卫生洁具表面缺陷的成因及对策

陶瓷洁具生产过程中,釉泡和针孔是出现频率很高的一种缺陷,如何减少釉面缺陷成为生产环节控制的重点.本文以佛山某卫浴陶瓷厂一款高档坐便器为例,根据产品缺陷出现的部位和缺陷状态,分析了该釉面缺陷产生的主要原因并提出了解决办法.     

爆炸复合钢板设备制造中的焊接缺陷及质量控制

爆炸焊接复合钢板设备在制造过程中焊接接头易产生裂纹等缺陷,本文就焊接接头缺陷产生原因进行分析,提出相应措施以避免缺陷产生。     

钢结构涂装缺陷及防治的技术管理

本文分析了产生涂装缺陷的不同因素,提出必须加强涂装质量管理问责制,增强钢结构涂装设计管理和对涂装缺陷试样的阶段控制,制作试样以预测涂装设计涂层的耐久性等,并重点论述了通过对涂装过程进行质量管理,以达到防治涂装缺陷的目的。     

无损探伤缺陷类型的波形分析

采用扫描电镜、金相显微镜对环件探伤缺陷进行分析以找出探伤波形和缺陷之间的对应关系。结果表明:探伤缺陷为钙铝酸盐夹杂,钙铝酸盐夹杂属内生夹杂物,这种缺陷波形为单峰、尖锐、无草状波。与环件探伤裂纹波形相比这种缺陷波形峰值较低、当量较大。通过探伤波形的分析对判定环件缺陷类型具有实际意义。     

钢结构涂装缺陷及防治的技术管理

本文分析了产生涂装缺陷的不同因素，提出必须加强涂装质量管理问责制，增强钢结构涂装设计管理和对涂装缺陷试样的阶段控制，制作试样以预测涂装设计涂层的耐久性等，并重点论述了通过对涂装过程进行质量管理，以达到防治涂装缺陷的目的。     

超高压水晶釜超声检测方法及缺陷评定

在对超高压水晶釜结构特点及缺陷产生方式分析的基础上,提出了采用准确有效的纵波、横波超声检测方法,并提出了缺陷评定方法,以确保危险缺陷的检出。     

表面缺陷对硅橡胶密封件接触特性的影响

以典型舱门橡胶密封件为研究对象,基于自制的密封接触特性试验装置,研究不同直径表面缺陷对硅橡胶密封件表面接触特性的影响。结果表明:缺陷直径对接触面积和平均接触压力影响较大,缺陷直径越大,接触面积越小,平均接触压力略有增大;缺陷直径对缺陷周围接触效果影响较大,直径越大,接触特性越差;表面缺陷对密封件密封性能影响显著。     

表面缺陷对硅橡胶密封件接触特性影响的试验研究

以典型舱门橡胶密封件为研究对象,基于自制的密封接触特性试验装置,研究不同直径表面缺陷对硅橡胶密封件表面接触特性的影响。结果表明：缺陷直径对接触面积和平均接触压力影响较大,缺陷直径越大,接触面积越小,平均接触压力略有增大;缺陷直径对缺陷周围接触效果影响较大,直径越大,接触特性越差;表面缺陷对密封件密封性能影响显著。     

车灯塑料件真空镀铝缺陷分析与对策

讲述了车灯镀铝和镀层性能测试的基本要求,对镀铝的缺陷类型进行分析,重点分析了注塑毛坯件缺陷、镀铝工序缺陷、包装与运输缺陷、试验件报废等4种情况,分享了部分对策。指出还应从灯具设计源头进行优化,尽量采用遮挡等方式掩盖镀铝缺陷,以减少镀铝件报废。     

陶瓷墙地砖常见缺陷分析

介绍了陶瓷企业在生产陶瓷砖过程中常见的一些缺陷以及产生缺陷的原因,并针对相关缺陷提出了该如何去调整和解决,确保产品质量的稳定,以提高产品的优等品率,降低生产成本。     

Flaws Responsible for Slow Cracking in the Delayed Fracture of Alumina

The early stages of crack extension from inherent flaws were observed directly in order to identify flaws responsible for crack initiation. The specimen surface was immersed in fluorescent dye penetrant while cracks were forming; this procedure allowed the dye to penetrate into the fine cracks. Once the cracking sites were located, scanning electron microscopy was used to identify the flaws. An eccentrically loaded column testing system was used to produce a number of crack initiations on a surface of a specimen without causing catastrophic failure of the specimen. There were many inherent flaws which, either by themselves or as an assembly, became potential crack origins. The initial stage of delayed fracture was shown to involve the interaction and coalescence of nearby flaws with intergranular cracking. It was also found that the crack origins were multiple in delayed fracture.     

Effect of Cleaning and Abrasion-Induced Damage on the Weibull Strength Distribution of Sapphire Fiber

Fractographic analysis revealed the presence of concurrent flaw populations in sapphire fibers which were tensile tested in the as-received condition (sized and unsized) and after various cleaning procedures. The following flaw populations were identified: surface flaws attributed to handling and abrasion damage (type A), volume or internal flaws attributed to shrinkage voids which form during the manufacturing process (type B), localized fiber surface reaction flaws introduced during the flame-cleaning procedure (type C), and self-abrasion surface flaws intentionally introduced on unsized fibers (type D). The strength distribution associated with each flaw type was characterized using a censored data Weibull analysis for both the least-squares and maximum-likelihood estimation methods. The strength distribution for type C (flame-cleaning) flaws exhibited an approximately 20% degradation in strength compared to the distribution for type A flaws. The strength distribution for type D (self-abrasion) flaws exhibited an approximately 35% degradation in strength compared to the strength distribution for type A flaws. This result underscores the need for fiber sizings to prevent damage during shipping and handling. However, higher purity sizings and/or improved procedures for sizing removal are required to mitigate cleaning-induced fiber strength degradation during composite fabrication.     

缺陷对粘胶基炭纤维强度的影响及补强处理方法

综述了粘胶基炭纤维 (RCF)中缺陷的几种可能来源 ,并分析了缺陷对粘胶炭纤维强度的影响。热解碳沉积法、氧化刻蚀法、氯化氢和惰性气氛补强法、金属盐溶液体系补强法等方法可以通过减少或消除 RCF中缺陷 ,从而提高 RCF的抗拉强度。     

Determination of Flaw-Size Distribution by the Crack-Off Process

The crack-off process is a new alternative to diamond sawing for the cutting of brittle materials. The process involves exposing brittle rods (or plates) to biaxial fluid pressure. Fluid penetration into surface flaws causes fracture at pressures strongly dependent on the severity of the flaws. A method for calculating the probability-density distribution of surface flaws in a batch of brittle rods, using the crack-off pressures for a random sample, is presented here. The scatter in the pressure data is a consequence of the statistical nature of surface flaws. Parameters defining the flawsize distribution can hence be deduced from the crack-off pressure distribution. The method has been tested on two batches of glass rods that have undergone different treatments, with satisfactory results.     

玻璃的脆性(三)

玻璃的缺陷可分为纳观缺陷、微观缺陷和宏观缺陷。纳观缺陷为纳米尺度的缺陷,指玻璃结构缺陷,包括微相、微不均、配位不全,空穴等。微观缺陷指微米尺度缺陷,主要为玻璃表面Griffith裂纹。宏观缺陷为玻璃制造中产生的缺陷,如气泡、结石、条纹,以及使用过程中的损伤。这些缺陷的存在增加玻璃的脆性。描述了玻璃表面Griffith裂纹的尺寸、分布以及形貌。     

Duality in the Creep Rupture of a Polycrystalline Alumina

Creep rupture experiments performed on a polycrystalline alumina have revealed a duality in fracture behavior associated with a crack blunting threshold. At high stresses, or in the presence of large preexisting flaws, fracture is dictated by the slow creep growth of flaws and exhibits substantial statistical variability. At lower stresses, preexisting flaws blunt, and failure is delayed. In this regime, failure occurs by the coalescence of creep damage, manifested as shear bands, and the failure strain becomes inversely dependent on the applied stress.     

Effect of Surface Damage on the Strength of Al2O3 Ceramics with Compressive Surface Stresses

In fully dense fine-grained Al₂O₃ ceramics, fracture originates at surface flaws. The severity of these flaws depends on the methods used to form the surface and any subsequent damage that may have occurred. It is desirable to find ways to minimize the severity of these flaws. Both untreated and quenched Al₂O₃ rods were scratched by rotating them under a diamond point with various loads. The strengths of the quenched rods decreased less than those of the untreated rods. Microscopic examination showed that the compressive surface stresses induced by quenching reduced the penetration of surface damage.     

陶瓷制品无损检测最佳灵敏度影响因素的研究

红外热成像无损检测的本是测量物体表面的温差，温差越大，同检测灵敏度越高。本文就陶瓷制品红外热成像无损检测影响最佳检测灵敏度的因素进行了研究，发现被检测材料本身的导热系数和缺陷材料的导热系数是最主要的影响因素，而热激发温度或热流和环境温度则是影响红外无损检测重要的外部因素；缺陷在制品内存在的深度、缺陷的尺寸及缺陷的类型则是影响红外检测的重要因素。     

关于球罐缺陷简述

本文就非低温球罐中常见的缺陷类型加以描述，并对其发生机理作了分析说明，提出了解决及避免缺陷的对策。     

Effect of Indenter Geometry on Controlled-Surface-Flaw Fracture Toughness

Fracture toughness values obtained using both Knoop and Vickers-indentation-produced controlled surface flaws were compared as a function of indentation load for a well-characterized glass-ceramic material. At the same indentation load, Knoop cracks were larger than Vickers. As-indented K_c values calculated from fracture mechanics expressions for surface flaws were higher for Knoop flaws than Vickers, but both types gave low K_c values due to indentation residual stress effects. Analysis suggested that theoretical formalisms for indentation residual stress effects based on fracture mechanics solutions for a center-loaded penny crack in an infinite medium should apply to both indentation types. K_c values calculated using the residual stress approach were identical for Knoop and Vickers controlled surface flaws when a "calibration" value for a constant term in the expression for K_c was used for both indentation types.