Block 1For the French, see Les paris gagnés de DCN
100 HLES, steel for the deep
A submarine’s dive performance is determined first and foremost by the strength of the hull material. Since the Narval – the country’s first post-World War II submarine built in 1954 – the yield strength of French hull steels has more than doubled. HLES-grade steels are in a class of their own. (HLES stands for haute limite d'élasticité soudable or ‘high-yield weldable’.)
DCN and steel-maker Creusot-Loire Industrie developed HLES 100-grade steel specifically for the Le Triomphant programme. This steel can withstand a tensile stress of 100 kg/mm2, making it four times stronger than mild steel. By 1991, Creusot-Loire Industrie was supplying DCN with HLES steel to specifications unmatched by steelmakers delivering to either the US Navy or the United Kingdom’s Royal Navy.
The product was developed by Creusot Loire laboratories in Burgundy and produced by its Chateauneuf steel mill. Heavy-gauge sheets of HLES 100 steel are shaped, stamped, cold formed and milled then welded together at DCN’s Cherbourg shipyard. The next challenge will be to produce HLES 120 and even HLES 130 steel.
Caption: Collar for reactor pool. Approx. diam.: 6 m.Running commentary
- HLES is important as it is the product's formal name. It also seems worthwhile to give both the long form of this French acronym and a translation.
- 'Stronger' is not a precise engineering term but is, I think, acceptable in this technical journalism context.
- Italics for the names of ships:
In literature and general journalism, italics is the rule.
In naval technical writing many writers only use italics for the names of ships in service, but not for vessels that have yet to be commissioned or have been decommissioned.
In the shipbuilding industry, projects go through many phases before the first vessel is commissioned and the name of the proposed ship or class may change frequently. Writers are thus easily confused as to when they should and should not use italics. My advice to any shipbuilder or naval projects office that asks is simple: No italics. Many may disagree. But many will disagree whatever the writer chooses to do.