basis知识资料of知识资料welding知识资料engineering焊接工程基础

朽木易折，金石可镂。千里之行，始于足下。第页/共页1.Conceptofthewelding焊接概念Inthewayofaddingthepressureatthejointorheatthejointuntilitmelt,forcetheformationofbondingbetweenthetwoseparatesolidmaterialsbecauseoftheformationoftheatomsjoint.在衔接处加压或加热至熔融,使两种分离的固体材料以原子结合的方式形成衔接.2.Theshapeofthecontactinwelding焊接接触形状Differentweldingmethodsinvolveindifferentshapeofcontactbutsomeweldingforexampleshieldedmetalarcweldingcanweldanytypesofjoint不同的焊接主意适用于不同的接触形状但是有一些焊接例如手工电弧保护焊适用于任何的焊接接头。(1)Squarebuttjoint直对接接头暗示图(2)VbuttjointV型对接暗示图(3)Lapjoint搭接接头（resistancespotwelding电阻焊;laserbeamwelding激光焊;electronbeamwelding电子束焊）暗示图(4)TjointT型接头暗示图(5)Thecross-sectionofaweldingbuttjoint焊接时对接截面：fusionzone熔化区；heat-affectzone热影响区；basematerial母材3.Typesofwelding焊接的基本种类和举例分类（1）fusionwelding熔焊：electricarc电弧焊：1）MIG熔化极气体保护焊；2）TIG惰性气体保护电弧焊；3）SMAW手工电弧保护焊。Gaswelding气焊；laserbeamwelding激光焊（2）pressurewelding压焊：1）frictionwelding摩擦焊；2）resistancespotwelding电阻焊（3）brazing钎焊1.SMAW(shieldedmetalarcwelding)手工电弧焊:Process：Itisusuallycalled“stick”welding,itisthemostwidelyusedweldingprocess.Whenthearcisstruckbetweenthemetalrodandtheworkpiece,boththerodandtheworkpiecesurfacemelttofromaweldpoor.Atthesametimemeltingofthefluxcoatingontherodwillformgasandslagwhichprotectstheweldpoolfromthesurroundingatmosphere.Theslagwillsolidifyandcoolandmustbechippedofftheweldbeadoncetheweldruniscomplete.手工电弧焊也被称为焊条焊接，它是焊接中最常见的一种。当电弧击打在金属焊条和工件之间是，焊条和工件表面同时都会产生一个熔池。同时笼罩在焊条上的熔化的焊剂会形成气体和焊渣，它们保护焊缝不受周围气氛影响。焊渣冷却后凝结，所以必须在焊接完成时及时清除焊渣。Processcharacteristic：Usearodthatisquicklyconsumed用一根会消耗很快的焊条Theequipmentissimpleandinexpensive设备容易成本低Usearodthatprovidesandregulatesitsownflux焊条提供和调控了其自身的焊剂Provideallpositionflexibility焊接位置灵便Lesssensitivetowindordraft对外界风等因素不敏感Thequalitydependsontheoperatorskill质量的好坏取决于焊工的技术暗示图：Capableofproducingtheweldjoint适用接口：buttjoint对接;lapjoint搭接;t-jointT型接口;filletweld角焊Weldmaterialincludes适用材料包括：mildsteel低碳钢;castiron铸铁;stainlesssteel不锈钢2.TIG惰性气体保护焊：Process：inTIGwelding,anarcisformedbetweenanon-consumabletungstenelectrodeandthemetalbeingwelded.Gasisfedthroughthetorchtoshieldtheelectrodeandmoltenweldpool.Iffillerwireisused,itisaddedtotheweldpoolseparately.在惰性气体保护焊中，电弧在无消耗钨极和被焊接的材料中间形成。气体通过焊枪进入，保护电极和熔池。倘若要使用焊丝，它需要和焊缝保持距离。暗示图：AdvantageofTIG:Useanon-consumabletungstenelectrodeduringtheweldingprocess焊接时使用无消耗的钨做电极UseanumberofshieldinggasesincludingHeandAr可使用无数种气体做保护气体包括氦气和氩气Easilyappliedtothinmaterials对薄的材料异常适用Produceveryhigh-quality,superiorwelds焊接质量异常好Leavesnoslagorsplatter不产生焊渣和飞溅LimitationofTIG:TIGrequiresgreaterwelderdexteritythanMIGorSMAWTIG焊接对焊工的要求比MIG和SMAW更高TIGismorecostlyforweldingthickmetalsection对于厚金属板焊接，TIG的成本更高Capableofproducingtheweldjoint：similarwithSMAW3.MIG熔化极气体保护焊：Process：duringtheMIGweldingprocess,theelectrodemeltswithinthearcandbecomesdepositedasfillermaterial.Theshieldinggasthatisusedpreventsatmosphericfromcontaminationandprotectstheweldduringsolidification.Theshieldgasalsoassistswithstabilizingthearcwhichprovidesasmoothtransferofmetalfromtheweldwiretothemoltenweldpool.在熔化极气体保护焊中，电极在电弧作用下熔化并且变成沉积填料。保护气体被用于保护焊接气氛不受污染并且在焊件凝结时起到保护作用。保护气体也起到辅助电弧稳定的作用，可以使金属从焊丝到熔池的改变变得流畅。暗示图：CharacteristicofMIG:Provideauniformweldbead有一个匀称稳定的焊缝Produceaslag-freeweldbead不产生焊渣UseashieldinggasusuallyArwith1-5%oxygen;Arwith3-25%co2;combinationArandHegas使用保护性气体通常是氩气和氧气氩气和二氧化碳氩气和氦气Isconsideredasemi-automaticweldingprocess通常可以使用半自动化焊接工艺Allowweldinginallposition可以在随意位置焊接RequirelessoperatorskillthanTIG不需要很高的焊工技术Allowlongweldstobemadewithoutstartsorstops可以做很长的焊接而不需要中间开始或停止Needlittlecleanup几乎不需要清扫Capableofproducingtheweldjoint适用接口：buttjoint对接;lapjoint搭接;t-jointT型接口;edgejoint端接接头暗示图：Suitableweldingmaterial适用焊接材料：dependsonthedifferenceofshieldgases.Arco2blendsuitformildsteel,aluminum,alloymetal;Hesuitformildsteelinhighspeedprocessandalsocopperandstainlesssteel;carbondioxideismostoftenusedtoweldcarbonandlowalloysteels.按照保护气体的不同，适用焊接的材料也不同。氩气和二氧化碳混合气体适用于低碳钢，铝，合金；氦气适用于高速工艺中的低碳钢的焊接和铜及不锈钢的焊接；二氧化碳适用于