共查询到17条相似文献,搜索用时 62 毫秒
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分析了马钢低碳冷镦钢系列、自攻螺钉系列、中碳冷镦钢系列、免退火系列、超细晶粒非调质钢线材质量异议的主要原因,即表面裂纹、折叠、划伤引发了表面开裂,成分偏析、组织结构异常及非金属夹杂物导致性能不均匀,热处理工艺及冷成型工艺不当造成加工缺陷,据此提出了相应的改进措施,使质量异议比例下降65%以上. 相似文献
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针对无头轧制产线薄规格带钢头部在卷取夹送辊穿带时容易飞翘、卷取后产生折叠缺陷的问题,从设备结构和钢种、带钢厚度规格方面分析了造成带钢头部折叠缺陷的成因,并提出了针对性改进措施。结果表明:受产线工艺、设备结构影响,带钢在1~#夹送辊穿带时容易撞击出口导板产生飞翘,带钢头部顶在2~#夹送辊上辊产生折叠缺陷;折叠缺陷的严重程度受钢种、带钢厚度规格的影响,薄规格、强度低的带钢产品容易产生折叠缺陷甚至造成堆钢事故。通过开发夹送辊偏心功能、对防飞起装置进行改造、优化设备超前率等措施,有效改善了带钢头部折叠缺陷,缺陷发生率由15%下降至1%。 相似文献
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以某型号弹壳为研究对象,针对初始设计方案中弹壳底部成形后底火室侧壁微折叠的问题,通过微观组织观察和数值模拟确定微折叠产生于打凹成形,而导致微折叠产生的原因为:打凹成形过程中,隔板处金属的径向和轴向流动明显快于内侧壁,导致隔板与内壁连接处圆角的曲率半径持续变小,直至出现微折叠缺陷。同时,该微折叠缺陷在平底成形时保留并随着侧壁金属的轴向流动向下移动,与实际观测到的微折叠缺陷位置相吻合。为提高弹壳成形质量和避免该缺陷问题,提出一种修改打凹成形模具尺寸以改善打凹成形金属流动的改进方案,数值模拟和工艺试验结果均表明,采用改进方案后,打凹壳、平底壳均无微折叠缺陷,其他尺寸达到设计要求,改进工艺方案能够满足实际生产需求,提高了弹壳底部成形质量。 相似文献
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针对圆线材表面缺陷检测中出现的外界杂质干扰问题,对圆线材常见的6种表面缺陷进行建模,分析3种常见的图像噪声模型,并采用多种滤波算法进行处理比较,通过评估各算法对应的PSNR值确定了合适的图像预处理方案,同时对比分析3种特征描述因子对图像的特征提取效果。所得结果如下:均值滤波算法对高斯噪声处理效果好,中值滤波对椒盐噪声处理效果好,均值滤波和中值滤波对泊松噪声都有较好的处理结果;使用SURF算法进行图像特征提取效果好。研究结论可为解决线材表面缺陷的检测问题提供参考。 相似文献
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ML20MnTiB冷镦钢丝在镦制内六角螺栓时发生了开裂现象。用光学显微镜、扫描电子显微镜和洛氏硬度计对ML20MnTiB高强度螺栓开裂的显微组织、硬度和合金元素分布状态进行分析。结果表明,导致ML20MnTiB盘条镦制螺栓开裂的原因是盘条组织异常和表面缺陷。 相似文献
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Evaluation of two AISI 4037 cold heading quality steel wires for improved tool life and product quality 总被引:1,自引:0,他引:1
T. Das J. Y. Li M. Painter E. Summerville 《Journal of Materials Engineering and Performance》2002,11(1):86-91
One automobile fastener is manufactured from a cold heading quality (CHQ) steel wire obtained from two different sources.
Both wires are spheroidize annealed and phosphate coated. Their microstructures, compositions, and mechanical properties have
been evaluated in order to establish the characteristics of a good stock wire that can improve the tool life leading to higher
productivity and product quality. The present study revealed that a good quality feed stock for cold heading must be a subtle
combination of a uniform microstructure and a phosphate coating without any presence of roll seam and/or rust. The spheroidization
ratio indicates the effectiveness of an annealing process. The aspect ratio of cementite as a result of spheroidize annealing
influences the mechanical properties of the stock material. The higher the spheroidization ratio (with an aspect ratio of
cementite less than 2), the lower will be the flow stress of the material and the better will be its formability. This could
improve tool life. Stock wire containing inclusions of MnS-stringers, approximately 30 μm long, and aligned along its length
can badly affect the quality of a fastener, and can contribute to an early failure when employed in service. However, small
inclusions of both sulphides and oxides, less than 6 μm long, have little influence on product quality. 相似文献