Characteristics of the austenitic steels used in the LHC main dipoles

The LHC dipole structure is assembled using austenitic steel collars and austenitic steel end-laminations. The collars will be fine-blanked starting from 11000 tons of steel; the end-laminations require 1700 tons of steel. The procurement of the austenitic steels was divided in two phases: first, we qualified different grades from different producers, and then, we made the call for tender, adjudicated the contract and started the series production. The first part of this paper summarizes the results (of the first qualification phase when extensive checks and measurements were carried out on five different grades. The second part describes the approach used to control the series production and the results obtained. At the time of writing about 19% of the steel for collars and end-laminations has been manufactured and delivered.