The coil cooling and its role in a hot strip mill were reviewed. A mathematical model was developed to describe and analyze the thermal history and its impact on precipitation phenomena during coil cooling for plain c...The coil cooling and its role in a hot strip mill were reviewed. A mathematical model was developed to describe and analyze the thermal history and its impact on precipitation phenomena during coil cooling for plain carbon, HSLA-V and HSLA-Nb steels. The predicted result of the thermal model was compared with that measured from industrial coil. The effect of cooling condition and coil dimension on the thermal history and final mechanical properties of the steel strip was examined. The coiling temperature and cooling rate have crucial influence on the precipitation strengthening.展开更多
The thermal evolution of steel coil during cooling was simulated and investigated by the use of in-house Q-CSP software. The dependence of the thermal evolution of steel coil on cooling methods, temperature distributi...The thermal evolution of steel coil during cooling was simulated and investigated by the use of in-house Q-CSP software. The dependence of the thermal evolution of steel coil on cooling methods, temperature distribution of the strip before coiling, coil size and steel grades was also discussed. The study plays a significant role in helping steel makers to better understand and control the cooling process.展开更多
The effects of hot-strip coiling temperature on Ti（C,N） precipitation, texture and hydrogen permeation behavior in DC06 EK enamel steel were investigated by TEM, EBSD test and electrochemical hydrogen permeation exp...The effects of hot-strip coiling temperature on Ti（C,N） precipitation, texture and hydrogen permeation behavior in DC06 EK enamel steel were investigated by TEM, EBSD test and electrochemical hydrogen permeation experiment. It was found that the Ti（C,N） particles in hot-strip coarsened with increasing coiling temperature, whereas after cold-rolling and annealing, the size difference of Ti（C,N） particles was lessened. The hot-strip coiling temperature has a significant impact on the recrystallized texture in the subsequent cold-rolled and annealed sheet. Hot-strip using high temperature（700 ℃） coiling leads to strong {111} recrystallized texture in annealed sheet, with peak intensity 9.2. On the contrary, in annealed sheets using hot-strip coiling at 650 ℃, their {111} recrystallized textures were weaker, which was also reflected in their rmvalues. Even though the hydrogen diffusion coefficient is slightly lower（7.76×10^（-5） mm^2/s） in annealed sheet using low temperature coiling（600 ℃）, appropriately higher coiling temperature is more suitable for DC06 EK enamel steel combining both good drawability and fish-scale resistance.展开更多
The effect of coiling temperatures on the evolution of texture in Ti-IF steel during ferritic hot rolling, cold rolling and annealing was studied. It was found that texture evolution at high temperature coiling is abs...The effect of coiling temperatures on the evolution of texture in Ti-IF steel during ferritic hot rolling, cold rolling and annealing was studied. It was found that texture evolution at high temperature coiling is absolutely different from that at low temperature one. The hot band texture includes a strong α-fiber as well as a weak γ-fiber after ferritic hot rolling and low temperature coiling. Both of them intensify after cold rolling and a γ-fiber with peak at {111}〈112〉 is the main texture of annealed samples. However, the main component of the hot band texture after high temperature coiling is v-fiber. After cold rolling, the intensity of γ texture reduces; α fiber （except {111}〈110〉 component） intensifies and a strong and well-proportioned γ-fiber forms in the annealed samples.展开更多
The effects of cooling rate and coiling temperature on microstructure and mechanical properties of a plain carbon steel were investigated by combining metallography and tensile experiments. The results indicate that f...The effects of cooling rate and coiling temperature on microstructure and mechanical properties of a plain carbon steel were investigated by combining metallography and tensile experiments. The results indicate that ferrite grain size is refined and bainite transformation occurs to ensure high strength and elongation, as the cooling rate is quick enough. Yield strength and tensite strength improve with the decreased finish cooling temperature, but the elongation decreases too significantly to meet the requirements. Thus, the cooling rate must be quick enough, and the appropriate coiling temperature should be carefully selected to obtain refined ferrite and a small amount of bainite to improve the strength while the plasticity is also ensured. Under this condition, the Mn element concentration can be reduced to save cost or produce higher strength steel with same chemical composition.展开更多
To solve the problems in the quality control and improvement of coiled tubing steel strips production, such as scattered and inefficient production data, difficult performance fluctuation factor analysis, complex mult...To solve the problems in the quality control and improvement of coiled tubing steel strips production, such as scattered and inefficient production data, difficult performance fluctuation factor analysis, complex multivariate statistical analysis, and low accuracy and difficulty in mechanical property prediction, an industrial data analysis platform for coiled tubing steel strips production has been preliminarily developed.As the premise and foundation of analysis, industrial data collection, storage, and utilization are realized by using multiple big data technologies.With Django as the agile development framework, data visualization and comprehensive analyses are achieved.The platform has functions including overview survey, stability analysis, comprehensive analysis(such as exploratory data analysis, correlation analysis, and multivariate statistics),precise steel strength prediction, and skin-passing process recommendation.The platform is helpful for production overviewing and prompt responding, laying a foundation for an in-depth understanding of product characteristics and improving product performance stability.展开更多
The sensitivity of magnetic Barkhausen noise (MBN) profile to changes in the excitation field strength and the number of turns of the detection coil was investigated in inhomogeneous material. Generally, the 0.5 mm ca...The sensitivity of magnetic Barkhausen noise (MBN) profile to changes in the excitation field strength and the number of turns of the detection coil was investigated in inhomogeneous material. Generally, the 0.5 mm case depth EN 36 steel specimen shows a double peak profile indicative of inhomogeneity through the detected depth the magnetized landscape. Various excitation field amplitudes were applied to the specimen and the induced MBN emission was analyzed for each magnetizing current. Excitation field at the lowest level induced an MBN emission of two peaks of equivalent heights. The first peak occurs at lower field than the second peak in the magnetization period. As the excitation field increased, the height of both peaks increased but the second peak increased in a higher rate than that of the first peak. Beyond certain excitation level, both peaks began to saturate and no increase in the MBN intensity was observed with increased excitation field strength. However, peak position and the number of Barkhausen events, indicated linearly as a function of the applied field strength. The experiment also establishes that the number of turns in the detection coil is important parameter which controls the height of the first peak. Low field peak height increases as the number of turn of the detection coil increases. The results indicate that the potential difference applied to the electromagnet and the sensitivity of the detection coil, determine the MBN profile characteristics.展开更多
钢丝绳金属横截面积损失(Loss of Metallic area)直接影响钢丝绳承载强度等特性,因此其检测及定量分析对于设备安全可靠运行具有重要意义。针对目前主磁通检测中存在的线圈绕制困难、参数确定模糊等问题,基于仿真模型提出一种基于印制...钢丝绳金属横截面积损失(Loss of Metallic area)直接影响钢丝绳承载强度等特性,因此其检测及定量分析对于设备安全可靠运行具有重要意义。针对目前主磁通检测中存在的线圈绕制困难、参数确定模糊等问题,基于仿真模型提出一种基于印制电路板(Printed Circuit Board)的分体式线圈结构,分析了线圈匝数、线圈层数、线距等参数对检测信号的影响;建立主磁通检测模型,探究损伤宽度对主磁通检测信号的影响规律,并针对损伤宽度变化造成的信号损失设计补偿方法;最后通过钢丝实验验证金属横截面积定量检测效果,表明该方法定量误差在1%以内,能够有效检测钢丝绳的LMA。展开更多
文摘The coil cooling and its role in a hot strip mill were reviewed. A mathematical model was developed to describe and analyze the thermal history and its impact on precipitation phenomena during coil cooling for plain carbon, HSLA-V and HSLA-Nb steels. The predicted result of the thermal model was compared with that measured from industrial coil. The effect of cooling condition and coil dimension on the thermal history and final mechanical properties of the steel strip was examined. The coiling temperature and cooling rate have crucial influence on the precipitation strengthening.
基金This work was financially supported by the National High-Tech Research and Development Program of China (No.2001AA339030),the National Natural Science Foundation of China (No.50334010) and the Ministry of Sciences and Technology of China.
文摘The thermal evolution of steel coil during cooling was simulated and investigated by the use of in-house Q-CSP software. The dependence of the thermal evolution of steel coil on cooling methods, temperature distribution of the strip before coiling, coil size and steel grades was also discussed. The study plays a significant role in helping steel makers to better understand and control the cooling process.
基金Funded by the National Natural Science Foundation of China(No.51501056)Natural Science Foundation of Hebei Province(No.E2016209341)+2 种基金Educational Commission of Hebei Province(No.BJ2014031)Project of Science and Technology of Tangshan(Nos.14130243B and 15130202C)Foundation of North China University of Science and Technology(No.JP201510)
文摘The effects of hot-strip coiling temperature on Ti（C,N） precipitation, texture and hydrogen permeation behavior in DC06 EK enamel steel were investigated by TEM, EBSD test and electrochemical hydrogen permeation experiment. It was found that the Ti（C,N） particles in hot-strip coarsened with increasing coiling temperature, whereas after cold-rolling and annealing, the size difference of Ti（C,N） particles was lessened. The hot-strip coiling temperature has a significant impact on the recrystallized texture in the subsequent cold-rolled and annealed sheet. Hot-strip using high temperature（700 ℃） coiling leads to strong {111} recrystallized texture in annealed sheet, with peak intensity 9.2. On the contrary, in annealed sheets using hot-strip coiling at 650 ℃, their {111} recrystallized textures were weaker, which was also reflected in their rmvalues. Even though the hydrogen diffusion coefficient is slightly lower（7.76×10^（-5） mm^2/s） in annealed sheet using low temperature coiling（600 ℃）, appropriately higher coiling temperature is more suitable for DC06 EK enamel steel combining both good drawability and fish-scale resistance.
基金National Natural Science Foundation of China for financial support, under Grant No. 50104004.
文摘The effect of coiling temperatures on the evolution of texture in Ti-IF steel during ferritic hot rolling, cold rolling and annealing was studied. It was found that texture evolution at high temperature coiling is absolutely different from that at low temperature one. The hot band texture includes a strong α-fiber as well as a weak γ-fiber after ferritic hot rolling and low temperature coiling. Both of them intensify after cold rolling and a γ-fiber with peak at {111}〈112〉 is the main texture of annealed samples. However, the main component of the hot band texture after high temperature coiling is v-fiber. After cold rolling, the intensity of γ texture reduces; α fiber （except {111}〈110〉 component） intensifies and a strong and well-proportioned γ-fiber forms in the annealed samples.
文摘The effects of cooling rate and coiling temperature on microstructure and mechanical properties of a plain carbon steel were investigated by combining metallography and tensile experiments. The results indicate that ferrite grain size is refined and bainite transformation occurs to ensure high strength and elongation, as the cooling rate is quick enough. Yield strength and tensite strength improve with the decreased finish cooling temperature, but the elongation decreases too significantly to meet the requirements. Thus, the cooling rate must be quick enough, and the appropriate coiling temperature should be carefully selected to obtain refined ferrite and a small amount of bainite to improve the strength while the plasticity is also ensured. Under this condition, the Mn element concentration can be reduced to save cost or produce higher strength steel with same chemical composition.
文摘To solve the problems in the quality control and improvement of coiled tubing steel strips production, such as scattered and inefficient production data, difficult performance fluctuation factor analysis, complex multivariate statistical analysis, and low accuracy and difficulty in mechanical property prediction, an industrial data analysis platform for coiled tubing steel strips production has been preliminarily developed.As the premise and foundation of analysis, industrial data collection, storage, and utilization are realized by using multiple big data technologies.With Django as the agile development framework, data visualization and comprehensive analyses are achieved.The platform has functions including overview survey, stability analysis, comprehensive analysis(such as exploratory data analysis, correlation analysis, and multivariate statistics),precise steel strength prediction, and skin-passing process recommendation.The platform is helpful for production overviewing and prompt responding, laying a foundation for an in-depth understanding of product characteristics and improving product performance stability.
文摘The sensitivity of magnetic Barkhausen noise (MBN) profile to changes in the excitation field strength and the number of turns of the detection coil was investigated in inhomogeneous material. Generally, the 0.5 mm case depth EN 36 steel specimen shows a double peak profile indicative of inhomogeneity through the detected depth the magnetized landscape. Various excitation field amplitudes were applied to the specimen and the induced MBN emission was analyzed for each magnetizing current. Excitation field at the lowest level induced an MBN emission of two peaks of equivalent heights. The first peak occurs at lower field than the second peak in the magnetization period. As the excitation field increased, the height of both peaks increased but the second peak increased in a higher rate than that of the first peak. Beyond certain excitation level, both peaks began to saturate and no increase in the MBN intensity was observed with increased excitation field strength. However, peak position and the number of Barkhausen events, indicated linearly as a function of the applied field strength. The experiment also establishes that the number of turns in the detection coil is important parameter which controls the height of the first peak. Low field peak height increases as the number of turn of the detection coil increases. The results indicate that the potential difference applied to the electromagnet and the sensitivity of the detection coil, determine the MBN profile characteristics.
