从失效案例中探讨发纹缺陷的常见表现及危害

Discussion on Common Morphology and Harms of HairlineCrack Defects Based on Failure Cases

通过对由发纹引发失效案例的简要介绍,讨论工程上发纹缺陷的常见形态、特点,以及发纹缺陷的常见危害。分析认为,发纹在材料中的表现形式多样,既有近一维线状形态也有二维片状形态,甚至在小角度切面上可以呈现三维缺陷形态;既有断续、连续分布走向一致的长发纹,也有粗短、随机分布的短发纹。发纹的微观表现形式和内容物也不尽相同。发纹缺陷常见的危害除了促进裂纹萌生外,还体现在引发无损检测伪裂纹显示、形成不可接受表面缺陷、导致密封结构泄漏失效等诸多方面。通过对发纹缺陷表现形式、工程危害进行研究总结,能更为准确地判断发纹成因,针对性地提出预防措施和检验评价方法,有助于在结构设计初期提出必要的结构设计、材料与检验要求,提高产品的质量和可靠性。

Based on analyzing failure cases due to hairline crack defects,the common patterns,characteristics and harms of hairline crack defects in engineering were discussed.It is found that hairline crack defects present diverse patterns,including one-dimension linear pattern,two-dimension flake pattern,and three-dimension small angle section pattern.There are both long hair cracks distributed intermittently or continuously in the same direction and short ones distributed at random.In addition,hairline crack defects present various micro morphology and have different contents within them.Hairline cracks have many harms,such as promoting initiation of cracks,leading to fake crack presentation during nondestructive detection,resulting in unacceptable surface defects,and leading to leakage failure of leak-proof parts.Based on summarizing their patterns and harms,the factors contributing to hairline crack defects can be more easily determined,and then proper prevention measures and evaluation methods can be put forward,so that necessary demands for structure design,material and examination can be come up with in the early stage of structure design to improve the quality and reliability of products.