THE EFFECTS OF CARBON AND SILICON ON STRUCTURE AND PROPERTIES OF AN FE-27CR-15NI-N ALLOY AT 1250-DEGREES-C

In order to design a new kind of low-cost oxidation-resistant high-tem perature alloy with good weldability which might be used as structure material of iron-ore sintering furnaces and magnesium-smelting tanks, the complex effects of carbon and silicon on the structure and propert ies of the Fe-27Cr-15Ni-N alloy are investigated simultaneously by the orthogonal experiment. It has been shown that as the carbon content i ncreases, the alloy rupture at 1250 degrees C increases at first until carbon content reaches about 0.45%, and then decreases notably. Meanw hile its oxidation resistance degrades apparently. As the silicon cont ent increases, the alloy rupture strength at 1250 degrees C decreases acutely, while its oxidation resistance improves at first and then det eriorates remarkably. At 1250 degrees C, the grain-boundary (GB) is vi tal to the alloy rupture strength, the variation of carbon content in the alloy affects the CB structure obviously so as to influence the al loy strength. However, the solubility of carbon in solid and its activ ity are strongly dependent on the silicon addition to the alloy. The s uitable carbon content to the alloy ranges from 0.30 to 0.40%, and the silicon content from 2.00 to 3.00%.