1

ATLAS Upgrade Meeting

LBNL Sept 6th 2012

Richard French, Hector Marin-Reyes, Simon Dixon, Paul Kemp-Russell

The University of Sheffield

Martin Gibson, John Matheson, John Hill, John Noviss – RAL Ian Mercer - Lancaster

Orbital Welding Development

Started orbital welding in 2007 with the design methodology of:

• 100% reliable connector-less system.

• The tube will be galvanically more stable than the parts joined to it (e.g. grounding,

supports).

• The exceptions are joints, seals and connectors, these will have the same electro-

potential as the tube.

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Step back and sanity check?

Correct technology/materials?

Tube material, diameter, wall thickness, equipment portability are all obvious factors of which

joining method to adopt. There are hundreds of subtle influences that blur these definitions.

• Assuming ideal tube is no longer 316L stainless steel of ~200um wall > Now CP2 Ti, 125um wall

or thinner would I choose TIG orbital welding again without our knowledge of this technique?

• On paper the equipment specifications say no – nothing other than laser, EB, microplasma

diffusion bonding or brazing should work reliably at this wall thickness to make a welded

joint in CP2 Ti. Non-specialist “experts” would also suggest no.

• IGNORE SPECS – TIG WORKS WELL & IS PROVEN WITH HIGH REPEATABILITY as a

result of the last 6 years R&D and work with specialists in industry.

• I’ve learnt a significant amount about joining process for both 316L and CP2 Ti materials.

• Get the material right - the joining process follows naturally.

• Get the process correct and you have highly repeatable joint. • 6 years of materials development and refinement to make 2 bullet points!

TITANIUM DEVELOPMENTS

Assuming we are still on the correct side of sane…………

Achieving the correct material to work with in the first place.

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Oxidation of the Ti tubes - complete Removal investigated through wet and dry etchants

Dry etchants “Fun stuff”

Plasma cleaning of ends – Looks like this might

work, on short samples a reasonable result is achieved.

For the full circuit mods to the plasma cleaning machine

are required for a UHV seal to the tube.

Shot blasting with glass bead – Works fine but

requires very careful cleaning.

NONE APPLICABLE TO IN-SITU REPAIR (Scotchbrite)

Attempting to remove this HN03:HF dilute

HN03:HF

concentrate

Wet etchants “Nasty Chemistry”

HF based solutions and trials carried

out by,

Martin Wilson – STFC. Repeat/refine

Swantek – Jerry Lancaster. fin

HTT/ Anipol?NDT ltd. fin

Tube developments

• Need to begin pressure drop measurement component manufacture for

realistic results of mass flow etc to refine tube dimensions (ex & cap).

• 6Al4V Ti tube procured for alternative weld trials (is a better material all round)

but impossible to obtain stock in our small dimensions because of low volume

required. Could be made if we know a final quantity but our consumption is

likely still to be too low. Will continue to gather joining data as will be done and

published – an ideal but maybe not realistic

• GETTING A LEAK TIGHT SEAL ON ODD SIZED TUBE FOR TESTING IS A

PAIN IN THE A##. Everything is custom! Still a bad idea. 2 - 2.5mm OD please!

• Can only manufacture in 3m lengths due to EU cleaning chemical rules – working on

special dispensation but will need assistance as not much information available.

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CP2 Ti well proven and now established in use, oxide

issues solved in production using chemical etch

solution (pickling) and cleaning process ok and

proven, inspected & tested at CERN.

Now need final CT images (125um wall) and

evaluation from NAMTEC (freebie) to finalise

reporting. # Still not made many items in this material

Exhaust dimensions or on-Stave cooling tube

guessed> 2.175 OD x 0.125mm wall (CP2 Ti), shared

by IBL/PIXEL = sharing statistics and reporting. 50um image of tube end – small edge defects

Ti tube capillaries

• Capillaries – diameters and wall thicknesses now being prototyped. Initial

problems, 3m length, 150um wall was difficult to get round (stock sizes).

• Current capillary dimensions on offer (easy as drawn from stock) • MINIMUM BORE 0.3mm, MINIMUM WALL 0.150mm, MAXIMUM LENGTH 3000mm

1.2mm OD x 0.90mm ID x 3000mm

0.80mm OD x 0.50mm ID x3000mm

0.60mm OD x 0.30 ID x 3000mm

• Prototype capillary tubing fresh from the mill has now reduced wall to

• 0.750mm OD x 0.490mm ID x 0.1300mm Wall.

• 0.670mm OD x 0.405mm ID x 0.1325mm Wall.

• 0.595mm OD x 0.330mm ID x 0.1325mm Wall.

• 130um is about as low as sensible to pass pressure testing with headroom – we need good old

fashioned measurements now to determine the ID.

• 0.330mm ID is the smallest ID possible using this manufacturing process and UK factories.

• Larger ID’s than 0.5mm possible through to 0.9mm ID.

• Real testing is needed to enable further refinement, but it’s a start………..

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AIMING TO REDUCE MASS OF WALL

TO 0.125mm. Unlikely to be lower!

Tube stock availability & lead time

Production

Sample

Material OD mm ID mm Wall um length m Stock Due

Offcut

Qty Qty P/S/O

CP2 Ti 3.175 2.775 200 2.2m 22 P

CP2 Ti 2.275 2.025 125 3.0m 2 50 P

CP2 Ti 2.275 1.995 140 3.0m 18

CP2 Ti 1.775 1.525 125 3.0m 8

CP2 Ti 1.200 0.400 200 3.0m 6 P

CP2 Ti 1.200 0.900 150 0.6m 4 17 S

CP2 Ti 1.000 0.450 275 3.0m 2 P

CP2 Ti 0.900 0.360 270 3.0m 2 P

CP2 Ti 0.800 0.500 150 3.0m 18 P

CP2 Ti 0.750 0.490 130 0.6m 6 S

CP2 Ti 0.670 0.405 132.5 0.6m 6 S

CP2 Ti 0.595 0.330 132.5 0.6m 6 S

316L SS 3.175 220 5.0m 14 P

316L SS 3.175 220 1.8m 5 O

316L SS 3.175 140 2.7m 18 P

316L SS 3.175 220 1.8m 4 O

316L SS 3.175 750 2.0m 4 S

316L SS 2.000 140 2.0m 53 P

Aluminium 3.175 360 5.0m 32 P

Aluminium 3.175 660 5.0m 74 P

Aluminium 2.480 660 3.0m 69 P

Aluminium 4.760 340 2.5m 69 P

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• Capillaries had too much mass in

tube wall for optimal xo performance.

• Looking at max burst pressure v watt

thickness but large manufacturing

constraint as stock sizes dictating

final drawn size of ~130um wall

• Can only purchase as international

community to persuade Sandvik to

supply stock in small enough

volume. ~0.25 Tons.

• I still doubt that we can achieve

MOQ collectively so a rethink is

needed.

• Need to finalise a suitable joining

solution as EU REACH preventing

production longer than 3m – check if

international shipping dispenses

company from regs and store tube at

CERN? VAT?

PEEK capillaries 8

This is not a serious proposal! Ti production currently limited to 3m lengths

10m PEEK capillaries purchased for fun with ingenious finger tight 500bar connectors

• PEEK (polyetheretherketone) finger tight

fitting are convenient, inert, and bio-

compatible.

• 1/16 inch O.D. PEEK, stainless steel,

titanium, Tefzel, or PTFE tubing.

• Compatible with most solvents (not

concentrated sulfuric and nitric acids),

• PEEK ferrules do not permanently lock

into place on the tubing.

OD ID

360 µm 75 µm

1/32" 0.13 mm

1/16" 0.064 mm

OD ID

1/8” 75 µm

1/8”" 1.59mm

1/8" 2.0mm

Orbital TIG joint repeatability • CP2 Titanium1/8”OD x 0.20mm wall

• 1042 repetitive welds

• First 20 welds suffered from same lack of refinement as 316L process.

• Testing at CERN for random batch samples – shipped.

• OXIDE was a problem specific to this batch of Ti tubes only.

• Regular cleaning is increasing repeatability.

• More attention is paid to the joint preparation. And electrode.

• WPS being written (best practice)

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•The process is highly repeatable for both materials (316L & CP2 Ti) and now highly optimised. •I need to check this again with a number of fixed tubes representing detector service connections then repeat the process for the CP2 Ti 2.275mm OD x 120um wall when happier with the weld itself.

•Weld head angle. Electrode start position. Clearance for weld head •Internal gas purge pressure may be the tricky item to manage correctly during installation in the cryostat.

CP2 Ti weld joint

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– Flare one end of the tube to bring extra material into the overlapped joint. = 120μm + 120μm give a bulbous weld bead (now controlled to outside of tube by altering angle and depth of flaring tool)

Welded joint wall of ~220um wall at highest measured point

= straight tube flared tube insert

weld

~60μm

Welding of CP2 Titanium 120μm wall tube

First butt weld joint in 2.275mm CP2 Ti – pin hole every time.

– Can successfully join the 2.275mm OD x 120μm tube with orbital welding using the above process. Initial NDT results are underway (x-ray). Data returned (x-ray only) and have refined inclusions by

– better cleaning methods.

– This can be refined much further as not happy with visual results. ON THE LIMIT OF THE MACHINE

– Gas purge issue is due to custom fittings not sealing correctly on tube OD. Refined but not fantastic.

– Thrown fittings away and use soft Si tube (gas contamination)

Best welded joint to date using new tooling to

create sleeve joint. Still have a indentation

from post weld cooling [pressure or

cleanliness]

Will now start high repeatability trials with this material. 1000 samples (Ti shortage)

Welding system evaluation

• From my 2007 market survey, the Swagelok M200 TIG Orbital

welding system was the best priced system:

• CHEAP BY COMPARISON with other systems.

• EASY TO USE software removes operator knowledge

• WORKED OK FOR BASELINE 316L TUBE

• SERVICEABLE & SUPPORTED

• Has broken once, we’ve blown it up once or twice.

• Original system at Sheffield working fine

• 2nd System based at RAL.

• CAN NOT WELD 125um CP2 Ti

• FAILS TO WELD 180um wall tube.

• Weld heads all need to be modified to work well.

• Software all needed serious messing with.

• Effort v cost = not so good.

• Once the Ti wall went to 125um it caused me problems

• With enough time – most things work in the end.

• Biggest issue is high powered arc starting AV causing

potential issues for damage to electronics

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Swagelok M200 COTTS

Sheffield micro-weld head

Future plans for M200 development 12

• Weld head mods at Sheffield – have tried UHP small

weld head on loan from manufacturer. Have

constructed digital IO to analogue module to interface

to M200, unsure if was sensible use of effort as

virtually removes all M200 useful functionality.

• Modified version of the smaller scissor jawed weld

head from Swagelok is working well but needs further

refinement for joining 125um CP2 Ti.

• Electronics damage – slowly understanding more with

the system outputs and quirks, producing a best

practice guide to avoid majority of misfires.

• Reprogramming the system outputs (altering M200

welding software) for lower initial start arc – trade off

with arc ramp down – may be a waste of time but

worth a try.

• Adding grounding system to drop initial arc start

voltage – proving problematic so again, firmware

needs altering inside machine to allow arc to start

• Keep popping bits of the machine but it is easy to

repair and quite robust.

• Weld head internal temperature measurement is

in progress.

• Set up under construction for use with Tim’s

FEIR camera. Tech effort dependent.

• LASER WELDING – still on going investigations

from Ian Mercer, we did expect some delay from

SPI before final ideas placed on paper.

Hopefully news soon.

Ultra pure gas purge system

Understanding system performance

• Getting to grips with the M200 quirks.

• Misfires mainly caused by bad practice, poor joint alignment and

laziness. Correct procedure does solve this.

• Occasionally there is a weird event.

1000 welds on identical CP2 Ti stalks has seen 3 misfires = 3 failed joints. 1000+ welds on 316L tube has seen 5 misfires = 5 failed joints.

WHY?Tmperature alters gas pressure so need to adjust as lab warms up

RH should not affect closed chamber welds – measured, undecided as low stats

• We have no real way of measuring this. Right now I don’t believe the

OSD/GUI showing A/V of the weld = RMS + fudge factor.

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• SO- measurements needed – HOW?

• Looks nasty on first investigation but possible.

• Swaglok M200 has reverse engineering protection

in the system – connection of scopes and probes

etc cause misfire or failure to start weld procedure.

• It pretty simple in reality so we’ve figured out how to

get round this & can now take

measurements…………….. But before this……..

We made something new

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New welding system development

• Over the past 5 years in conjunction with our industrial partner Sheffield has

developed an fully automatic TIG welding system that produces accurate low

current narrow bead welds sourced from our partners aerospace joining

knowledge. It was obvious that nothing like this was commercially available.

• From the use of high frequency pulsing interposed within the pulsed weld current

gives the system its unique characteristic and is capable of joining two razor blade

edges together without distortion.

• The benefit of this technique is that increased arc force or penetration is achieved

with a lower input current which is crucial to thin wall Ti tube welding by allowing

for improved heat management on critical welds whist still attaining full

penetration.

• Has additional grounding to prevent

high arc start voltages through work piece

• Production version fully tested in Sheffield

available to ATLAS Upgrade for R&D.

• Looks to be capable of joining >125 um Ti using minimal power

– how thin? No idea at all (yet)

• ~0.3A, 30v on 250um CP2 Ti tube (automatic weld)

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16 Waveform arc v profile

PLEASE DO NOT REPRODUCE

System Details

• Initial Current 0.1 – 60 Amps

• Upslope time 0.0 – 20 Seconds

• Downslope time 0.0 – 20 Seconds

• Finish Current 0.1 – 60 Amps

• Finish time 0.0 – 25 Seconds

• Pre purge gas 0.0 – 100 Seconds

• Post purge gas 0.0 – 100 Seconds

• Main Current 0.1 – 60 Amps

• Background Current 0.1 – 60 Amps

• Main time 0.01- 5 Seconds

• Background time 0.01- 5 Seconds

• InterPulse Current 0.0 – 60 Amps

• Time per level 0.01- 99.9 Seconds

• Supply 230Volts 13 Amps 50Hz

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2.275mm OD tube weld cassette &

head with arc start grounding

Current set up in old lab, 3 TIG weld

systems 2 auto, 1 manual.

First weld set to offer the ability to weld single

crystal and difficult to weld alloys such as Inconel

738, 713, MAR-M 247, PK33 and Titanium without

a chamber or trailing gas shield.

Pulsing switched off

60 Amps at 14 Volts

(10 minutes welding 5 minutes cooling)

Pulsing switched on

50 Amps (60 A Main, 40A Background)

(10 minutes welding 1 minute cooling)

50 Amp Auto TIG version

(130 Amp too big for ATU)

Weld head 18

• Set up of electrode distance with

shim – needs refining

• Additional clamp for grounding

during arc start

• Remember start position and

direction

19 New system programming/test

2 years work in 6 hours!

Joints made with 0.4A & ~14v – no pulsing

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Weld Parameter Sheet

Parameters Values Joint type Tube-Tube, Tube,rod?

Material Ti, SS?

Diameter (mm)

Wall thickness (mm)

Tube length (mm)

Electrode Gap/Arc Gap/Set

(mm)

Electrode diameter (mm)

Electrode type 2% Th02, 2% La02?

Electrode length (mm)

Electrode Angle (deg)

Electrode Usage New, # Welds?

Tip Angle

Weld Head Orbit, Manual (turntable)?

Levels 1, 2,..?

• By simplifying the weld build up as

individual parameters, we can make

accurate reproducible joints.

• This approach is essential to automatic

welding

Generic weld system measurements

• Initial set up (principle so may refine)

• Torch micro-positioner & rotary table

• Can enclose in environmental chamber to match head

conditions. FTIR window for arc profile

• Some nice shunts for both A/V (plug and play to USB

with some of our own software) monitoring both

positive & negative outputs (electrode negative TIG

system)

• Power analyser measuring consumed power at 4

points in the system, mains input, pre start cap, pre

main weld IC, ramping IC. Will refine as understood.

• Using timestamp and data values linked via pc to both

measurement systems we should see the variations.

• We will then induce failure to measure and understand

what happens.

• We can then plug in the separate work-piece ground

and remeasure.

• Doubles up to measure electrode tip angle effects on

arc profile and subsequent power / heat input to tube.

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Turntable Manual torch micro-

positioner & fast scope

USB shunts

22 System measurement schematic

Input measured by

power analyser

Output by shunts

Timestamp and data

collected together in

LabVIEW programme

NOT tried out in anger

23 System measurements

• Single & 3 phase measurement

• Input voltage/current measurement

• Output voltage/current measurement

• Triggers at arc start

• Configures to open and closed

chamber weld heads or torch

• Synchronised data taking

• Hopefully learn nothing nasty!

Electrodes for TIG • Will drive you crazy….

• Swagelok items have to achieve CE certification. They are not fantastic for our

use. Need to understand tip/length reproducibility v performance.

• Custom electrodes made in-house at Sheffield outperform standard items.

Measured by reduced heat damage, deeper penetration of weld = ~35% less arc

power needed – need to work out how to cut tungsten to length accurately

without shattering electrode (causes premature wear / arc failures)

• Struggling for “clean” space – electrode prep contaminates area and reduces

weld performance. New lab taking time – refurbishment very slow.

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Tube/Electrode preparation area

• Current issues are debris contamination so need

some form of extraction – building does not

permit ventilation to outside world (Dyson?)

• Should store electrodes dry – drawers needed

• Bake out before use – oven?

• Separate grinding machines (or wheels) for

different materials – final choice = 1 wheel only

• Tube cutting proving laborious

• Tube facing tool performance satisfactory

• TOO MUCH STUFF FOR ONE PLACE

TIG grinder (wet)

Tube cutter

Tube facing

Decision time

• Theoretically there is only one of me, my time is split many

ways and I need to be more efficient.

• Assuming that 125um wall tube is desirable I’d sooner put effort into

new system testing and give up with pushing the M200 past its limits

and use this for tube wall >200um (services).

• I reckon we have ~50 separate measurements to make for each weld

to fully quantify and understand each.

• I’ve not made the time to document this work but have reasonable

notes. I’m in danger of forgetting as pace picks up.

• Odd OD’s cause huge tooling costs in fittings, weld heads etc.

• Pressure drop work is now ~ 1 year behind where we wanted

to be.

• We have many of the components but not enough to move forwards to

allow us to decide on tube ID’s (EX &Cap).

• Laser welding has gone very quiet – needs a push.

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Next 12 months overview Assuming we have minimal decisions made so rather vague or exceptionally obvious

• Stave, Stavelet cooling circuits

• Re-stock of cooling circuits and stavelet circuits. Include pressure testing > DATABASE entry.

• Re-stocking of tube material and bending trials on capillary tubing

• Pressure drop measurements –

• Components part produced – design finalisation required

• CO2 plant booking expired. This area has stalled and we are in trouble here.

• TIG Orbital Welding.

• Reprogramming M200 and using grounding system from new system

• Gas purge over long distance and multiple manifold measurements/effects on weld quality.

• Measurements of electrode tip angle – arc gap and power v weld quality

• Finalised electrode – seeking mass production or tooling to make in house.

• Continuing to refine Swagelok weld head for heat sinking and improved tube alignment.

• Bring online the InterPulse system and test on 2.275mm OD 125um wall CP2 Ti.

• Laser welding

• Hopefully news soon.

• Material reduction

• Changing bulbous sleeve joint to butt weld on 125um tube with tooling from PIPE ltd.

• Reducing mass in capillary tube wall – production limits.

• Fittings

• Vac brazed stubs full statistical trial.

• CP2 ti fittings – material sourced from Sandvik. Need to check cost out v custom fitting from Swagelok or Fti plus the

effort put in at QMUL.

• Re-manufacture of 6LV VCR thin wall fittings as run out.

• Thermal shock etc in the pipe line at some point – hardware almost completed at RAL.

• Burst testing of circuits to see where calculated headroom is v actual – mass reduction maybe.

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ADDITIONAL INFORMATION Alternative joining technique Vacuum Brazing of CP2 Ti to 316L Stave 250 drawings of cooling tubes at z=~1.3m

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• Overview • Stainless Steel to Titanium joining (temp connection)

• Copper to Titanium (pressure drop measurements)

ATLAS Upgrade dissimilar metal joining activities

Richard French, Paul Kemp-Russell: Sheffield Keith Birmingham: Aerobraze Europe Neil Austin: VBC Group Ltd (brazing division) Trevor Smith: Firmachrome Ltd Peter Cookson: Bodycote

Connectors

• Swagelok VCR in 316L works well as temporary fitting. Used 316L weld on

VCR either with a TIG weld or Vac Brazed joint.

• Mass of nut is an issue, also nuts are sliver plated inside to prevent

galling which has proved problematic for vac brazing.

• LOW mass fittings – VCR in CP2 Ti could be possible, can only find

reasonable stock in Grade9 Ti to produce. QMUL CNC? Units of

production too low for Swaglok MOQ

• Vac brazed stubs work well – need statistics

• Ideally remove the stub preferring tube-tube joint for low mass and

increased reliability - relatively easy to do with a sleeve jointed TIG weld

(common in nuclear reactors etc) – not ideal for dissimilar material joining

• Can vac braze 316L stainless to CP2, Grade 9 and 6Al4V Ti without

issues (other than getting the final ones back).

• Vac brazing ceramic to Ti & 316L next (ideally write up so far before this)

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Stainless VCR connector to Ti tube Used to make temporary test fitting stubs for cooling circuits…………

Method A = cheap idea

• Electroless Nickel Plating. • Electroless Nickel coating is an alloy of nickel and

phosphorous. Ability to work to close tolerances

without post-plating grinding, whilst holding the

original surface finish.

• Electroless Nickel can improve corrosion resistance,

wear resistance, lubricity, solderability or be used to

rectify and recover close tolerance undersize parts.

• The big advantage of elecroless (chemical) plating

over electrolytic plating is it will adhere to Titanium,

in a very controlled manner. We do not need to

plate the entire circuit, just local areas as wherever

the solution touches it will plate.

Method B = proven but expensive

• Vacuum Brazing using an

aerospace proven method • Using a silver copper eutectic braze alloy, coat the Ti

with the alloy, assemble the Stainless VCR fitting to the

tube (post electro-polishing) and place in furnace at a

lower temperature somewhere around 850°C. • http://www.vbcgroup.com/focus/Brazing-Division/Brazing-Alloy-selection-tables/BrazePrecious.htm

• Excellent joint, clean and pressure handling proven up

to 250bar.

• 3.175mm Ti has heavy oxidisation that is proving

difficult to remove. This is needed for the Cusil alloy to

adhere to the Ti tube.

• Once tube is cleaned (glass bead blasting) good

adhesion is found.

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•Both methods are the “active” or direct joining of dissimilar materials with a braze filler metal

(BFM). This is ideal for Ti as the BFM forms a strong permanent joint with the base

materials.

•What we did not realise is that at certain temperatures the Ti can suddenly start taking on

alloying abilities with the BFM. This should not have happened when correctly controlled.

•Titanium is a strong oxygen-getter, and thus will react with any oxygen that it can as it is

heated from room temperature up to brazing temperature, therefore, "reacting" too early.

•This is with free oxygen or water-vapor in the furnace atmosphere, or with metal-oxides on

the metal surfaces during heat-up (such as when the metals are not properly cleaned prior

to brazing), then the so called “brazing” (joining/bonding) of alloy-to-metal may be

completely prevented from happening.

Method A • During this process, the bonding was be

very successful but, the difference in the

thermal expansion between the 6LV

stainless steel – Nickel – Titanium which

it is being joined caused premature

cracking to develop in the brazed joint

upon cooling. If we did not see the cracks

at this stage they would present

themselves during subsequent use in

service.

• It is very important to try to match the

expansion characteristics of the metals to

filler to metal joint, so that huge stresses

in the joints are not built up.

• During the furnace cycle (1100C)

something really odd happened. High

temp was down to a miscommunication.

• The braze alloy has a initial melting temp

of around 400C. The furnace temp was in

the region of 1100C. Therefore we

managed to alloy Ni with Ti:

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Stress cracking CTE mismatched

Ni-Ti alloyed tube

As the Ti reaches 600C the oxygen in the Ti starts getting thirsty and in the resulting

exchange drags the Ni into the microstructure. As the assembly cools, it falls apart as

the CTE mismatch is beyond what the structure can cope with.

GOOD NEWS – we don’t necessarily need to vac braze all our components and can

do this with any induction furnace (have small tube furnace in lab ready). Ni plating

works fine so will drop the cost of the heater block joining for pressure drop work.

Method B = OK!

•For mechanical tolerance, achieve

a good push fit in the Ti tube to

VCR fitting. Micropolish fitting.

•Using Cusil braze alloy from VBC

simply clean components and plate

the Stainless Steel component.

•Mechanically clean Ti, chemically

clean the Ti, assemble components

and remember your nuts.

•Place in furnace at 850C and cycle

once allowing time to cool.

•Bingo – one joint.

•Items of weirdness to note:

•The VCR nut threads are silver

plated to prevent gauling during

assembly. This silver is reflowed

during the furnace cycle.

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NEW REFLOWED

1/8” Ti to VCR

1/8” Ti to VCR

2.275mm OD Ti to VCR

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What is length tube sticking out from

stave end? Universal decision for 250.

EOS – how does this shape up?

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Image of z=1.3 Stave end