关键词: 辊压开裂；大梁钢；故障树分析；冷态划伤

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