高耐候钢手持激光填丝焊不同板厚对接接头组织与力学性能对比研究

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Abstract：Usingthe 2.5mm and 4.0mm platethickness high weathering steel Q35OEWR1 hand-held laserwire welding butjointas the researchobject，the microstructure ofeach area of the joint was observedandthe mechanical properties were tested to analyze the influence of plate thickness on the microstructure and mechanical properties of thejoint.Theresults show thatthe base material iscomposedofferiteand pearlite.Inthe heat affected zone，there is only normal fire zone without coarse crystal zone.The weld is composed of proeutectoid feriteand bainite.The hardness distributionof the two joints is inthe shape of“mountain”.Due to the changes inthe microstructure and grain size of the weld and heat afected zone under the action of welding heatcycling，the relationship between the hardness size of the joint regions isas follows：weld zone > heataffected zone > base material.Due to the difference in pearlite and ferrite content in the base material area， the tensile strength of the 4.0mm butt joint is lower than that of the 2.5mm buttjoint，andthe tensile strength is 491MPaand 558MParespectively，bothof whichbreakatthe base material.Under the specified cycle life condition of N=107 ，thefatigue strength of the 2.5mm butt joint is 203MPa The fatigue strength of the 4.0mm butt joint is 144MPa ，which is lower than that of the 2.5mm butt joint. Keywords： high weathering steel; hand-held laser wire welding; microstructure; mechanical properties

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激光加工具有光点小、能量集中、热影响区小、不接触工件及对工件无污染等特点，因此，涌现出激光切割、激光焊接、激光增材等各种形式的新工艺新技术[1]。（剩余5533字）