LHC Collimators Phase 2 - Visit to Plansee 28th August 2008 1

Materials for Phase II collimators

LHC Collimators Phase 2 - Visit to Plansee 28th August 2008 2

Rib Stiffener, why molybdenum

Active part where most of heat is deposited tends to deflect due to thermal gradient Stiffener linked in a midpoint

to limit deflection of the active part

X-deflection simulation

Stiffener material requirements:Minimise own thermal distortion

Low CTE High thermal conductivity

Minimise deflection by the force in the midpoint link

High Young’s modulus

Shafts, fixed points

Link

LHC Collimators Phase 2 - Visit to Plansee 28th August 2008 3

Stiffener, why molybdenum

Thermal conductivity / Thermal expansion coefficient -15 -10 -5 0 5 10 15 20 25 30 35 40 45 50 55

You

ng's

mod

ulus

(G

Pa)

0

50

100

150

200

250

300

350

400

450

500

550

Tungsten (f)

Iridium, Commercial Purity, min 99.9%, softOsmium, Commercial Purity, soft

Ruthenium, Commercial Purity, soft

Rhenium, Commercial Purity, soft

Rhodium, Commercial Purity, hard

Molybdenum, 360 grade, wrought, stress relieved

Nickel-Iron Alloy, "INVAR", hard (cold worked)

Nickel-Iron Alloy, "INVAR", soft (annealed)

Wrought PH stainless steel, Custom 455, H1000

Wrought austenitic stainless steel, AISI 304, annealed

Tungsten, Commercial Purity, annealed

Tungsten, Commercial Purity, 25 micron wire

Al-C-fiber composites

LHC Collimators Phase 2 - Visit to Plansee 28th August 2008 4

Stiffener made of Mo, old monolithic version

LHC Collimators Phase 2 - Visit to Plansee 28th August 2008 5

Stiffeners made of Mo, assembled by bolts and pins

• How are the stiffners

Long plates 15 x 47 x 1100 mm³ Thinner extremities Circular holes and slots Tolerance ~0.1 mm Threaded holes for cooling clamps

Spacers

Positioning system

Bolts and pins

LHC Collimators Phase 2 - Visit to Plansee 28th August 2008 6

Stiffener, raw material• Overall dimension of long plate (mm)

– ≥15 x 47 x 1100

• Standard dimensions by Plansee– 12.7 x 500 x 600– 20 x 500 x 600

• Possibility of having customized production

• Ideas to make it out of standard dimension plate for prototypes (4÷8 plates), eventually for series (~250 plates)

– EB butt weld

– Connect overlapped plates, bolted or riveted

• Also– Spacers– Positioning system– Bolts and pins

EBW EBW

LHC Collimators Phase 2 - Visit to Plansee 28th August 2008 7

Stiffener, machining

• Recommended machining parameters

• Plansee as possible supplier of finished components– Tolerances achievable

• Extremity holes

• Positioning system elements

– Do you see any other issue

not mentioned?

LHC Collimators Phase 2 - Visit to Plansee 28th August 2008 8

Cooling coil, interest of using molybdenum

Phase 1, implemented solution: Phase 2, increased energy deposition.-Cooling capacity has to be increased

- 6 x tubes ID8 mm- reduce contact thermal resistance

-Geometrical stability has to be maintained- use material with optimised k/CTE

Ideal solution:Cooling coil back-casted in M-CD block

C-C

GlidCop

CuNi

BrazingBrazingContact

LHC Collimators Phase 2 - Visit to Plansee 28th August 2008 9

Cooling coil, interest of using molybdenum

• Cooling coil material for Ideal solution requires

– Metallurgical compatibility with metal of the block• Avoid dissolution of the coil in the liquid metal• Avoid inconvenient inter-metallic phases at the interface

– CTE matching with M-CD• Avoid distortion, residual stresses or debonding at the interface when

solidifying and cooling from infiltration temperature• Gaps at the interface leads to poor thermal conduction and virtual leaks

– Feasibility of the coil

• Cooling coil materials believed to be good candidates from the first two points of view

– For Cu-CD: molybdenum, niobium, tantalum– For Al-CD: zirconium (preliminary test program is in progress in

cooperation with L. Weber EPFL including also stainless steel)

LHC Collimators Phase 2 - Visit to Plansee 28th August 2008 10

Cooling coil, interest of using molybdenum

• Molybdenum coil in Cu-CD block– CTE– Phase diagram– Feasibility of the coil

Thermal expansion coefficient (µstrain/°C)-15 -10 -5 0 5 10 15 20 25 30 35 40

The

rmal

con

duct

ivity

(W/m

.K)

0

50

100

150

200

250

300

350

400

Silver, Grade 99.90, cast bar, hard (cold worked)

Antimony metal, Commercial Purity, "Regulus"

Gold, Commercial Purity, min 99.5%, hard (cold-worked)

Niobium, Type 2 (Commercial Grade Unalloyed Niobium)

Rhenium, Commercial Purity, soft

Hafnium, Commercial Purity, min 97.0%

Osmium, Commercial Purity, hard

Carbon steel, AISI 1015 (annealed)

Zirconium, Unalloyed, Industrial Grade, wrought, "Zr702"

Nickel-Iron Alloy, "INVAR", soft (annealed)

Unalloyed titanium, Annealed

Tantalum, Commercial Purity (>99.7% Ta), cold worked

Electrolytic tough-pitch, h.c. copper, soft (wrought) (UNS C10100)

70/30 Copper-nickel, CuNi30Mn1Fe, soft (wrought) (UNS C71500)

Wrought aluminum alloy, 5052, O

Wrought aluminum alloy, 5086, O

Wrought ferritic stainless steel, AISI 430, annealed

Nickel 205, Commercial Purity, annealed

Cobalt, Commercial Purity, soft (annealed)

Molybdenum, 360 grade, wrought, stress relieved

Iridium, Commercial Purity, min 99.9%, hard

Ruthenium, Commercial Purity, soft

Rhodium, Commercial Purity, hard

Tungsten, Commercial Purity, annealed

Cu-CDAl-CD

LHC Collimators Phase 2 - Visit to Plansee 28th August 2008 11

Cooling coil, interest of using molybdenum

Liquid Cu would dissolve Ti or Zr tube !

LHC Collimators Phase 2 - Visit to Plansee 28th August 2008 12

Cooling coil, interest of using molybdenum

Mo, Nb and Ta have limited solubility in liquid Cu and do not form inter-metallic phases

LHC Collimators Phase 2 - Visit to Plansee 28th August 2008 13

Cooling coil, interest of using molybdenum

• Feasibility of long intricate coil is a question mark.– ID 8 mm x L 3800 mm– Bending radius as small as 18 mm

• Tests and trials– Tensile test at RT on molybdenum tube OD10xID8 (our CA1491024)

• Rp0.2 = 570 MPa Rm = 685 MPa• A ≥ 40% !!! but transversally very low ductility• Inner wall of the tube is oxidised

– Bending tests to be done at CERN workshop• What are your recommendations?

– Butt welding, your recommendations

LHC Collimators Phase 2 - Visit to Plansee 28th August 2008 14

• Avoid virtual leaks (confined volumes with low aperture that make long time to evacuate)

• Avoid any welding or brazing between water and beam vacuum ! use of continuous seamless tube

• Other solutions if the last constrain can be relaxed:– Cooling circuit machined in a block, closed by brazing or welding

• Brazed to the main block• Back-casted inside the main block

– Any other? – Any experience in similar large surface brazing

Cooling coil, vacuum related constrains