-
4658 East 355th Street, Willoughby, Ohio 44094
Phone (800) 626-9501, (440) 946-3300
Fax (440) 942-9083
Web: www.fusion-inc.com
E-Mail: [email protected]
North American Sales OfficesChicago Cincinnati Detroit Los
Angeles
New York Raleigh Rochester Calexico, CA
Mexico City, Mexico Monterrey, Mexico Toronto, Canada
Overseas Sales LocationsKorea Hong Kong Japan South Africa
Israel
The Netherlands United Kingdom Spain Sweden
Switzerland Australia Denmark Eastern Europe
Turkey France Italy Germany Taiwan
Peoples Republic of China
SubsidiariesFusion Automation, Inc.
Harlow, England
Phone (44) 1279 443122
Fax (44) 1279 4 24057
E-Mail: [email protected]
Fusion Automation China
Guangzhou, Guangdong, P.R. China
Tel / Fax: ++86(China)-20(Guangzhou)- 32068216
Email: [email protected]
Bulletin A-101/ENG 2007 Fusion, Inc. All Rights Reserved Printed
in U.S.A.
Fusion Automation Japan
Tokyo, Japan
Phone (81) 4 2709 5223
Fax (81) 4 2709 5224
E-Mail: [email protected]
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Fusion PasteDivision
ISO9001:2000Certified
Paste Brazing
& Soldering
Alloys
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T he F u s i o nPa s t e P ro c e s s
ApplicatorsUnlike solderingor brazing alloysin other
forms,Fusion Paste Alloyspermit single-stepapplication of
fillermetal and flux to theassembly. The paste alloyitself is
stored in a pressurized reservoir, generallysized to meet
production requirements for a full8-hour shift. Fusion
positive-displacement applicatorsmay be built into high-speed
production equipmentfor fully automatic assembly, or hand held
forsemi-automatic processing.
HeatingHeating may be accomplished by most conventionalmethods,
including open flame, atmospheric ornon-atmospheric furnace,
infra-red, resistance orinduction. At specified temperature, the
liquid flux isreleased from the paste alloy, cleaning the joint
areafor maximum bond reliability. The atomized fillermetal then
liquifies and flows onto the newly-cleaned area, cooling to form a
structurally soundbrazed or soldering joint.
Total ResponsibilityAmong the numerous benefits of Fusion Paste
Braz-ing and Soldering are elimination of pre-fluxing,more precise
measurement of filler metal and flux,reduced costs via automation
of manual steps, andmore consistent joint quality through
elimination ofhuman error. In addition, Fusions TotalResponsibility
approach ensures a coordinatedeffort in the manufacture of paste
alloys, applicators,and equipment, plus expert system installation
andservice follow-up. (Request Bulletin T-101 forinformation on
Fusion Automatic Brazing& Soldering Machines.)
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Paste AlloysCustom blended to meet your requirements, eachFusion
Paste Brazing or Soldering Alloy contains thefollowing basic
components:
Finely atomized filler metal, alloyed to exactingstandards for
composition, melting range, andcompatibility with base metals to be
joined. Ingeneral, Fusion alloys conform to all acceptedindustry
standards.
Fluxing agent, designed to remove and preventreformation of
surface oxides during heating. Typeand amount are carefully matched
to the individualapplication, ensuring consistent, dependable
jointswith minimal flux residue.
Paste-like binder, which holds flux and filler metalin stable
suspension; prevents metal-flux interac-tion. Controlled
formulation ensures consistentapplication and keeps paste alloy
localized in thejoint area.
Table of Contents
Introduction
The Fusion Paste Process 2-3Selecting a Brazing or Soldering
Flux 4Selecting a Brazing or Soldering Filler Metal 5
Fusion Paste Soldering
Selection Guide: Paste Solder Fluxes 6-7Selection Guide: Paste
Solder Filler Metals 8-9
Fusion Paste Brazing
Selection Guide: Paste Brazing Fluxes 10-11Selection Guide:
Silver Brazing Filler Metals 12Furnace Brazing With Fusion Paste
Alloys 13Selection Guide: Specialty BrazingFiller Metals 14-15
Joining Aluminum With The Fusion Paste Process
Selection Guide: Aluminum BrazingFluxes & Filler Metals
16Selection Guide: Aluminum SolderFluxes & Filler Metals
17Cleaning Brazed or Soldered Joints 18
Glossary of Brazing & Soldering Terms 19
Fil lerMetal
FluxAgent
NeutralBinder
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Among the benefits of Fusion
Paste Brazing or Soldering is the
fact that the atomized filler
metal may be custom alloyed or
otherwise formulated to meet
specific requirements. From the
simplest soldering job to the
most complex assembly opera-
tion, proper selection of filler
metal is vital in controlling cost
and performance. Included in
this section are some of the
criteria which will aid in proper
selection.
As defined in the Glossary (page
19), a brazing or soldering flux
serves to remove and prevent
reformulation of base metal
oxides during heating. Since
oxides inhibit effective
wetting of the assembly with
molten filler metal, it is impor-
tant that an adequate flux be
employed during the joining
operation. This does not,
however, preclude prior cleaning
of the assembly (chemical or
mechanical) to remove grease,
oil, paint, and other impurities.
These must be cleaned away to
ensure that the flux can act
directly on the metal surfaces to
be joined. General criteria for
flux selection are explained in
this section.
4
the joint, the residue will eventuallyattack the solder and the
base metals.Most brazing flux residues are active innature and
should be removed.
Active Fluxing TemperaturesIn both brazing and soldering, the
fluxmust be active at the liquidus tempera-ture of the filler
metal. If it is not activeat this temperature, oxides will
re-formand prevent a metal-to-metal bond. Ac-tive fluxing
temperature range isdependent upon time and temperature.A slower
heating rate increases thepossibility of burning out the fluxbefore
reaching the melting tempera-ture of the filler metal.
Joint ConfigurationIndividual flux-binder combinationsaffect the
flow characteristics of pastebrazing or soldering alloys.
When brazing or soldering assembliesthat require the filler
metal to flow aconsiderable distance, a free-flowingflux-binder
combination should beselected. Conversely, if the paste isapplied
to a joint with a narrow shoul-der or a vertical surface, a
sluggish flux-binder combination is required to stayin place until
just below the liquidustemperature of the filler metal. Sincethe
paste flow is also a function of thefiller metal, fluxes are
selected whichaugment the flow characteristics of theparticular
filler metal.
Base MetalsBase metal oxides vary in regard to rateof formation
and tenacity. The fluxselected must be capable of removingthe
oxides from the base metals andkeep them oxide-free during
heating,when oxidation accelerates.
In soldering, some metals such asaluminum, chrome, and zinc have
verytenacious oxides. Oxide removal isfrequently marginal on these
metalseven with the use of highly corrosive,acid fluxes. To
successfully solder suchmetals, plating the surface with
easilysoldered materials is sometimes desirable.
Brazing of metals with tenacious oxidesis often performed in a
pure hydrogenor vacuum controlled atmosphere.
Residue RemovalSoldering fluxes are classified by thecorrosive
properties of their post-solder-ing residue. The three major flux
cate-gories are Non-corrosive, Intermediate,and Corrosive.
Non-corrosive fluxesshould be selected for applicationswhere
residue removal is impossible.Active constituents may be added
tothese non-corrosive fluxes for strongerfluxing action, provided
they do notpromote corrosion after soldering.Depending on the
corrosive nature ofthe service environment, the residue
ofIntermediate fluxes may or may nothave to be removed. If the
solderedassembly is to function under normalatmospheric conditions,
it is advisableto remove the intermediate flux residue,since water
vapor and oxygen willaccelerate corrosion. Corrosive fluxesshould
be used only when the solderingflux residue can be removed. If left
on
5
filler metal will have to flow is an impor-tant factor in filler
metal selection. Sincethe flow properties of filler metals
differ,one must be selected that will movecompletely around or
through the joint.These flow properties are importantbecause paste
filler metals are usuallydispensed at only one point on the
joint,and capillary attraction is relied on toequally distribute
the filler metalthroughout the joint. When brazing orsoldering an
unusually long or irregularlyconfigured joint, for example, a
fillermetal with narrow melting range shouldbe selected because of
its free-flowingproperties.
Joint ClearanceAssembly tolerances are of primeimportance when
selecting a filler metal.For most applications, joint
clearancesfrom .002 to .004 are optimum. Aparticularly
tight-fitting joint normallydictates the use of a free-flowing
alloy,while wide tolerances require a moresluggish filler metal
that will remain inthe joint area during heating. As tojoint
design, it should be noted that tol-erances far outside the optimum
rangegiven above may impair the success ofcapillary attraction in
distributing fillermetal throughout the joint.
When brazing or soldering two dissimi-lar base metals, the rate
of thermalexpansion becomes an importantfactor. In such cases, the
base metalcomponent with the higher expansionrate may cause an
increase or decreasein joint clearances when heated.
Thus,assemblies composed of dissimilar basemetals may require
adjustment in toler-ance to maintain desired clearancesat brazing
or solderingtemperatures.
Base MetalsThe Fusion Paste
Alloy used shouldcontain a filler metal
that is able to wet the basemetals and be metallurgically
compatible with them in order to forma strong bond.
Base Metal/Filler Metal InteractionThe degree of metallurgical
interactionat the grain boundaries is a direct func-tion of time at
melting temperature.Depending upon the specific applica-tion, a
high degree of metallurgicalinteraction between base metal
andfiller metal may be either desirable orundesirable. Therefore,
the degree ofinteraction wanted should be estab-lished in advance.
The two mostimportant factors in determining basemetal/filler metal
interaction are heat-ing time and filler metal melting
tem-perature. The more rapid the heatingcycle, and the lower the
meltingtemperature of the filler metal, the lessinteraction occurs.
The degree of inter-action affects the mechanical andphysical
properties of the base metalsas well as the joint.
Service RequirementsThe filler metal selected must conformto
application specifications regardingstrength, both at room
temperatureand, if necessary, elevated or subzerotemperatures. The
corrosion resistanceproperties of the filler metal may alsobe
important if the assembly will besubjected to moist or humid
operatingconditions.
Joint ConfigurationThe desired distance that the molten
S e l e c t i ng aPa s t e B r a z i ng o r
S o l de r i ng F i l l e r Me t a l
Gas/Oxygen
burners bring
brazing fi l ler
metal to melting
temperature,
yielding strong
carbide/steel joints.
S e l e c t i ng aPa s t e B r a z i ng o rS o l de r i ng F l u
x
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Intermediate FluxesThese fluxes usually consist of mildorganic
salts, with considerablystronger fluxing action than non-corro-sive
types. Residue after soldering isnormally not harmful to the
solderedjoint. However, residue should beremoved whenever possible,
as mois-ture in the atmosphere may initiatecorrosion. Standard
intermediate fluxesfor Fusion Paste Solder Alloys are
asfollows:
WC Mild halide flux with excellentfluxing properties. At
soldering temper-atures, a reaction takes place whichtends to
neutralize the flux residue.May be used on joints with a
narrowshoulder.
PMS Mild halide flux with excellentfluxing properties. At
soldering temper-atures, a reaction takes place whichtends to
neutralize the flux residue.Provides minimum slump duringheating
until the alloy melts.
PWC Similar to WC and PMS withresidue that is readily water
washable.Least hot and cold slump of theintermediate line.
PA Restrictive, activated flux whichstays in place well on
vertical ornarrow-shouldered joints. At solderingtemperatures, a
reaction takes placewhich tends to neutralize the fluxresidue.
Provides minimum slumpduring heating until the alloy melts.
PAN Restrictive, activated flux withproperties similar to PA.
Recommendedfor use with unusually low temperaturesolder alloys.
Fusion PasteSolder
Fluxes
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Non-Corrosive FluxesFluxes are classified as Non-Corrosivewhen
their residue after soldering willnot corrode and eventually
destroy thejoint if allowed to remain. Generallyincorporating a
rosin base, these fluxescontain mild organic acids which areneutral
at room temperature butbecome slightly acidic upon heating.Neutral,
rosin fluxes are particularly use-ful in electrical applications,
where theirnon-conductive, non-corrosive residuemay be safely left
on the assemblies.
For applications where flux residuecannot be removed, but
surface oxidesrequire stronger fluxing action, specialadditives may
be included to producean Activated Rosin flux. The
activeconstituents are designed to decom-pose at soldering
temperatures, yieldinga neutral flux residue. Standardnon-corrosive
fluxes for Fusion PasteSolder Alloys are as follows:
GPR General purpose electronics grade(RMA) formula with average
restrictivityand excellent shelf-life. Hard, slightlyopaque residue
is non-corrosive andnon-conductive, making residueremoval
optional.
LPS Mildly activated rosin flux, formu-lated specifically for
electrical applica-tions due to non-corrosive, almostcolorless
residue. Restrictive binderlocalizes paste deposit both before
andafter soldering. Best suited for lowertemperature filler metals.
(See fluxingrange, page 7).
LPT A rosin flux similar to LPS with thecapacity to be paired
with highertemperature alloys.
MBC A very mildly activated rosin withcharacteristics similar to
LPT andincreased spread.
* Extended heating times can cause fluxes to oxidize
prematurely** Unusual service conditions may facilitate stress
corrosion of certain brass parts joined with fluxes containing
ammonia. Laboratory evaluation suggestedLT Laboratory testing is
recommended due to widely varied metallurgical surface
conditions.
Corrosive FluxesMost corrosive fluxes contain activeinorganic
acids and salts. Due to theirincreased strength and ability to
quicklyremove surface oxides, these fluxes areideally suited to
high-speed, automatedsoldering operations. Although corro-sive
fluxes generally produce the mostreliable soldered joints, their
residueafter soldering must be removed, or itwill eventually attack
and destroy thejoint. Standard corrosive fluxes forFusion Paste
Solder Alloys are asfollows:
SSE Strong, inorganic flux with excel-lent fluxing action on
surfaces withtenacious oxides. Due to moderatelyrestrictive flow
properties, SSE may beused on most joints with a
narrowshoulder.
SMH Strong, inorganic flux with activitysimilar to SSE. Exhibits
minimal out-gassing when heated. Recommendedwhere unusually large
paste depositsare used. Especially useful in longheating cycles
(i.e. ovens).
WCE Active halide flux, suitable for useon most steel, stainless
steel, andplated surfaces. Strong fluxing actionproduces extremely
reliable solderedjoints. Restrictive nature permits use onboth
vertical and narrow-shoulderjoints.
Solder paste PWC-430-830
automatically applied to
brass assembly.
Fusion Paste Solder FluxesRecommended For Use On
Flux Fluxing Suggested to Flow Copper Steel Plated StainlessType
Range* Remove Residue Characteristics Brass** Surfaces Steel
Non-Corrosive
300-525F Mineral Spirits orGPR 149-273C Chlorinated Fair Spread
Yes No LT NoHydrocarbon Solvent
300-525F Mineral Spirits orLPS 149-273C Chlorinated Restrictive
Yes No LT NoHydrocarbon Solvent
300-525F Mineral Spirits orLPT 149-273C Chlorinated Restrictive
Yes No LT NoHydrocarbon Solvent
450-595F Mineral Spirits orMBC 232-313C Chlorinated Fair Spread
Yes No LT NoHydrocarbon Solvent
Intermediate
300-525F Stays in place, Mild MostWC 149-273C Hot Water little
spread Yes (LT) (LT) LTuntil molten
300-525F Stays in place, Mild Most 300 SeriesPMS 149-232C Hot
Water no spread Yes (LT) (LT) (LT)until molten
300-525F Stays in place, Mild Most 300 SeriesPWC 149-232C Hot
Water no spread Yes (LT) (LT) (LT)until molten
300-450F Stays in place, Mild Most 300 SeriesPA 149-232C Hot
Water little spread Yes (LT) (LT) (LT)until molten
125-300F Stays in place, Mild Most 300 SeriesPAN 52-149C Hot
Water little spread Yes (LT) (LT) (LT)until molten
Corrosive
250-600F Hot Detergent Stays in place, Most Most 300 &
400SSE 121-316C Water no spread Yes (LT) (LT) Series (LT)until
molten
300-600F Hot Detergent Stays in place, Most Most 300 &
400SMH 149-316C Water no spread Yes (LT) (LT) Series (LT)until
molten
300-600F Hot Detergent Stays in place, Most Most MostWCE
149-316C Water little spread Yes (LT) (LT) (LT)until molten
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360 stripe of PWC-505-830
deposited onto copper coupling.
Other alloys are available upon request.
8
By definition (see Glossary page 19), a
soldering filler metal has a melting
range generally below 840F and
always below that of the base metal to
be joined. As shown in the chart on
page 9, Fusion Paste Solder Alloys may
be blended to meet specific require-
ments in performance and melting
range. Following are the most
commonly used combinations and their
particular characteristics.
Tin/Lead PasteTin/lead filler metals havegood wetting and
flowproperties and can be usedwith non-corrosive, interme-diate,
and corrosive fluxes.The filler metals high in leadcontent are not
as free flow-ing as the filler metals with ahigher percentage of
tin.
Tin/Antimony PastePastes containing these filler metalsretain
good strength characteristics atelevated temperatures. Since
theirsolidus temperature is considerablyhigher than tin/lead
alloys, they arefrequently specified for applicationswhere high
service temperatures will beexperienced.
Tin/Silver PastePastes containing these metals also ex-hibit
better strength than the standardtin/lead series. Although
slightlyhigher in cost, they areexceptionally freeflowing and
offerexcellent electricalconductivity. Theabsence of leadmakes
thesepastes suitable foruse in food-handlingvessels where lead
isprohibited.
Tin/Lead/Silver PasteOften selected for use on silver-plated
surfaces in the electronicsindustry. The presence of silver in
thealloy improves creep resistance andreduces the tendency to
scavenge silverplating from base metals.
Fusion PasteSolder
Filler Metals
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Tin/ Silver fi l ler metal melts
at 473F, producing
leak-free joints.
Fusion Paste Solder Filler MetalsFusion Nominal Alloy
Composition Solidus Liquidus Specs.Number Sn Pb Bi Other Temp.
Temp. ASTM-B32136 12 18 49 21In 136F 58C 136F 58C
158 13.3 26.7 50 10Cd 158F 70C 158F 70C
165 12.5 24.95 50 12.5Cd, .05Ag 158F 70C 165F 74C
300 43 43 14 289F 142C 325F 163C
360 60 40 361F 183C 374F 190C 60B
361 62 36 2Ag 354F 180C 354F 180C
365 63 37 361F 183C 361F 183C 63B
440 45 55 361F 183C 441F 228C 45B
450 50 50 361F 183C 421F 217C 50B
455 40 60 361F 183C 460F 238C 40B
470 30 70 361F 183C 491F 255C 30B
490 25 75 361F 183C 511F 267C 25B
560 5 93 2Ag 530F 277C 568F 297C
570 10 88 2Ag 514F 268C 554F 290C
575 10 90 514F 268C 570F 299C 10B
595 5 95 572F 269C 594F 312C 5B
Lead-Free216 26 54 20Cd 216F 101C 217F 103C
281 42 58 281F 138C 281F 138C
430 96.5 3.5Ag 430F 221C 430F 221C 96.5TS
441 99 1Cu 440F 228C 440F 228C
460 95 5Sb 452F 233C 464F 240C 95TA
500 100 449F 231C 449F 231C
505 95 5Ag 430F 221C 473F 245C
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Dispenser gun applies
copper/phosphorus paste
deposits to tube/header joints.
www. f u s i o n - i n c . c om 15
Note: For information on karat gold alloys, request Bulletin
A-106.
14
Gold-Bearing Filler Metals (BAu)Fusion pastes containing these
fillermetals are most often used for applica-tions requiring high
resistance to corro-sion and oxidation. In addition, sincethese
metals exhibit a very low rate ofinteraction with the base metal,
theyare often used to join assemblies havinga relatively thin
section. Iron, nickel,and cobalt base metals are amongthose which
may be successfully brazedwith gold-bearing filler metals.
The higher-temperature gold filler met-als are used almost
exclusively in theaircraft industry to meet requirementsfor high
service temperature combinedwith excellent resistance to
corrosionand oxidation. Generally, brazing isdone in a vacuum or
reducing atmos-phere, without the use of flux.
Nickel-Bearing Filler Metals (BNi)Filler metals of this type are
most com-monly used for their resistance to heatand corrosion at
elevated temperatures.Depending on the specific
composition,nickel-bearing alloys are resistant toservice
temperatures up to 1800F.Although best results are obtained
bybrazing in a reducing atmosphere orvacuum, other heating methods
areoccasionally used with the addition ofan appropriate flux.
Nickel-bearing fillermetals are most commonly used to
brazestainless steel (300 and 400 Series) andnickel and
cobalt-based alloys.
Copper-Bearing Filler Metals(BCu, BCuP, RBCuZn)Pure copper and
copper-bearing braz-ing alloys exhibit excellent strengthproperties
with the strength of somepure copper joints approaching that ofthe
base metal itself. Although hightemperature, pure copper
brazingmandates the use of vacuum or reducingatmosphere, other
alloyed coppercompositions are suitable for open-airbrazing via
most conventional heatingmethods.
When copper is combined with zinc ortin (RBCuZn), melting
temperature and resistance to corrosion are low-ered substantially.
The addition of cop-per oxide and/or iron oxide somewhatrestricts
filler metal flow, yieldingimproved filleting properties.
Whenphosphorus or phosphorus and silverare added (BCuP), the
resulting fillermetal exhibits self-fluxing propertieson copper
base metals. These BCuPfiller metals, however, should notbe used on
iron or nickel basemetals due to the possibility ofPhosphorus
Embrittlement aweakening condition caused bybase metal/filler metal
interactions.
Fusion SpecialtyBrazing Filler
Metals
In addition to the widely-used silver
brazing alloys, specialized Fusion filler
metals are available to meet specific
requirements for brazing. Among these
criteria are joint strength, service tem-
peratures, economy, and compatibility
with the metals being joined. Classified
according to their primary metal
content, Fusion specialty brazing alloys
are explained below and summarized in
the selector charts on page 15.
Gas/Oxygen torches melt
copper/phosphorus fi l ler metal
at 1256F, sealing capil lary
tube joints.
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Fusion Specialty Brazing Filler MetalsNickel-Bearing
Fusion Solidus Liquidus Specs.Number Temp. Temp. AWS A5.81610 89
11 1610F 877C 1610F 877C BNi 6
1630 75.9 14 10.1 1630F 888C 1630F 888C BNi 7
4775 74 14 4.5 4.5 3 1790F 977C 1900F 1038C BNi 1
4777 82.6 7 3 4.5 2.9 1780F 971C 1830F 999C BNi 2
4778 92.5 4.5 3 1800F 982C 1900F 1038C BNi 3
4779 94.5 3.5 2 1800F 982C 1950F 1066C BNi 4
Copper-BearingFusion Solidus Liquidus Specs.Number Temp. Temp.
AWS A5.81190 75.0 7.25 17.75 1190F 643C 1191F 644C
1300 92.75 7.25 1310F 710C 1462F 794C BCuP2
1306 86.75 7.25 6 1190F 643C 1325F 718C BCuP4
1310 86.25 6.75 7 Sn 1184F 640C 1256F 680C
1320 91.75 8.25 1310F 710C 1320F 716C
1440 27 65.5 7.5Sn 1385F 751C 1440F 782C
1565 53 9 38 1450F 788C 1565F 851C
1600 54 4.5 41.5 1410F 766C 1635F 890C
1650 55 44.75 .25Mn 1610F 877C 1635F 890C
1660 58 39.60 1Sn .25Mn .1Fe .15Si 1590F 866C 1630F 888C
RBCuZn-C
1800 80 20Sn 1470F 799C 1635F 890C
1830 90 10Sn 1750F 954C 1830F 999C
1850 100Cu220 2040F 1116C 2100F 1149C
1900 100 1980F 1082C 1980F 1082C BCu1a
1900-C 90 10Cu20 1980F 1082C 1980F 1082C
1900-F 95 5Fe2O3 1980F 1082C 1980F 1082C
1900-FC 90 7Cu2O/3Fe2O3 1980F 1082C 1980F 1082C
Gold-BearingFusion Solidus Liquidus Specs.Number Temp. Temp. AWS
A5.81742 82 18 1740F 949C 1740F 949C BAu 4
Alloy CompositionNi Cr Fe Si B P
Alloy CompositionAu Ag Cu Zn Cd Ni
Alloy CompositionCu P Ag Zn Other
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BNC Similar to TNC with higher tem-perature fluxing and reduced
(visible)post brazing residue; not waterwashable. Pair with 1070
and 1040filler metals.
KNC For use with lower melt pointaluminum base metals like 6061
and6262. Also suitable with 6063 and3003 base metals; not water
washable.Pair with 1040, 1022, and A071 fillermetals.
GNC Similar to TNC; specially formu-lated to braze 5000 series
aluminumand other magnesium-containingalloys. Also suitable for
commonly usedalloys; not water washable. Pair with1070, 1040, 1022,
and A071 fillermetals.
Furnace Brazing FluxFAB A non-corrosive formulationwith reduced
post-brazing residue.Pair with fine mesh 1070E, 1040E,1022E, and
A071E filler metals.
Water WashableNDA Most potent fluxing action (con-tains halides)
in this group. Affords thelongest flux life for extended
heatingcycles. Flux residues are completelywater washable. Pair
with 1070, 1040,1022, and A071 filler metals.
NPA Similar to NDA with milder, morecontrolled fluxing, which
reduces basemetal erosion and etching. Recom-mended for thin walled
parts; waterwashable. Pair with 1070, 1040, 1022,and A071 filler
metals.
NTA Similar to NDA with controlledfluxing and non-slumping
characteris-tics. Creamy and smooth appearancedue to fine mesh
filler metals. Recom-mended for small diameter stripingapplications
or any time paste must stayin place; water washable. Pair
with1070E, 1040E, 1022E, and A071E fillermetals.
Non-Corrosive FluxesTNC Chloride-free flux that does notrequire
post cleaning of the joint area.Flux residue has no detrimental
effecton joint service life; not water wash-able. Pair with 1070,
1040, 1022, andA071 filler metals.
Fusion has several paste alloys for
joining aluminum in open air, using
conventional heating techniques and
automated processes. Since the
melting range of Fusion filler metals is
very close to that of the base metals
themselves, control of heat is most
important. Both water washable and
non-corrosive flux formulations permit
joining of several commercially available
aluminum base metals.
Non-Corrosive,
KNC-1040-400
aluminum
paste
deposited to
tube/core
joints.
Non-Corrosive FluxASN A non-corrosive solder flux recom-mended
for applications such as alu-minum heat exchangers,
inlet/outlettube assemblies, condenser piccolojoints, and other
assemblies consistingof 6061 and 6262 base metals. The fluxresidue
left after soldering is non-corro-sive, thus no flux removal is
required.Pair with all solder filler metals listed inthe chart
below.
Fusion has developed solder pastes
which allow aluminum base metals to
be joined at temperatures 300F below
their melting points. This is a significant
advantage over conventional
brazing filler metals, which typically
permit a narrow 40100F mar-
gin of safety. These pastes
can be used in open air,
using conventional heating
techniques and automated
processes.
Fusion AluminumSolder Fluxes &
Filler Metals
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Fusion Aluminum BrazingFluxes &
Filler Metals Melting Ranges for Popular Aluminum Base
MetalsBase Metal Melting Range1000 Series 1190 1215F 643 657C
3003 1190 1210F 643 654C
5005 1170 1210F 632 654C
6061 1080 1200F 582 649C
6063 1140 1210F 616 654C
6262 1078 1204F 582 652C
7072 1195 1215F 646 657C
Fusion Aluminum Brazing Filler MetalsFusion Nominal Alloy
Composition Solidus LiquidusNumber Al Si Zn Cu Temp. Temp.
Specs.1040 76 10 10 4 960F 516C 1040F 560C Alum. Assn. 42451070 88
12 1070F 577C 1080F 582C AWS BAISi-41022 50 5 45 896F 480C 1022F
550C A071 50 5 40 5 878F 470C 986F 530C
Fusion Aluminum Solder Filler MetalsFusion Nominal Alloy
Composition Solidus LiquidusNumber Zn Al Temp. Temp. Specs.738 98 2
720F 378C 738F 388C
A031 95 5 710F 373C 710F 373C
A131 88 12 718F 380C 815F 435C
845 85 15 718F 380C 845F 452C
892 80 20 756F 402C 892F 478C
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water vapor of a given concentration willbegin to condense, or
become liquid.
Eutectic A specific alloy composition(two or more metals) that
melts at asingle temperature and not over arange: i.e., Solidus and
Liquidustemperatures are the same.
Filler Metal An alloy or pure metalwhich, when heated, liquifies
to flowinto the space between two close-fittingparts, creating a
brazed or solderedjoint.
Fillet A clearly-defined bead of solderor brazing alloy which
forms on andaround the completed joint.
Fitup The joint clearance between twobase metals to be soldered
or brazed.Although requirements vary bytechnique and type of joint,
optimumrange for paste brazing and soldering isgenerally .002 to
.004 inch.
Flux A material which, when heated,serves to remove and exclude
surfaceoxides from the base metal. Brazingfluxes are generally of a
highly corrosivenature. Solder fluxes may be classifiedinto one of
the following groups: Non-corrosive A rosin or mildly activeorganic
acid used in wetting cleansurfaces and producing a residuewhich is
neither electrically conduc-tive nor corrosive to the
finishedjoint. Although such fluxes are activeat elevated
temperatures, they areinert at ambient temperature.
Intermediate Generally, a mildorganic acid which activates
uponheating to achieve considerablestronger fluxing action
thannon-corrosive types. Relatively inertresidue should be removed
to ensurejoint reliability.
Atmosphere A controlled brazing orsoldering environment achieved
byexcluding oxygen and replacing it withone or a mixture of other
gases. Inproduction, this technique will minimizeor eliminate the
need for flux, as theatmosphere itself, combined with heat,acts to
reduce existing surface oxides.Most often associated with
furnacebrazing.
Base Metal (Also, Parent Metal) Thealloy or pure metal which is
to bejoined via soldering or brazing.
Binder A blending agent which, whenadded to paste brazing or
solderingalloys, keeps the atomized filler metaland flux in stable
suspension, preventsinteraction of the two, and maintainsextended
shelf life.
Brazing A joining process whereby anon-ferrous filler metal is
heated tomelting temperature (above 840F) anddistributed between
two or more close-fitting parts by capillary attraction. Atits
liquidus temperature, the moltenfiller metal interacts with a thin
layer ofthe base metal, cooling to form anexceptionally strong
joint due to grainstructure interaction.
Capillary Attraction A natural force ofadhesion governed by the
relativeattraction of liquid molecules for eachother and for those
of two adjoiningsolids. As applied to soldering or braz-ing, the
process by which liquid fluxand filler metal are transported
alongthe length of a close-fitting joint.
Dew Point A reference method ofdetermining the amount of water
vapor(and resultant oxygen) in a controlled-atmosphere brazing
operation. TheDew Point is that temperature at which
G l o s s a r yAs App l i e d t o F u s i o n Pa s t e
B r a z i ng & So l de r i ng
Cleanliness of a brazed or soldered
joint both before and after assembly
is most important. Fusion offers Fuze-
Clean metal preparation chemicals for
precleaning and postcleaning of base
metals. These products are supplied in a
dry powder form and prepared by mix-
ing with water at a specific ratio and
temperature. Since these materials do
not contain strong acids, they are gen-
erally safer than most conventional
cleaning agents. Although conditions
vary depending on the type of base and
filler metals used, joint design, and
performance requirements of the
finished part, the following general
guidelines may be helpful.
Precleaning (SurfacePreparation)Although a proper flux will
remove andexclude light oxidation during heating,foreign matter
such as grease, oil,paint, cutting fluids, etc. should becleaned
away before the part reachesthe assembly point. If not removed,such
materials may inhibit proper capil-lary attraction during heating
and/orprevent the flux itself from actingdirectly on the metals
being joined.Pre-cleaning methods may be dividedinto the following
two categories:
Chemical Cleaning with solvents, acidor pickling baths
compatible with thecontaminants and the metals used.Such procedures
should always befollowed by thorough rinsing. Fusionoffers the
following pre-cleaner:18
Intermediate and Corrosive SolderFluxes (Halides) These fluxes
leave afused residue which absorbs airbornemoisture, causing a slow
chemicalreaction at the joint. Removal is gener-ally accomplished
by thorough washingin warm detergent water, or in hotwater
containing dilute hydrochloricacid, followed by hot water
rinse.
Aluminum Brazing Fluxes (Water Wash-able) Generally about 90% of
suchresidues may be removed by immersingthe hot part in water. For
more thor-ough cleaning, immerse parts in a 15%nitric acid/85%
water solution, underagitation for 30 seconds at roomtemperature,
followed by two hotwater (60-70C) rinses at 20 secondseach, then a
final cold water rinse.
Low-Temperature Brazing Fluxes Theseresidues may be removed with
hotwater along or with detergents, alka-line cleaners, or acid
cleaners. The mosteffective method is largelydependent on the base
metals involved.
High-Temperature Brazing Fluxes(Borates) These hard,
glass-likedeposits are insoluble in many cleaners.They may be
cracked off, however, byquenching the hot assembly in
waterimmediately after brazing. A solution ofdilute hydrochloric
acid may also behelpful. Fusion offers an all-purposebrazing
postcleaner:
Fuze-Clean FS Dissolves flux residuesand heat scale on both
ferrous andnon-ferrous metals after brazing. Iteliminates the use
of strong acids andabrasive processes, besides removingrust, mill
and heat scale directly onthe production line. Use in an
ultra-sonic tank is recommended.
Fuze-Clean AB An alkaline cleanerthat removes heavy deposits of
oil,grease, and soils from aluminum andbrass surfaces.
Mechanical Removal of exceptionallyheavy deposits via brushing,
grinding orblasting with an abrasive agent. In thecase of blasting,
care must be takenthat the abrasive itself is not left
tocontaminate the joint area. It issuggested that soldering or
brazing beperformed as soon as possible after anypre-cleaning
operation.
Postcleaning (Flux Residues)A significant benefit of the Fusion
PasteProcess is that the type and amount offlux is carefully
controlled, yielding mini-mal flux residues. Nonetheless,
fluxresidues of a corrosive nature must beremoved to prevent damage
to the jointover an extended period. Suggestedcleaners for most
popular Fusion fluxesare noted in the selector charts onpages 7 and
11. Since these, too, mayvary depending on the base metal,heating
techniques, etc., the followingadditional guidelines are
offered:
Rosin Type Flux Residues Generally,these are non-corrosive and
may be lefton the part without damage to thejoint area. If residue
removal is desired,it may be removed using alcohols orchlorinated
hydrocarbon solvents, orcombinations of both families.
Activated Rosin Fluxes Some rosinactivators will cause corrosion
underunusually hot or humid conditions.Most may be removed using
alcohols orchlorinated hydrocarbon solvents, orcombinations of both
families.
Oily or Greasy Flux Residues Generallymay be removed with an
alkalinecleaner such as Fuze-Clean S.
C l e a n i ngB r a z e d o r
S o l de r e d Jo i n t s
Corrosive Generally composed ofstrong organic or inorganic
acidswhich promote high-speed cleaningof metals with strong surface
oxides.Corrosive residue should be removedto prevent damage to the
joint.
Liquidus The lowest temperature atwhich a particular metal or
metal alloywill remain in a completely moltenstate. Generally
considered the meltingpoint of a particular filler metal.
Oxidation (Also, Surface Oxides) Achemical reaction promoted by
oxygenand moisture in the air, wherein cleanmetal surfaces are
covered with a metaloxide film which prevents properwetting with
soldering or brazing fillermetal. Since oxidation acceleratesduring
heating, the metal must not onlybe cleaned initially, but protected
fromoxidation during the joining process.
Slump The relative tendency of a pastealloy to sag or flow away
from a slop-ing or vertical joint. Largely a functionof paste
rheology, this may occur whilethe assembly is cold, or
duringheating before the paste alloy hasreached melting
temperature.
Soldering A joining process whereby anon-ferrous filler metal is
heated tomelting temperature (below 840F andbelow that of the base
metal) anddistributed between two or moreclose-fitting parts by
capillary attraction.Upon cooling, the filler metal adherestightly
to the base metal of either part,achieving coalescence.
Solidus The highest temperature atwhich a particular metal or
metal alloywill remain completely solid.
Wettability (Also, Wetting Action) Theability of a specific flux
and/or fillermetal to flow onto a clean metalsurface, unrestricted
by oxidation orother impurities at the pointof contact.