共查询到20条相似文献,搜索用时 171 毫秒
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压力容器在焊接之后,会在焊缝处产生一定的残余应力,对容器的质量会产生一定的影响,而且,根据容器焊接的具体情况的不同,焊接残余应力的大小也会有所差别,为了降低残余应力对焊接容器造成的质量影响,需要采取有效的方法消除容器焊接中产生的残余应力。 相似文献
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焊接不可避免产生残余应力,对结构完整性造成很大影响。提出利用高压水射流喷丸技术降低焊接残余应力,并利用有限元法进行计算模拟。分别开发了模拟焊接的移动双椭球热源子程序及模拟高压水射流喷丸的移动压力载荷子程序,得到了经高压水射流喷丸处理前后焊接残余应力分布的变化规律。计算结果表明,经高压水射流喷丸处理后,焊缝和热影响区存在的焊态残余应力得到降低,在焊缝区已经产生压缩应力。证明高压水射流喷丸具有降低焊接残余应力的效果。 相似文献
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宗小艳 《机械工人(热加工)》2010,(16):34-38
厢西堡枢纽互通式立交桥钢箱梁为全焊接钢箱梁,结构关系复杂,焊缝较多,焊接工作量大,且桥长方向为曲线线形,所产生的焊接变形和残余应力较大。为了探索该桥钢箱梁的焊接技术,采用试验和理论研究的方法对该桥钢箱梁焊接制造的焊接材料选择、焊接工艺制定、焊接变形控制、提高抗疲劳能力、消除应力措施及焊接检验进行了分析研究,并对重点部位的焊缝提出了相应的工艺措施。 相似文献
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由焊接残余应力带来的焊接接头应力腐蚀开裂问题,是石油化工行业广泛使用的输送管道的主要失效形式。很多情况下,改变接头的应力分布状态,是解决这一问题的有效方法。结合小直径管道的特点,文中提出一种新的消除应力方法——协调变形法,即在管道焊缝两侧压应力区制造温差,使该区产生一定的与焊缝区相协调的收缩变形。对比协调形变法消除小直径管道焊接残余应力的数值模拟结果和实验结果,分析协调形变法消除残余应力的机理。结果显示,数值模拟结果与实际情况一般都符合得较好,可以达到100%的消除应力效果(内表面轴向应力)。该方法使用简单、效果好,表明协调形变法是消除残余应力的有效方法,可以解决小直径管道由于消除应力难而产生的应力腐蚀问题。 相似文献
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Jl Shude Astronautical Science Technology Academy Shenyang Institute of Aeronautical Engineering Shenyang China FANG Hongyuan YANG Jianguo State Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin China 《机械工程学报(英文版)》2006,(1)
Numerical simulation on Francis turbine runner's welding temperature field and welding tress field is carried out on the base of solving the problem of welding heat source's movement along any spatial routes and the problem of heat elimination between the complicated blade and air. The evolvement law of welding stress and the distribution of the stress field after welding are obtained. The results indicate that the peak value of the welding residual stress appears on the outlet edge of blade near the contact area between blade and band or blade and crown. Associated with the distribution of the runner's working stress, the invalidation reason of the Francis turbine runner is explained. 相似文献
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针对铝/钢异种金属薄板焊接时容易产生残余应力与变形问题,提出采用随焊冷却氩气激冷对其进行控制。建立随焊氩气冷却激冷铝/钢异种金属熔钎焊的数值分析模型,研究不同冷却距离对残余应力和变形的控制效果,探究随焊激冷技术控制焊接变形与残余应力机理;同时,进行随焊激冷铝/钢异种金属熔钎焊试验,对焊接温度场、残余应力与变形进行测量,验证模型的准确性。结果表明,采用最优冷却距离(d=10 mm),进行随焊冷却氩气激冷焊接试验时,纵向残余拉应力峰值和残余压应力峰值分别减小42.1%和74.4%,横向残余拉应力峰值和残余压应力峰值分别降低11.3%和14.4%,铝板和钢板外边缘焊接变形量分别减小67.9%和69.5%。随焊冷却氩气激冷技术可有效控制铝/钢薄板焊接时产生的残余应力与变形。 相似文献
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Hui-Jun Yi Jong-Yun Kim Jin-Ho Yoon Sung-Soo Kang 《Journal of Mechanical Science and Technology》2011,25(12):3185-3193
In the present work, both experimental and numerical simulation methods are used to investigate the characteristics of welding
distortion and residual stress distribution. A 3D thermo-mechanical Finite Element Analysis (FEA) method is used to predict
the welding distortion and residual stress of cylinder-shaped multi-pass layer weldments. Each weld pass is performed using
a quarter-circle balanced welding procedure. To investigate the influence of deposition sequence and welding heat input on
the welding distortion and residual stress, a continuous welding procedure is also calculated. The corresponding FEA models
considered a moving heat source, the deposition sequence, and temperature-dependent thermal and mechanical properties. The
results predicted by 3D FEA model are generally in good agreement with the measurements. Finally, the numerical and experimental
results suggest that both deposition sequence and heat input affect welding distortion and residual stress distribution. Furthermore,
the 3D thermal-mechanical FEA method can predict cylinder-type welding distortion. 相似文献
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The effects of initial deflection and initial residual stress in steel plate on the out-of-plane deformation and residual
stress due to welding are investigated from analysis results of thermal elastic-plastic FEM modeling with large deflection
theory. Initial residual stress due to plate forming has very little effects on welding deformation and welding residual stress.
For initial deflection, with concave profile (Type I), welding induced deformation has the same type as initial deflection
and its magnitudes are small. When initial deflection is in the direction parallel to weld Une (Type II), welding induced
deformation has minor variations. When initial deflection is bended in the direction normal to weld line (Type III), welding
deformation was largely generated along the width direction of the steel plate. On the other hand, the variation in type of
initial deflection does not affect the residual stress and plastic strain. 相似文献
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运用有限元方法对正交接管结构在常规焊接和在线焊接条件下的温度场和残余应力场进行了数值模拟。考虑残余应力,对结构在内压作用下的应力及载荷应变曲线进行了分析。结果表明,在研究该结构的强度性能时,常规焊接条件下可不考虑残余应力的影响,而在线焊接残余应力对强度性能有较大的影响。 相似文献
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焊接顺序对T形接头焊接残余应力场的影响 总被引:9,自引:0,他引:9
为了得到T形接头焊接顺序的优化方案,在确定合理的焊接热源形式以及建立有限元模型的基础上,利用单元死活技术从多道焊、分段焊与多层焊的角度对焊接顺序对T形接头焊接残余应力场的影响进行数值分析.对于多道焊来说,焊接残余拉应力出现在焊缝及其附近区域,且峰值出现在焊缝区域;相邻焊道之间采用首尾相接的方法得到的焊接残余拉应力峰值是最小的.对于分段焊来说,采用先焊两端后焊中间的方法不仅可以增加整个焊缝的焊接残余低应力区域;而且可以有效地降低先焊区域的焊接残余应力,降低效果与后焊焊段的焊接方向以及先焊焊段上的点到后焊焊段端部的距离有关.在多层焊的过程中,采用对称施焊的方法得到的焊接残余拉应力峰值是最小的. 相似文献
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机械应力消除法对焊接残余应力的影响 总被引:2,自引:0,他引:2
大直径全焊接阀体球阀制造的最后一道工序是焊接,由于采用橡胶圈密封,为防止密封圈的损坏,导致密封性能降低,焊后不能采用焊后热处理消除焊接残余应力。为了控制阀体焊接残余应力,选择机械应力消除法,建立阀体机械应力消除法的加载压力与时间的关系曲线,采用有限元分析和试验相结合的方法,研究机械应力消除法对焊接残余应力的影响。机械应力消除法前后采用盲孔法测量阀体外表面的残余应力。结果表明,采用二维轴对称有限元法可以模拟机械应力消除法过程,机械应力消除法可以降低阀体外表面轴向应力和环向应力的峰值,使残余应力分布更加均匀,可以作为焊后热处理的替代工艺。 相似文献