differences#-our, -or, spelling differences) is a covering used to protect an object, individual, or vehicle from physical injury or damage, e ...

in warships of several countries, including the

British British may refer to: Peoples, culture, and language * British people, nationals or natives of the United Kingdom, British Overseas Territories and Crown Dependencies. * British national identity, the characteristics of British people and culture ...

Japanese Japanese may refer to: * Something from or related to Japan, an island country in East Asia * Japanese language, spoken mainly in Japan * Japanese people, the ethnic group that identifies with Japan through ancestry or culture ** Japanese diaspor ...

and perhaps

Italian Italian(s) may refer to: * Anything of, from, or related to the people of Italy over the centuries ** Italians, a Romance ethnic group related to or simply a citizen of the Italian Republic or Italian Kingdom ** Italian language, a Romance languag ...

navies. After WW2 the highest grades of the commercial shipbuilding steels were based on this type of steel.

Royal Navy

HMS Rodney in support of the Normandy landings

Ducol steel was used in and (1927) to save weight. It was used in British anti-torpedo-system design practice in its last battleships. The internal hull and torpedo bulkheads and internal decks were made of Ducol or "D"-class steel, an extra-strong form of HTS. Much of the load-bearing portions of King George V-class battleships including the weather deck and the bulkheads were made from Ducol 's fully-enclosed armoured hangar and the armoured flight deck which it supported were constructed of Ducol. Other types of armour used on Navy ships: * HTS =

High-tensile steel Carbon steel is a steel with carbon content from about 0.05 up to 2.1 percent by weight. The definition of carbon steel from the American Iron and Steel Institute (AISI) states: * no minimum content is specified or required for chromium, cobalt ...

* STS =

Special treatment steel Special treatment steel (STS), also known as protective deck plate, was a type of warship armor developed by Carnegie Steel around 1910. History STS is a homogeneous Krupp-type steel developed around 1910. The development of such homogeneous st ...

= homogenous armour

Imperial Japanese Navy

Japanese Cruisers of the Seventh Squadron

The

(IJN) made considerable use of Ducol made under licence by Japan Steel Works in

Muroran is a city and port located in Iburi Subprefecture, Hokkaido, Japan. It is the capital city of Iburi Subprefecture. As of January 31, 2024, the city had an estimated population of 76,385, with 43,494 households and a population density of . The ...

Hokkaidō is the second-largest island of Japan and comprises the largest and northernmost prefecture, making up its own region. The Tsugaru Strait separates Hokkaidō from Honshu; the two islands are connected by railway via the Seikan Tunnel. The ...

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

: the company was set up with investment from

Vickers Vickers was a British engineering company that existed from 1828 until 1999. It was formed in Sheffield as a steel foundry by Edward Vickers and his father-in-law, and soon became famous for casting church bells. The company went public in 18 ...

Armstrong Whitworth Sir W G Armstrong Whitworth & Co Ltd was a major British manufacturing company of the early years of the 20th century. With headquarters in Elswick, Tyne and Wear, Elswick, Newcastle upon Tyne, Armstrong Whitworth built armaments, ships, locomot ...

and

Mitsui is a Japanese corporate group and '' keiretsu'' that traces its roots to the ''zaibatsu'' groups that were dissolved after World War II. Unlike the ''zaibatsu'' of the pre-war period, there is no controlling company with regulatory power. Ins ...

. The ''Mogami''-class cruisers were originally designed with all-welded Ducol bulkheads which were then welded to the ship's hull. The resultant faults caused by electric welding used in the structural portions of the hull resulted in deformation, and the main gun turrets were unable to train properly. They were re-built with riveted construction, and the other two were redesigned. All of the following ships or classes (the list is not complete) used Ducol in structural bulkheads and protective plating: # Japanese aircraft carrier ''Kaga'' (1928) # Japanese cruiser ''Takao'' # ''Mogami''-class cruisers (x2, 1931), (x2 1933-34) # ''Nagato''-class battleships x2, (1920, upgraded 1934-36) # Japanese aircraft carrier ''Shōkaku'' (1939) # Japanese battleship ''Yamato'' (1940) # Japanese battleship ''Musashi'' (1940) # Japanese aircraft carrier ''Hiyō'' (1941) # Japanese cruiser ''Oyodo'' (1941) # ''Agano''-class cruisers x4, (1941–44) # Japanese aircraft carrier ''Shinano'' (1944) In addition, the IJN's '25-ton' type river motor gun boat had an all-welded hull, protected by 4-5mm Ducol steel.

Italian Navy

The Italian Navy used a similar type of steel to Ducol in its Pugliese torpedo defense system. This underwater "bulge" system was introduced in the Italian Littorio-class battleships, and in the completely rebuilt versions of the and the Conte di Cavour-class battleships. The inboard-facing side consisted of a layer of silicon-manganese high-tensile steel from 28-40mm thick called "Elevata Resistenza" (ER) steel, which was probably somewhat similar to the British Ducol ("D" or "Dl") Steel used for light armour and torpedo bulkheads in WWII. :"However, the power of the torpedoes used during WWII rapidly outclassed even the best bulge protection systems and the

magnetic pistol Magnetic pistol is the term for the device on a torpedo or naval mine that detects its target by its magnetic field, and triggers the fuse for detonation. A device to detonate a torpedo or mine on ''contact'' with a ship or submarine is known as a ...

, when finally perfected, allowed the torpedo to completely bypass the bulge by detonating under the keel of the ship."Plus good info on p. 72 about the names of the British WWI monitors inc. & .

Tanks

During WWII many Soviet

tank A tank is an armoured fighting vehicle intended as a primary offensive weapon in front-line ground combat. Tank designs are a balance of heavy firepower, strong armour, and battlefield mobility provided by tracks and a powerful engine; ...

s used Ducol type steel due to a lack of chromium and nickel.

Bridges

Sumida River

The Eitai-bashi (1926) and Kiyosu-bashi (1928) bridges over the

Sumida River The is a river that flows through central Tokyo, Japan. It branches from the Arakawa River at Iwabuchi (in Kita-ku) and flows into Tokyo Bay. Its tributaries include the Kanda and Shakujii rivers. It passes through the Kita, Adachi, Arak ...

Tokyo Tokyo, officially the Tokyo Metropolis, is the capital of Japan, capital and List of cities in Japan, most populous city in Japan. With a population of over 14 million in the city proper in 2023, it is List of largest cities, one of the most ...

seem to have been some of the first bridges to be made with Ducol, at the time a state-of-the-art technology. The bridges were built by Kawasaki Dockyard Co., to replace earlier crossings which were destroyed in the 1923

Great Kanto earthquake Great may refer to: Descriptions or measurements * Great, a relative measurement in physical space, see Size * Greatness, being divine, majestic, superior, majestic, or transcendent People * List of people known as "the Great" * Artel Great (bo ...

. High-tensile Ducol was used for the lower supports of the Eitai-bashi

tied-arch bridge A tied-arch bridge is an arch bridge in which the outward-directed horizontal forces of the arch(es) are borne as tension by a chord tying the arch ends rather than by the ground or the bridge foundations. This strengthened chord may be the deck ...

, and for the upper cables of the Kiyosu-bashi

self-anchored suspension bridge A self-anchored suspension bridge is a suspension bridge type in which the main cables attach to the ends of the deck, rather than directly to the ground or via large anchorages. The design is well-suited for construction atop elevated piers, or ...

. The steel was made at Kawasaki's Hyogo Works,

Kobe Kobe ( ; , ), officially , is the capital city of Hyōgo Prefecture, Japan. With a population of around 1.5 million, Kobe is Japan's List of Japanese cities by population, seventh-largest city and the third-largest port city after Port of Toky ...

. :"The Ducol steel was used as the material in cases of the construction of the Eitai bashi and the Kiyosu bashi. The author is not aware if the material has been previously used for a bridge. :The material investigated by the author has the C content of 0.24-0.30% and Mn of 1.4-1.6% giving a tensile strength 63-71kg/mm2, elongation 20-23% in 200mm gauge and elastic limit 42kg/mm2. :The Ducol steel seems to be preferable as the bridge building material both in quality and in the cost compared with others such as Ni steel, Si steel and C steel."

Chelsea Bridge

Ducol was also used in the construction of the stiffening girders of

Chelsea Bridge Chelsea Bridge is a bridge over the River Thames in west London, connecting Chelsea on the north bank to Battersea on the south bank, and split between the City of Westminster, the London Borough of Wandsworth and the Royal Borough of Kensin ...

(1934-1937) joined by HTS rivets. A small amount of copper was added to the mix to improve corrosion resistance.

Glen Quoich Road Bridge

Used in the construction of the Glen Quoich Road Bridge,

Aberdeenshire Aberdeenshire (; ) is one of the 32 Subdivisions of Scotland#council areas of Scotland, council areas of Scotland. It takes its name from the Shires of Scotland, historic county of Aberdeenshire (historic), Aberdeenshire, which had substantial ...

- built 1955 by Sir William Arrol & Co. crossing the Qoich Water between

Mar Lodge Mar Lodge is a sporting lodge to the west of Braemar and the principal building on the Mar Lodge Estate in Aberdeenshire, Scotland. It was built in 1895, replacing an earlier building, by Alexander Duff, 1st Duke of Fife. Location Mar Lodge is a ...

and Allanaquoich, not far from where it joins the River Dee.

Pressure vessels

Ducol has been used in

pressure vessels A pressure vessel is a container designed to hold gases or liquids at a pressure substantially different from the ambient pressure. Construction methods and materials may be chosen to suit the pressure application, and will depend on the size o ...

including steam boilers and solid wall

ammonia Ammonia is an inorganic chemical compound of nitrogen and hydrogen with the chemical formula, formula . A Binary compounds of hydrogen, stable binary hydride and the simplest pnictogen hydride, ammonia is a colourless gas with a distinctive pu ...

converter shells as used in the

Haber–Bosch process The Haber process, also called the Haber–Bosch process, is the main industrial procedure for the production of ammonia. It converts atmospheric nitrogen (N2) to ammonia (NH3) by a reaction with hydrogen (H2) using finely divided iron metal as ...

. Normalised and tempered Ducol W30 has been used in heavy walled

nuclear reactor A nuclear reactor is a device used to initiate and control a Nuclear fission, fission nuclear chain reaction. They are used for Nuclear power, commercial electricity, nuclear marine propulsion, marine propulsion, Weapons-grade plutonium, weapons ...

s. In the UK, the

British Standard British Standards (BS) are the standards produced by the BSI Group which is incorporated under a royal charter and which is formally designated as the national standards body (NSB) for the UK. The BSI Group produces British Standards under th ...

for low alloy steels used for high temperature pressure purposes is BS EN 10028-2:2006. It replaced the old BS1501 Part 2: 1988.

Steam locomotives

The boiler plates for the Southern Railway 4-6-0 Lord Nelson class locomotives, designed by

Richard Maunsell Richard Edward Lloyd Maunsell (pronounced "Mansell") (26 May 1868 – 7 March 1944) was an Irish Locomotive Engineer who held the post of chief mechanical engineer (CME) of the South Eastern and Chatham Railway from 1913 until the Railways A ...

in 1926 to work at , were made of Ducol.

Incidents

A number of pressure vessels & boilers constructed with Ducol (or similar materials) have failed. Such failures have all been because of faulty fabrication or testing of the vessel, rather than the steel itself.

Sizewell 'A'

Ducol was used in the boiler shells at Sizewell ‘A’ nuclear reactor. Failure of Sizewell ‘A’ boiler under hydrostatic test, May 1963. "The boiler was 18.9 m long, 6.9 m diameter, and was fabricated from plates 57 mm thick in a low alloy steel, conforming to BW87A specification (similar to Ducol W30, but with lower C), of composition 0.1C, 1.4Mn, 0.5Cr, 0.25Mo, 0.2Ni, 0.1 V. The cause of the failure was attributed to a shock impact loading, when the wooden chocks on which the vessel was resting during the hydro-test suddenly gave way." Ducol would have been used for the later stations, but was superseded by prestressed concrete pressure vessels (PCPV). The advantage of prestressed concrete is that once the initial compression has been applied, the resulting material has the characteristics of high-strength concrete when subject to any subsequent

compression forces In mechanics, compression is the application of balanced inward ("pushing") forces to different points on a material or Structural system, structure, that is, forces with no Net force, net sum or torque directed so as to reduce its size in one ...

, and of ductile high-strength steel when subject to tension forces.

John Thompson pressure vessel

In December 1965 a boiler made of Ducol was under construction by John Thompson,

Wolverhampton Wolverhampton ( ) is a city and metropolitan borough in the West Midlands (county), West Midlands of England. Located around 12 miles (20 km) north of Birmingham, it forms the northwestern part of the West Midlands conurbation, with the towns of ...

, for ICI's ammonia plant at

Fisons Fisons plc was a British Multinational corporation, multinational pharmaceutical, scientific instruments and horticultural chemicals company headquartered in Ipswich, United Kingdom. It was listed on the London Stock Exchange and was once a cons ...

' Immingham works. It was being pressure-tested after heat treatment when it exploded, throwing one chunk weighing 2 tons right through the workshop wall and landing 50 metres away. In Ducol W30, embrittlement of the heat-affected zone (HAZ) in welds occurs unless post-weld heat treatment takes place at a sufficient temperature (675C). The amount of pre-heating and the type of welding consumables (eg low hydrogen) can affect

hydrogen embrittlement Hydrogen embrittlement (HE), also known as hydrogen-assisted cracking or hydrogen-induced cracking (HIC), is a reduction in the ductility of a metal due to absorbed hydrogen. Hydrogen atoms are small and can Permeation, permeate solid metals. O ...

(or cracking) in the weld.

Cockenzie power station

A boiler drum made with Ducol plates, manufactured by

Babcock & Wilcox Babcock & Wilcox Enterprises, Inc. is an American energy technology and service provider that is active and has operations in many international markets with its headquarters in Akron, Ohio. Historically, the company is best known for their stea ...

Ltd (now Altrad Babcock) at

Renfrew Renfrew (; ; ) is a town west of Glasgow in the west central Lowlands of Scotland. It is the historic county town of Renfrewshire. Called the "Cradle of the Royal Stewarts" for its early link with Scotland's former royal house, Renfrew gaine ...

, near Glasgow, to BS 1113 (1958) was installed at Cockenzie Power Station in

East Lothian East Lothian (; ; ) is one of the 32 council areas of Scotland, as well as a Counties of Scotland, historic county, registration county and Lieutenancy areas of Scotland, lieutenancy area. The county was called Haddingtonshire until 1921. In ...

, Scotland. It exploded on 6 May 1967 under repeated pressure testing. According to Jim Thomson, the failure was caused by a crack (created during the original manufacturing process) which occurred next to an economiser nozzle replaced during testing; the crack had penetrated part-way through the thick wall of the pressure vessel.

References

;Notes ;Citations

Sources

{{columns-list, colwidth=30em, * {{cite journal , editor-last=Caruana , editor-first=Joseph , journal=Warship International , title=Special Reprint , volume=3 , issue=1 , date=Winter 1966 , page=58 , publisher=International Naval Research Organization , jstor=44886983, last1=Caruana , first1=Joseph * {{cite book , publisher= Cranfield Institute of Technology , title=Effect of Welding and Post-Weld Heat Treatment on Ducol 30 , last1=Allen , first1= D. , last2=Smith , first2=E. , last3=Apps , first3=R. L. , series=Cranfield Report Mat. No. 4 , date=September 1970 , url=https://repository.tudelft.nl/file/File_8f0cf5c7-1ca4-4588-8698-41c615db63b4 * {{cite book , editor-last=Frick , editor-first= John P. , title=Woldman's Engineering Alloys , series=Materials Data series , publisher=ASM International , year=2000 , isbn=978-0-87170-691-1 , url=https://books.google.com/books?id=RzMOiOEQ-oMC&pg=PA364 * {{cite book , last=Jordan , first=John , title=Warships after Washington: The Development of Five Major Fleets 1922-1930 , page=80 , publisher=Seaforth Publishing , year=2011 , isbn=978-1-84832-117-5 , url=https://books.google.com/books?id=ttmkAwAAQBAJ&pg=PA80 * {{cite book , last=Kerensky , first=O.A. , title=Use of high tensile (low alloy) steels in bridges: Recent development in British practise , publisher=IABSE publications, Vol. 9 , year=1949 , doi=10.5169/seals-9705 (free download) * {{cite book , last=Knott , first=J. F. , chapter=Design and material issues in improving fracture/fatigue resistance and structural integrity in power plants , editor1-last=Shirzadi , editor1-first=Amir , editor2-last=Jackson , editor2-first=Susan , title=Structural Alloys for Power Plants , pages=319–354 , publisher= Woodhead Publishing , year= 2014 , doi=10.1533/9780857097552.2.319, isbn=978-0-85709-238-0 {{subscription required * {{cite journal , title=The Development of the "A Class" Cruisers in the Imperial Japanese Navy, Part I , last=Lacroix , first=E. , journal=Warship International , volume=14 , issue=4 , pages=337–357 , year=1977 , publisher=International Naval Research Organization , jstor=44890161 * {{cite journal , last=Lacroix , first=E. , title=The Development of the "A Class" Cruisers in the Imperial Japanese Navy, Part IV , journal=Warship International , volume=18 , issue=1 , pages=40–76 , year=1981 , publisher=International Naval Research Organization , jstor=44890892 * {{cite journal , ref={{harvid, Lacroix, 1981a , last=Lacroix , first=E. , series=The Development of the "A Class" Cruisers in the Imperial Japanese Navy: Part V. , title= Pre-war Modernization of the "A Class" Cruisers , journal=Warship International , volume=18 , issue=4 , pages=323–367 , year=1981 , publisher=International Naval Research Organization , jstor=44890867 * {{cite journal , last=Lacroix , first=E. , series=The Development of the 'A Class' Cruisers in the Imperial Japanese Navy: Part VI. , title=Wartime Modifications, Activities and Final Fate of the "A Class" Cruisers , journal=Warship International , volume=20 , issue=3 , pages=232–282 , year=1983 , publisher=International Naval Research Organization , jstor=44888424 * {{cite journal , last=Lacroix , first=E. , series=The Development of the "A Class" Cruisers in the Imperial Japanese Navy: Part VII. , title=The "Mogami" "B Class" Cruisers modified to "A Class" standard, etc. , journal=Warship International , volume=21 , issue=3 , pages=246–305 , year=1984 , publisher=International Naval Research Organization , jstor=44894563 * {{cite book , last=Lancaster , first=John , title=Handbook of Structural Welding: Processes, Materials and Methods Used in the Welding of Major Structures, Pipelines and Process Plant , publisher=Woodhead Publishing , year=1997 , isbn=978-1-85573-343-5 , url=https://books.google.com/books?id=U8rTuuD85XoC&pg=PA392 * {{cite book , last1=Lengerer , first1=Hans , first2=Tomoko , last2=Rehm-Takahara , chapter=The Japanese Aircraft Carriers Junyo and Hiyo , editor-last=Andrew , editor-first=Lambert , title=Warship IX , year=1985 , publisher=Conway Maritime Press , location=London , isbn=978-0-85177-403-9 * {{cite book , first=Hans , last=Lengerer , chapter=The Aircraft Carriers of the Shōkaku Class , editor-last=Jordan , editor-first=John , title=Warship 2015 , publisher=Conway , location=London , year=2015 , isbn=978-1-84486-276-4 * {{cite book , chapter=The IJN Light cruiser Oyodo , first=Hans , last=Lengerer , title=Warship 2018 , editor-last=Jordan , editor-first=John , year=2018 , publisher=Osprey , isbn=978-1-4728-3001-2 , chapter-url=https://books.google.com/books?id=nR9dDwAAQBAJ&pg=PA102 * {{cite book , editor-last=McKetta , editor-first=John J. Jr , title=Encyclopedia of Chemical Processing and Design, Volume 42: Pressure-Relieving Devices , publisher=CRC Press , year=1992 , isbn=978-0-8247-2492-4 , url=https://books.google.com/books?id=s8F83TJ6jloC&pg=PA218 * {{cite book , title=The heavy cruiser Takao , last=Skulski , first=Janusz , publisher=Anova Books , year=2004 , isbn=978-0-85177-974-4 , url=https://books.google.com/books?id=u8m25XA4BhYC&pg=PT19 * {{cite book , last=Skulski , first=Janusz , title=Battleships Yamato and Musashi , others=Illustrated by Stefan Draminski , publisher=Bloomsbury Publishing , year=2017 , isbn=978-1-84486-317-4 * {{cite book , last=Stuart , first=Sam , title=Nuclear Power Generation: Modern Power Station Practice , edition=2nd, revised , publisher=Elsevier , year=2013 , isbn=978-1-4831-5739-9 , url=https://books.google.com/books?id=z6Q3BQAAQBAJ&pg=PA337 * {{cite journal , last=Taniyama , first=I. , title=Ducol Steel for Bride-Buildiing icMaterial , journal=Tetsu-To-Hagane / Journal of the Iron and Steel Institute of Japan , volume=15 , issue=4 , date=April 1929 , doi=10.2355/tetsutohagane1915.15.4_268 , doi-access=free

External links

Kiyosu Bridge, Tokyo, c. 1930
''Old Tokyo''. Steel alloys Naval armour