燃油-液压油散热器泄漏失效分析

摘要

A fuel-hydraulic oil radiator was found to leak in use. The failure mode and cause were analyzed by macro and micro observation, microstructure examination and welding depth testing. The results show that the circumferential welding crack between output head and shell body is fatigue crack, which was caused by incomplete fusion welding defects. The axial welding crack of shell body is fatigue crack, which was caused by welding porosity and unqualified melting depth. The leak of the fuel-hydraulic oil radiator was caused by the welding fatigue crack between output head and shell body. The shell body welding fatigue crack brought in larger pressure and tympany, which promoted the leakage of the radiator.%燃油-液压油散热器在使用过程中发生了泄漏。通过宏微观形貌观察、金相检查和焊缝熔深测试，确定了燃油-液压油散热器的泄漏性质及原因。结果表明：出口封头与壳体焊缝处的周向裂纹为疲劳裂纹，未焊合焊接缺陷的存在是导致其疲劳开裂的原因；壳体拼接焊缝处的轴向裂纹也为疲劳裂纹，焊接气孔缺陷的存在和焊缝熔深不足是导致其疲劳开裂的原因。燃油-液压油散热器泄漏是由于出口封头与壳体焊缝发生疲劳开裂造成的，壳体拼接焊缝发生疲劳开裂会造成壳体表面出现鼓胀，进一步增加了出口封头与壳体焊缝处的张应力，对最终的散热器泄漏起到促进作用。