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超细晶粒钢在不同焊接热循环作用下,热影响区晶粒会有不同程度的长大,从而对接头的塑性和韧性产生影响。本文在激光深熔焊接热源模型简化为点热源叠加线热源的基础上,提出特征晶粒概念,建立了激光焊接热影响区晶粒长大的数学模型,并对超细晶粒钢激光焊接热影响区的晶粒长大进行了计算,计算结果与实测结果吻合良好。发现激光焊接由于具有极小的能量输入,超细晶粒钢激光焊接接头晶粒尺寸长大并不严重,当线能量为96J/mm时,热影响区最大晶粒尺寸为20μm左右。
Under the effect of different welding thermal cycles, the grains in the heat-affected zone will have different degrees of growth in the ultra-fine grain steel, which will affect the plasticity and toughness of the joint. Based on the simplification of laser deep welding heat source model to point heat source superposition line heat source, the concept of characteristic grain is proposed, and the mathematical model of grain growth in heat affected zone of laser welding is established. The laser welding heat of ultrafine grain steel The grain growth in the affected area was calculated, the calculated results agree well with the measured results. It is found that the grain size of laser welded joints of ultrafine grained steel is not serious due to the minimal energy input. The maximum grain size of heat affected zone is about 20μm when the energy of the line is 96J / mm.