For our butterfly valves a technical change of the shaft material is necessary and mandatory.
Based on problems with strength calculation for our shafts in material grade 1.4104 we need to change the specification to the material 1.4104 - QT 650 to enforce the mechanical resistance.
As of now we need to add to the description of the material 1.4104 - QT 650. With this quenching and tempering the yield strength of 650-850 N/mm² could be reached.
If you have the approval from the Center of Competence to use an alternative material instead of 1.4104 please make sure that the yield strength of 650-850 could be reached.
The phase-in and Phase-out of the shafts must be handled locally and done as soon as possible.
Please, inform Mr. M.Weuster about your scheduled transition period / change-over and define the end the usage of the todays 1.4104 material .
Please, inform all your local team members accordingly and feed back to Mr. Weuster til 1. August 2014