Block 7For the French, see Les paris gagnés de DCN
High-tech welding of missile launch tubes
The missile launch tubes for Le Redoutable-class SSBNs were welded by hand. In December 1989, DCN’s Cherbourg shipyard adopted electron-beam welding to assemble the launch tubes for new-generation Le Triomphant-class SSBNs. In principle, the technique is simple enough. A focused beam of electrons melts and welds the two sections to be welded together. On striking the metal, the beam’s kinetic energy is converted into heat. Electron-beam welding offers several advantages, including:● elimination of weld shrinkage● no need to pre-heat, hence significant savings.
Despite the machine's weight (around 30 tonnes) and size, welding is done on site rather than taking each workpiece to the machine. During this process, the launch tubes also serve as vacuum chambers. When its was introduced in 1990, the technique represented a world first in industrial production.
DCN’s Indret centre produced the propeller for SSBN Le Triomphant and her successors using a similar technique. The process is similar to that used in the automotive and nuclear power industries.
Caption: Workshop mockup of a ballistic missile launch tube. In red, the vacuum chamber containing the launch tube to be seam welded
- In the heading, I have used "of" to translate "pour les" as it sounds more logical in English.
- The short-cut device in French using "et non l'inverse" has been made explicit.
- Given the change of subject, the sentence beginning "DCN Indret" has been moved to a new paragraph.
- In the last sentence the subject changes again, but two one-sentence paragraphs does not sound like a good idea, especially as it is not clear what point is being made. Doesn't the use of this process in the automotive industry make it sound less technologically sophisticated?
- Caption: The meaning of the word 'reconstitution' is not entirely clear. I have assumed that it means 'mockup'.
- Caption: The origin of the acronym TELM is not clear. I chose to ignore it in the English.