材料期刊网

沟槽式管接件断裂分析

孙宜强 龚桂仙 张萍 王志奋

物理测试

为分析球墨铸铁制造的某自动灭火系统中的沟槽式管接件的断裂原因，采用光学金相显微镜、扫描电镜和能谱分析仪对断裂试样的组织、石墨形态、夹渣成分等进行检测分析。结果表明,该试样断裂的原因是试样上存在大型夹渣、球化不良和石墨漂浮等缺陷。

关键词: 断裂分析 , grooved coupling and fitting , ductile iron , slag inclusion , spheroidization failure

EFFECT OF SILICON ON PRODUCING DUCTILE IRON WITH COMPLEX STRUCTURE OF BAINITE AND MARTENSITE

Y. P. Zhang , J.X. Zhu , Y. Q. Wang and J.Y.Su(Institute of Cast Iron Research , Xi'an University of Technology , Xi'an 710048 , China)(Department of Mechanical Engineering , Xi'an Jiaotong University , Xi'an 710049 , China)

金属学报(英文版)

This paper deals with an important role of silicon in producing ductile iron with quenched complex structure of bainite and martensite. The samples are cast in permanent mold and quenched in solution of sodium silicate. The result of thc experiments shows that the austenizing temperature should rise with increasing silicon content, otherwise much undissolved ferrite is present in the matrix after quenching. However the undissolvec ferrite can be decreased greatly or even eliminated by adding appropriate amount of ooron. On this condition, the amount of bainite gets increasing and the amount of residual austenite decreasing with the silicon cortent increasing. An approach has also been made to the mechanism of the effect of silicon on the transformation of bainite in ductile iron. The T.T.T. curves measured show that the increase of sllicon content causes the curve to shift to the left. This is quite different from the fact in steel.

关键词: ductile iron , null , null , null

EFFECT OF AUSTENITIC DENDRITES ON MECHANICAL PROPERTIES OF DUCTILE IRON

ZHOU Jiyang XIE Zuhua ZHONG Fenqi Dalian University of Technology , Dalian , China

金属学报(英文版)

Impact toughness of ductile nodular cast iron loaded perpendicular to the austenitic dendrites is found to be 43% higher than that parallel to ones.Yet tensile strength and elongation of the former are 23% and 30% lower than the later respectively.It is belived that the dendritic segregation may cause such differences.

关键词: ductile iron , null , null

PHASE STRUCTURE FACTOR AND INTERFACE CONJUNCTION FACTOR OF CAST IRON AND ITS COMPOSITION DESIGN

Z.L.Li , Z.L.Liu , F.Y.Li , X.P.Yang and Z.G.Gu Departmentof Materials Science and Engineering , Liaoning Institute of Technology , Jinzhou 121001 , China

金属学报(英文版)

Theempiricalelectrontheory of solidsand molecules( EET) and theimproved TFDtheory wereapplied tocalculatethe phasestructurefactorsand interfaceconjunction factorsofcom mon alloying elementsincastiron. Akind of Si- Mo- Cu ductileiron with rareearth Mg asnodularizer was designed accordingtothese valenceelectron structure parameters. Actual applicationtestsshow thatthelongevity of thisiron is 1.5 timesof thatof high manganesesteel. This accordance of theoretical results and actual effectsshows the composition design methodcan beused in othercastiron research.

关键词: phasestructure factor , null , null , null , null

钛含量与冷却速率对球墨铸铁中含钛夹杂物的影响

郭文涛 , 常国威 , 李冲 , 岳旭东 , 孙加梅

机械工程材料

研究了钛含量和冷却速率对球墨铸铁中含钛夹杂物形貌、平均尺寸与分布的影响。结果表明：在3℃·S^-1的冷却速率下，当钛的质量分数由0．005％增加至0．025％时，夹杂物的平均尺寸由2．14扯m增加到3．04μm；钛的质量分数为0．015%时，当冷却速率由1℃·S1增大至6oC·S^-1后，夹杂物平均尺寸由4μm减小到1．5μm；钛能够与稀土、钡、镁等元素形成夹杂物。而且钛含量越低、冷却速率越大，越容易形成单相夹杂物；这些夹杂物大部分呈块状，棱角清晰，少量呈球状，多数尺寸在1．5～7μm，分布在珠光体、铁素体及晶界处。

关键词: 含钛夹杂物 , 钛含量 , 冷却速率 , 球墨铸铁

球墨铸铁固体渗硼及渗层生长动力学

慕东 , 沈保罗

材料热处理学报

采用LSB型渗硼剂分别在渗硼温度为1123、1173和1223 K,保温时间为2、4、6和8h的工艺参数下对球墨铸铁表面进行固体渗硼处理.用扫描电子显微镜(SEM)对渗层横断面进行了显微组织观察,用X射线能谱仪分析了沿渗层表面到心部的元素分布.用X射线衍射仪(XRD)分析出渗硼层为Fe2B单相,用显微硬度计测试渗层的硬度分布,其显微硬度值在1170 ～1392HV0.025之间.渗层厚度随着渗硼时间和渗硼温度的增加而增加,其范围约为35～118 μm.对实验数据进行分析和拟合,得出渗层动力学曲线和等厚度图,并且经回归分析计算出硼在球墨铸铁中的扩散激活能约为175 kJ/mol.

关键词: 球墨铸铁 , 渗硼 , 硬度 , 动力学 , 扩散激活能

奥－贝球铁断裂与疲劳研究的新近进展

戴品强 , 何则荣 , 毛志远

材料科学与工程学报 doi:10.3969/j.issn.1673-2812.2000.04.024

奥－贝球铁具有很强的强度、塑性、韧性、疲劳强度和耐磨性等综合性能，应用日益广泛，已成为一种重要的工程材料。近年来对其断裂与疲劳的研究发展很快，得到不断的深入，本文详细介绍了其新近进展。

关键词: 奥－贝球铁 , 球墨铸铁 , 断裂 , 疲劳

球墨铸铁微弧氧化陶瓷层扩散退火前后的组织状态

赵霞 , 刘爱莲 , 徐家文

材料保护

过去,对铸铁件热浸镀铝再微弧氧化仅有少量的研究,且还存在残留铝影响氧化层性能的问题.为此,对球墨铸铁先热浸镀铝后再微弧氧化形成陶瓷层,采用扫描电镜、能谱分析和X射线衍射分析了陶瓷层的相组成及形貌,并探讨了对陶瓷层进行扩散退火处理的可行性.结果表明:球墨铸铁浸镀铝后微弧氧化获得的陶瓷层主要由α-Al_2O_3相和Υ-Al_2O_3相组成;600℃扩散退火时,因陶瓷层与纯铝层之间热膨胀系数不匹配会导致界面处产生热应力,造成陶瓷层与纯铝层的界面处出现明显孔洞;球墨铸件微弧氧化形成的陶瓷层不适合扩散退火处理:对微弧氧化后,热浸镀铝层剩下多少为佳及处理的问题,应进一步研究.

关键词: 微弧氧化 , 热浸镀铝 , 球墨铸铁 , 扩散退火 , 组织状态

Influence of Mold Preheating and Silicon Content on Microstructure and Casting Properties of Ductile Iron in Permanent Mold

钢铁研究学报(英文版)

关键词:

热浸镀铝球墨铸铁的耐蚀性能和冲击韧性

程乾 , 黄兴民 , 戴光泽

材料热处理学报

研究了热浸镀铝球墨铸铁在3.5％ NaCl溶液中的耐腐蚀性能和不同温度下的冲击韧性.极化曲线和阻抗谱测试结果表明,热浸镀铝球墨铸铁在3.5％ NaCl溶液中耐蚀性能得到了显著提高,主要原因为表面铝层易形成Al2O3钝化膜,降低了腐蚀电流密度.纯铝热浸镀形成的不规则舌状Fe2Al5硬脆相/铁素体基体界面处可能产生应力集中,承受冲击载荷时呈现为解理断裂.采用Al-3.6％ Si浸镀液可改善Fe2Al5硬脆相/基体界面形貌,降低Fe2Al5合金层厚度,在良好低温冲击韧性的前提下,显著提高了球墨铸铁在3.5％ NaCl溶液中的耐蚀性能.

关键词: 球墨铸铁 , 热浸镀铝 , 腐蚀性能 , 冲击韧性