training materials化學(xué)基礎(chǔ)培訓(xùn)pretreatment presentation

1、Better Manufacturing.through ChemistryMAKING IT WORKPRETREATMENT BASICSOPERATIONAL ISSUES CONTROLS MAINTENANCE PERFORMANCE SPECIFICATIONS ENVIRONMENTAL CONCERNSPROCESS OPTIMIZATION/COST REDUCTION/ENVIRONMENTAL COMPLIANCE WITH TECHNOLOGYTROUBLESHOOTING PROBLEMSPretreatment BasicsSubstratesSoilsBasic

2、ChemistrySurface Preparation Mechanical Chemical SUBSTRATESSteel - CRS - HRS - HRS, P&OSteel electrolytically - zinc - zinc + app 10% nickel - zinc + app 16% iron Stainless SteelSteel coated with molten metals - zinc + 0.1-0.2% Aluminum (Galvanized) - zinc + 0.1-0.2% Aluminum + app 10% Iron (Galvann

3、eal) - zinc + app 5% Aluminum + app 1% mix metal (Galfan) - zinc + app 30% Aluminum + app 0.2% magnesium (Lavegal) - zinc + app 55% Aluminum + app 1.5% silicium (Galvalume)SUBSTRATESNON-FERROUS METALS ALUMINUM BRASS COPPER TITANIUM MAGNESIUM TYPES OF SOILSOrganicInorganic ORGANIC SOILSMill Oil (Quak

4、er 61-AUS)Oil from secondary processesMetalworking lubricants - Oils - Waxes/Paraffins - Soluble oils - Semi-synthetics - Synthetics - Buffing Compounds INORGANIC SOILS Weld Smut/Scale Rust Shop Dust Metallic Residue Solder/FluxSurface ContaminationRolling OilsCorrosion Protection OilsPressing OilsA

5、dhesive, etc.Carbon, Soot, SmutDustCorrosion ProductsSaltsChemistry BasicspH: The negative logarithm of the hydrogen ion concentration (expressed in moles/liter)- OR -A scale of measurement spanning 0 to 14, typically0 7 14+-+-+Acid Neutral Alkaline (Basic/Caustic)Phosphates Water CleanersChemical S

6、ymbolsH Hydrogen ZnZincNiNickelNaSodiumFeIronOOxygenNNitrogenKPotassiumCrChromiumNaOHSodium HydroxideKOHPotassium HydroxideH2OWaterH3PO4Phosphoric AcidFe3(PO4)2Iron PhosphateMECHANICAL TREATMENT DEGREE OF CLEANLINESS REQUIRED SURFACE PROFILE REQUIRED MECHANICAL TREATMENTCOMPRESSED AIR - Pressure - V

7、olumeABRASIVE PARTICLES - Steel grit - Steel shot - Silica sand - Aluminum oxide - Glass bead - Mineral slag - Plastic - Corn cob - Wheat starch DEGREE OF CLEANLINESS WHITE METAL BLAST 100% removal of all contaminants (rust, scale, etc.) NEAR WHITE METAL BLAST 95% removal of all visible contaminants

8、, some staining remainsDEGREE OF CLEANLINESS COMMERCIAL BLAST 66% of the surface is free of all visible residue BRUSH-OFF BLAST Removal of only the loose materials, tightly adhering mill scale and rust remainSURFACE PROFILEAbrasive particles cut into substrate to form many peaks and valleysThe conto

9、ur allows the coating to obtain a tight grip on the substrateControlled by the type, size and hardness of the abrasive and the pressure, distance and angle of the blast nozzleSURFACE PROFILEProfiles are measured in either mils or micronsA mil is 1/1000th of an inchA micron is 1/25 of a mil ( 25 micr

10、ons = 1 mil)Precise profiles are not possible due to varying sizes in the abrasiveCoating must be applied to cover the peaks of the profileCOATING OVER A BLAST PROFILE CHEMICAL TREATMENTCLEANINGRINSINGWATER QUALITYPHOSPHATINGFINAL SEALSChoice of Cleaning Method Level of Cleanliness Level of Surface

11、Contamination Substrate Environment Economy CLEANERSBASIC TYPES Water (aqueous) - Acid, Alkaline Solvent (organic) Emulsion (combination)Aqueous CleanersPractical, Recyclable pH Type Soil Example8 Alkaline Organic oils12 High Alkaline Organic smut, minor rust ACID CLEANINGPrimarily Used To:Remove in

12、organic soils (smut/oxides)Types of acids used - Phosphoric - Hydrochloric - Sulfuric - Organic (Acetic, Citric, Gluconic, Oxalic, Formic) - Ammonium Bifluoride (Hydrofluoric) for AluminumSurfactantsInhibitorsALKALINE CLEANINGConsists of:Alkaline BuildersInhibitorsSurfactantsCan be used in either sp

13、ray, dip, or in a combination of bothWorking CriteriaTime:10 sec - 5 minTemp:100 - 200 FConc:0.5 - 15%pH:9.0 - 13Primarily used to remove organic soilsEtching Effect on Coated Steel and AluminumRelates to the working pH and the type of inhibitors in the builder packageORGANIC SOLVENTS Manual Methods

14、Naphtha, Chlorinated solvents Vapor DegreasersEnvironmentally Unsafe SystemsStrictly RegulatedSolvent EmulsionsWorking Concentration 0.5 - 3%Working Process Dip/SprayWorking Temperature 70 - 140 FProcess Time 40 sec - 5 min CLEANER COMPONENTS 10 ElementsWaterBuildersWater ConditionersCouplersSurfact

15、antsDispersantsBuffersDefoamersSolventsCorrosion InhibitorsCLEANER COMPONENTS Builder PackageSodium or Potassium HydroxideSodium CarbonateTrisodium/Potassium PhosphateSodium/Potassium TripolyphosphateSodium/Potassium MetasilicateComplexing AgentsActivation CompoundsCLEANER COMPONENTS Surfactant Pack

16、ageCationic SurfactantsAnionic SurfactantsNon-ionic SurfactantsReduces the Surface TensionDetergencyFoam ControlIncreases WettabilityEmulsifies OilCLEANER COMPONENTSWater Conditioners EDTA (ethylenediamine tetraacetic acid) STPP (sodium tripolyphosphate) Phosphonates Other (Chelants) Sodium Gluconat

17、e Sodium GlucoheptonateCLEANER COMPONENTS SolventsWater SolubleGlycol Ethers2 Butoxy Ethanol - most common (also known as EB or Butyl Cellosolve)CLEANER COMPONENTS Corrosion InhibitorsAminesBenzoatesBoratesCarboxylatesMolybdatesNitritesThiolsTriazolesUreaPhosphatesSilicatesHow Cleaners WorkRemoval o

18、f identified soil plished by 7 methodsSolubilizationEmulsificationWettingSaponification Sequestration Displacement DeflocculationFactors Influencing Cleaning PowerTemperatureConcentrationTreatment TimePressure“Aging”CHECKING FOR CLEANLINESSVISUAL(OPTICAL/MICROSCOPIC)WATER-BREAK FREE SURFACEWHITE GLO

19、VE TESTFLUORESCENCECONTACT ANGLESURFACE CONDUCTIVITYSURFACE CARBON ANALYSISSEMCOPPER DISPLACEMENTRINSINGRemove Chemical and Loose SoilsSeparation Between Alkaline & Acid ProcessesContamination Should Be Kept at a Minimum- Overflow- Regular Dumping & CleaningProduct Should Remain Wet Between Process

20、StagesRINSINGWater rinsing is needed to obtain proper pretreatment quality.Water usage is directly related to:Chemical dragout from previous treatment stageOverspray from stage to stageEffectiveness of wetting risersTemperature of surrounding stagesProcess ControlTotal Alkalinity (rinse after cleani

21、ng)Total Acid (rinse after phosphate)Conductivity LevelpH LevelTemperatureWATER QUALITYCITY WATER/WELL WATER - Hard water salts/water spotsRECYCLED WATER - Potential contaminantsSOFT WATERREVERSE OSMOSIS - Greater than 10 micromhosDEIONIZED - Less than 5 micromhos - Very low contaminationPHOSPHATING

22、 ON STEELIRONZINCTYPES OF PHOSPHATESIRON - Lower coating weight - Various types of acceleratorsZINC - Medium zinc - Heavy zinc - Calcium modified - Low zinc, manganese modified(tri-cation)IRON PHOSPHATEConversion Coating:Phosphate conversion coating is formed on Iron, Steel, Galvanized Steel, Zinc,

23、or Aluminum by reacting them chemically with a dilute solution of phosphoric acid and other chemicals.The insoluble metal phosphate is deposited on metal surface.Iron Phosphate ApplicationsThe insoluble metal phosphate provides:A physical barrier against moisture/mild corrosionA base for paintA base

24、 for oil and rust preventive materialA base for adhesives in plastic laminationA surface that facilitates cold formingLubricity and resistance to wearThe degree of corrosion protection depends on:Uniformity of coating coverageCoating thicknessType of final seal/rinsePhosphating In Simple TermsMETAL

25、+ PHOSPHORIC ACID (Pickle Step)SOLUBLE PHOSPHATE SALT (Intermediate Step)INSOLUBLE METAL PHOSPHATE SALT (Bonded at Metal Surface)TYPES OF PHOSPHATESIRON(20 - 80 mg/ft2) - Molybdate - Chlorate - Organic (HAS, SNBS) - Works well with wet and powder coatings - Excellent mechanical properties - Environm

26、entally more friendly IRON PHOSPHATEOrganic accelerated ZINC PHOSPHATEDEFINITION CRYSTALLINE CONVERSION COATING FORMED ON A METAL SUBSTRATE UTILIZING THE CHEMICAL REACTION BETWEEN METAL IONS THAT HAVE BEEN DISSOLVED IN MINERAL ACIDS(GENERALLY NITRIC AND PHOSPHORIC) AND THEN DILUTED WITH WATER TO FOR

27、M THE PROCESS SOLUTIONTYPES OF PHOSPHATESZINC - Medium zinc(400 - 1400 mg/ft2) 18 - 40 microns - Heavy zinc(1400+ mg/ft2) 40 microns + - Low zinc, manganese modified (150 350mg/ft2) 2 8 microns - Calcium modified(150 - 400mg/ft2) 1-7 microns ZINC PHOSPHATE Medium ZincCalcium modified Heavy zincZINC

28、PHOSPHATE (LOW ZINC, MANGANESE MODIFIED)Product SelectionSelection of Phosphate: Zinc phosphate or Iron Phosphate?Evaluation: Several factorsIron PhosphateFewer stagesFewer controlsLess sludgeLow temperatureCorrosion resistance inferior to zinc phosphateExcellent adherence & resistance to flaking fr

29、om impact or flexingEasy disposalLow operational costZinc PhosphateMore stagesMore controlling factorsHeavy sludgeHigher operating temperatureSuperior corrosion protectionNot good to bending or impactExpensiveHigh operational costALUMINUM PRETREATMENT CHROMIUM TREATMENTS CHROME OXIDE, CHROME PHOSPHA

30、TENO RINSE CHROMIUM TREATMENTNON-CHROMIUM TREATMENTIRON PHOSPHATE PROCESSZINC PHOSPHATE PROCESSPHOSPHATING ON ALUMINUMIRONZINCCOMMON ALUMINUM ALLOYSALLOYS ELEMENT MAJOR APPLICATION Cu HIGH-STRENGTH/AIRCRAFT Mn CANNING Mg STRUCTURAL/ARCHITECTURAL Mg,Si EXTRUSIONS7000 Zn,Mg,Cu HIGH STRENGTH/AIRCRAFT C

31、LEANING ALUMINUMETCHING CLEANERS RUN AT ELEVATED pH REMOVE ORGANIC SOILS DISSOLVE SURFACE OXIDE FILM REMOVE SOME OF THE BASE METAL LEAVE SMUT ON THE SURFACE BUILD UP OF ALUMINUM IN THE BATH PRECIPITATION OF ALUMINUM HYDROXIDE (ROCK HARD PRECIPITATE ON WALLS/RISERS)CLEANING ALUMINUMNON-ETCHING CLEANE

32、RS RUN AT LOWER pH REMOVE ORGANIC SOILS IDEAL FOR POLISHED SURFACES DISSOLVE SURFACE OXIDE FILM USE INHIBITORS TO MINIMIZE THE ATTACK ON THE SURFACE(METASILICATE, BENZOATE, BORATE) GENERALLY, DO NO LEAVE SMUT ON THE SURFACE LITTLE BUILD UP OF ALUMINUM IN THE BATH IRON PHOSPHATE PRETREAMENTMIX OF PHO

33、SPHORIC ACID, AMMONIMUM BIFLUORIDE, BUFFERS, DETERGENTS AND BUILDERSPHOSPHORIC ACID DISSOLVES AWAY THE LAYER OF ALUMINUM OXIDE, EXPOSING THE REACTIVE ALUMINUM SUBSTRATEAMMONIUM BIFLUORIDE REACTS QUICKLY TO CONVERT THE SURFACE TO ALUMINUM TRIFLUORIDE, AlF3 IRON PHOSPHATE PRETREAMENTALUMINUM TRIFLUORI

34、DE IS FAIRLY INERT, BUT DOES NOT RENDER THE SURFACE PASSIVE INDEFINITELYOVER TIME, THE SURFACE WILL OXIDIZE BACK TO Al2O3COATINGS ADHERE WELL TO AlF3COATINGS SHOULD BE APPLIED ASAP TO PREVENT REOXIDATION OF THE SURFACEZINC PHOSPHATE PRETREATMENTNORMAL ZINCLOW ZINCLOW ZINC, MANGANESE MODIFIEDZINC PHO

35、SPHATE PRETREATMENTSet up to simultaneously coat steel, galvanized steel and aluminum (less than 10%)Zinc phosphate material must contain fluoridesAluminum fluorides, fluoaluminates and phosphates build in the bathAluminum cations act as a poison to the bath and must be continuously removedThis is p

36、lished with the addition of sodium nitrite as the accelerator and fluoride in the bathSoluble aluminum es insoluble sodium fluoaluminate and drops as sludgeZINC PHOSPHATE PRETREATMENTCoatings are predominantly hopeiteCoating weight and complete deposition are very dependent upon the fluoride level N

37、ickel and fluoride levels can deplete if not present in sufficient quantity in the zinc phosphate replenisherIn general, 150 ppm F minimum is a satisfactory level for treating small quantities of aluminum in a trimetal systemHow Does A Final Rinse Work?Phosphate coatings are porous.Final rinses seal

38、 the free pore areas of the phosphate coating. Reduce the free pore area of the phosphate coating.Also remove any excess soluble materials present on the surface. Importance of a Final RinseImproves Corrosion ResistanceImproves Paint AdhesionMinimizes Filiform CorrosionReduces Paint BlisteringMinimi

39、zes Rusting of Parts During Line Stops FINAL SEALSChemical Options Chrome Non-Chrome- Phosphoric Acid- Amine- Acidulated Molybdate- Tannin- Phenolic Polymer- Organo-Metallic PolymerNew Technology RinsesOrgano-metallic polymerBifunctional in its properties - Reacts with the metal pretreatment - React

40、s with organic functionalities hydroxyl(OH), carboxyl(COOH), amino(NH), phenolic(OH)Non-hazardous materialEnvironmentally safe OPERATIONAL ISSUESCONTROLSMAINTENANCEPERFORMANCE SPECIFICATIONSENVIRONMENTAL CONCERNSSYSTEM CONTROLSTitrationsProcess Control ManualsLog Books Chemical Additions TITRATIONSP

41、ERFORMED AT LEAST TWICE PER SHIFTPERFORMED BY A TRAINED OPERATORDONE WITH THE PROPER EQUIPMENT BURETTES, NOT DROPS PROPER INDICATORS, TITRANTSPROCESS CONTROL MANUALSEQUALS QUALITY FOR YOUR COMPANY BIBLE FOR THE LINE CONTAINS ALL OPERATIONAL PARAMETERS(TEMP, CONC) TITRATIONS PRODUCT SPECS REPLENISHME

42、NT INFORMATION TROUBLESHOOTING GUIDE LOG BOOKSRECORD KEEPINGALL PERTINENT INFORMATION PRESSURES, TEMPERATURES, TITRATION RESULTS, DRUM CHANGES WITH LOT NUMBER, NOTES ON PROBLEMS, PARTS RUN, ETC.DATES AND INITIALSKEPT BY MANAGEMENTPROVIDES TRACEABILITY CHEMICAL ADDITIONSMANUAL (REMEMBER SAFETY)METERI

43、NG PUMPSAUTOMATIC CONTROLSMAINTAIN CONSISTENT LEVELS, NOT HIGH/LOW/HIGHSYSTEM MAINTENANCEDumping & Cleaning Process Tanks Cleaning NozzlesFlushing Headers & RisersRemoving Hooks & PartsLubrication of Motors, Pumps, etc.Make Needed RepairsYearly Descaling Maintenance ScheduleA maintenance schedule sh

44、ould be set up to ensure a well-controlled, continuous pretreatment operation. A general guideline is given below.DailyRemove and clean screens on all recirculating pumps chambers.Check for clogged nozzles. Clean if necessary.Check for proper spray pattern. Adjust nozzles and risers if required.Insp

45、ect pressure gauges and thermometers to ensure that they are operating properly.Inspect for leaks in pumps, tanks, and make-up feed lines.If automatic feed equipment is used, make sure it is operating properly.If filtration of the baths is employed, check for proper operation.Weekly (or as required)

46、Dump, clean out, and refill all rinse tanks.Remove “l(fā)ost” parts that have fallen off hangers.Check conveyor and hangers for cleanliness.Monthly, Bimonthly, Quarterly (or as required)Dump process chemical tanks and clean out all sludge, parts, and debris.High pressure wash or chemically clean the hol

47、ding tank, heating surfaces, and interior chamber.Remove the end caps from the risers to remove sludge or debris.DEVELOPING A PERFORMANCE SPECIFICATIONCOATING WEIGHTADHESIONIMPACTCONICAL MANDRELWATER IMMERSIONHUMIDITYSALT SPRAYBOND STRENGTHDEVELOPING A PERFORMANCE SPECIFICATION MEET EXPECTATIONS OF

48、THE END USERS NEEDS TO BE RELEVANT NEEDS TO BE ACHIEVABLE NEEDS TO BE REPEATABLEMEETING SPECIFICATIONS SYSTEM SELECTION CHEMICAL SELECTION COATING SELECTION SYSTEM SELECTIONBEST FITS YOUR END PRODUCT (SIZE AND SHAPE)IMMERSIONSPRAYSYSTEM SELECTIONOVERALL REQUIREMENTS - Indoor or outdoor use - Consume

49、r Expectations - Longevity of product - Corrosion requirements - ImageMETALWORKING FLUIDS USED - Coolants - Drawing compoundsMETAL PROCESSING - Welding - Stamping or drawing CHEMICAL SELECTON NUMBER OF STAGES RIGHT TYPE OF CONVERSION COATING TO MEET OVERALL REQUIREMENT TYPE OF SUBSTRATE PART SIZE/CO

50、NFIGURATION CONTAMINANTS2 STAGE PHOSPHATE SYSTEMClean, rinseClean/phosphate, rinseGenerally, no corrosion specifications or requirementsMarginal to good cleaningLight oils, soils No heavy compoundsMinimal corrosion protection3 STAGE PHOSPHATE SYSTEMClean, rinse, rinseClean/phosphate, rinse, rinse Cl

51、ean/phosphate, rinse, final sealGenerally, no or low corrosion specifications or requirementsMarginal to good cleaningLight oils, soilsNo heavy compoundsMinimal corrosion protection, unless final rinse is used4 STAGE PHOSPHATE SYSTEMClean, rinse, phosphate, rinseClean/phosphate, clean/phosphate, rin

52、se, rinse or final sealGenerally, low to medium specifications or requirements (less that 500 hours salt spray)Good to excellent cleaningMost oils, soils including heavy compoundsCorrosion protection - Iron phosphate - Good - Zinc phosphate - Very good5 STAGE PHOSPHATE SYSTEMClean, rinse, phosphate,

53、 rinse, final sealClean/phosphate, clean/phosphate, rinse, rinse, final sealGenerally, medium to high specifications or requirements (500 hours salt spray or more)Most oils, soils including heavy compoundsCorrosion protection - Iron phosphate - Good/Very good - Zinc phosphate - Very good/Excellent6

54、STAGE PHOSPHATE SYSTEMClean, rinse, rinse (activation), phosphate, rinse, final sealGenerally, medium to high specifications or requirements (500 hours salt spray or more)Most oils, soils including heavy compoundsCorrosion protection - Iron phosphate - Very good - Zinc phosphate - Very good/Excellen

55、tCOATING SELECTIONOVERALL REQUIREMENTSSOLVENT BASEDWATERBORNEE-COATPOWDERDIPSPRAYMEETING SPECIFICATIONSHAVE CONTROL OVER SYSTEM MECHANICS SYSTEM CONTROLS SYSTEM MAINTENANCEENVIRONMENTAL CONCERNSLOCAL, STATE, FEDERAL REGSWATER USAGE ISSUESPHOSPHATE SLUDGETOXIC METALSLIQUID OR SOLID WASTENON-HAZARDOUS

56、/HAZARDOUS DISPOSALCRADLE TO GRAVE RESPONSIBILITYENVIRONMENTAL CONCERNSLOCAL REGULATIONS ON PHOSPHATES, MOLYBDATES, FOGS, BOD, COD, TSSGREAT LAKES INITIATIVEMP&M REGUALTIONSRISING COST OF COMPLIANCEWhat is the Metal Products and Machinery (MP&M) Effluent Guideline?EPA wants 50 80% metals reductionMP

57、&M will cover facilities that manufacture, rebuild and maintain metal parts, products and machinesInitially, MP&M rulemaking was divided into two phases.Phase I regulation was proposed May 30, 1995.Compliance costs estimated at $150 500,000 per facilityMP&M SCHEDULEThe two phases have been combined

58、into one regulationProposal Date: October 2000Promulgation Date: December 2002Issued in Federal Register in December 2000120 day comment periodHold 3 public meetings 2/06/01 in Oakland, CA; 2/13/01 in Dallas, TX; 2/22/01 in Washington, DC MP&M SectorsMP&M Phase IMP&M Phase IIAerospaceAircraftElectro

59、nic EquipmentHardwareMobile Industrial EquipmentOrdnanceStationary Industrial EquipmentBus and TruckHousehold EquipmentInstrumentsMotor VehiclesOffice MachinesRailroadShips and BoatsPrecious Metals and JewelryPrinted Wiring BoardsJob Shops Purpose of MP&M RuleCover Sites not Currently Covered as wel

60、l as those covered by 40 CFR 413 and 40 CFR Part 433 Reduce Metals in POTW Sludge Incorporate Pollution Prevention Develop Implementable Rule Satisfy NRDC Consent Decree Fulfill Requirements of the Clean Water ActOverlap with Other Effluent GuidelinesReplace 40 CFR 413 and 433 with MP&M for all dire