基于一种预制坯形状下铁座多向锻造成形缺陷分析

Analysis on multi-ram forging defects of railway clamp based on a certain kind of preformed blank

设计了某预制坯形状下的铁座多向锻造成形工艺,通过工业试验得到了铁座样件,针对铁座零件在多向锻造成形过程中产生的折叠、毛刺等缺陷的产生原因进行了分析。通过建立有限元模型,选择合理的模拟参数,采用Deform体积成形软件对铁座多向锻造成形工艺过程进行数值模拟,并结合Deform软件后处理中的点跟踪功能对成形过程中金属的流动规律进行了有限元分析。结果表明:铁座样件粗大毛刺产生的根本原因是试验模具结构设计不合理导致的成形上模合模力剧增,增加量高达3776.82 k N,成形载荷超出了设备的能力范围,使模具在成形过程中未完全打靠;铁座折叠缺陷产生的临界压下量为14 mm,试验过程中9 mm的压下量不足以产生折叠缺陷,折叠缺陷产生的根本原因是热态下铁座预制坯两侧体积块与上模的初始装配间隙过小,上模下行与预制坯一接触便产生了干涉。针对铁座样件缺陷产生原因的分析提出了解决方案,并在模拟条件下得到了成形良好的铁座锻件,验证了预制坯形状的合理性及成形工艺的可行性。

The multi-ram forging process of railway clamp under a certain kind of preformed blank was designed,and samples were gained by industrial experiment. It was studied the causes of forging defects,such as folding,burr in railway clamp＇s multi-ram forging process.By establishing a finite element model and choosing the proper simulation parameters,the numerical simulation of the forming process was carried out based on Deform,and the metal flow rule in the forming process was researched with the aid of point tracing function of Deform. The result shows that the fundamental reason of burr is sharply increase clamp force of the top die caused by the unreasonable die structure,and the increasing amount can up to 3776. 28 kN,The forming die cannot be clamped because of deficiency of equipment tonnage. Critical reduction of folding defect is 14 mm,however,9 mm reduction in the industrial experiment cannot cause folding defects.The main reason of sample folding defects depends on the small assembly clearance between the top die and the hot preformed blank,which results in interference at the beginning of the forging process. According to the analysis,the solving measures were proposed and the well-formed samples were gained under simulation condition,the rationality of preformed blank shape and feasibility of the multi-ram forging process were verified.