楔横轧一次轧制铝合金连杆坯料的数值模拟研究.pdfVIP

楔横轧一次轧制铝合金连杆坯料的数值模拟研究 摘 要 楔横轧（cross wedge rolling ，简称CWR ）是高效生产轴类件的主要方 法之一。由于生产效率高、产品质量好、设备载荷小等优点，受到国内外 的广泛关注。但因其模具设计和变形规律复杂，在变形机理和缺陷产生机 理等方面尚未形成统一的定论，仍存在深入研究的价值。 现存的楔横轧研究多以钢材为原料，对其他材料的研究较少，而高强 铝合金连杆是应用广泛的机械零件。因此，本文以发动机铝合金连杆预制 坯为研究对象，采用一次楔横轧工艺，结合热力耦合有限元模拟方法，探 索其变形规律，为其他铝合金轴类件的楔横轧工艺提供借鉴。 分析结果表明：轧件表面金属受“两压一拉”的应力状态；轧件径向 金属的不均匀变形使轧件心部易受拉应力，心部的应力应变状态使该处的 材料质量容易受到破坏；在轧件心部与小头连接处，单位网格的纵向拉长 程度偏大，Z 向拉应力和Z 向应变、X 向应变、Y 向应变、等效应变明显 相对较大，使该处金属易向Z 向流动，发生剧烈变形。随着展宽角的增大， 轧件心部与小头连接处的应力应变和金属流动有所改善，有效避免缩颈； 随着轧制初始温度的升高或表面温度梯度的降低，金属的不均匀流动得到 平衡，降低了心部X 向和Z 向拉应力，但却增大了等效应力和等效应变， 使疏松出现的可能性增大。对比二次楔横轧，一次楔横轧明显提高了加工 效率，改善了轧件心部质量。 关键词：楔横轧 一次轧制 铝合金 连杆 数值模拟 I NUMERICAL SIMULATION OF ONCE CROSS WEDGE ROLLING ON THE BILLETS OF ALUMINUM ALLOY CONNECTING ROD ABSTRACT Cross wedge rolling (referred CWR) is one of the most efficient methods for producing shaft parts. It has gotten extensive attention due to its high production efficiency, excellent products quality and low equipment load, etc. However, the unified conclusion in deformation mechanism and defect control has not been formed owing to the complexity of mold design and deformation law. Therefore, this method still deserves further researches. The scholars mainly utilize steel as raw material to research on cross wedge rolling nowadays, but other materials were ignored. While it is the high-strength aluminum alloy connecting rods that is widely used as mechanical parts. Therefore, combining the method of thermal-force coupled finite element simulation, this article will take engine aluminum alloy connecting rod performs as the research object and adopt the once cross wedge rolling process to explore the deformation law, thus providing a reference for cros