Specification of niobium sheets
O. Capatina
31/05/2010
G. Arnau Izquierdo
W. Weingarten
S. Atieh
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GENERAL CHARACTERISTICS
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 – 09e1
EN 10204:2004
ASTM E112-96(2004)e1
prEN 4050-4:1994
ISO 4287:1997
ISO 4288:1996
Standard specification for Niobium and Niobium Alloy Strip, Sheet, and Plate.
Metallic products: Types of inspection documents
Standard method for determining average grain size
Aerospace series - Test method for metallic materials; ultrasonic inspection of bars, plates, forging
stock and forgings - Part 4: Acceptance criteria
Geometrical Product Specifications (GPS) -- Surface texture: Profile method -- Terms, definitions
and surface texture parameters
Geometrical Product Specifications (GPS) -- Surface texture: Profile method -- Rules and
procedures for the assessment of surface texture
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:
Element
Max. Content wt%
Ta
W
Ti
Mo
All other metallic impurities, each
0.050
0.007
0.005
0.005
0.003
H2
N2
O2
C
0.0002
0.0010
0.0010
0.0010
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Structure:
Grain size number 6 or finer According to ASTM E112-96(2004)e1
GENERAL CHARACTERISTICS
Mechanical:
Tensile strength
Yield stress
Rm
Rp 0.2%
Elongation at break
Vickers hardness HV10
min.
min.
max.
A5 min.
max.
140 N/mm2
50 N/mm2
100 N/mm2
30%
60
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.
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QUALITY CONTROL
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
Test
Chemical analysis other than H2, N2, O2 and C
H2, N2, O2 and C
Structural analysis
Tensile mechanical properties
Hardness
RRR
Visual inspection
Eddy current inspection (option)
Ultrasonic for continuity faults
Ultrasonic for variations of attenuation
Roughness
Dimensions
31/05/2010
Frequency
Every melt
Every batch on final product
Every batch on final product
Every batch on final product
Every item (location to be agreed)
Every batch on final product
Every item, 100 % on both sides
Every item, 100 % on both sides
Every item and/or intermediate product, 100 %
Every item, 100 %
Every batch on final product
Every item
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Dimensions
• 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:
Starting thickness 3 mm & 4 mm
Loss in thickness ≈ 0.6 mm
Tacking into account
spinning t loss
- 0.6 mm
thickness tolerances
- 0.1 mm
chemical etching and EP
- 0.2 mm
optimised start thickness is 3.5 mm
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Final sheet dimension: 520 mm x520 mm x t 3.5 mm
Dimensions
t 3.5 mm
Ø 520 mm
Sampling, witness pieces, tests, etc.
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Open points
• 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
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