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1.
崔金星  韩世超  孙建亮  彭艳 《钢铁》2019,54(5):39-46
 针对中厚板使用过程中的变形行为,研究了中厚板因减薄引起横向残余应力重新分布规律。基于剥层法理论建立了中厚板减薄过程中残余应力分布模型和挠曲变形模型,应用有限元分析法模拟了厚板减薄过程。对比分析了残余应力分布形式和中厚板挠曲变形程度的计算结果和有限元仿真模拟结果,验证了两种分析方法的可行性,并进一步分析了应力分布状态及厚板减薄方式对薄板减薄过程变形的影响。结果表明,两种分析结果都能反映中厚板减薄变形特征,但有限元仿真模拟方法能够随薄板减薄而改变中厚板约束状态,结果更为准确;中厚板内部原始残余应力分布状态及使用过程减薄方式对其减薄过程变形有重要影响,为中厚板的合理生产设计和使用提供理论依据。  相似文献   

2.
石油套管残余应力对抗压溃强度影响的数值模拟   总被引:6,自引:0,他引:6  
运用弹性力学理论,建立石油套管的力学模型,通过有限元计算,得到残余应力与石油套管抗压溃强度之间的关系。研究表明残余应力在很大程度上影响着石油套管的抗压溃强度,当切向残余应力存在时,拉应力明显有利于提高石油套管的抗压溃强度,而压应力的存在会显著降低石油套管的抗压溃强度;而当在石油套管上存在轴向残余应力时,拉应力使石油套管的抗压溃强度降低,而压应力使石油套管的抗压溃强度有所提高;非均匀分布挤压载荷对石油套管抗压溃强度的影响同均匀分布载荷相似。因此,为了提高石油套管的抗压溃强度,应根据管体的受力状态,使石油套管的管体上产牛最件的残余应力值,提高石油套管的抗压渍强度,延长使用寿命。  相似文献   

3.
辊弯成形方形型钢的残余应力   总被引:2,自引:0,他引:2  
 残余应力对于型钢产品的使用性能有重要影响。应用X射线衍射方法对方形型钢的残余应力进行了测量,分析了残余应力在型钢各个部位的分布情况,探讨了不同成形工艺、尺寸、厚度材料生产的方形型钢产品残余应力分布的差异。研究结果表明型钢焊缝处的残余应力最大,残余应力在外表面为拉应力,内表面为压应力,不同成形工艺与外形尺寸对于残余应力的分布有较大影响。研究结果可为工艺设计人员和型钢使用人员提供有益的参考。  相似文献   

4.
搅拌摩擦焊接残余应力的研究进展   总被引:1,自引:0,他引:1  
搅拌摩擦焊(FSW)是一种新型的固态焊接技术。作为一种新技术,还存在着许多问题需要更深入广泛地研究,如材料的流动、温度场、接头的残余应力等。本文介绍了FSW残余应力的试验测量方法和有限元数值模拟方法的研究进展,以及FSW接头残余应力控制技术,分析了接头残余应力的影响因素,揭示了FSW焊接接头残余应力分布的一般规律。  相似文献   

5.
研究了套管在不同工艺条件下的残余应力分布特点,通过保证较高的矫直温度,严禁冷矫直,配合合理的定径工艺,可以获得满意的残余应力分布.  相似文献   

6.
淬火工艺是工件制作过程中不可或缺的环节,而温度梯度又会导致残余应力的产生,因此准确表征GH4169工件内部残余应力及探索建立有效的有限元模拟分析对了解和改善其性能具有重要意义。利用中子衍射的手段研究了GH4169合金淬火残余应力分布,并对淬火过程的温度场和应力场进行有限元数值模拟分析。结果表明:淬火后工件中心的残余应力状态为3向拉应力,约为400MPa;工件近表层形成单向或双向压应力状态,约-300~-400MPa。将有限元计算得到的试样中心和表面处的残余应力和应变与中子衍射测试结果进行对比,结果表明二者应力分布规律较为一致。结合中子衍射和有限元模拟的结果,较为合理地阐述了快速冷却过程中残余应力的形成机制。  相似文献   

7.
郑乔 《宝钢技术》2021,(5):18-24
以Q960超高强钢为研究对象,基于有限元软件,建立热—冶金—力学有限元模型,模拟焊接温度场和残余应力分布.计算结果与接头截面熔池形貌和盲孔法测量的表面应力结果吻合良好,验证了有限元模型的准确性.基于验证模型,讨论和分析了考虑固态相变对Q960超高强钢多道重熔过程中表面及内部应力的分布特征.结果表明:考虑固态相变时,Q960超高强钢单道焊后,焊接接头以拉伸残余应力为主,峰值应力位于热影响区.同时,固态相变效应能够显著降低焊缝中残余应力的大小,以及显著影响横向残余应力的分布.此外,随着焊道数的增加,焊缝中心的横向残余应力呈"阶梯"趋势上升,且在热影响区位置出现局部压应力峰值.  相似文献   

8.
套管的残余应力对抗挤毁强度的影响   总被引:1,自引:0,他引:1  
李连进 《钢铁研究》2005,33(5):23-26
运用弹性力学理论,建立了石油套管的力学模型.通过理论和有限元计算,得到了残余应力与石油套管的抗挤毁强度间的关系.研究表明,残余应力在很大程度上影响着石油套管的抗挤毁强度.为提高石油套管的使用寿命,必须根据管体受力状态使残余应力最佳化,以提高套管的抗挤毁强度.  相似文献   

9.
 在石油套管制造过程中,一般要采用定径工艺消除石油套管轧制和热处理后的尺寸及圆度等误差。这一热轧无缝钢管的最后生产环节决定了石油套管的尺寸和几何形状,同时也影响其力学性能。为此,研究了满足石油套管的尺寸和圆度要求下的定径压下量与残余应力之间的关系,进行了石油套管定径轧制时的变形规律分析,以便减小定径工艺所产生的残余应力,获得最佳的定径效果,提高石油套管的力学性能,为定径工艺的制定提供理论依据。  相似文献   

10.
汽车大梁钢带的温度及分布对组织性能和残余应力有直接的影响。为优化轧制工艺和提高最终产品的质量,通过对轧件轧制过程传热关系的分析,采用有限元法对汽车大梁钢带轧制过程温度场进行了数值模拟,得到了轧制过程的温度场,模拟结果与现场实测值吻合。  相似文献   

11.
利用ansys workbench以及ansys/ls-dyna软件相结合的方法,对60 kg/m的重轨在利用九辊水平矫直时的压下量进行分析,分别在实测值的压下量以及利用虚拟支点理论建立的理论压下量的基础上,建立了矫直规程并进行了模拟仿真,对两种规程下的重轨平直度、重轨纵向残余应力的大小和分布、横截面的应力大小和分布进行分析,结果表明:利用理论值矫直后的重轨平直度有了很大的提高,残余应力也有了显著的减少,并且分布更加均匀.  相似文献   

12.
The knowledge of residual stresses in rails due to roll straightening has become increasingly important for the evaluation of the fatigue behaviour of rails. The residual stresses are induced both by the bending process and the roll contact leading to a very complicated distribution especially near those parts of the surface where the roll contact had taken place. So far, no clear picture has emerged with respect to the residual stress field, either from experiments or from simulations. This study intends to clarify the residual stress distribution by simulation with a fully three-dimensional model taking into account both the bending and contact process. This work shows that especially in those areas where the roll contact happens compressive residual longitudinal stresses appear on the surface. Furthermore, a very steep gradient of the residual longitudinal stress distribution near the surface is observed which is reported also in very recent X-ray and neutron diffraction experimental investigations.  相似文献   

13.
套管抗挤强度的主要影响因素有平均壁厚、几何尺寸精度、屈服强度、残余应力等儿方面。提高管体几何尺寸精度尤其是壁厚不均度、以及采取合理热矫直工艺,可以使套管的抗挤强度超过API要求的70%以上。  相似文献   

14.
H型钢辊式矫直过程及矫直后的残余应力对其承载能力有很大影响,传统上以残余几何形态评价矫直效果存在一定不足.基于弹塑性理论,对辊式矫直过程中H型钢断面上弹性核高度和残余应力进行了理论研究,推导出了相关解析公式,结合实例计算及仿真,验证了解析公式的正确性,对现场工艺参数的制定提供了理论依据.  相似文献   

15.
In the straightening of steel sheet, it is necessary to calculate the optimal reduction of the steel blank by the working rollers of the straightening machine so that the sheet produced has the minimum residual stress and curvature. In the simulation of sheet straightening in multiroller machines, the curvature and bending torques of the steel sheet at contact points with the working rollers are first calculated and then the straightening forces are determined. In straightening steel sheet, it is important to calculate the forces in the multiroller straightening machine. Such calculations are based on determination of the reaction of the roller bearings and the forces at the upper and lower working-roller cassettes in straightening. With insufficient bending torque, it is impossible to eliminate harmful residual stress and surface defects in the sheet. Extreme roller torques and forces at the roller cassettes often lead to defects of the sheet, fracture of the working and supporting rollers, and failure of the straightening machine. In the present work, an approximate method is proposed for calculation of the optimal cold-straightening parameters of the steel sheet in a multiroller machine. The calculations permit determination of the curvature of the neutral plane in the sheet on straightening, the residual curvature of the sheet after straightening, the bending torque and the reaction of the working-roller bearings, the residual stress in the sheet, the penetration of the plastic deformation into the depth of the steel sheet, and the relative deformation of the longitudinal surface fibers of the sheet on straightening as a function of the radius of the working rollers, the distance between the rollers of the straightening machine, the reduction of the sheet by the upper rollers, the sheet thickness, and its properties (Young’s modulus, yield point, and strengthening modulus). The results may be widely used at manufacturing and metallurgical plants.  相似文献   

16.
冷轧镀锌机组的带钢在拉矫过程中,拉矫机机辊和带钢上成组出现宽度约为100mm的明暗相间色差条纹。为了减轻色差影响,结合带钢拉矫的力学基本理论,通过微观的角度对色差机理进行了研究,并采用Solidworks软件对拉矫设备进行了1∶1的实体模型建立。然后基于实际生产工况,采用ANSYS/Workbench软件对带钢拉矫过程进行建模优化并进行了全面的有限元数值模拟分析,确定了镀锌带钢拉矫色差的主要成因机理。最后,采用Workbench的目标驱动优化组件,以带钢表面应力分布最均匀化为目标,对支承辊辊组的结构分布以及带钢拉矫工艺参数进行了优化设计及对比验证分析,优化后带钢表面的应力分布最大差值降低了69.77%。最终提出了镀锌机组拉矫色差缺陷的改善与控制策略。  相似文献   

17.
According to the elastic- plastic bending theory, the straightening reduction could be calculated by the curvature integral method. The 3D dynamic finite element model of bimetal composite plate was established during straightening process. And then the change rules of longitudinal displacement of composite plate and the influence on the residual stress of composite plate under different reduction procedures during straightening process were analyzed by simulation. The results show that the part of the initial wave shape can be eliminated in initial pass time, and the crown of straightened plates can be largely reduced after properly increasing the subsequent inflection during the straightening process, residual stress of the plate is small and uniformly distributed. The flatness of straightened composite plate is complied with the national standards.  相似文献   

18.
Repeated tempering of bulk-quenched rail reduces the residual stress without significant change in the mechanical properties and hardness of the metal. Double tempering with optimal cold straightening is suitable for the manufacture of rail that is resistant to corrosion-fatigue cracks.  相似文献   

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