本文对稀土在冶金方面应用的有关报导予以概括和评论,并分析了其中引入的冶金学原理。稀土是活泼的,易与氧、氢、氮、硫和其他元素结合成化合物,但不易与碳结合。在炼钢工艺中稀土用来生产较纯的、不含气体的钢,其含硫低,夹杂少。硫化物夹杂呈球形,热轧时仍为球形,它均匀布于晶内,这就增加钢的热塑性和可弯曲性,使其韧性更加各向同性。加稀土处理过的钢达到较高的屈服强度和冲击韧性,并具有较低的脆性转变温度。它使低合金钢获致较高的硬度,很高的耐磨和抗蚀性能,使含高铬的铁素体不诱钢获得更高的抗氧化能力,在循环加热试验中结果良好,并可替代镍铬合金作发热体用。稀土促进了铸铁中的石墨化和球化,细化了石墨体,铁素体和共晶体;从而提高了铸铁的延性、韧性和强度。制延性铸铁时,加铈可减少镁的添加量,因而防止了镁的挥发和烧损。随着稀土的添加,灰口铁成为较有延性的,白口铁更为耐磨,使可加工铸铁的热处理时间缩短,而合金铸铁可获得更好的抗蚀和抗氧化能力。 This article summarizes and comments on the reports on the application of rare earth in metallurgy and analyzes the principle of metallurgy introduced therein. Rare earth is lively, easy to combine with oxygen, hydrogen, nitrogen, sulfur and other elements into compounds, but not easy to bond with carbon. In the steelmaking process rare earth is used to produce purer, gas-free steels with low sulfur content and less inclusions. Sulfide inclusions are spherical, and are still spherical during hot rolling, which is uniformly distributed in the crystal, which increases the thermoplasticity and bendability of the steel to make the toughness more isotropic. Rare earth treated steels achieve higher yield strength and impact toughness and have lower brittle transition temperatures. It makes the low alloyed steel get higher hardness, high wear resistance and corrosion resistance, so that high chromium content of ferrite does not induce steel to obtain higher oxidation resistance. The result of cyclic heating test is good, and Nickel-chromium alloy for heating element. Rare earths promote graphitization and spheroidization in cast iron, refine graphite, ferrite and eutectics; thereby increasing the ductility, toughness and strength of cast iron. Made of ductile iron, plus cerium can reduce the amount of magnesium added, thus preventing the volatilization and burning of magnesium. With the addition of rare earth, gray iron becomes more ductile, white iron is more wear-resistant, so that the processing of cast iron heat treatment time is shortened, and the alloy cast iron can get better corrosion and oxidation resistance.