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《机械制造文摘:焊接分册》2009,(6):17-18
铝合金随焊控制焊接应力与变形的几种新方法
采用力学手段,对铝合金焊接熔池后方的脆性温度区间施加横向挤压应力,同时使焊缝纵向保持塑性延展,从而达到随焊控制焊接应力与变形并防止焊接热裂纹的目的。介绍了随焊冲击碾压、随焊旋转挤压、双向预置应力和随焊电磁冲击等几种控制焊接应力与变形的新方法。在台适的工艺参数条件下,可以将铝合金平板对接焊件的残余变形量降低到很低的程度,同时可以防止焊接热裂纹的产生。 相似文献
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采用普通交流TIG焊和随TIG焊旋转挤压两种方法对2A12铝合金薄板进行焊接,分别对焊接熔合区、热影响区和焊缝区的显微组织进行晶相分析.结果表明,与普通交流TIG焊相比,随TIG焊旋转挤压法对变形和气孔的控制效果较好,得到的焊缝组织品粒细小而均匀,有效降低了残余应力,提高了焊接接头的力学性能.对焊接接头进行拉伸试验,拉伸试样断裂的位置均为焊缝区,焊缝在冷却过程中由于偏析而生成的低熔点共晶θ相和S相使得力学性能下降,且随焊旋转挤压法焊接接头的抗拉强度和屈服强度约为普通交流TIG焊接头的1.2倍. 相似文献
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薄板钛合金由于在焊后存在较大的残余压应力,使得其易发生失稳变形.采用随焊旋转挤压方式,对焊缝高温部位进行塑性延展,减少焊接时所发生的塑性收缩量,降低残余压应力的值,从而降低焊接变形量.采用拉伸试验、拉伸断口SEM分析和焊后薄板的变形挠度的测量等试验.结果表明,随焊旋转挤压焊件的变形挠度可以下降到常规焊件挠度的2/3,并且随着加载应力的增加,变形的挠度可以进一步下降.说明在焊接过程中采用随焊旋转挤压方式控制薄板TC4失稳变形是可行的. 相似文献
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氢化锂(LiH)是重要的热核材料,其状态方程参数是惯性约束聚变研究的重要内容。本工作采用真空热压技术制备氢化锂薄膜,在真空度小于5.0×10-4 Pa,温度450 ℃,升温速率10 ℃/min,采取分段加压、退火,获得了厚度小于100 μm、厚度一致性约98%的氢化锂薄膜,表面粗糙度小于100 nm,热压后密度增加,达到0.780 g/cm3。X射线衍射分析结果表明:薄膜的主要成分为氢化锂,薄膜存在择优取向、内应力、晶粒细化等特征。 相似文献
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The new technology of welding with impacting rotation is put forward to decrease the wave-like deformation of the TC4 thin plate weldment.The thermal stress and strain are vital to understand the mechanism of controlling the wave-like deformation.In order to know the development of internal thermal stress and strain,finite element method is utilized for the stress and strain are difficult to be investigated by experimental methods during the welding process.Temperature field,thermal stress evolution and distortion of thin plate are compared with the test results such as weld thermal cycle,residual stress sectioning measurement,and the deflection of the thin plate respectively.By the finite element analysis and test results verification,the mechanism of the technology to control the wave-like deformation is brought forward,non-uniform thermal elastic strain between compressive plastic region and elastic extensive region is diminished by a certain amount of extensive plastic deformation by welding with impacting rotation process. 相似文献
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Rajesh Manti D.K. Dwivedi A. Agarwal 《Journal of Materials Engineering and Performance》2008,17(5):667-673
This article reports the influence of pulse tungsten inert gas (TIG) welding parameters on the microstructure, hardness and
tensile strength of weld joints of two Al-(0.5-0.8%)Si-(0.5-0.6%)Mg alloy (T4) produced by using three pulse frequencies (25,
33, and 50 Hz) and two duty cycles (40 and 50%). It has been observed that the mechanical properties (hardness and tensile
strength) are sensitive to microstructure of weld metal, which is appreciably affected by the pulse parameters. Low frequency
produced higher strength and hardness than high pulse frequency under identical welding conditions. Weld metal and HAZ were
found stronger than the base metal. SEM study showed that the fracture of weldment was mostly brittle type. 相似文献
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为了研究温度、变形速率对TC4焊接件的力学性能影响,分别采用100~800℃下变形速率为0.001,0.1,1和10s-1的拉伸试验来表征焊接件的动态力学性能,并基于Johnson-Cook模型对相应变形速率下的屈服强度进行理论计算,而后比较了计算值和实验所测的数值,结果说明可以采用Johnson-Cook模型来表征焊接件的动态力学性能。 相似文献