共查询到15条相似文献,搜索用时 46 毫秒
1.
2.
3.
4.
分析了影响数控等离子切割下料质量的各种因素,提出了减少切割缺陷、控制质量的措施,针对形状复杂异形件质量检验提出了不同的测量方法. 相似文献
5.
6.
7.
8.
对于非对称断面、大壁厚且空心的复杂断面空心铝型材,采用常规分流模挤压时很难平衡金属流速,型材挤出后经常产生弯曲或扭拧现象。为此,提出了在常规分流模前增加一级分流模,使传统的分流-焊合-成形的3个阶段变为预分流-分流-焊合-成形的4个阶段,进而达到平衡金属流速目的。研究结果表明:双级分流模比常规分流模挤压时金属流动均匀性得到了改善;各孔金属流速平均值为6.41 mm·s-1,方差为0.2511且降低了65%;挤压温度场分布均匀,温差在7~12℃之间范围内,抵消了温差不均匀的影响;焊合室内静水压力平均值约为290 MPa,模芯周围静水压力分布均匀,模芯不易发生移动。 相似文献
9.
《塑性工程学报》2017,(5)
铝合金微通道扁管热挤压成形中温度变化对成形质量有重要的影响。通过Gleeble热压缩试验,研究了AA3102铝合金的流变应力关系,并基于带线性软化项的修正的Voce硬化模型建立了该合金的本构关系。基于此模型,利用Qform-Extrusion软件平台建立了微通道扁管挤压成形的有限元模型,并通过与现场生产试验对比验证了模型的准确性。利用验证的有限元模型,以峰值挤压力和模孔出口处产品温度为目标变量,进行了仿真模拟正交试验研究。研究结果表明,峰值挤压力随着坯料温度梯度的增大而增大,模孔出口处扁管峰值温度随着挤压速度的增大而增大,调整挤压速度可以减小扁管温差。 相似文献
10.
11.
Die design for axisymmetric hot extrusion 总被引:2,自引:0,他引:2
N. Venkata Reddy P.M. Dixit G.K. Lal 《International Journal of Machine Tools and Manufacture》1997,37(11):1635-1650
A comprehensive finite element model is presented to obtain the temperature distribution in the workpiece as well as in the tooling in hot and warm extrusion processes. Thermo-mechanical analysis of hot extrusion process is carried out by combining the comprehensive finite element thermal model with the deformation models [upper bound and rigid-plastic finite element models presented earlier (N. Venkata Reddy, P. M. Dixit and G. K. Lal, J. Mater. Process. Technol. 55, 331 (1995); N. Venkata Reddy, P. M. Dixit and G. K. Lal, ASME J. Engng Ind. 118 (1996)) [1, 2]. The predictions of the combined thermo-mechanical finite element method (TMFEM) are first compared with experimental results to validate the method. Then it is shown that the temperature distribution and the extrusion power obtained by the combined upper bound/finite element method (UBFEM) are in good agreement with those of TMFEM. Since UBFEM takes significantly less computational time than TMFEM, it is used to obtain the optimal die profile at various process conditions by minimizing the extrusion power.A simple fracture criterion proposed by Venkata Reddy et al. [ASME J. Engng Ind. 118 (1996)] [2] based on the concept of the hydrostatic stress component in the deformation zone falling to zero is used along with TMFEM to predict the die lengths at which the initiation of internal defects takes place. Finally, it is shown that the optimal die profiles satisfy the conditions for prevention of internal defects. 相似文献
12.
13.
大挤压比铝型材挤压过程的数值模拟 总被引:21,自引:3,他引:21
通过采用有限元法与有限体积法相结合,并在有限体积法中进行分步计算的模拟方法,在MSC Super-forge有限元商业软件上成功实现了薄壁大挤压比铝型材挤压过程的数值模拟仿真,获得壁厚t=1.0 mm、挤压比λ=98.27的卷闸门型材挤压过程的材料流动速度场、应力场、应变场、温度场分布图,数值模拟结果与理论分析结果吻合较好。结果表明:采用带导流槽的平模挤压大尺寸、大挤压比型材,可有效分配金属,平衡金属流动速度。 相似文献
14.
分析了热挤压模具工作条件,对影响热挤压模具寿命因素进行探讨,从模具设计和制造、材料选择、表面强化、润滑等环节提出预防控制措施,达到提高模具寿命,提高产品质量的目的. 相似文献