耐蚀性强的新型合金

日本三菱材料公司生产了一种具有良好的耐蚀性的新型合金。其组成为:铬22%、钼13%、铁4%、钨3%,余量为镍。这种合金在氧化性气氛下的耐蚀性。

Electrochemical corrosion properties of Zr- and Ti-based bulk metallic glasses

The corrosion behaviors of Ti-based and Zr-based amorphous alloys and their corresponding crystallized alloys were studied by electrochemical methods. It is found that the corrosion potentials of Zr-based amorphous alloy and its corresponding crystalline counterpart are both lower than those of the Ti-based amorphous alloy in the 1 mol/L H2SO4 solution. In the 3.5% NaCl solution,Zr-based crystallized alloy exhibits the lowest corrosion potential among the experimental samples. No passivation is observed in the corrosion process for the Zr-based crystalline alloy. However, Zr- and Ti-based amorphous alloys both exhibit passivation characteristics. EIS measurements indicate the amorphous alloys exhibit better corrosion resistance than the crystallized one in the NaCl solution. Surface analysis shows that both amorphous alloys in the NaCl solution are eroded by pitting corrosion. In the H2SO4 solution, all the alloys display similar behaviors and their surfaces can mostly keep intact except for some cracks on the corroded surface at local region.

双相不锈钢换热器设计中应考虑的相关因素

工程设计中,因双相不锈钢材料的化学成分和耐点腐蚀当量值的要求不同,以及双相不锈钢换热器管束与管板的焊接和胀接要求考虑不当,使得换热器管接头在使用中出现了很多问题,其中腐蚀情况也常有发生。如果从设计一开始就能比较好地提出采购双相不锈钢材料的化学成分和耐点腐蚀当量值的要求,给出符合换热器管束外经与管板孔径配合要求,制定合理的焊接工艺,双相不锈钢换热器管接头的制造质量可能会有新的提高。

镍基合金ENiCrMo-10焊条的研制

鉴于目前工程上基本依赖进口ENiCrMo-10焊材的现状,开展了ENiCrMo-10焊条的国产化研究。结果表明,通过调整药皮中大理石、氟化物及硅酸盐的比例,添加约20%的金属粉,优化熔渣流动性,控制焊缝中S,P,B,Mo,Cr,W等元素的含量,研制的ENiCrMo-10焊条具有优良的平、立焊工艺性,较出色的耐晶间腐蚀、耐点腐蚀及抗裂性能,能够满足工程应用的技术要求。