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Journal of Iron and Steel Research(International) 2023年第9期30卷 1769-1781页

作者： Zhi-yuan Liu Li-hao Zhang Cheng Ji Miao-yong Zhu Chong-jun Wang Engineering Research Center of Frontier Technologies for Low-carbon Steelmaking(Ministry of Education) Shenyang 110819LiaoningChina School of Metallurgy Northeastern UniversityShenyang 110819LiaoningChina Tangshan Medium and Heavy Plate Co. Ltd.Tangshan 063000HebeiChina

In order to describe the thermal–mechanical behavior of the ship plate steel continuous casting slab during solidification end heavy reduction(HR)process accurately,its constitutive behavior was investigated by a single-pass thermal compression experiment.According to the deformation features of wide thick continuous casting slab with HR,the simulation temperature ranged from 1173 to 1573 K with strain rates of 0.0001,0.001,0.01 and 0.1 s^(-1).Three different constitutive models,the modified Johnson–Cook(JC)model,the modified Zerilli–Armstrong(ZA)model and the Arrhenius model,were established according to the obtained true stress–strain curves.The average relative error of the modified JC model,the modified ZA model and the Arrhenius model are 10.82%,9.96%and 6.21%,respectively.Considering the obvious softening effect of the flow curve at a low strain rate,the secondary softening factor under the interaction of low strain rate and the temperature was introduced in the original Arrhenius model.Compared to the Arrhenius model,the modified Arrhenius model error decreased from 6.21%to 4.73%.

关键词： Ship plate steel Wide thick slab Continuous casting flow stress Constitutive model

Novel extended C-m models of flow stress for accurate mechanical and metallurgical calculations and comparison with traditional flow models

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Journal of Magnesium and Alloys 2022年第9期10卷 2516-2533页

作者： Man Soo Joun Mohd Kaswandee Razali Jae Dong Yoo Min Cheol Kim Jeong Muk Choi ReCAFT Gyeongsang National UniversityGraduate School of Mechanical and Aerospace EngineeringJinju 52828South Korea Gyeongsang National University Graduate School of Mechanical and Aerospace EngineeringJinju 52828South Korea MFRC Research CenterJinju 52818South Korea Jinhap Daejeon 34302South Korea

Here,we developed novel extended piecewise bilinear power law(C-m)models to describe flow stresses under broad ranges of strain,strain rate,and temperature for mechanical and metallurgical calculations during metal forming at elevated temperatures.The traditional C-m model is improved upon by formulating the material parameters C and m,defined at sample strains and temperatures as functions of the strain rate.The coefficients are described as a linear combination of the basis functions defined in piecewise patches of the sample strain and temperature domain.A comparison with traditional closed-form function flow models revealed that our approach using the extended piecewise bilinear C-m model is superior in terms of accuracy,ease of use,and adaptability;additionally,the extended C-m model was applicable to numerical analysis of mechanical,metallurgical,and microstructural problems.Moreover,metallurgy-related values can be calculated directly from the flow stress information.Although the proposed model was developed for materials at elevated temperatures,it can be applied over a broad temperature range.

关键词： flow stress Power law model Piecewise bilinear function Numerical analysis Microstructural prediction Peak strain

flow stress model considering the transformation-induced plasticity effect and the inelastic strain recovery behavior

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International Journal of Minerals,Metallurgy and Materials 2011年第2期18卷 185-191页

作者： Hai-yan Yu Li Bao School of Automotive Engineering Tongji University Shanghai 200092 China

On the basis of continuum mechanics and the Mori-Tanaka mean field theory, a micro-mechanical flow stress model that considered both the transformation-induced plasticity （TRIP） effect and the inelastic strain recovery behavior of TRIP multiphase steels was presented. The relation between the volume fraction of constituent phases and plastic strain was introduced to characterize the transformation-induced plasticity effect of TRIP steels. Loading-unloading-reloading uniaxial tension tests of TRIP600 steel were carried out and the strain recovery behavior after unloading was analyzed. From the experimental data, an empirical elastic modulus expression is extracted to characterize the inelastic strain recovery. A comparison of the predicted flow stress with the experimental data shows a good agreement. The mechanism of the transformation-induced plasticity effect and the inelastic recovery effect acting on the flow stress is also discussed in detail.

关键词： flow stress transformation-induced plasticity inelastic strain elastic modulus

flow stress and tribology size effects in scaled down cylinder compression

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Transactions of Nonferrous Metals Society of China 2009年第S2期19卷 516-520页

作者：郭斌龚峰王春举单德彬 School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China Key Laboratory of Micro-Systems and Micro-Structures Manufacturing Ministry of EducationHarbin Institute of TechnologyHarbin 150080China

Microforming is an effective method to manufacture small metal parts.However,macro forming can not be transferred to microforming directly because of size effects.flow stress and tribology size effects were studied.Scaled down copper T2 cylinder compression was carried out with the lubrication of castor oil and without lubrication.The results show that the flow stress decreases with decreasing the initial specimen diameter in both lubrication conditions,and the flow stress decreases by 30 MPa with the initial specimen diameter decreasing from 8 mm to 1 mm.The friction factor increases obviously with decreasing the initial specimen diameter in the case of lubricating with castor oil,and the friction factor increases by 0.11 with the initial specimen diameter decreasing from 8 mm to 1 mm.However,the tribology size effect is not found in the case without lubrication.The reasons of the flow stress and tribology size effects were also discussed.

关键词： microforming size effects flow stress friction factor cylinder compression

flow stress Behaviors and Microstructure Evolution of 300M High Strength Steel under Isothermal Compression

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Journal of Iron and Steel Research(International) 2014年第12期21卷 1116-1123页

作者： Rong-sheng QI Bao-feng GUO Xin-gang LIU Miao JIN Key Laboratory of Advanced Forging & Stamping Technology and Science(Yanshan University) Ministry of Education of China

The compressive deformation behaviors of 300M high strength steel were investigated over a wide range of temperatures （850- 1200 C） and strain rates （0. 001- 10 s^- 1 ） on a Gleeble-3800 thermo-mechanical simulator. The measured flow stress was modified by the corrections of the friction and the temperature compensations, which nicely reflect negative effects of the friction and temperature on the flow stress. The corrected stress-strain curves were the dynamic recrystallization type on the conditions of higher deformation temperature and lower strain rate. flow stress increases with the increase of strain rate at the same deformation temperature and strain. By contrast, flow stress decreases with the increase of temperature at the same strain rate and strain. Dependence of the peak stress on temperature and strain rate for 300M steel is described by means of the conventional hyperbolic sine equation. By re gression analysis, the activation energy （Q） in the whole range of deformation temperature is determined to be 367. 562 kJ/mol. The effects of the temperature and the strain rate on mierostructural evolution are obvious. With the increase of the deformation temperature and the decrease of the strain rate, the original austenite grain sizes of 300M steel increase. At the same time, the corrected flow stress curves more accurately determine the evolution of the microstrueture.

关键词： 300M high strength steel flow stress curve correction microstructural evolution

Research on flow stress of spray formed 70Si30Al alloy under hot compression deformation

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Rare Metals 2006年第6期25卷 665-670页

作者： WEI Yanguang XIONG Baiqing ZHANG Yong＇an LIU Hongwei ZHU Baohong WANG feng State Key Laboratory for Fabrication ＆ Processing of Non-ferrous Metals Beijing General Research Institute for Non-ferrous Metals Beijing 100088China

The flow stress of spray formed 70Si30Al alloy was studied by hot compression on a Gleeble- 1500 test machine. The experimental results indicated that the flow stress depends on the strain rate and the deformation temperature. The flow stress increases with an increase in strain rate at a given deformation temperature. The flow stress decreases with the deformation temperature increasing at a given strain rate. The relational expression among the flow stress, the swain rate, and the deformation temperature satisfies the Arrhenius equation. The deformation activation energy of 70Si30Al alloy during hot deformation is 866.27 kJ/mol from the Arrhenius equation.

关键词： 70Si30Al alloy spray forming flow stress hot compression An＇henius equation

A flow stress Model for High Strength Steels with Low Carbon Bainite Structure

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Journal of Iron and Steel Research(International) 2016年第4期23卷 372-379页

作者： Bao-sheng XIE Qing-wu CAI Wei YU Shi-xin XU Ban WANG Collaborative Innovation Center of Steel Technology University of Science and Technology Beijing National Engineering Research Center of Advanced Rolling University of Science and Technology Beijing

Two kinds of steels （YP960 and YP690） with low carbon bainite structure were designed, and their flow stress and strain hardening exponents were studied. The results showed that, when Hollomon relation was applied to descrihe the flow stress, there were significanl errors between the experimental and calculated points in specimens tempered below 400 ℃, while a high precision was ohserved in samples tempered above 400℃. Whereas, the modijied Voce relation could effectively predici the flow stress as well as the strain hardening exponent at different tempe ring temperatures, which was verified by unbiased estimators such as maximum relative error （MRXE） and average ahsolute relative error （AARE）. Besides, the modified Voee relation was also applied to estimate the maximum uniform strain, and the correlation coefficients （R） between the experimental data and calculated maximum uniform strain were more than 0.91. The high correlation coefficients indicated that the modified Vote relation could effec lively predict the uniform deformation ability of high strength steels with low carbon bainite structure at different tempering temperatures.

关键词： tempering temperature flow stress low carbon bainite Voce type relation strain hardening exponent

Prediction model for flow stress during isothermal compression in α+β phase field of TC4 alloy

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Rare Metals 2018年第5期37卷 369-375页

作者： Shun Yang Hong Li Jiao Luo Yin-Gang Liu Miao-Quan Li School of Materials Science and Engineering Northwestern Polytechnical University

Isothermal compression of TC4 alloy was performed on a Thermecmaster-Z simulator at the deformation temperatures ranging from 1093 to 1243 K, the strain rates ranging from 0.001 to 10.000 s^-l and a maximum strain of 0.8. The experimental results show that the flow stress increases with the decrease in the deformation temperature and the increase in the strain rate. The apparent activation energy for deformation is much lower at lower strain rates than that at higher strain rates. The flow stress model considering strain compensation was established. The average relative error between the calculated flow stress and experimental results is about 7.69%, indicating that the present model could be used to accurately predict the flow stress during high temperature in α＋β phase field of TC4 alloy.

关键词： TC4 alloy Isothermal compression Model flow stress

Research on flow stress in ferrite deformation of a Ti-IF steel

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Journal of University of Science and Technology Beijing 2006年第1期13卷 34-36页

作者： Guang Xu Chushao Xu Jiarong Zhao Xianjun Liu College of Material Science and Engineering Chongqing University 400044 Chongqing China College of Materials and Metallurgy Wuhan University of Science and Technology 430081 Wuhan China

The experiments of the ferrite warm deformation of ultra-low carbon （ULC） Ti-IF steel were carded out on a hot simulator and the influences of deformation temperature, strain, and strain rate on the flow stress were analyzed. New flow stress models suitable to ferrite warm forming of Ti-IF steel were given on the basis of analyzing the influence of deformation technology parameters on the flow stress.

关键词： ULC Ti-IF steel ferrite deformation flow stress model

Size effects on flow stress of C3602 in cylinder compression with different lubricants

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Rare Metals 2009年第5期28卷 528-532页

作者： GONG Feng GUO Bin ZHOU Jian SHAN Debin School of Materials Science and Engineering Harbin Institute Qf Technology Harbin 150001 China

Micro parts are more difficult to be formed than macro parts because of size effects. The size effects on the flow stress of copper alloy C3602 with different lubricants were studied. Specimens were heat treated at 350℃ for 1 h and 700℃ for 3 h in nitrogen atmosphere, respectively. The initial diameters of the specimens were varied from 5 to 1 mm with a height-to-diameter ratio h0/D0 = 1.5. Cylinder compression was carried out in the lubrication condition with talc powder, without lubricant, with petroleum jelly, and with vegetable oil. The experiment was carried out at room temperature on a universal testing machine INSTRON 5569 with a strain rate of ε = 0.0025 A. The results show that with the same lubricant, the yield strength decreases with a decrease in specimen size for the specimens annealed at 350℃ for 1 b; however, it increases with a decrease in specimen size for the specimens annealed at 700℃ for 3 h. The yield strength decreases with an increase in grain size. The influences of lubricants on yield strength become larger with miniaturization of the specimens.

关键词： microforming size effects cylinder compression flow stress lubricant