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原料遗传性对球墨铸铁显微组织的影响 总被引:1,自引:0,他引:1
采用不同配比的生铁和废钢,通过硅铁及电极石墨增碳剂的调节,在相同铸造工艺下,制成化学成分基本相同的球墨铸铁,并对试样的显微组织进行了分析.结果表明,原料的遗传性对球铁石墨球的形态、大小、分布以及球铁的基体组织存在明显的影响. 相似文献
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《铸造技术》2020,(5)
球墨铸铁是一种重要的工程材料,球化率是评定球墨铸铁质量的关键指标。本文综述了国内外主要标准的球墨铸铁球化率定义及相应的评定方法,指出了这些标准中对球化率评定方法存在的差异和问题。"ISO 945-4铸铁显微组织球墨铸铁球化率评定方法"是由我国牵头负责制定的国际标准,该标准规定了目测法和图像法评定球墨铸铁球化率。本文介绍ISO 945-4:2019主要内容,包括标准的术语和名称解释、试样制备、评定方法、检验结果表示等,重点对球形石墨颗粒的定义及其测定方法、球化率的定义及其测定方法、球化率评定相关临界值的确定等进行了解读。本文还介绍了球墨铸铁单位面积石墨颗粒数定义的修正以及球墨铸铁单位面积石墨颗粒数评定方法、表示方法。 相似文献
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试验了用石墨颗粒对大断面球铁原铁液进行前期处理,研究了其对模拟大断面球墨铸铁试验石墨形态的影响,结果表明,上述前期处理可显著增加石墨球数,减小石墨球径。此外,还初步分析了此种前期处理的作用机理。 相似文献
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以球墨铸铁图像为研究对象,利用图形处理软件Image J,并且运用体视学原理,开发了一套研究球铁石墨形态与基体组织的新方法.该方法能精确分析球铁中的石墨相,计算石墨球的个数、面积、百分比、形状系数、取向角,能快速精确的计算球化率,能定量计算基体组织中各相的比例.该方法操作简便,易于普及,有效的解决了人工测量的繁琐及误差,提高了测量的精度和准确性. 相似文献
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《中国铸造装备与技术》2019,(2)
球墨铸铁中石墨绝大多数呈球团状,但随着球墨铸铁壁厚增加,凝固时间的延长,球化孕育的衰退,反球化微量元素的富集,石墨会出现:蠕虫状、开花状、碎块状、水草状等形态,铸件表层到心部石墨形态由球团状,逐渐变为团絮状、蠕虫状、开花状,碎块状等三明治现象。石墨的分布也会出现一些特殊规律,如:列队石墨球,偏聚石墨球,石墨球漂浮等。这些现象已严重影响了球墨铸铁厚大部位的球化率。我们采用合适的碳当量、铁水中加入0.005%的Sb,采用低稀土球化剂,使用高效、长效孕育等工艺方法,成功将500mm×500mm×500mm的试块心部球化率提高至Ⅵ+Ⅴ≥80%。 相似文献
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原料配比对球墨铸铁珠光体片层间距及硬度的影响 总被引:1,自引:0,他引:1
采用不同配比的生铁和废钢,硅铁及电极石墨作为增碳剂,在相同铸造工艺下,制备化学成分基本相同的球墨铸铁,并对试样的显微组织和硬度进行了分析.结果表明,原料配比对球墨铸铁中珠光体的形态、片层间距的大小以及球铁的硬度存在显著的影响.随着原料中生铁所占比例的降低,球铁基体中珠光体的片层间距逐渐减小,球铁的硬度逐渐升高.特别是全部使用废钢生产时,球铁硬度较大幅度地提高. 相似文献
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球墨铸铁活塞环金相组织定量分析系统 总被引:3,自引:1,他引:2
采用灰度变换、图像增强、种子填充及边缘跟踪等一系列提高图像处理效果的技术,开发了球墨铸铁活塞环金相组织定量分析计算机处理系统。提出了通过对象物的骨骼直线模拟.较好地解决了对连体球的识别和定量计算问题。所开发的软件系统能满足生产中对球墨铸铁活塞环金相组织定量分析的要求。 相似文献
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Flake and spheroidal graphite cast irons with similar composition were subjected to high temperature oxidation to investigate graphite morphology and distribution effects on the oxidation behavior. High temperature oxidation tests were conducted between 400 and 750 °C in air. For comparison low carbon steel was also tested.Graphite morphology obviously affected high-temperature oxidation resistance. The flake graphite cast iron exhibited the worst high-temperature oxidation resistance compared with spheroidal graphite cast iron. Since graphite flakes provide suitable sites for the iron oxide growth and are almost interconnected, the iron oxide grows faster and penetrates along the graphite flakes boundaries resulting in the subsurface oxidation. Due to the severe subsurface oxidation flake graphite cast iron parabolic rate constants are five times higher than that of the spheroidal graphite cast iron. However, spheroidal graphite cast iron parabolic rate constants and oxide layer thickness are similar to those of the low carbon steel. Therefore, graphite flakes have negative effect on the cast iron high temperature oxidation resistance. 相似文献
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风力发电机组中球墨铸铁得到大量的使用。球墨铸铁的无损检测一般采用超声波检测和磁粉检测,国外风电企业都有严格的球墨铸铁检测规程,随着国内对球墨铸铁检测的重视程度不断提高,球墨铸铁检测的风力发电行业规范也颁布实施。介绍了球墨铸铁的超声波检测特点,以及国外风电企业对球墨铸铁超声波检测的规程,最后介绍风电典型球墨铸铁结构的超声波检测方法。 相似文献
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欧洲标准EN1563:1997在大量实验数据基础上,大幅度扩充和改进了球铁铸件标准,更加适应巨型重要球铁铸件的生产和技术发展需要。已为英法德意丹麦等27个欧洲国家等效采用作为国家标准。新版国际标准ISO1083:2004《球墨铸铁-分级》,也等效采用了欧洲标准EN1563:1997。 相似文献
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灰铸铁、蠕铁、球铁被统称为灰口铸铁,在现代工业中应用广泛.在主要成分相近情况下,由于微量元素等条件的不同引起石墨生长形态各异,从而同属灰口铸铁的三类铸铁性能迥异.懂得其基本规律及相关原理,有益于铸造工程技术人员在灰铁、蠕铁、球铁的生产实际中理性而有效地控制产品质量.本文基于灰口铸铁的奥氏体-石墨共晶凝固方式,从基本概念及原理、G形成过程、实际组织观察与分析的全新视角,主要针对灰铁和球铁概述了石墨形态的形成规律和机理.文中诸多图片等实例是以往国内教科书及专业书籍中未见的,文章内容也体现了对相关现象描述及观点上新的发展,有助于读者对该方面有关问题获得更为清晰的理解和认识. 相似文献
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J. Asensio-Lozano J. F. Álvarez-Antolín 《Journal of Materials Engineering and Performance》2008,17(2):216-223
The aim of the present research is to identify the manufacturing factors that exert an active influence on the graphite phase
formation in mottled Nihard cast irons constituting the roll shells of duplex work rolls processed by the double pour method
during centrifugal casting. The studied rolls, referred to as alloy indefinite chill, were processed at industrial scale and
had a core consisting of spheroidal graphite cast iron with a matrix of ferrite and pearlite. An additional aim of this study
was to evaluate the effect and extent of these factors on the dynamic toughness response of the roll shell material.
The research methodology employed consisted of the application of a saturated design of experiments with seven factors, eight
experiments, and resolution III. The measured responses for graphite were: the volume fraction, count number per unit area,
and morphology, determined by quantitative metallography. Impact testing was characterized by Charpy tests on U-notched specimens
at 350 °C. The manufacturing factors studied were: the final weight percent of silicon, sulfur, and manganese; the liquidus
and the casting temperatures; and, finally, inoculation with SiCaMn and A-type FeSi (with Zr).
The statistical experimental method conducted allowed us to confirm the significance of factors such as the %Si, the liquidus
temperature and inoculation with SiCaMn on the precipitation of graphite in a white cast iron such as the Nihard irons used
in the roll shell, in agreement with the precipitation of graphite in gray cast irons widely reported in the literature. It
was also shown that the development of lamellar graphite shapes were favored by an increase in the total equivalent carbon
and also by the increase in the amount of A-type FeSi added. Furthermore, the impact toughness was shown to improve with the
increase in both the %Si and the liquidus temperature. 相似文献