氮对高铬铸铁性能的影响钢铁冶金专业论文.docxVIP

内 内蒙古科技大学硕士学位论文 I I 摘 要 在造纸业高速发展的同时，造纸所用磨片的性能也日益受到人们的关注。造 纸磨片大部分采用的是高铬铸铁材料，其优良的耐磨性能完全能够满足此行业的 需求，但是其较低的韧性无法适应较差的造纸原料环境。当原材料中混入沙石等 杂物时会由于过高的冲击功损坏磨片，对磨片性能提出更高要求。 本文采用在高铬铸铁熔炼过程中添加氮化金属铬的方式来对高铬铸铁进行增 氮变质处理，氮按质量百分数分别加入 0.05%、0.07%、0.1%、0.2%、0.4%，并 且将碳含量由原来的 3.3%降低到 2.9%。 加氮后的高铬铸铁性能有了明显的提升。其中在热处理制度为 1020℃空淬 +510℃回火时，加氮量 0.07%的高铬铸铁韧性可达 6.4J/cm2,硬度为 61.5HRC。当 加氮量增加时韧性会相应降低，硬度提高。通过 Factsage 软件模拟相图得知，氮 能够扩大奥氏体区域，加氮量越多常温下组织中残留的奥氏体量越多。用 Image- Pro Plus 软件对碳化物形貌分析得出氮能够降低碳化物尺寸，同时增加碳化物数 量，当加入过多的氮时碳化物反而变得粗大。 改变回火温度会对高铬铸铁的性能产生影响。当回火温度提高时高铬铸铁的 韧性上升，硬度下降。回火温度提高到 530℃时，加氮量为 0.07%的高铬铸铁韧 性为 6.6J/cm2，硬度降低到 55HRC。降低淬火温度可以提高高铬铸铁的韧性，当 淬火温度为 980℃时，加氮量为 0.07%的高铬铸铁韧性达到最高 7.2J/cm2，硬度保 持在 60.5HRC，此时的综合性能最佳。 关键词：高铬铸铁；氮化铬；造纸磨片；韧性 II II Abstract In the paper industry of rapid growth, disc refiner plates performance has become an increasing concern. The majority of pulp refiner plate use in high chromium cast iron materials, its excellent wear resistance can completely meet the needs of this industry, but its low toughness cannot adapt to poor paper material environment. Will be damaged due to excessive impact energy when the raw materials mixed with sand iron and other debris, the plate will be damaged by the high impact energy, which reduces the life of the plate. In this paper, the nitride chromium added to the high chromium cast iron in the smelting process for modification of the high chromium cast iron, which obtained good results, Which nitrogen were added to the mass percentage of 0.05%, 0.07%, 0.1%, 0.2%, 0.4% and the carbon content from 3.3% to 2.9%. For significantly improved performance of high chromium cast iron add nitrogen, The heat treatment system for the 1020°C air quenching + 510°C tempering and add nitrogen 0.07% ,the toughness of high chromium cast iron up to 6.4J/cm2 and hardness to keep in 61.5HRC.Add the amount of nitrogen increased, toughness will be reduced , the hardness increases. The Factsage software to simulate the phase diagram was informed that the nitrogen to expand th