Gilewski Robert, Kopyciński Dariusz, Guzik Edward, Szczęsny Andrzej
Faculty of Foundry Engineering, AGH University of Science and Technology, Al. A. Mickiewicza 30, 30-059 Kraków, Poland.
Electrical School Complex No. 1, ul. Kamienskiego 49, 30-644 Krakow, Poland.
Materials (Basel). 2021 Oct 12;14(20):5993. doi: 10.3390/ma14205993.
A suitable aluminum additive in cast iron makes it resistant to heat in a variety of environments and increases the abrasion resistance of the cast iron. It should be noted that high-aluminum cast iron has the potential to become an important eco-material. The basic elements from which it is made-iron, aluminum and a small amount of carbon-are inexpensive components. This material can be made from contaminated aluminum scrap, which is increasingly found in metallurgical scrap. The idea is to produce iron castings with the highest possible proportion of aluminum. Such castings are heat-resistant and have good abrasive properties. The only problem to be solved is to prevent the activation of the phenomenon of spontaneous decomposition. This phenomenon is related to the AlC hygroscopic aluminum carbide present in the structure of cast iron. Previous attempts to determine the causes of spontaneous disintegration by various researchers do not describe them comprehensively. In this article, the mechanism of the spontaneous disintegration of high-aluminum cast iron castings is defined. The main factor is the large relative geometric dimensions of AlC carbide. In addition, methods for counteracting the phenomenon of spontaneous decay are developed, which is the main goal of the research. It is found that a reduction in the size of the AlC carbide or its removal lead to the disappearance of the self-disintegration effect of high-aluminum cast iron. For this purpose, an increased cooling rate of the casting is used, as well as the addition of elements (Ti, B and Bi) to cast iron, supported in some cases by heat treatment. The tests are conducted on the cast iron with the addition of 34-36% mass aluminum. The molten metal is superheated to 1540 °C and then the cast iron samples are cast at 1420 °C. A molding sand with bentonite is used to produce casting molds.
铸铁中添加合适的铝可使其在各种环境中耐热，并提高铸铁的耐磨性。需要注意的是，高铝铸铁有可能成为一种重要的生态材料。其构成的基本元素——铁、铝和少量碳——都是价格低廉的成分。这种材料可以用受污染的铝废料制成，而这种废料在冶金废料中越来越常见。目标是生产铝含量尽可能高的铁铸件。这种铸件耐热且具有良好的耐磨性能。唯一需要解决的问题是防止自发分解现象的激活。这种现象与铸铁结构中存在的AlC吸湿碳化铝有关。此前不同研究人员试图确定自发分解原因的尝试都没有全面地描述它们。在本文中，定义了高铝铸铁铸件自发分解的机制。主要因素是AlC碳化物相对较大的几何尺寸。此外，还开发了应对自发衰变现象的方法，这是研究的主要目标。研究发现，减小AlC碳化物的尺寸或去除它会导致高铝铸铁自分解效应消失。为此，采用提高铸件冷却速率的方法，以及向铸铁中添加元素（Ti、B和Bi），在某些情况下辅以热处理。试验在添加了34 - 36%质量分数铝的铸铁上进行。将金属液过热至1540°C，然后在1420°C下浇铸铸铁样品。使用含膨润土的型砂制作铸模。
