Maoqiu Wang - Academia.edu (original) (raw)
Papers by Maoqiu Wang
Materials Science and Engineering: A
Materials Science and Technology
Acta Metallurgica Sinica, 2020
Journal of Materials Engineering and Performance, 2020
Materials Science and Engineering: A, 2019
Materials & Design (1980-2015), 2013
ABSTRACT Fatigue properties of two Al-containing steels have been investigated by rotating bendin... more ABSTRACT Fatigue properties of two Al-containing steels have been investigated by rotating bending fatigue tests. Results show that the fatigue limits (the fatigue strength at 107 cycles) were improved remarkably by plasma nitriding due to the high hardness of 1000 Hv and compressive stress of 400 MPa in the nitrided layer. Scanning electron microscopic observations show that after nitriding the fatigue crack initiation sites moved from the surface flaws or near-surface matrix into the AlN inclusions at around the case-core interface. Degassing treatment can increase the fatigue limit because it prevented fatigue crack initiation at AlN inclusions due to the reduced [N] contents and refined inclusion size.
Advanced Steels, 2011
Steels are now considered to be a category of new materials, which have progressed year by year t... more Steels are now considered to be a category of new materials, which have progressed year by year to meet the market requirements for high performance. Although it is well known that the performance of steel is dependent upon microstructure, the potential of microstructure evolution is really unknown by people at present due to the steadily developing steel metallurgy. The study
Advanced Steels, 2011
In recent years, economic and environmental considerations have increased the need to safely exte... more In recent years, economic and environmental considerations have increased the need to safely extend the service life of components and structures beyond their original design life. It well known that fatigue and delayed fracture are the two important mechanisms for the failure of steel components and structures in service. Based on our systematic studies of the fatigue failure and delayed
Journal of Zhejiang University SCIENCE A, 2010
Journal of Zhejiang University-SCIENCE A, 2011
Metals and Materials International, 2012
Materials Science and Engineering: A, 2011
Microstructure and mechanical properties of medium manganese steel (Fe–0.2C–5Mn) processed by ann... more Microstructure and mechanical properties of medium manganese steel (Fe–0.2C–5Mn) processed by annealing at 650°C with annealing time up to 12h after accelerated cooling were studied. It was found that the martensite structure was gradually transformed into a superfine ferrite and austenite duplex structure by austenite reverted transformation during annealing process. The annealing heat treatment results in a large volume fraction
Journal of Materials Science, 2011
Yield strength enhancement for martensitic steel fabricated by vacuum induction melting is invest... more Yield strength enhancement for martensitic steel fabricated by vacuum induction melting is investigated. It is found that the addition of Ti can improve the yield strength property of the martensitic steel, which can be attributed to increase in precipitation hardening from formation of TiC precipitates in the martensitic matrix. Moreover, the yield strength can be further enhanced by tempering and
Journal of Iron and Steel Research International, 2011
International Journal of Fatigue, 2009
ABSTRACT Fatigue properties of two case hardening steels after carburization have been investigat... more ABSTRACT Fatigue properties of two case hardening steels after carburization have been investigated by means of rotating bending fatigue tests and rolling contact fatigue tests. Results show that the steel with higher Al and N contents has higher rotating bending fatigue limit and rolling contact fatigue limit, increasing from 865 to 950MPa and from 3575 to 3725MPa, respectively. It is also shown that the steel with higher Al and N contents has finer prior austenite grain sizes and higher hardness in the carburized case. Scanning electron micrographic observations on the fractured surface of specimens for rotating bending fatigue tests show that fatigue crack usually initiated from oxide inclusions and propagated along prior austenite grain boundaries, indicating that the finer grain size and higher hardness in the carburized case of the steel with higher Al and N contents can contribute to its higher fatigue properties.
Acta Metallurgica Sinica (English Letters)
Materials
This paper focuses on the effect of gear steel on distortion due to phase transformation in carbu... more This paper focuses on the effect of gear steel on distortion due to phase transformation in carburizing and quenching. The carburizing and quenching process of C-rings under suspension was studied by using the finite element method based on the thermo-mechanical theory, considering phase transformation. The phase transformation kinetics parameters, depending on different carbon contents, were measured by Gleeble-3500. The distortion behavior of the carburized C-ring during the cooling stage was analyzed, as well as the carbon concentration distribution and martensite volume fractions. The accuracy of the simulation was also verified by comparing the experimental data with the simulated result of the distortion and microstructure. A reliable basis is provided for predicting the distortion mechanism of gear steels in carburizing and quenching.
Materials Science and Engineering: A
Materials Science and Technology
Acta Metallurgica Sinica, 2020
Journal of Materials Engineering and Performance, 2020
Materials Science and Engineering: A, 2019
Materials & Design (1980-2015), 2013
ABSTRACT Fatigue properties of two Al-containing steels have been investigated by rotating bendin... more ABSTRACT Fatigue properties of two Al-containing steels have been investigated by rotating bending fatigue tests. Results show that the fatigue limits (the fatigue strength at 107 cycles) were improved remarkably by plasma nitriding due to the high hardness of 1000 Hv and compressive stress of 400 MPa in the nitrided layer. Scanning electron microscopic observations show that after nitriding the fatigue crack initiation sites moved from the surface flaws or near-surface matrix into the AlN inclusions at around the case-core interface. Degassing treatment can increase the fatigue limit because it prevented fatigue crack initiation at AlN inclusions due to the reduced [N] contents and refined inclusion size.
Advanced Steels, 2011
Steels are now considered to be a category of new materials, which have progressed year by year t... more Steels are now considered to be a category of new materials, which have progressed year by year to meet the market requirements for high performance. Although it is well known that the performance of steel is dependent upon microstructure, the potential of microstructure evolution is really unknown by people at present due to the steadily developing steel metallurgy. The study
Advanced Steels, 2011
In recent years, economic and environmental considerations have increased the need to safely exte... more In recent years, economic and environmental considerations have increased the need to safely extend the service life of components and structures beyond their original design life. It well known that fatigue and delayed fracture are the two important mechanisms for the failure of steel components and structures in service. Based on our systematic studies of the fatigue failure and delayed
Journal of Zhejiang University SCIENCE A, 2010
Journal of Zhejiang University-SCIENCE A, 2011
Metals and Materials International, 2012
Materials Science and Engineering: A, 2011
Microstructure and mechanical properties of medium manganese steel (Fe–0.2C–5Mn) processed by ann... more Microstructure and mechanical properties of medium manganese steel (Fe–0.2C–5Mn) processed by annealing at 650°C with annealing time up to 12h after accelerated cooling were studied. It was found that the martensite structure was gradually transformed into a superfine ferrite and austenite duplex structure by austenite reverted transformation during annealing process. The annealing heat treatment results in a large volume fraction
Journal of Materials Science, 2011
Yield strength enhancement for martensitic steel fabricated by vacuum induction melting is invest... more Yield strength enhancement for martensitic steel fabricated by vacuum induction melting is investigated. It is found that the addition of Ti can improve the yield strength property of the martensitic steel, which can be attributed to increase in precipitation hardening from formation of TiC precipitates in the martensitic matrix. Moreover, the yield strength can be further enhanced by tempering and
Journal of Iron and Steel Research International, 2011
International Journal of Fatigue, 2009
ABSTRACT Fatigue properties of two case hardening steels after carburization have been investigat... more ABSTRACT Fatigue properties of two case hardening steels after carburization have been investigated by means of rotating bending fatigue tests and rolling contact fatigue tests. Results show that the steel with higher Al and N contents has higher rotating bending fatigue limit and rolling contact fatigue limit, increasing from 865 to 950MPa and from 3575 to 3725MPa, respectively. It is also shown that the steel with higher Al and N contents has finer prior austenite grain sizes and higher hardness in the carburized case. Scanning electron micrographic observations on the fractured surface of specimens for rotating bending fatigue tests show that fatigue crack usually initiated from oxide inclusions and propagated along prior austenite grain boundaries, indicating that the finer grain size and higher hardness in the carburized case of the steel with higher Al and N contents can contribute to its higher fatigue properties.
Acta Metallurgica Sinica (English Letters)
Materials
This paper focuses on the effect of gear steel on distortion due to phase transformation in carbu... more This paper focuses on the effect of gear steel on distortion due to phase transformation in carburizing and quenching. The carburizing and quenching process of C-rings under suspension was studied by using the finite element method based on the thermo-mechanical theory, considering phase transformation. The phase transformation kinetics parameters, depending on different carbon contents, were measured by Gleeble-3500. The distortion behavior of the carburized C-ring during the cooling stage was analyzed, as well as the carbon concentration distribution and martensite volume fractions. The accuracy of the simulation was also verified by comparing the experimental data with the simulated result of the distortion and microstructure. A reliable basis is provided for predicting the distortion mechanism of gear steels in carburizing and quenching.