脉冲埋弧焊接头力学性能研究及工程应用

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1、攮要摘要埋弧焊是当前广泛使用的机械化焊接工艺方法之一。针对埋弧焊在焊接时焊接燕输入量较大，造成焊接接头晶粒粗大、脆性增大、塑性和韧性指标下降、裂纹敏感性增大的缺点，本文研究了一种新型的采用直流脉冲电流的埋弧焊工艺．脉冲埋弧焊。本文简要_介绍了以单片祝为核心的脉冲控制器的原理，利髑正交试验设计法设计并进行了脉冲埋弧焊试验。本文以16MnR(8=12mm)钢板为试验母材，研究了陡降外特性焊接电源匹配变速送丝系统的脉冲埋弧焊的脉冲参数(基值电流、峰值电流、脉冲频率、脉宽比)对焊缝成形和焊接接头力学性能特别是冲击韧性的影响。通过对试验结果分析表明：在焊接热输入相同

2、的条件下，脉冲埋弧焊焊接接头的力学性能尤其是冲击韧性较普通埋弧焊有明显的提高。深入分析了脉冲埋弧焊对改变焊接接头力学性熊的机理：脉冲电流的周期性交化，使熔池受到有规律的搅拌和振荡，从而细化了晶粒，降低了熔池金属的浓度起伏，减小了熔敷金属的成分偏析，提高了焊缝金属的力学性能。总之，本文研究麴脉冲电流埋弧焊工艺方法简便，新采用的脉冲控制器操作简便、运行可靠。该项研究对于低温钢焊接及要求保证焊接接头力学性能特别是低温冲击韧性的重要焊接结构(低温压力容器、船舶等)其有广阔的应用前景，具有重要的工程应用价值。关键词：脉冲，埋弧焊，热输入，力学性能，冲击韧性Abstr

3、actNowSubmergedArcWelding(SAW)hasbeenusedasoneoftheweldingtechnologiesofhighmechanizationwidelyTosolvethedisadvantagesofnormalSAWsuchasgraincoarsening，increaseinthebrittleness，decreaseinthetenacityandincreaseinthesensifivi移offlawwhenSubmergedArcW

4、eld(SAW)isappliedwithhighheatinput

5、，thispaperputforwardanewpulsedcurrentSAWtechnology．ThispaperpresentedthebriefprincipleofMCU-coredpulsecontroller．Numbersofexperimentsweredesignedandfinishedwiththehelpoforthogonalmeans。111ispaperchoosesthearmorplateof16MnR(8=12mm)asthetestmaterial．studiestheeffectsofpulseparameter

6、s(backgroundcurrent，peakpulsecurrent，frequencyanddutycycle)onthewelds-shapingandmechanicalproperties。TheresultsoftheexperimentsshowsthatmechanicalpropertiescallbeobviouslyincreasedbypulsedSAW,especiallyimpacttenacityofweldingjointwhenusmgsharp一巍lloutputcharacteristicspowerSOUI℃ean

7、dvarying-speedwirefeedercomparingwiththeordinarySAWwhenusingequalheatinput．ThispaperhasanalyzedthemechanismofimprovingmechanicalpropertiesofweldingjointweldingbypulsedSAW：Sll攮regularchangeofpulsedcurrenthelpsmoltenpool’Ssurgingandchurninganditcallobtainlessergrainsize，reduceconcen

8、trationchangeofmoltenpoolmetal，decreasethecompositionsegregationofdepositedmetal，andenhancemechanicalpropertiesofdepositedmetal．Inconclusion,thetechnologyofpulsedSAWthatputforwardinthispaperisaneasyandefficientmethodofweldingtechnology,andthedevelopedpulsecontrolleriseasytomanipul

9、ateanddependabletorun．Theresearch