摘要
通过在不同温度高温回火,研究了回火温度对含Nb高碳钢力学性能的影响;对比分析在演变过程中Nb对其组织与性能的影响。结果表明:高碳淬火组织为板条马氏体和孪晶马氏体,随回火温度的升高,逐渐转变为大尺寸的渗碳体+等轴铁素体。强度和硬度都随回火温度升高而逐渐降低,而伸长率和断面收缩率则随回火温度的升高而逐渐增大;含Nb高碳钢的塑性和强度都要优于不含Nb的高碳钢。原因是添加Nb可以通过细化晶粒(原奥氏体晶粒和马氏体亚结构尺寸、再结晶铁素体晶粒大小)、抑制位错回复提高位错密度的形式提高强度,同时也因细化晶粒,促进碳化物析出而提高塑性。
By the high-temperature tempering at different temperatures, the influences of tempering process on mechanicalproperties of high carbon steel containing Nb were studied. The effects of Nb addition on the microstructure evolution were analyzed by comparing two kinds of samples with and without Nb. The results show that the quenched structure including lath and twinned martensite changes gradually into the cementite ＋ equiaxed ferrite with the increase of tempering temperature. Both of the strength and hardness decreases as the tempering temperature increasing, but the elongation and the reduction of cross-section area improve. It is found that the ductility and strength in the Nb-bearing steel are better than Nb-free steel. It was attributed to that the addition of Nb can enhance the strength by refining grain size （the prior austenite grain size, martensite substructure size and the recrystallized ferrite grain size） by inhibiting the recovery of dislocations, and the ductility improves by refining grain size and promoting carbides precipitation.
出处
《热加工工艺》
CSCD
北大核心
2012年第20期161-164,共4页
Hot Working Technology
基金
国家基础研究计划项目("973"计划2010CB630805)
关键词
NB
高温回火
塑性
强度
碳化物析出
Nb
high-temperature tempering
ductility
slrength
carbide precipitation
