Abstract: To investigate the occasional cracking of the frame longitudinal beam of a certain vehicle model during the roll forming process, this paper adopts the fault tree analysis (FTA) quality tool and focuses on the investigation and analysis of the physical and chemical failure analysis of faulty parts, the surface state inspection of coil raw materials, and the entire roll forming process of longitudinal beams. The results show that the main cause of the cracking of frame longitudinal beams during roll forming is the presence of cold scratches on the inner ring of the material, and such cold scratches are induced by coil loosening, equipment scratch, handling collision and other factors. By optimizing the packaging method of raw materials to reduce scratches during handling, standardizing the recoiling process and cutting off material sections with severe scratches, and additionally setting up special visual inspection for uncoiling before production and grinding repair procedures after water washing in the subsequent processes to ensure no severe scratch defects on the material before roll forming, the cracking of the material during the roll forming process can be effectively avoided.

Key words: roll cracking; large beam steel; fault tree analysis; cold scratch

摘要： 为探究某车型车架纵梁在辊压过程中偶发开裂问题，文章通过应用故障树分析（FTA） 质量工具，重点围绕故障件的理化失效分析、卷料原材料表面状态检查以及纵梁辊压全过程 工艺进行排查分析。结果表明，车架纵梁辊压开裂的主要诱因是材料内圈存在冷态划伤，而 冷态划伤的产生源于卷料松卷、设备刮擦、转运磕碰等因素。通过优化原材料打包方式以减 少转运划伤、规范重卷工艺并切除存在严重划伤的料段，同时在后续工序中增设上线开卷外 观专检及水洗后打磨修复环节，确保辊压前材料无严重划伤缺陷，可有效规避该类材料辊压 过程中的开裂问题。

关键词: 辊压开裂；大梁钢；故障树分析；冷态划伤