书书书
收稿日期:2013 - 04 - 22
基金项目:国家重点基础研究发展计划项目(2010CB630801).
作者简介:夏文真(1987 - ),男,安徽枞阳人,东北大学博士研究生;赵宪明(1965 - ),男,辽宁桓仁人,东北大学教授,博士生导师.
第34 卷第1 1 期
2 0 1 3 年 11 月
东 北 大 学 学 报 ( 自 然 科 学 版 )
Journal of Northeastern University(Natural Science)
Vo l. 34,No. 11
Nov. 2 0 1 3
新热处理工艺对低碳 Nb - Ti 微合金钢
组织性能的影响
夏文真,赵宪明,张晓明,吴 迪
(东北大学 轧制技术及连轧自动化国家重点实验室,辽宁 沈阳 110819)
摘 要:采用不同的新淬火工艺路径,研究再加热温度和弛豫过程对低碳 Nb - Ti 微合金钢组织性能的
影响
. 结果表明,试样经再加热后直接淬火时,随着再加热温度的升高,析出物数量迅速下降,尺寸增加且分布
更加不均匀,且马氏体板条束增大,板条宽度减小;当再加热温度为 850 ℃ 时,试样经弛豫至 700 ℃ 后再淬火
时,其析出物数目与直接淬火相比减少,平均尺寸增加且分布更加不均匀. 当再加热温度为 900 ℃ 经弛豫至
700 ℃ 后再淬火时,Nb - Ti 碳氮化物大量在原有析出物表面进一步析出;钢材最佳再加热温度为 900 ℃ ,且空
冷 20 s 时抗拉强度达到最大值,抗拉强度可提高 24 MPa.
关 键 词:再加热 + 弛豫 + 淬火工艺;低碳 Nb - Ti 微合金钢;组织机械性能;析出强化
中图分类号:TP 142. 33 文献标志码:A 文章编号:1005 - 3026(2013)11 - 1566 - 05
Effects of New Heat Treatment Process on Microstructure and
Mechanical Properties of Low Carbon Nb-Ti Micro-alloyed Steels
XIA Wen-zhen,ZHAO Xian-ming,ZHANG Xiao-ming,WU Di
( State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819, China.
Corresponding author
:XIA Wen-zhen,E-m ail:xiawenzhen1987@ hotmail. com)
Abstract:The test steels were quenched to room temperature using a new heat treatment process,
and the effects of the reheating temperature and relaxation-quenching process on microstructure and
mechanical properties of low carbon Nb-Ti micro-alloyed steels were investigated. The results
showed that the number of precipitates decreased,while the mean size increased with the size
distribution getting even nonuniform. The martensitic lath bundle size growed and the size of each
martensitic lath decreased with the increase of the reheating temperature. Compared with the
sample quenched directly
,the number of precipitates in the sample reduced,which was reheated
to 850 ℃ and then relaxed by slowly cooling to 700 ℃ before quenching. Its mean diameter
increased and the size distribution was more uneven. When the sample was reheated to
900 ℃ and
also relaxed by slowly cooling to 700 ℃ before quenching,( Nb,Ti)
x
( CN)
y
continued to
precipitate on the surface of intrinsic granular precipitates. The best reheating temperature was
900 ℃. Moreover,the tensile strength of the sample which was air-cooled about 20 s increasesd
24 MPa and reached its maximum value.
Key words: reheating-relaxation-quenching process;low carbon Nb-Ti micro-alloyed steels;
microstructure and mechanical properties;precipitation hardening
微合金元素,如 Nb,V,Ti 在钢的连续冷却过
程中,可与钢中间隙原子
C,N 结合成碳氮化物,
在基体中起析出强化作用,同时阻碍变形奥氏体
的再结晶和晶粒长大从而细化晶粒,可以起到细
晶强化作用
[1 - 3]
. 所以添加适量的微合金元素是
一种重要的提高钢材机械性能的手段
. 目前,在高
强度低合金钢( HSLA)中加入 Nb,V,Ti 等微合
金元素已经得到广泛的应用
[4 - 5]
,且采用降低 C
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