16mn钢双丝埋弧焊工艺及性能研究

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1、****毕业设计（论文）16Mn钢双丝埋弧焊工艺及性能研究摘要双丝埋弧焊技术具有生产效率高、机械化程度高，焊接质量优良等特点。因此该技术己经在生产中得到了应用，然而关于其理论研究还比较少。所以，本文就焊接工艺参数对双丝埋弧焊接头性能的影响进行了研究，为实际生产应用提供试验依据，为进一步研究双丝埋弧焊接头性能提供参考。本文采用双丝埋弧焊焊接工艺分别在不同的焊接电流和焊丝间距条件下，以20mm厚的16Mn钢为母材，进行了焊接实验。之后又分别对不同参数下焊接接头进行了拉伸试验，并对接头截面形状和金属组织进行分析及硬度测试。研究结果表明:在其它焊接条件一定的情况下，随着焊接电

2、流和焊丝间距的增大，焊缝成形系数逐渐增大。焊接接头金属的显微组织晶粒随着焊接电流的增大越来越粗大且不均匀性增强，接头的硬度值曲线变化越来越明显，且焊接接头的延伸率和屈服强度相应增加，但电流过大或过小都会使接头抗拉强度降低，经比较，前丝焊接电流为700A后丝电流为600A时，接头的力学性能较好。随着焊丝间距的增大，接头金属的显微组织晶粒尺寸稍有减小;接头的显微硬度峰值均出现在焊接热影响区;三组试样抗拉强度均高于母材，所以断裂都发生在母材上。关键词：双丝埋弧焊，焊接接头，显微硬度，力学性能1****毕业设计（论文）STUDYOF16MNSTEELDOUBLEWIRESAW

3、PROCESSANDPERFORMANCEABSTRACTTwo-wiresubmergedarcweldinghasmanycharacteristicslikehighefficiency,highmechanization,highqualityweldingandsoon.Soithasbeenusedinproduction,buttheresearchisstillrelativelyfewonitstheory.Theinvestigationisfocusedonweldingprocessparametershowtoimpactingontheme

4、talpropertyoftwo-wiresubmergedarcweldedjointsinpresentpaper.Theexperimentalbasisforthepracticalproductionandthereferenceforstudyingfurtherthejointpropertiesoftwo-wiresubmergedarcweldingisprovidedbypresentinvestigation.Theresultsobtainedareasfollowing.Keepingotherweldingparametersconstan

5、t,withtheincreaseoftheweldingcurrentandthewirespacing,theaspectratioofweldisincreased.Withtheincreaseoftheweldingcurrent,themetalmicrostructureofweldedjointsismoreandmorecoarse,hoterogeneityofmicrostructureisincreased,andhardnesscurvesofjointschangemoreandmoreobviously,andtheelongationa

6、ndyieldstrengthofweldedjointsareincreasedcorrespondingly,butthecurrentisoverlargeorsmallwillcausethetensilestrengthofjointstoreduce.Bycomparison,whenweldingcurrentofthefrontwireis700Aandweldingcurrentoftherearwireis600A，mechanicalpropertyoftheweldedjointisbetter.Withtheincreaseofwirespa

7、cing,themetalmicrostructuregrainsizeofweldedjointsisslightlydecreased;thedifferentwirespacingmicrohardnesspeakofweldedjointsallappearsinheataffectedzone;thetensilestrenbasemetalgthofthreegroupweldedjointsarehigherthanthatofthebasemetal，sothefractureoccursinthebasemetalzone.KEYW