ZHAO Hongzhuang
,
Seokjae LEE
,
Youngkook LEE
,
LIU Xianghua
,
WANG Guodong
钢铁研究学报(英文版)
This study aims at the experimental analysis of the transformation induced plasticity (TRIP) phenomenon. Experiments are conducted in which martensite is allowed to grow under the influence of a series of externally applied stresses. The magnitude of the applied stresses is less than 67% of the yield strength of austenite σγ(Ts). Since there is no obvious difference between the transformation plasticity under tension and the compression for the lower applied stresses, only compressive stresses are applied. The results confirm that the transformation plasticity is proportional to the applied stress if the latter does not exceed 67% of σγ(Ts). The TRIPstrain, the kinetics, and their dependence on the applied stresses are studied. The comparison between calculated results and experimental results shows that the model accurately describes the phenomenon.
关键词:
applied stress;TRIP;martensite transformation;lowalloy steel
XU Yunbo
,
YU Yongmei
,
LIU Xianghua
,
WANG Guodong
钢铁研究学报(英文版)
Based on thermodynamics and kinetics, a new mathematical model was developed to calculate the CCT diagrams and the transformation kinetics in low carbon niobium steels, in which the effect of deformation on the degree of supercooling was taken into account. The undercooling caused by deformation is the major reason for the increase of the starting transition temperature during continuous cooling. The critical cooling rate of bainite formation is within 2-5 ℃/s for the studied niobium steels and deformation is suitable for the occurrence of pearlite. The ferrite volume fraction increases with the increase of the austenite boundary area, and decreases with the increase of the cooling rate. The calculated CCT diagrams and the volume fraction of each phase are in good agreement with the measurements.
关键词:
low carbon niobium steel;thermodynamics;supercooling degree;continuous cooling transformation;computer model
ZHU Fuwen
,
ZENG Qingliang
,
HU Xianlei
,
LI Xian
,
LIU Xianghua
钢铁研究学报(英文版)
Owing to a lack of gaugemeter and the variety of steel grades and standards in some plate mills, the long and shortterm selflearning models of rolling force based on gauge softmeasuring with high precision were brought up. The softmeasuring method and target value locked method were used in these models to confirm the actual exit gauge of passes, and thick layer division and exponential smoothing method were used to dispose the deformation resistance parameter, which could be calculated from the actual data of the rolling process. The correlative mathematical methods can also be adapted to selflearning with gaugemeter. The models were applied to the process control system of AGC (automatic gauge control) reconstruction on 2 800 mm finishing mill of Anyang steel and favorable effect was obtained.
关键词:
plate;selflearning;soft measuring;rolling force
WANG Bingxin
,
JIANG Yingtian
,
XU Xudong
,
LIU Xianghua
,
WANG Guodong
钢铁研究学报(英文版)
The effect of compressive deformation of austenite on continuous cooling transformation microstructures for 22CrSH gear steel has been investigated using a Gleeble 1500 thermal simulator. The experimental results show that the deformation of austenite promotes the formation of proeutectoid ferrite and pearlite, and leads to the increase of critical cooling rate of proeutectoid ferrite plus pearlite microstructure. The grain boundary allotriomorphic ferrite occupies the austenite grain surfaces when the prior deformation takes place or the cooling rate is decreased, which causes a transition from bainite to acicular ferrite. The deformation enhances the stability of transformation from austenite to acicular ferrite, which results in an increase of M/A constituent.
关键词:
gear steel;prior compressive deformation;austenite;transformation;microstructure
DU Linxiu
,
ZHANG Zhongping
,
TIAN Yuwei
,
LIU Xianghua
,
WANG Guodong
钢铁研究学报(英文版)
gy Center, Benxi Steel Group, Benxi 117000, Liaoning, China)
Abstract： The fatigue properties of 400 MPa grade supersteel, plain low carbon steel SS400 and microalloyed steel Q340TM were investigated through tensilecompression fatigue experiment with R=-1. The results indicate that the fatigue limit of the 400 MPa supersteel is higher than that of SS400 steel and close to that of the 340TM steel. According to the analysis of fatigue fracture, the fatigue striations of supersteel SS400 is thinner than that of SS400 steel and 340TM steel, and grain refinement can increase the fatigue limit.
关键词:
supersteel;grain refinement;fatigue property
YU Hailiang
,
LIU Xianghua
,
WANG Chao
,
Park Haedoo
钢铁研究学报(英文版)
The acting force on the roll system of Sendzimir mill was analyzed using 3D FEM. The roll gap pressure distribution and the acting force between rolls S and O, rolls O and I, rolls O and J, rolls I and A, rolls I and B, as well as rolls J and B were analyzed. The results showed that the roll gap pressure mainly affected the roll surface layer, 50 mm for backup roll; the roll gap pressure distribution is of double peaks among the work roll, the 1st intermediate roll (IMR), and the 2nd IMR; the maximum value of the roll gap pressure between the backup roll and the second IMR appears on the edge of the barrel of rolls; the component force presents the inparacurve distribution. These are important for reducing the wear of rolls and the break of the backup roll and guiding for production.
关键词:
roll gap pressure;Sendzimir mill;FEM
YU Hailiang
,
LIU Xianghua
,
LI Changsheng
,
WANG Guodong
钢铁研究学报(英文版)
The deformation of slab with dogbone shape during the horizontal rolling process was simulated using FEM, and the influences of apical dislocation of dogbone on the slab spread as well as the minimum crop end loss and the lost width at slab head and tail were analyzed. The results show that with the increase in the apical dislocation of dogbone (LA), the slab spread and the minimum crop end loss at slab head and tail decrease, while the lost width at slab head and tail increases. Meanwhile, the relationships of S/LALA, LH/LALA, WH/LALA, LT/LALA, and WT/LALA were obtained.
关键词:
dogbone;apical dislocation;horizontal rolling;FEM
LIU Xianghua
钢铁研究学报(英文版)
Rolling of gauge changeable (RGC) is a new technology to produce flat with different thickness (FDT), which could be used to replace conventional flat products in order to save metals and reduce structure weight. This paper introduced the method of RGC, investigated new problems in rolling theory of RGC, proposed the new formulas for caluclating parameters of RGC, and described some results of numerical simulation by FEM. As example, the products applications of FDT in bridge construction, ship building and auto manufacturing were presented. Finally the prospect for RGC and FDT was discussed.
关键词:
variable gauge rolling;longitudinal profile plate;tailor rolled blank
GUO Yanhui
,
WANG Zhaodong
,
ZOU Wenwen
,
LIU Xianghua
,
WANG Guodong
钢铁研究学报(英文版)
The texture evolution in a high strength TiIF steel during the processing of hot rolling, cold rolling, and annealing is studied. For comparison, both ferrite rolling and austenite rolling are employed. It is found that the texture type is the same after ferrite rolling and austenite rolling, but the texture intensity is much higher in the ferrite rolled sample. Furthermore, texture characteristics at the surface are absolutely different from those at the midsection in both ferrite rolled and austenite rolled samples, as well as under the cold rolled and annealed conditions. The shear texture {110}<001> disappears and orientation rotates along {110}<001>→{554}<225>→{111}<112>→{111}<110>→{223}<110> during cold rolling. Compared to the austenite rolled sample, the properties of the cold rolled and annealed sheet which is subjected to ferrite rolling are higher.
关键词:
high strength TiIF steel;ferrite rolling;austenite rolling;texture
