Effect of Pores on Nitriding Behavior of 12mass%Cr Ferritic Steel Compacts
Effect of Pores on Nitriding Behavior of 12mass%Cr Ferritic Steel Compacts
复制标题
效果%20of%20孔隙%20on%20氮化%20行为%20of%2012质量%Cr%20铁素体%20钢%20复合体
DOI：
10.2497/jjspm.41.468
复制
发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Y. Tokunaga
中科院分区：
文献类型：
--
作者：
N. Nakamura;S. Takaki;Y. Tokunaga
采用金相显微镜、化学分析和气孔率测定等方法，研究了气孔对12mass%Cr铁素体钢（SUS410L）压坯在氮气气氛中渗氮行为的影响。通过改变1473K下的预烧时间和预烧压坯的复压压力来控制压坯的气孔率。通过三点弯曲试验对氮化后的力学性能进行了评价。结果表明：（1）在1473K氮化时，压坯的开孔率大于5vol.%可以容易地通过开放的孔隙在整个样品上吸收0.26质量%的氮。当开孔率降至5vol.%以下时，然而，通过预烧结和复压，压坯仅从表面氮化，使得总的氮化速率变小。（2）由于0.26mass%的氮的吸收，铁素体相转变为奥氏体，冷却至室温时奥氏体转变为马氏体。（3）复压对烧结体的致密化非常有效，使具有完全马氏体组织的烧结体的抗弯强度提高。
Effect of pores on the nitriding behavior of 12mass%Cr ferritic steel (SUS410L) compacts in nitrogen gas atmosphere was investigated by means of optical microscopy, chemical analysis and measurement of porosity. Porosity of compacts was controlled by varying presintering time at 1473K and repressing pressure of presintered compacts. Mechanical property of nitrided compacts was also estimated by three-point bending test. The results obtained are as follows: (1)In the nitriding at 1473K, compacts with the open-porosity of more than 5vol.% can easily absorb 0.26mass% of nitrogen all over the specimen through open pores. When the open-porosity has been reduced to less than 5vol.% by presintering and repressing, however, compacts are nitrided only from the surface, so that the general nitriding rate becomes smaller. (2)Owing to the absorption of 0.26mass% nitrogen, ferrite phase changes to austenite and the austenite transforms to martensite on cooling to room temperature. (3)Repressing of sintered compacts is very effective for the densification, and this results in the increase in bending strength of sintered compacts with fully martensitic structure.