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为了研究激光焊接对5mm厚异种材料45#钢与40Cr钢焊接的接头组织性能影响,利用6kW高功率激光器在不同参数下进行拼焊试验,采用佳能7D型单反相机拍摄焊缝表面宏观形貌,采用X-350A型应力测定仪检测垂直焊缝方向的表面残余应力,通过HXD-1000型显微硬度计检测焊缝深度方向的显微硬度。结果表明:相对其余情况,焊接速度为1.2m/min时,焊缝表面形貌形状饱满,气孔等缺陷少,表面质量最好;离焦量为-2mm,热输入量为210J/mm时焊缝区出现高而窄的压应力分布,最大值为-187 MPa,能有效提高焊缝疲劳性能;离焦量为-2、-4mm和0mm三种情况时焊缝区整体显微硬度都比母材区高,并且离焦量为-2mm时硬度分布最好,呈平缓减小趋势,最大值为38 HRC,比母材平均值高出14 HRC。选择适当的激光焊接参数能有效的改善45#钢与40Cr钢焊接接头组织性能。
In order to study the influence of laser welding on the microstructure and properties of welded joint of 45 # steel and 40Cr steel with different thickness of 5mm thick material, the welding experiment was carried out under different parameters with 6kW high power laser. The Canon 7D SLR camera was used to capture the macro- The surface residual stress in vertical weld direction was measured by X-350A stress tester. The microhardness in the depth direction of weld seam was measured by HXD-1000 micro hardness tester. The results show that when the welding speed is 1.2m / min, the surface morphology of the weld is full, the porosity and other defects are less, and the surface quality is the best when the welding speed is 1.2m / min; when the defocus amount is -2mm and the heat input is 210J / mm High and narrow compressive stress distribution appears in the seam area with a maximum value of -187 MPa, which can effectively improve the fatigue performance of the weld seam. When the defocus amount is -2, -4 mm and 0 mm, the overall microhardness of the weld zone The base material area is high, and the hardness distribution is the best when the defocus amount is -2 mm, showing a gentle decreasing trend, the maximum value is 38 HRC, which is 14 HRC higher than the average value of the base metal. Select the appropriate laser welding parameters can effectively improve the 45 # steel and 40Cr steel welded joints organizational performance.