CuNi90/10合金电子束焊接工艺研究

Study on EB Welding Technology of CuNi90/10

对10 mm厚CuNi90/10合金进行电子束焊接试验。液态金属表面张力较小,导致焊接工艺窗口较窄,较大的热输入将导致正面下凹,单面焊双面成形效果不如钛合金的;采用优化的参数可实现正面轻微下凹,同时保证背面成形基本良好。按照优化参数进行试板电子束焊接,并进行GTAW盖面。对焊接试板进行了射线检测和渗透检测,均满足NB/T 47013—2015的Ⅰ级标准;对焊接接头按照NB/T 47014—2011进行了力学、工艺性能测试,测试结果均满足标准要求。电子束焊接区域柱状晶特征明显,焊缝冲击性能优良,冲击功可达200 J以上,同时焊缝区硬度相比母材的有所下降。电子束焊接区域为典型的大深宽比形貌,焊缝区为枝晶α,热影响区为孪晶α;富镍α表现为较亮形貌,富铜α表现为较暗形貌。

The electron beam welding experiment is carried out on 10 mm thick CuNi90/10 plate.The small surface tension of the liquid metal results in the narrow welding process window,therefore,the large heat input would lead to the weld face concave.The effect of one-side welding with back formation for the CuNi90/10 alloy is not as good as that of the titanium alloy.The optimized parameters can obtain the weld face slightly concave and overall good back side appearance.RT and PT results of the weld with GTAW covering can meet grade I standard of NB/T 47013-2015,and the mechanical properties can meet the requirements of NB/T 47014-2011.The columnar crystal feature in the weld zone is obvious,the impact performance is good,with the impact energy reaching 200 J,and the hardness of the weld zone decreases compared with that of the base metal.The appearance of EB weld zone is characterized by large depth to width ratio.The microstructure of weld zone is dendriteαand that of the heat affected zone is twinα.The nickel-richαphase is bright and the copper-richαphase is dark under the optical microscope.