鞍座支架以铸代焊工艺设计与性能分析

Process Design and Performance Analysis of Casting Substitute Welding for Saddle Bracket

针对传统钢板焊接工艺生产的鞍座支架在焊缝处存在应力集中和晶粒组织粗大、易发生疲劳断裂等问题,提出了以铸代焊工艺技术方案。通过对铸造充型和凝固过程仿真分析,发现在限位挂钩处出现微小缩松、缩孔缺陷,总体积约为0.32 cm^(3)。进一步通过有限元方法对缺陷位置进行应力分析,发现该缺陷处应力仅为5 MPa,不会影响铸件整体性能。利用所提方案进行试铸试验,并测试了试铸件的抗拉强度、屈服强度、伸长率、硬度等指标均符合设计要求,珠光体含量为80%以上,铸件承受的最大应力为60 MPa,远小于材料的许用应力,铸造鞍座支架疲劳寿命是钢板焊接鞍座支架的1.2倍。试验结果表明:铸造鞍座支架整体性能优于钢板焊接鞍座支架。

The saddle bracket produced by traditional steel plate welding process had the problems of stress concentration,coarse grain structure and fatigue fracture at the weld.The process technology of casting instead of welding is proposed.Through the simulation analysis of casting filling and solidification process,it was found that there were small shrinkage cavity and porosity at the limit hook,and the total volume was about 0.32 cm3.Further,the stress analysis of the defect position was carried out by the finite element method.It was found that the stress at the defect was only 5 MPa,which would not affect the overall performance of the casting.The casting test was carried out by using the proposed scheme,and the tensile strength,yield strength,elongation,hardness and other indicators of the test castings were tested to meet the design requirements.The pearlite content was more than 80%,and the maximum stress of the casting was 60 MPa,which was far less than the allowable stress of the material.The fatigue life of the casting saddle bracket was 1.2 times that of the steel plate welding saddle bracket.The test results show that the overall performance of casting saddle bracket is better than that of steel plate welding saddle bracket.