1. Specification of niobium sheets 031/05/2010 O. Capatina G. Arnau Izquierdo W. Weingarten S. Atieh

2. 1 GENERAL CHARACTERISTICS Chemical composition: PURE NIOBIUM “based on ASTM B393, Type 5, UNS R04220 with further requirements“ RRR 300 grade (Type 5, UNS R04220) Limits for the main impurities: ElementMax. Content wt% Ta0.050 W0.007 Ti0.005 Mo0.005 All other metallic impurities, each0.003 H2H2 0.0002 N2N2 0.0010 O2O2 C 31/05/2010 Technical Specification Sheets shall be made from ingots produced by electron beam vacuum melting. Forging and rolling shall be made in clean conditions to avoid any contamination with foreign particles. Final annealing shall be made in a proper vacuum of 2∙10 -5 torr or better. ASTM B393 – 09e1Standard specification for Niobium and Niobium Alloy Strip, Sheet, and Plate. EN 10204:2004Metallic products: Types of inspection documents ASTM E112-96(2004)e1Standard method for determining average grain size prEN 4050-4:1994Aerospace series - Test method for metallic materials; ultrasonic inspection of bars, plates, forging stock and forgings - Part 4: Acceptance criteria ISO 4287:1997 Geometrical Product Specifications (GPS) -- Surface texture: Profile method -- Terms, definitions and surface texture parameters ISO 4288:1996Geometrical Product Specifications (GPS) -- Surface texture: Profile method -- Rules and procedures for the assessment of surface texture

3. 2 GENERAL CHARACTERISTICS 31/05/2010 Homogeneity and surface quality: Parallel surfaces ( RF side & back side) and bulk material have to be free of defects Surface defects: RF side, surface roughness Rt ≤ 15 µm. back side, surface roughness Rt ≤ 60 µm. visual inspection and optionally by Eddy current (according to a written procedure approved by CERN) Bulk defects: shall be ultrasonically inspected for the presence of continuity faults and for variations of attenuation which are indicative of microstructural heterogeneities. Structure: Grain size number 6 or finer According to ASTM E112-96(2004)e1 Mechanical: Tensile strength Rmmin.140 N/mm2 Yield stress Rp 0.2% min. max. 50 N/mm2 100 N/mm2 Elongation at break A5 min.30% Vickers hardness HV10max.60

4. 3 QUALITY CONTROL 31/05/2010TestFrequency Chemical analysis other than H2, N2, O2 and CEvery melt H2, N2, O2 and CEvery batch on final product Structural analysisEvery batch on final product Tensile mechanical propertiesEvery batch on final product HardnessEvery item (location to be agreed) RRREvery batch on final product Visual inspectionEvery item, 100 % on both sides Eddy current inspection (option)Every item, 100 % on both sides Ultrasonic for continuity faultsEvery item and/or intermediate product, 100 % Ultrasonic for variations of attenuationEvery item, 100 % RoughnessEvery batch on final product DimensionsEvery item Tests carried out by the manufacturer for each item delivered. Items are considered in the same batch if they have in common: melt, rolling and have been annealed in the same charge

5. 4 Dimensions 31/05/2010 Sheet dimension (half cell shape) are determined by the manufacturing process For small series spinning is more adapted than deep drawing or hydro forming Establish sheet main dimensions, spinning test has been carried out with following outcomes:  Required sheet Ø ≈ 520 mm → dimension 520 mm x 520 mm  Thickness: optimised start thickness is 3.5 mm spinning t loss - 0.6 mm thickness tolerances- 0.1 mm chemical etching and EP- 0.2 mm Starting thickness 3 mm & 4 mm Loss in thickness ≈ 0.6 mm Tacking into account

6. 5 Dimensions 31/05/2010 t 3.5 mm Ø 520 mm Sampling, witness pieces, tests, etc. Final sheet dimension: 520 mm x520 mm x t 3.5 mm

7. 6 Open points 31/05/2010 Stiffening rings in Nb RRR40→ specification is done Interface Nb to NbTi and Ti tank to done Extremities to done in tubes or spinning? Quantities to checked