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焊接过程中锆合金板材的温度在300℃以上时锆合金易吸收氢、氧、氮等气体杂质,这些气体杂质使得锆合金的力学性能急剧下降,加强焊缝及热影响区的隔离保护和合理制定焊接工艺参数是获得优良焊接质量的关键。以光纤激光器为热源,对厚度为0.7 mm的Zr-Sn-Nb-Fe(锆-锡-铌-铁)合金薄板进行激光对接焊试验,采用ANSYS有限元软件,建立激光对接焊非线性三维传导有限元模型,模拟计算Zr-Sn-Nb-Fe合金薄板的温度场分布。结果表明:模拟计算获得的熔池形状、尺寸与实际焊缝基本吻合,验证了采用高斯面热源模型来模拟Zr-SnNb-Fe合金薄板激光对接焊温度场的合理性;温度场最终呈现流星状的稳定分布,焊缝附近等温线密集,焊缝熔宽窄,热影响区小,板材表面温度在300℃以上的区域的宽度随激光功率的增大而增大,随焊接速度的增加而减小;在激光功率为1300~1500 W,焊接速度为50~70mm/s,离焦量为+1~+2mm,氩气保护喷嘴直径为8~12mm的条件下,Zr-Sn-Nb-Fe合金焊接试样的抗拉强度与母材基本相当,获得了良好的焊缝质量,焊缝无气孔、裂纹等缺陷,晶粒细小,主要元素含量相对母材无明显变化,焊接试样具备较高力学性能。
Zirconium alloy is easy to absorb gaseous impurities such as hydrogen, oxygen and nitrogen when the temperature of zirconium alloy plate is above 300 ℃ in welding process. These gaseous impurities cause the mechanical properties of zirconium alloy to drop sharply, and strengthen the isolation and reasonable protection of weld and heat affected zone Setting welding process parameters is the key to good welding quality. A laser butt welding test of Zr-Sn-Nb-Fe (Zr-Sn-Nb-Fe) alloy sheet with a thickness of 0.7 mm was carried out by using a fiber laser as a heat source. ANSYS finite element software was used to establish a nonlinear three- Finite element model was used to simulate the temperature field distribution of Zr-Sn-Nb-Fe alloy sheet. The results show that the shape and size of the molten pool obtained by the simulation are basically in line with the actual weld, which verifies the reasonableness of using Gaussian surface heat source model to simulate the temperature field of butt welding of Zr-SnNb-Fe alloy sheet. The width of weld zone is narrow, and the heat affected zone is small. The width of the area where the surface temperature is above 300 ℃ increases with the increase of laser power and decreases with the increase of welding speed In the condition of laser power of 1300-1500 W, welding speed of 50-70 mm / s, defocus amount of + 1 ~ + 2 mm and argon protection nozzle diameter of 8 ~ 12 mm, Zr-Sn-Nb-Fe alloy The tensile strength of the welded samples is almost the same as that of the base metal, and good weld quality, no defects of pores and cracks in the weld, small grain size, no significant change in the major element content relative to the base metal, and high welding specimen quality Mechanical properties.