LI Changsheng
,
YANG Hua
,
WANG Yanfang
,
et al
钢铁研究学报(英文版)
Fe-3%Si steel strip was experimental produced by thin slab casting and rolling (TSCR) process in the laboratory. The microstructure and texture of hot rolled strip by different total reduction and rolling schedule was observed through EBSD technique and X-ray diffraction method. The changeable rule of texture density on the α、ε and γ, and fibers was analyzed. When the total reduction was increased from 82.9% to 97.1%，the gradient of microstructure and texture for A steel surface layer and center layer was found, {001}‹110› texture had higher intensity, and {001}‹110› texture was changed to{110}‹001›和{112}‹111›. The texture distribution with different reduction schedule for B steel was basically similar, but the Goss texture orientation density and volume fraction for B steel were higher, the hot rolling reduction schedule of C1 was effective to the formation of Goss texture. The research works were useful theoretical basis and reference data to develop electrical steel by thin slab continuous casting and direct rolling technology.
关键词:
Silicon steel;texture;hot rolling;thin Slab;Continuous casting and direct rolling
WANG Yun-hua
,
et al
钢铁研究学报(英文版)
On the background of the bright continuous simulative annealing experimental machine, the process control model of heating system is built in the paper. The heating model was simplified and the self-learning parameter was normalized in the paper in order to enhance the precision of the temperature control. By way of dividing temperature layers and exponential smoothing disposal with the data of the annealing experiment, self-learning of heating model was carried out, and at the same time, by way of exponential smoothing with the deviation of self-learning parameter of the heated phase in heating process, dynamic modifying of self-learning parameter was carried out, and so that dynamic modifying of heating electric current was carried out, and so, the precision of temperature control was confirmed. Application indicates that the process control model of heating system can control temperature with high precision, the deviation can be controlled in 8℃,it can offer reference to the research of similar equipments, and the method of self-learning is also adapt to process control of cooling system
关键词:
annealing;simulative;experimental machine;process control;self-adaptive
YANG Jing-ming
,
ZHANG Qing
,
CHE Hai-jun
,
et al
钢铁研究学报(英文版)
Based on rolling feature of continuous tandem cold rolling mill, such as multi-variable, strong coupling, non-linear, analyze and set the equal relative load, preventing slippage and profile well as the multi-objective optimization goal, BP neural network with self-learning function is adopted to replace traditional rolling force models and then Levenberg-Marquardt algorithm is adopted to predict the rolling force. Then use multi-objective fuzzy theory to solve the problem of multi-objective optimization of tandem cold rolling schedule. With the example of 1370mm tandem cold rolling, the rolling schedule of the common rolling, the single-object optimization design and the multi-objective fuzzy optimization design are compared with each other, optimization result shows the proposed optimization method decreases the value of three objective functions simultaneous. The performance of the optimal rolling schedule is satisfying and it is promising.
关键词:
rolling schedule;tandem cold rolling;neural network;multi-objective fuzzy optimization
YANG Jing-hong
,
et al
钢铁研究学报(英文版)
The transformation behavior and microstructural characteristics of a low carbon high Nb-bearing microalloyed pipeline steel have been investigated by deformation dilatometry and microstructure observation. The continuous cooling transformation curves (CCT) of the tested steel was constructed. High Nb content and deformation enhancing the formation of acicular ferrite; the microstructures are range from PF, QF to AF with increasing cooling rates from 0.5 to 50℃/s and dominated by acicular ferrite in a broadened cooling rate higher than 5℃/s. The chaotic microstructure consists of non-equiaxed ferrite and interwoven ferrite laths distributed high density dislocations and sununits. The results of isothermal holding show that acicular ferrite microstructure is formed in region of 550-600℃. With the holding time or temperature increased, some low misorientations boundaries change to high misotrentationn as dislocations moving and grain boundaries coarsening.
关键词:
microalloyed steel;acicular ferrite;transformation;continuous cooling transformation curves
LUO Zhi-jun
,
SHEN Jun-chang
,
SU Hang
,
et al
钢铁研究学报(英文版)
Substructure of M/B mixed structure in a low carbon NiCrMoV steel obtained through different cooling mode were quantitative analysis by optical microscope, SEM, EBSD and TEM to investigate the effect of the substructure on toughness. The results indicated that with the same prior austenite grain size and mixed by different ratio of M and B, toughness of steel enhanced with decrease of packet and block size and the lath width was about 0.38um. Calculation showed that packet and block boundary have the same effect on delaying crack extension, furthermore, effect of block width on impact energy was notably bigger than packet one. Therefore, block could work as a contributing microstructure controlled substructure in low carbon martensite steels, which means that block size was “the effect grain size controlling toughness”.
关键词:
lath martensite/bainite mixed structure;toughness;EBSD;crack extension
WANG Shuhan
,
LIU Zhenyu
,
WANG Guodong
,
et al
钢铁研究学报(英文版)
In the present paper, tensile tests of Fe-30Mn-5Si -2Al steel were carried out for different strains of 0.05, 0.14, 0.26, and up to the strain-to-failure in order to observe the evolution of microstructure during deformation and investigate the strain hardening behavior. Three-stage strain hardening behavior was observed in this steel during tensile test. In stage I, planar dislocation structure was observed by TEM to be the main deformation mechanism, and low strain hardening rate exponent was exhibited. Primary deformation twinning occurred in stage II, and the strain hardening rate exponent increased due to the blockage of dislocations’ motion by twin boundaries. In stage III, the strain hardening rate exponent had increased to be higher than 0.5. The obstacle effect of twin boundaries and twin-twin interaction had been observed by TEM, and the interactions between primary and secondary twins were found to cause the additional hardening in addition to the obstacle effect on dislocations’ motion, which led to the twinning induced plasticity effect in the later stage of deformation.
关键词:
TWIP steel;strain hardening;Twins;dislocations
WANG Hongming
,
LI Guirong
,
LI Bo
,
et al
钢铁研究学报(英文版)
B2O3 is selected as fluxing agent of CaO-based ladle refining slag to decrease the melting temperature as well as to improve the speed of slag forming and the refining efficiency. The effects of B2O3 on the melting temperature of two series of refining slags including the low basicity slags (the mass ratio of CaO/SiO2 is 3~4) and the high basicity slags (the mass ratio of CaO/SiO2 is 5~8.75) were investigated. The slag melting temperature was measured using the hemisphere method. The results indicate that the fluxing action of B2O3 is better than that of CaF2 and Al2O3. For the CaO-based refining slag with low basicity, the melting temperature is decreased effectively when B2O3 is used to substitute for equal mass of CaF2, Al2O3 and SiO2, respectively. For the CaO-based refining slag with high basicity, when CaF2 is substituted with B2O3, the melting temperature can be decreased remarkably. Especially, when the mass ratios of CaO/Al2O3 and CaO/SiO2 are in range of 1.1~4.0 and 5.25~8.0, respectively, the slag melting temperature is lower than 1300℃. Therefore, the B2O3-containing refining slags with high ratios of CaO/Al2O3 and CaO/SiO2 have ultralow melting temperature. As a result, not only the slag forming speed but also the capabilities of desulfurizing, dephosphorizing and absorbing deoxidation products are expected to be improved.
关键词:
Fluoride-free slag;Boron oxide;CaO-based refining slag;Melting temperature;Basicity
JIAO Duo-tian
,
CAI Qing-wu
,
WU Hui-bin
,
et al
钢铁研究学报(英文版)
By analysing the stepped test pieces with optical microscope, the influence of the Technological parameters including rolling temperature and reduction amount on the Austenitic recrystallization fraction of Nb content of 0.08％ steel deformed in high temperature processing was studied, and the deformed austenite recrystallization figures of the test steel were obtained. The result indicates when the reduction amount is 60%, the critical temperature of complete recrystallization is 1070℃ and the borderline temperature of non recrystallization is 900℃. In contrast with general HSLA steel, the recrystallization and non recrystallization temperatures are respectively 120℃ and 100℃ higher so the steel contenting high Nb has better hot processing performance because Nb has great function of holding back recrystallization.
关键词:
Austenicic Recrystallization;Technological Parameter;high content Nb
DU Wei
,
JIANG Lai-zhu
,
SUN Quan-she
,
et al
钢铁研究学报(英文版)
The effect of hot band annealing processes, namely simulated batch annealing and continuous annealing, on microstructure, texture, grain boundary character and r-value of ferritic stainless steel was investigated. The hot band displayed a highly elongated ribbon-like structure and a pronounced deformation texture. The fully recrystallized grains were observed after continuous annealing while the “typical” hot-rolled structure was remained after batch annealing. Also, the α-fibre texture formed during hot rolling almost disappeared after continuous annealing and a weak γ-fibre texture was obtained. By contract, the α-fibre texture remained very stable after batch annealing. After cold rolling and recrystallization annealing, the favorable γ-fibre texture was achieved in the continuous annealed steel. Instead of forming the γ-fibre texture, the recrystallization texture was notably shifted toward {223}<582> in the batch annealed steel. Finally, the improvement in drawability with high r-value and low △r-value were also displayed in sheet through the initial continuous annealing process.
关键词:
microstructure;texture;grain boundary character;drawability;hot band annealing
