ENVIRONMENTALLY SAFE BRAZING FLUXES DR. Y. BASKIN SUPERIOR FLUX & MFG. CO. INTERNATIONAL BRAZING & SOLDERING CONFERENCE FEBRUARY 18, 2003 SAN DIEGO, CA
MOTIVATION FOR SAFER FLUX DEVELOPMENT Cleaner effluents Better workplace air quality Improved health and safety in brazing operations
ELIMINATION OF HAZARDOUS CHEMICALS AND METALS Cadmium from Brazing Filler Metals Lead from Plumbing Soft-Solders CFC Solvents from All Applications Hydrazine from Industrial Applications Asbestos from Insulation
HAZARDS ASSOCIATED WITH GENERAL-PURPOSE FLUXES Working with raw flux Brazing at elevated temperatures when HF and BF 3 gases are released Discharging raw flux and flux residues into plant effluent, and entry into water system
POTENTIAL HEALTH ISSUES FROM FLUORIDE-BEARING FLUX 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 water supply.
PHYSICAL PROPERTIES OF SILVER- BRAZING FLUX WITHOUT POTASSIUM BIFLUORIDE * Form:Creamy Paste Color:Off White Specific Gravity:1.5 Water Content:Less than 35% Viscosity @ 22 C/72 F:140,000±14,000 Centipoises Fluorine Content:18.0% Flash Point:None Freezing Effects:None Heating Effects to 50 C / 122 F:None Activity Temperature Range:485–870 C / 900-1600 F * not boron-modified
PHYSICAL PROPERTIES OF FLUORIDE-FREE SILVER- BRAZING FLUX Form:Creamy Paste Color:White Specific Gravity:1.4 Viscosity @ 22 C/ 72 F:225,000 ± 20,000 Centipoises Fluoride Content:Less than 50 ppm Flash Point:None Freezing Effects:None Heating Effects to 50 C/122 F:Minimal Activity Temperature Range:670-870 C / 1235-1600 F
TEMPERATURE RANGES FOR FLUXES AND FILLER METALS Recommended Activation Maximum Flux TemperatureTemperature Average Fluoride-Bearing570 C / 1050 F870 C / 1600 F Fluoride-Free670 C / 1240 F870 C / 1600 F Recommended Filler Liquidus Maximum Alloy TemperatureTemperature BAg-28 (40% Ag)710 C / 1315 F802 C / 1475 F BAg-36 (45% Ag)688 C / 1270 F785 C / 1450 F BCuP-4 (6% Ag) 718 C / 1325 F 785 C / 1450 F
FILLER METAL SPREAD AS A FUNCTION OF BASE METAL, FILLER ALLOY, AND FLUX BASE FILLER ALLOYS METAL FLUXBAg-28BAg-36BCuP-4 Brass Fluoride-FreeExcellent ExcellentExcellent Fluoride-BearingExcellent ExcellentExcellent Copper Fluoride-FreeModerate ModerateModerate Fluoride-BearingExcellent ExcellentPoor Mild Fluoride-FreeModerate ModeratePoor Steel Fluoride-BearingModerate ModeratePoor Furnace Temperature: 785C/1450FTime in Furnace: 60 Seconds Excellent Spread: >2.0cm 2 Moderate Spread: >0.5cm 2 <2.0cm 2 Poor Spread: <0.5cm 2
PHYSICAL PROPERTIES OF HIGH TEMPERATURE FLUX WITHOUT POTASSIUM BIFLUORIDE Form:Creamy Paste Color:Dark Brown Specific Gravity:1.7 Water Content:Less than 30% Viscosity @ 22 C / 72 F:200,000 ± 20,000 Centipoises Fluorine Content:3% or Lower Flash Point:None Freezing Effects:None Heating Effects to 50 C/122 F:None Activity Temperature Range:760 - 1205 C / 1400 - 2200 F
PHYSICAL PROPERTIES OF FLUORIDE-FREE HIGH TEMPERATURE BRAZING POWDER FLUX Form:Powder Color:White Specific Gravity:1.5 (Average) Fluorine Content: Less than 50 ppm Volatile Content: <0.1% Flash Point: None Freezing Effects: None Heating Effects to 50 C/122 F: None Activity Temperature Range:760–1205 C/1400-2200 F
BASE METAL, AND FILLER METAL RELATIONSHIPS Flux CategoryBase MetalsFiller Metals Silver Brazing Copper and Copper-based All (BAg) Alloys without Potassium Alloys, Ferrous AlloysPhos-Copper Bifluoride Stainless Steel (BCuP) Alloys Silver BrazingCopper and Copper-basedCd-Free BAg Alloys Fluoride-FreeAlloys, Select FerrousPhos-Copper BCuPAlloys High TemperatureFerrous Alloys, CarbidesCDA 681, CDA 773; Brazing withoutManganese containing Potassium BifluorideNickel Alloys High TemperatureFerrous Alloys, CarbidesCDA 681, CDA 773; Brazing, Fluoride-FreeManganese containing Nickel Alloys
PRIMARY SKIN IRRITATION STUDY OF SILVER BRAZING FLUXES FLUX WITHOUT FLUORIDE-FREE POTASSIUM POTASSIUMFLUXBIFLUORIDE BIFLUORIDEFLUX PRIMARY 1.5 2.3 5.9 DERMAL IRRITATION INDEX (PDII) CLASSIFICATIONNot a primary Not a primary A primary irritant. Non-irritant. Non- irritant. corrosive to skin.corrosive to skin.Corrosive to skin. * The Non-Corrosive/Corrosive dividing measurement is 5.0. The Draize scoring system is used for defining the skin irritation levels.
BENEFITS OF USING FLUORIDE-FREE FLUX Addresses workplace safety by reducing toxic emissions Addresses the long-time issue of skin and fingernail irritation Substantially reduces the fluoride effluent emission in local and regional waterways Complements the Cadmium-Free workplace with much safer fluxes
SUPERIOR MANUFACTURES QUALITY FLUXES. OUR BUSINESS IS SOLVING PROBLEMS
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