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电子束焊接残余应力的实测需要花费大量成本,因此采用数值模拟其焊接残余应力的大小和分布具有重要意义.利用三维有限元分析程序,建立了TC4钛合金板电子束焊接温度场和残余应力场的有限元分析模型,着重分析了高压和中压两种工艺参数对其接头焊接残余应力的影响.旨在探讨不同工艺参数对电子束焊接过程的影响规律,从而优化工艺,降低成本.计算结果表明,采用中压参数焊接的电子束焊接接头残余应力的峰值比采用高压参数的接头残余应力峰值高;而且其残余应力分布更集中于焊接接头中段. 相似文献
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采用小孔法测定了14.5mm厚TC4钛合金平板电子束焊接,研究了电子束焊接和局部热处理集成加工工艺下残余应力的分布,分析了局部热处理对焊接接头残余应力分布特征的影响.结果表明,在实验条件下电子束局部热处理后纵向残余拉应力的分布区间由焊接状态下焊缝中心线两侧距焊缝中心线5mm的区域减小到2mm的区域,纵向残余拉应力峰值同焊接状态相比降低了76%,横向残余压应力峰值降低了65%.电子束局部热处理未扫描的母材区域,残余应力数值同焊接状态相比几乎没有变化. 相似文献
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研究钛合金电子束焊接构件残余应力的大小和分布,了解残余应力的形成机理,具有十分重要的理论和实际意义。作者利用ANSYS程序模拟了BT20钛合金电子束焊态和焊后电子束局部热处理的实际焊接温度场以及焊接接头应力场的变化和残余应力的分布。计算结果表明,钛合金薄板焊缝中心残余拉应力的峰值达到焊缝金属屈服强度σn的60%-70%;焊后电子束局部热处理可以降低焊缝中心处的拉伸残余应力值,降低约50%左右;用所建模型计算得到的数值结果规律与实测的残余应力值基本一致。 相似文献
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基于轮廓法测试镍基高温合金惯性摩擦焊接头内部残余应力 总被引:2,自引:0,他引:2
采用轮廓法(contour method)测试小直径FGH96镍基高温合金惯性摩擦焊接接头的内部环向应力。详细介绍了轮廓法测试步骤,包括试样切割、切割面轮廓测试、数据处理和有限元分析;获得了FGH96镍基高温合金惯性摩擦焊接接头内部环向应力分布全貌并分析其分布特征。测试结果表明:镍基高温合金惯性摩擦焊接接头的焊缝中心位置环向应力为非常大的拉应力,峰值拉应力为1200 MPa,达到材料室温时的屈服强度;焊缝区域(距焊缝中心±5 mm区域)近内壁区域的环向应力大于外壁区域环向应力,垂直焊缝方向的环向应力变化梯度非常大;远离焊缝区域,焊缝两侧的环向应力不对称。 相似文献
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In order to estimate the residual stresses in Ti2AlNb alloy jointed by electron beam welding (EBW), a computational approach based on finite element method was developed. Meanwhile, experiments were carried out to verify the numerical results. The comparison between the simulation results and measurements suggests that the developed computational approach has sufficient accuracy to predict the welding residual stress distributions. The results show that the central area of the fusion zone suffers tensile stresses in three directions. When the other parameters remain unchanged, the focus current has great impact on the weld shape and size, and then affects the residual stress level significantly. Moreover, the thick plate full-penetrated EBW weld suffers near 1000 MPa tensile stress of Z-direction in the center of the fusion zone. The wider weld has lower tensile stress in Z-direction, resulting in lower risk for cracking. 相似文献
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The internal residual stress in the narrow inertia friction welding (IFW) welds of FGH96 nickel-based superalloy was measured with the contour method (CM). The as-welded internal hoop and axial residual stresses were obtained after two cuts and the detailed steps of the CM measurement were described. In addition, the hole-drilling method was used to obtain the surface stress. Furthermore, the internal hoop residual stress of a FGH96 superalloy IFW specimen after post-weld heat treatment (PWHT) was also measured with the CM after a single cut. The measured results show that the peak hoop residual stress is not symmetrical about the weld centreline. Axial residual stress on the outer surface at the weld centreline is compressive stress, while tensile stress appears on the inner surface, and it varies linearly along the thickness. The peak values of hoop tensile and compressive stresses decrease dramatically after PWHT. 相似文献
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采用电子束焊接TA12钛合金薄板焊缝表面成形良好,焊缝区以马氏体组织为主,细小的稀土相呈均匀弥散分布状态;随着距焊缝距离的增加,稀土相尺寸逐渐增大,数量逐渐减少,并逐渐趋于球形,沿接头呈一定的规律性分布.小孔法残余应力测试结果表明,垂直于焊缝方向残余应力以纵向应力主,应力呈梯度分布,横向应力较低;焊缝区为纵向拉应力区,应力峰值低于其屈服强度,横向应力为较小的压应力;沿焊缝试板中心区(±20 mm范围内)焊接残余应力分布趋于稳定. 相似文献
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《Science & Technology of Welding & Joining》2013,18(7):614-619
AbstractElectron beam welding (EBW), as a high performance welding method, is also subject to requirements of high integrity welds which particularly include residual stresses affecting distortion and fatigue behaviour. In this context multiple beam technique may provide new applications of specific thermal weld treatment. The present work introduces a promising method of local post-heating in a certain distance to the current welding location applying multiple beams for the reduction in residual stresses in EB welded sheet metals. The conducted investigations include finite element analysis (FEA) and stress measurements in the weld seam area. Using a systematic approach within the FEA decisive process parameters are optimised with reference to the achievable reduction in residual stress. All simulation results are validated by experiments applying strain gauges for the stress measurement. Both simulations and experiments revealed a considerable decrease in residual stress achievable by appropriate positioning of additional heat sources combined with the right power input and beam focusing. 相似文献
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真空电子束焊接具有高能量密度、束斑直径和位置精确可控,焊接残余应力小,焊缝无污染等优点,因此,电子束焊接在异种材料连接领域的应用成为近年来研究的热点,并取得了大量的研究成果,部分已经在工业生产中得到了应用.由于电子束焊接属于熔化焊接,因此在异种金属连接中也存在冶金过程带来的困难.文中对异种材料的真空电子束焊接的研究现状进行了分析,对不同类型的异种材料接头真空电子束焊接中存在的问题和解决方法进行了总结,并提出了今后异种材料真空电子束焊接的研究重点. 相似文献
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难加工材料铣削残余应力研究进展 总被引:3,自引:2,他引:1
镍基高温合金、钛合金等材料具有良好的高温强度、耐热性和耐腐蚀性等优异性能,已广泛应用于航空航天领域,然而这些材料属于典型的难加工材料,其相对切削加工性能很差,且已加工表面易产生显著残余拉应力,严重影响零部件使用寿命及性能。通过适当的方法调整和控制已加工表面的残余压应力,可以明显提高零件疲劳强度和耐腐蚀性。压应力制造技术是指以获得残余压应力为目标的制造技术,是一种典型的抗疲劳方法。将超声技术与其他加工方法复合实现残余压应力的主动控制,是目前抗疲劳制造技术的主要方法之一。然而,由于受超声加工的临界速度限制,超声与高速复合加工的研究相对较少,但两者均是目前压应力制造领域高度关切的先进加工方法,如果两者能有效复合,必将使核心部件制造在保证更加优良的抗疲劳性能的同时,获取更高的效率。通过分析铣削加工、高速加工以及超声振动加工中残余应力的研究现状,提出可将高速加工和超声振动加工相结合,从而实现难加工材料的高效压应力制造。 相似文献