水冷缸套断裂失效分析

Fracture Failure Analysis on Water-cooled Cylinder Liner

通过宏观检验、化学成分分析、力学性能测试、金相检验等手段对铬钼合金铸铁水冷缸套的断裂原因进行了分析。结果表明:缸套断裂的主要原因是其表层组织中存在不同程度的E、D型过冷石墨和大量游离铁素体。在后续滚花应力作用下萌生微裂纹,进而在使用过程中,因复杂的受力和恶劣的工作环境而导致断裂。

The fracture reasons for the chromium molybdenum alloy cast iron water-cooled cylinder liner were analyzed by macroscopic examination, chemical compositions analysis, mechanical property test and metallographic examination. The results show that the main reason for the fracture of the cylinder liner is that there are E, D type of supercooled graphite and a large amount of free ferrite with different levels in its microstructure of surface layer. The cylinder liner produces the tiny cracks with the pressure stress ofknurling. Then it fractures under the complex stress and bad environment during the course of working.