Hot dip fine Zn and Zn-Al alloy double coating for corrosion resistance at coastal area

A new hot dip Zn-7Al alloy coating was performed on a structural steel by double coating of fine Zn and Zn-7 wt.% Al alloy, to prevent severe corrosion in coastal area. The alloy-coated steels were exposed to seaside, quasi-industrial, and rural districts to compare with conventional Zn coating. Double coating was significantly effective in preventing corrosion, particularly in a seaside. It was estimated from the exposure test for 10 years that the life of the Zn-7Al alloy-coated steel would be almost four times that of the Zn-coated steel in the seaside. A bending test showed that no exfoliation occurred at the interface between the coated alloy and substrate steel. TEM observation revealed that the excellent adhesiveness of the doubly coated fine Zn and Zn-7Al alloy to the steel substrate was due to formation of the interface region consisting of heterogeneous fine phase mixture of zinc, aluminium and iron.     

基体组织对蠕墨铸铁热疲劳性能的影响

主要研究了基体组织对蠕墨铸铁抗热裂性能的影响，为高速列车制动盘的合理选材提供依据。试验结果表明：铁素体基体蠕墨铸铁的耐热疲劳性能优于珠光体基体蠕墨铸铁。     

Prediction model for surface temperature of roller and densification of iron powder during hot roll pressing

The hot roll pressing of iron powder with several rotating speeds was carried out on a pilot-plant scale. From these experiments, it was confirmed that the surface temperature of roller was increased with increasing its rotating speed. It was also known that the heat transfer coefficient between the iron powder and the roller surface is closely related with the rotating speed of roller. These results were quantitatively described by using a mathematical model which was derived based on the steady-state heat transfer during hot roll pressing. In addition, the densification behavior of iron powder during the hot roll pressing was simulated by a finite element model based on the arbitrary Lagrangian and Eulerian (ALE) method and a yield criterion for metal powder. From these models, the maximum critical rotating speed of roller during the hot roll pressing, in which the roller could hold out against the thermal fracture, could be determined.     

热镀锌钢白锈产生原因分析及预防

通过扫描电镜观察及X射线衍射测试,对热镀锌钢在海洋环境下产生的白锈进行了分析,结果表明,在海洋环境下白锈由ZnCl2.4Zn(OH)2、2ZnCO3.3Zn(OH)2和ZnO组成,腐蚀产物疏松,不能阻碍腐蚀进一步进行。探讨了白锈形成机理,总结了国内外热镀锌标准有关对热镀锌钢白锈的论述,并提出了有关的防护及处理措施。     

应用转炉渣对铁水预脱硅脱磷的实验研究

转炉渣中添加CaF2助熔剂降低其熔化温度可用于铁水预处理。实验确定合适的CaF2添加量为15%~20%。在此基础上,应用转炉渣对铁水进行脱硅、脱磷预处理实验。结果表明,采用转炉渣(80%)-CaF2(20%)的转炉渣剂对铁水脱硅、脱磷预处理,相应的脱硅、脱磷率可分别达到70%和78%左右。在1350℃~1450℃的温度范围内,温度的升降明显影响铁水脱硅、脱磷率。     

中频用极薄热轧硅钢片的研制

选用合适成分，采用两次折叠、16层叠轧的方法开发出性能优异的0．25mm厚的中频（400、1000Hz）用权薄热轧硅钢片，已用于生产，并取得良好成绩。     

传动轴凸缘叉精密成形研究

建立了传动轴凸缘叉热成形工艺的刚粘塑性有限元模型，采用三维有限元法对凸缘叉成形工艺进行了模拟分析，针对原有工艺出现的问题进行了改进及优化。基于模拟分析的结果，设计出结构合理、寿命较长的预成形及终成形模具，生产出的锻件尺寸精度和力学性能都有较大的提高。     

热水锅炉炉管腐蚀破坏事故分析

采用X射线衍射相分析技术对某热水锅炉炉管的腐蚀产物进行了分析，对炉管材质的化学成分，硬度，抗拉强度和显微组织分别进行了检测，并对锅炉给水的含氧量进行了测定，综合分析结果表明，造成锅炉炉管穿孔漏水的主要原因是氧腐蚀。     

DD3单晶高温合金的热腐蚀行为

用涂９０Ｎａ２ＳＯ４（ｗｔ％）和１０ＮａＣｌ（ｗｔ％）的混合盐膜法研究了单晶高温合金ＤＤ３在９００℃空气中的热腐蚀行为。结果表明，ＤＤ３单晶合金的高温热腐蚀是灾难性的；其动力学曲线无明显孕育期，但有明显的阶段性。文中对各阶段的腐蚀机理进行了简要的讨论。     

00Cr22Ni5Mo3N双相不锈钢热加工性能的试验研究

采用热压缩和热拉伸试验方法,对00Cr22Ni5Mo3N双相不锈钢的高温变形抗力、高温塑性以及在高温变形时的奥氏体相的数量进行了研究。试验结果表明,00Cr22Ni5Mo3N双相不锈钢的高温变形抗力和高温塑性较0Cr18Ni10Ti奥氏体不锈钢低,在1100～1250℃变形时,钢中奥氏体相的数量可以控制在适合热加工的范围,使钢具有较好的热加工性能。