STT-焊接工艺培训

MM-31STTSurfaceTensionTransferNovember2008表面张力过渡技术MichaelHuApplicationandProductDevelopmentManagerofAutomationDivisionofShanghaiLincolnElectricMM-32Basics基本概念•S.T.T.=SurfaceTensionTransfer•表面张力过渡•ResearchBeganJuly1985•1985年开始研究开发•Purposeistodevelopaweldingprocesswhicheliminatesspatterwhenuse100%CO2shieldinggas•目的是为了开发一种使用CO2保护气体而没有飞溅的焊接方法•STTisaUniqueGMAWProcess•一种独特的气保护焊接工艺MM-33Basics基本概念•NeitherCCNorCV•既不是恒流源也不是恒压源•BasedoninteractiveWAVEFORMCONTROLTECHNOLOGYTM•基于交互式波形控制技术•BasedonHighSpeedInverterTechnology•基于高速逆变技术•PrecisionCurrentControlledShortArc•精密电流控制的短路过渡焊接MM-34Advantages优点1.Lowspatter低飞溅量2.Lowfume低烟尘3.LowcostGas低气体成本4.ControlledHeatInput可控制的热输入量5.AllPosition可进行全位置焊接6.GoodFusion良好的焊接成型7.HandlesPoorFit-up适用较差的接头形式MM-35ManualWelding:STTvsShortArc手工焊接:表面张力过渡vs短路过渡StandardGMAW标准的气保护焊接SurfaceTensionTransfer表面张力过渡MM-36TraditionalGMAW传统气保护焊接MM-37STTWelding表面张力过渡焊接MM-38StandardGMAW标准的气保护焊接SurfaceTensionTransfer表面张力过渡RoboticsWelding:STTvsShortArc机器人焊接:表面张力过渡vs短路过渡MM-39•G.M.A.W=GasMetalArcWelding熔化极气体保护焊接•MIG/MAGWeldingMIG/MAG焊接-MIG=MetalInertGas惰性气体熔化极保护焊-MAG=MetalActiveGas活性气体熔化极保护焊•SolidWirewithExternalShieldingGas实芯焊丝和外部保护气体•DC+Polarity直流正接WhatisGMAW?什么是GMAW?MM-310OverviewofGMAWprocesses气保护焊接工艺概述•ConsistentVoltageGMAW(CV)恒压气保护焊接•PulseGMAW(MIG/MAG)脉冲气保护焊接•STT(SurfaceTensionTransfer)表面张力气保护焊接MM-311CVPowerSourceOutput恒压电源输出•WeldingCircuitConsistsofCVPowerSourceswithaWireFeeder焊接回路由恒压电源和送丝机组成•VoltageisProportionaltoArcLength电压与电弧长度成正比•CurrentChangesDramaticallytoMaintainConstantArcLength电流动态变化以维持恒定的电弧长度MM-312ModesofArcTransfer熔滴过渡形式•ShortCircuit(ShortArc)Transfer短路过渡•GlobularTransfer滴状过渡•SprayTransfer喷射过渡Conventional常规形式WaveformControlTechnologyTM波形控制技术•PulseSprayTransfer脉冲喷射过渡•SurfaceTensionTransfer表面张力过渡MM-313ShortArcTransfer短路过渡•LowVoltages&LowAmperages低电压&低电流•TypicallySmallerWireDiameters典型的小直径焊丝•TypicalShieldingGasesIncludeCO2,75/25Ar/CO2典型保护气体100%CO2,72/25Ar/CO2•TheWireShortstoWorkpiece.焊丝与工件短路•TheVoltage=0电压为零•TheAmperageAcceleratesRapidly电流快速增加•WireBreaksoffProducingaWeldBeadandSpatter焊丝断开产生焊缝和飞溅MM-314ShortArcTransfer短路过渡MM-315•LowHeatInput低热输入•AllPositionWelding全位置焊接•LowCost低成本•PoorFitUp适应较差的接头形式•Spatter飞溅大•PotentialLackofFusion容易产生熔合缺陷•LimitedtoThinMaterial只适用于薄板材料焊接Advantages优点Limitations缺点ShortArcTransfer短路过渡MM-316GlobularTransfer滴状过渡•HighVoltage&HighAmperages高电压和高电流•TypicallyLargerWireDiameters典型的大直径焊丝•100%CO2,75/25Ar/CO2GasMix(LowerCostShieldingCost)100%CO2,75/25Ar/CO2混合气体(低成本保护气体)MM-317GlobularTransfer滴状过渡•BallFormsontheEndoftheElectrode球形熔滴在焊丝端部形成•BeforeaShortCircuitOccurs,theHighAmperageandGravityPulltheBallofftoformweldandSPATTER在形成短路之前,高电流电磁力和重力将熔滴推离焊丝,过渡到熔池形成焊缝和飞溅MM-318GlobularTransfer滴状过渡•DeepPenetration较深的熔深•HighDeposition高熔敷率•LowCostGas低成本气体•ExcessiveSpatter过多的飞溅•Flat&HorizontalOnly只能进行平焊和横焊Advantages优点Limitations缺点MM-319SprayArcTransfer喷射过渡•HighVoltages&HighAmperages高电压和高电流•TypicallyusedwithWireDiametersof.035andLarger一般使用0.035直径以上的焊丝直径•AMinimumof80%ArgonintheGasMix使用最少含有80%以上氩气的混合气MM-320SprayArcTransfer喷射过渡•SharpPointFormsonEndofElectrode在焊丝端部形成铅笔状•FineDropletsAreDirectedinaStraightLineFromtheWiretoWeldPuddle很细小的熔滴形成一条直线从焊丝过渡到熔池中，形成焊缝。MM-321SprayArcTransfer喷射过渡•SmoothWeldBead光滑的焊缝成型•DeepPenetration熔深很深•HighDeposition高熔敷率•LittletoNoSpatter很少或没有飞溅•PotentialUndercut容易出现咬边•ExpensiveShieldingGas保护气体成本高•Flat&HorizontalOnly只能平焊和横焊Advantages优点Limitations缺点MM-322StableCVTransferModes稳定的CV过渡模式ShortArc短路过渡GlobularArc滴状过渡SprayArc喷射过渡WFS(current)Increasing送丝速度（电流）增加VoltageRange电压范围MM-323•SurfaceTension表面张力•PinchForces电磁收缩力•JetForces电弧推力ForcesinArc电弧的作用力MM-324SurfaceTension表面张力PinPoutRgPoutPingPin-Pout=2gRMM-325SurfaceTension表面张力Dropletonwire焊丝上的熔滴WeldPuddleMM-326SurfaceTension表面张力Thesmalldropisabsorbedintothebigdrop小的熔滴被大的熔滴吸收了MM-327SurfaceTensionandPinchForces表面张力和电磁收缩力•SurfaceTensionForces表面张力-WetDroplettoWeldPuddle润湿熔滴到熔池•PinchForces电磁收缩力-SeparateShortedElectrodefromPuddle将短路的焊丝与熔池分离MM-328PinchForce电磁收缩力II2(R2-r2)pR41.45x10-7P=PSIR=OuterConductorRadius(cm)r=InnerConductorRadius(cm)Maximumatr=0MM-329JetForces电弧推力•ThermalMechanism•热机械过程•CausedbyVaporizedandAcceleratedMetalintheAnodeandCathodeDropRegions•由在阳极和阴极之间蒸发和被加速的金属粒子产生•ComplexPhenomenon•复杂的现象•VeryPronouncedatHighCurrents•大电流时非常显著FAnodeFCathodeMM-330TransitionCurrent过渡电流•BelowTransitionCurrent低于过渡电流-ElectrodeisMelted焊丝被熔化-SurfaceTensionHoldsDropletontheWire-表面张力将熔滴留在焊丝端部•AboveTransitionCurrent高于过渡电流-DropletisExpelledfromWireandTransferredtoWork-熔滴被推离焊丝，过渡到工件Current电流Pulsed脉冲80Amps410AmpsMM-331TransitionCurrent过渡电流PinchPressurevsCurrent0123450100200300400500ArcCurrent(Amps)Pressure(PSI)0.0350.0450.062PpinchPg•PinchForcesExceedtheSurfaceTensionForces,MoltenMetalisExpelledandTransferredformtheElectrode•电磁收缩力超过表面张力，熔化金属被推离焊丝MM-332PulseSprayTransfer脉冲喷射过渡timeMM-333PulseArcWaveforms脉冲电弧波型MM-334PulseWelding脉冲焊接•PinchForce电磁收缩力•CurrentPulsesAboveTransitionCurrent电流脉冲高于转换电流•PinchForceExceedsStrengthofMoltenExtension电磁收缩力超过熔滴的表面张力•SprayTransferBecomesPossibleatLowCurrents喷射过渡可以在较低的电流下形成•HeatInputEffect热输入影响•PulsingIncreasestheMeltingRateofWirewithRe