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February 7, 2002 SME Brazing and Soldering Technologies Conference
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NEW DEVELOPMENTS NEW DEVELOPMENTS IN BRAZING FLUXESIN BRAZING FLUXES
DR. Y. BASKINSME BRAZING AND SOLDERING TECHNOLOGIES CONFERENCE
ORLANDO, FLORIDAFEBRUARY 7-8, 2002
February 7, 2002 SME Brazing and Soldering Technologies Conference
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DEVELOPMENT OF A FLUORIDE-DEVELOPMENT OF A FLUORIDE-FREE FLUX WAS DRIVEN BY FREE FLUX WAS DRIVEN BY
ENVIRONMENTAL AND SAFETY ENVIRONMENTAL AND SAFETY CONCERNSCONCERNS
Cleaner Plant Water Effluents Better Workplace Air Quality Improved Safety in Brazing
Operations
February 7, 2002 SME Brazing and Soldering Technologies Conference
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THE PAST DECADES HAVE THE PAST DECADES HAVE WITNESSED THE ELIMINATION WITNESSED THE ELIMINATION OF HAZARDOUS METALS AND OF HAZARDOUS METALS AND
CHEMICALSCHEMICALS Cadmium from brazing filler
metals Lead from plumbing soft-solders CFC solvents in all applications Hydrazine from different
formulations Asbestos from insulation
February 7, 2002 SME Brazing and Soldering Technologies Conference
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PRIMARY REASONS FOR PRIMARY REASONS FOR CONTINUED USE OF FLUORIDE CONTINUED USE OF FLUORIDE
BEARING FLUXESBEARING FLUXES Fluoride-bearing brazing fluxes perform
consistently in many applications, giving little reason for change.
There was an almost universal conviction that it was impossible to develop an acceptable fluoride-free brazing flux, leading to little R&D efforts.
Environmental and health studies concentrated on other sources that exhibited greater dangers, such as CFCs, lead, and other elements.
February 7, 2002 SME Brazing and Soldering Technologies Conference
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COMMON INGREDIENTS OF COMMON INGREDIENTS OF CONVENTIONAL BRAZING CONVENTIONAL BRAZING
FLUXESFLUXES Boric Acid Boron Oxide Elemental Boron Organic Additives Potassium Bifluoride Potassium
Fluoborate
Potassium Fluoride Potassium
Pentaborate Potassium
Tetraborate Silicon Dioxide Sodium Tetraborate Water
February 7, 2002 SME Brazing and Soldering Technologies Conference
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COMPOSITIONAL AREA OF COMMON BRAZING FLUXES
February 7, 2002 SME Brazing and Soldering Technologies Conference
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FLUX ACTIVATION TEMPERATURE AS A FUNCTION OF B/F RATIO
February 7, 2002 SME Brazing and Soldering Technologies Conference
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EFFECT OF TIME ON FLUX ACTIVATION TEMPERATURE
February 7, 2002 SME Brazing and Soldering Technologies Conference
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FLUX EXHAUSTION TEMPERATURE AS A FUNCTION OF B/F RATIO
February 7, 2002 SME Brazing and Soldering Technologies Conference
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THE HAZARDS ASSOCIATED THE HAZARDS ASSOCIATED WITH FLUORIDE-BEARING WITH FLUORIDE-BEARING FLUXES CHANGE DURING FLUXES CHANGE DURING
DIFFERENT BRAZING OPERATION DIFFERENT BRAZING OPERATION STAGESSTAGES
Working with raw flux
Brazing at elevated temperatures when HF and BF3 gases are released
Discharging raw flux and flux residues into plant effluent, and entry into water system
February 7, 2002 SME Brazing and Soldering Technologies Conference
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EXPOSURE LIMITS AND HAZARD EXPOSURE LIMITS AND HAZARD LABELS FOR FIVE FLUORIDESLABELS FOR FIVE FLUORIDES
FLUORINE ACGIH OSHA NIOSH OSHAD.O.T
COMPOUND TWA-TLV TWA-PEL TWA-REL LABELLABEL
Boron Trifluoride 1ppm 1ppm 1ppm -Poison
Hydrogen Fluoride 3ppm 3ppm 3ppm Toxic Corrosive
Potassium Bifluoride 2.5 mg/m3 2.5 mg/m3 2.5 mg/m3 Toxic Corrosive
Potassium Fluoborate 2.5 mg/m3 2.5 mg/m3 2.5 mg/m3
Toxic -
Potassium Fluoride 2.5 mg/m3 2.5 mg/m3 2.5 mg/m3 Toxic -
February 7, 2002 SME Brazing and Soldering Technologies Conference
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POTENTIAL HEALTH HAZARDS POTENTIAL HEALTH HAZARDS FROM USE OF FLUORIDE-FROM USE OF FLUORIDE-
BEARING FLUXESBEARING FLUXES Irritation to skin and fingernails by the
raw flux. Irritation of the eyes, mucous membranes,
and respiratory system by gases and fumes generated during brazing.
Calcium depletion (sclerosis) of the bones and mottled teeth from long-term exposure to fluoride gases and fine fume particles.
Potential health hazards from discharge of untreated flux and flux residues into the water supply.
February 7, 2002 SME Brazing and Soldering Technologies Conference
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EQUIPMENTEQUIPMENT
Thermolyne 1500 Furnace – Maximum Temperature: 1,200°C
Calibrated Pyrometer with Surface Probe. Maximum Temperature: 1,300°C
30 Tempilstik Temperature Indicators. Temperature Range: 400-1,200°C
Brookfield Viscometer Hot Plate Timer Balance
February 7, 2002 SME Brazing and Soldering Technologies Conference
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BASE METALSBASE METALS
Copper
Mild Steel
Brass C-260 (70%Cu/30%Zn)
February 7, 2002 SME Brazing and Soldering Technologies Conference
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FILLER METALSFILLER METALS
AWS LIQUIDUSCLASSIFICATION COMPOSITION
TEMPERATURE
BAg-28 40% Ag710°C/1,310°F
30%Cu28%Zn
2%Sn
BAg-36 45%Ag 688°C/1,270°F
27%Cu25%Zn3%Sn
BCuP-4 87.5%Cu 718°C/1,325°F
6%Ag7.25%P
February 7, 2002 SME Brazing and Soldering Technologies Conference
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PHYSICAL PROPERTIES OF PHYSICAL PROPERTIES OF FLUORIDE-FREE FLUXFLUORIDE-FREE FLUX
Form Creamy PasteColor WhiteSpecific Gravity 1.4Viscosity @ 22°C/72°F 225,000 ± 20,000 cpsFluorine Content < 100 ppmFlash Point NoneFreezing Effects NoneHeating Effects to 50°C/122°F MinimalActive Temperature Range 670-870°C/1,235-
1,600°F
February 7, 2002 SME Brazing and Soldering Technologies Conference
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TEMPERATURE RANGES FOR TEMPERATURE RANGES FOR FLUXES AND FILLER METALSFLUXES AND FILLER METALS
MAXIMUM ACTIVATION RECOMMEND
FLUX TEMPERATURE TEMPERATURE
Average Fluoride-Bearing 570°C/1,050°F 870°C/1,600°FFluoride-Free 670°C/1,235°F 870°C/1,600°F
MAXIMUMLIQUIDUS RECOMMENDED
FILLER METAL TEMPERATURE TEMPERATURE
BAg-28 (40%Ag) 710°C/1,310°F 802°C/1,475°FBAg-36 (45%Ag) 688°C/1,270°F 785°C/1,450°FBCuP-4 (6%Ag) 718°C/1,325°F 785°C/1,450°F
February 7, 2002 SME Brazing and Soldering Technologies Conference
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FILLER METAL SPREAD AS A FILLER METAL SPREAD AS A FUNCTION OF BASE METAL AND FUNCTION OF BASE METAL AND
FLUXFLUXBASE FILLER METALSMETAL FLUX BAg-28 BAg-36 BCuP-4
Brass Fluoride-Free Excellent Excellent Excellent
Fluoride-Bearing Excellent ExcellentExcellent
Copper Fluoride-Free Moderate Moderate Moderate
Fluoride-Bearing Excellent Excellent Poor
Mild Steel Fluoride-Free Moderate Moderate Poor
Fluoride-Bearing Moderate Moderate Poor
FURNACE TEMPERATURE: 785°C/1,450°F TIME IN FURNACE: 60 SecondsEXCELLENT SPREAD: > 2.0cm2 MODERATE SPREAD: >0.5cm2<2.0cm2
POOR SPREAD: <0.5cm2
February 7, 2002 SME Brazing and Soldering Technologies Conference
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BENEFITS OF USINGBENEFITS OF USINGFLUORIDE-FREE FLUXFLUORIDE-FREE FLUX
Greater Operator Safety
Better Workplace Air Quality
Cleaner Plant Water Effluents
February 7, 2002 SME Brazing and Soldering Technologies Conference
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PRIMARY SKIN IRRITATION PRIMARY SKIN IRRITATION STUDYSTUDY
FLUORIDE-FREE FLUORIDE-BEARING
FLUX FLUX
Primary Dermal Irritation Index 2.3 5.9(PDII)
Classification Not a primary irritant. A primary irritant
Non-corrosive to skin. Corrosive to skin.
February 7, 2002 SME Brazing and Soldering Technologies Conference
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APPLICATIONS FOR APPLICATIONS FOR FLUORIDE-FREE FLUXFLUORIDE-FREE FLUX
COPPER-TO-COPPER
COPPER-TO-BRASS
COPPER-TO-MILD STEEL
BRASS-TO-BRASS
BRASS-TO-MILD STEEL
MILD STEEL-TO-MILD STEEL