李闯王学敏尚成嘉郑长安贺信莱
金属学报
doi:10.3724/SP.J.1037.2010.00227
利用热模拟技术研究了一系列含Cu钢在不同冷速下的硬度变化. 借助金相和高分辨透射电镜研究了连续冷却过程中的含Cu相析出行为及其对硬度的影响. 结果表明: 在连续冷却过程中Fe-Cu合金中会发生第二相析出, 从而造成硬化. 第二相析出为富Cu过渡相, 以相间沉淀方式析出, 析出行为与冷速和Cu含量有关, 当冷却速率为0.1-1 ℃/s时, 随着冷却速率的增加第二相析出物变得更加细小且密度更大, 当冷却速率为1 ℃/s时析 出物密度最大. 当冷却速率超过1 ℃/s后, 随着冷却速率的增加析出物逐渐减少. 当样品以10 ℃/s冷速冷却时, 几乎没有析出物产生. 富Cu相析出状况对合金起明显的强化作用. 当Cu含量低于1%时, 析出现象并不明显.
关键词:
含Cu钢
,
continuous cooling
,
inter–phase precipitation
,
Cu–rich phase
李婧
,
王秉新
,
刘相华
,
赵德文
材料热处理学报
针对Q420钢特厚板的生产工艺特点,利用Gleeble-2000热模拟试验机研究了该钢变形和未变形条件下的连续冷却过程中相变行为及组织演变规律,绘制了该钢的连续冷却转变(CCT)曲线,分析了控轧控冷工艺对其连续冷却相变的影响.结果表明:Q420钢随着冷却速度的提高,奥氏体→铁素体开始转变温度Ar3降低,相变后铁素体晶粒细化;贝氏体开始转变温度(Bs)先升高后降低,贝氏体转变量逐渐增加.随着变形量的增加,CCT曲线整体向左上方移动,加速了铁素体和贝氏体相变.随着变形温度的降低,铁素体相变温度升高,扩大了铁素体区,贝氏体相变温度降低.
关键词:
特厚板
,
连续冷却
,
相变
,
CCT曲线
熊自柳
,
刘宏强
,
史远
,
胡加佳
,
代永娟
机械工程材料
通过热膨胀试验、显微组织观察等研究了DP590钢的静态CCT曲线以及加热温度对连续冷却相变规律的影响.结果表明:随着加热温度的升高,奥氏体转变量呈多速增加的趋势;其静态CCT曲线可分为三个区域,冷速在0.5～15℃·s-1范围内获得铁素体和珠光体组织,冷速超过15℃·s-1时出现贝氏体组织,冷速较高时(约30℃·s-1)出现马氏体组织;当加热温度降低时,珠光体区右移,贝氏体转变孕育期延长,马氏体开始转变温度降低,马氏体与贝氏体相变区域分离,马氏体开始转变温度随着冷速的增加而升高;随着冷速增加,铁素体、珠光体的析出被抑制,马氏体析出动力得以增加;随着加热温度升高,相同冷却速率下的铁素体含量增多,马氏体板条变细.
关键词:
DP590钢
,
静态CCT曲线
,
连续冷却
,
相变规律
J.B. Qu
,
Z.D. Wang
,
X.H. Liu and G.D. Wang (The State Key laboratory of Rolling and Automation
,
Northeastern University
,
Shenyang 110006
,
China)
金属学报(英文版)
On the thermodynamics basis of regular solution sub-lattice model and soperelement model, kinetics basis of Cahn's transformation kinetics theory, and according to Scheil's additivity rule and eoperimental results obtained by thermal dilation method,a prediction model of transformations from hot-deformed austenite to ferrite, pearlite and bainite in low alloy steels, which could be applied to continuoas cooling process, is developed. The calculated transformed junctions of each phase based on laboratory controlled rolling and controlled cooling conditions in a low alloy steel are in reasonable agreement with the measured ones.
关键词:
transformation kinetics
,
null
,
null
,
null
Z.D. Wang
,
J.B. Qu
,
X.H. Liu and G.D. Wang(State Key Lab of Rolling and Automation
,
Northeastern University
,
Shenyang 110006
,
China)
金属学报(英文版)
The influence of hot deformation conditions on continuous cooling bainitic transformation has been investigated for a low carbon microalloyed steel. The CCT diagrams show that deformation in unrecrpstallized austcnite ation can accelerate transformation process. Bainitic transformation in intermediate transformation temperature region is prominent, and the proeutectoid polygonal ferrite transformation at evelated high temperature is suppressed. According to optical and TEM analyses, low carbon bainitic ferrite is characterized by granular and lathlike ferrite, based on the cooling rate and deformation conditions. For nondeformation, groaps of coarse parallel ferrite lath form from the prior austenite grain boundaries with the same crystallographic orientation. For heavy deformaton, cell structure within the austenite grains due to the high dislocation density formed, which provides more nucleation sites for bainite ferrite. So deformation can discontinue the growth of ferrite laths and decrease the length of ferrite laths.
关键词:
bainite
,
null
,
null
,
null
,
null
D.S. Liu
,
G.D. Wang
,
X.H. Liu and G.Z. Cui(The State Key Laboratory of Rolling and Automation
,
Northeastern University
,
Shenyang 110006
,
China)
金属学报(英文版)
The influence of prior austenite deformed at different temperature on the subsequent continuous cooling bainitic transformation has been investigated in an C-Ma-Cr-Ni-Mo plastic die steel. The results show that the prior deformation in low temperature region of austenite retards significantly the bainitic transformation. For the same continuous cooling schedule, as austenite deformed at lower temperature, the quantity of the classical sheaf-like bainite becomes less. The present results show that severe deformation leads to mechanical stabilization of austenite and causes the difficulty of bainitic ferrite propagation into the austenite.
关键词:
plastic die steel
,
null
,
null
,
null
,
null
