A method of cutting tubes from the inside by electric arc welding
The research programme sets out to define the equipment required to dismantle the bundle of tubes of PWR steam generators (Inox or Inconel, diam. 22 x 1.27mm), and equipment to cut large diameter pipes (diam. greater than 200mm), by a cutting process employing an electric arc welding device. The equipment is conveyed and operated by remote control to cut contaminated active circuits from inside. Transversal cutting of steam generator tubes is completed in 90 seconds with an average current strength of 60 amperes and orbital electrode speed of 1,000 rpm. Electrode wear only allows cutting of two tubes at a time. Longitudinal cutting of steam generator tubes is achieved using a mechanically propelled tool: forward speed up to 12 mm/s, 1,750 rpm at 50 amperes. Electrode wear is negligible after more than one metre of cutting. Cutting of thick, large diameter tubes, with rotating, fully penetrating electrodes depends on the forward speed of the electrode, the maximum energy supplied by the generator, the volume worked/quantity of energy and the arc surface of electrode penetrating into the material. Generators of over 1,500 amperes are required for the cutting of a stainless steel tube (diam. 89 x 6 mm) at an adequate speed of 0.84 mm/s.
Bibliographic Reference: EUR 12883 FR (1990) 43 pp., FS, ECU 5
ISBN: ISBN 92-826-1693-2
Record Number: 199011349 / Last updated on: 1994-12-01
Original language: fr
Available languages: fr