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: info@fusion-inc.com

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: salesuk@fai-uk.com

Fusion Automation China

Guangzhou, Guangdong, P.R. China

Tel / Fax: ++86(China)-20(Guangzhou)- 32068216

Email: woody.wu@fusion-inc.com

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: rrai@fusion-inc.com

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Fusion PasteDivision

ISO9001:2000Certified

Paste Brazing

& Soldering

Alloys

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.

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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.

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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

Dispenser gun applies

copper/phosphorus paste

deposits to tube/header joints.

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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.