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Frederic Barlat - One of the best experts on this subject based on the ideXlab platform.

  • formability of austenitic and ferritic stainless steels at warm Forming Temperature
    International Journal of Mechanical Sciences, 2013
    Co-Authors: Hyuk Jong Bong, Frederic Barlat
    Abstract:

    Abstract The warm Temperature drawability of austenitic (STS 304) and ferritic stainless (STS 430) steel sheet samples was evaluated using the cup drawing test. The measured limiting drawing ratios (LDRs) increased about 44% and 25% for STS 304 and STS 430, respectively, compared to the isothermal case by introducing optimal Temperature gradients between punch and die/blank holder. The drawability improvement was more drastic with STS 304 than with STS 430 using this Temperature gradient approach. Fully coupled thermo-mechanical finite element (FE) analyses of the warm cup drawing tests were also carried out and validated using experimental data. For an accurate FE modeling, the mechanical properties measured in uniaxial and balanced biaxial tension tests were accounted for. For STS 304, an isotropic, Temperature-dependent, yield function led to a reasonable prediction of the cup drawing performance at all Temperature conditions. However, for STS 430, an anisotropic yield function was necessary to achieve good accuracy, in particular, for the prediction of the fracture location and cup height. Besides drawability, the earing profiles of the STS 430 cups were also simulated using three different yield functions, namely, von Mises, Hill48 and the non-quadratic anisotropic Yld2000-2d. Comparisons with experimental measurements indicated that the latter resulted in the best earing profile predictions for various Temperature conditions.

Xiao Zhang - One of the best experts on this subject based on the ideXlab platform.

  • Research on Forming Temperature of Metastable Austenitic Stainless Steel Head Based on Strain-Induced Martensitic Transformation
    Journal of Pressure Vessel Technology-transactions of The Asme, 2019
    Co-Authors: Jinyang Zheng, Xiao Zhang, Ding Huiming, Hui Peizi, Li Qingqing
    Abstract:

    The formation of strain-induced martensite (SIM) is found in metastable austenitic stainless steel (m-ASS) during cold Forming, and the presence of SIM may cause reductions in toughness, ductility, and corrosion resistance of m-ASS. These mechanical properties can be restored and improved by proper heat treatment after Forming, however, which obviously raises the manufacturing costs. One low-cost way to reduce the SIM amount during m-ASS Forming is to maintain the Forming Temperature at an appropriate level. This paper intends to investigate an approach to determine the optimum Forming Temperature at which the strain-induced martensitic transformation (SIM-Tr) of m-ASS head during Forming can be restrained within a limited intensity. First, static tensile tests were conducted on S30408 conventional cylindrical tensile specimens under different Temperatures varying from 20 °C to 180 °C, and then the effect of deformation Temperature on SIM was evaluated. Second, according to the stacking fault energy (SFE) calculation method, m-ASS's chemical composition was taken into further consideration to investigate its effect on SIM. Finally, a formula was established based on SIM and chemical composition for optimization of Forming Temperature. In addition, the results obtained by this formula were compared with those of the experiment by S30408 ASS head stamping tests, and the satisfactory matching is found for the proposed Forming Temperatures and predicted ferrite number (FN) values (readings of the Ferritescope measurement, as a representation of the amount of martensite in this study). Furthermore, an enhancement in the cryogenic impact properties and a fewer quantity of delta-ferrite in the microstructure of m-ASS heads are observed when warm stamping is performed as compared with the cold stamped head.

  • Research on Forming Temperature of Metastable Austenitic Stainless Steel Head Based on Strain-Induced Martensitic Transformation
    Volume 5: High-Pressure Technology; Rudy Scavuzzo Student Paper Symposium and 24th Annual Student Paper Competition; ASME Nondestructive Evaluation Di, 2016
    Co-Authors: Jinyang Zheng, Xiao Zhang
    Abstract:

    Formation of strain-induced martensite (SIM) is found in metastable austenitic stainless steel (m-ASS) during cold Forming. The presence of SIM may cause reductions in toughness, ductility and corrosion resistance of the m-ASS. Although these mechanical properties can be restored and improved after cold Forming by using proper heat treatment, the manufacturing cost rises greatly. However, the cost of warm Forming is cheaper and the SIM reduces with Forming Temperature increasing. Thus, the main purpose of this research is to investigate a suitable Forming Temperature, at which the strain-induced martensitic transformation (SIM-Tr) of m-ASS head in Forming will reduce. Primarily, a series of static tensile tests were conducted based on several batches of S30408 plates. The tests were carried out at different Temperatures varying from 20 °C to 180 °C, with the effect of deformation Temperature on SIM evaluated. Moreover, according to the stacking fault energy (SFE) calculation method, the m-ASS’s chemical composition was taken into further consideration to investigate its effect on SIM. Eventually, a formula was established that related to SIM and chemical composition for optimizing the Forming Temperature. The results obtained by this formula were compared to the experimental results of 304 ASS head stamping tests, and satisfactory matching is found for the proposed Forming Temperatures and the predicted FN values (readings of the Ferritescope measurement, as a representation of the amount of martensite in this study). Additionally, an enhancement of the cryogenic impact properties and a fewer quantity of delta-ferrite in the microstructure are observed when stamping Temperature is higher than 90 °C.

Hu Zhonglin - One of the best experts on this subject based on the ideXlab platform.

  • On the genesis of uranium deposit 720 with special reference to the double solution-mixing model
    Chinese Journal of Geochemistry, 1991
    Co-Authors: Li Zhenqiu, Hu Zhonglin
    Abstract:

    Presented in this paper is an approach to the analysis of “series-stage” division. The processes of hydrothermal evolution involved in ore deposition, the factors affecting the enrichment of uranium and the source of ore-Forming elements in uranium deposit 720 are also discussed. In addition, the ore-Forming Temperature and pressure as well as the pH, Eh and chemical composition of ore-Forming medium are studied with reference to the fluid inclusion data available. A double solution-mixing model has been proposed to explain the genesis of the uranium deposit studied.

  • On the genesis of uranium deposit 720 with special reference to the double solution-mixing model
    Chinese Journal of Geochemistry, 1991
    Co-Authors: Li Zhenqiu, Hu Zhonglin
    Abstract:

    Presented in this paper is an approach to the analysis of “series-stage” division. The processes of hydrothermal evolution involved in ore deposition, the factors affecting the enrichment of uranium and the source of ore-Forming elements in uranium deposit 720 are also discussed. In addition, the ore-Forming Temperature and pressure as well as the pH, Eh and chemical composition of ore-Forming medium are studied with reference to the fluid inclusion data available. A double solution-mixing model has been proposed to explain the genesis of the uranium deposit studied.

Jinyang Zheng - One of the best experts on this subject based on the ideXlab platform.

  • Research on Forming Temperature of Metastable Austenitic Stainless Steel Head Based on Strain-Induced Martensitic Transformation
    Journal of Pressure Vessel Technology-transactions of The Asme, 2019
    Co-Authors: Jinyang Zheng, Xiao Zhang, Ding Huiming, Hui Peizi, Li Qingqing
    Abstract:

    The formation of strain-induced martensite (SIM) is found in metastable austenitic stainless steel (m-ASS) during cold Forming, and the presence of SIM may cause reductions in toughness, ductility, and corrosion resistance of m-ASS. These mechanical properties can be restored and improved by proper heat treatment after Forming, however, which obviously raises the manufacturing costs. One low-cost way to reduce the SIM amount during m-ASS Forming is to maintain the Forming Temperature at an appropriate level. This paper intends to investigate an approach to determine the optimum Forming Temperature at which the strain-induced martensitic transformation (SIM-Tr) of m-ASS head during Forming can be restrained within a limited intensity. First, static tensile tests were conducted on S30408 conventional cylindrical tensile specimens under different Temperatures varying from 20 °C to 180 °C, and then the effect of deformation Temperature on SIM was evaluated. Second, according to the stacking fault energy (SFE) calculation method, m-ASS's chemical composition was taken into further consideration to investigate its effect on SIM. Finally, a formula was established based on SIM and chemical composition for optimization of Forming Temperature. In addition, the results obtained by this formula were compared with those of the experiment by S30408 ASS head stamping tests, and the satisfactory matching is found for the proposed Forming Temperatures and predicted ferrite number (FN) values (readings of the Ferritescope measurement, as a representation of the amount of martensite in this study). Furthermore, an enhancement in the cryogenic impact properties and a fewer quantity of delta-ferrite in the microstructure of m-ASS heads are observed when warm stamping is performed as compared with the cold stamped head.

  • Research on Forming Temperature of Metastable Austenitic Stainless Steel Head Based on Strain-Induced Martensitic Transformation
    Volume 5: High-Pressure Technology; Rudy Scavuzzo Student Paper Symposium and 24th Annual Student Paper Competition; ASME Nondestructive Evaluation Di, 2016
    Co-Authors: Jinyang Zheng, Xiao Zhang
    Abstract:

    Formation of strain-induced martensite (SIM) is found in metastable austenitic stainless steel (m-ASS) during cold Forming. The presence of SIM may cause reductions in toughness, ductility and corrosion resistance of the m-ASS. Although these mechanical properties can be restored and improved after cold Forming by using proper heat treatment, the manufacturing cost rises greatly. However, the cost of warm Forming is cheaper and the SIM reduces with Forming Temperature increasing. Thus, the main purpose of this research is to investigate a suitable Forming Temperature, at which the strain-induced martensitic transformation (SIM-Tr) of m-ASS head in Forming will reduce. Primarily, a series of static tensile tests were conducted based on several batches of S30408 plates. The tests were carried out at different Temperatures varying from 20 °C to 180 °C, with the effect of deformation Temperature on SIM evaluated. Moreover, according to the stacking fault energy (SFE) calculation method, the m-ASS’s chemical composition was taken into further consideration to investigate its effect on SIM. Eventually, a formula was established that related to SIM and chemical composition for optimizing the Forming Temperature. The results obtained by this formula were compared to the experimental results of 304 ASS head stamping tests, and satisfactory matching is found for the proposed Forming Temperatures and the predicted FN values (readings of the Ferritescope measurement, as a representation of the amount of martensite in this study). Additionally, an enhancement of the cryogenic impact properties and a fewer quantity of delta-ferrite in the microstructure are observed when stamping Temperature is higher than 90 °C.

Hyuk Jong Bong - One of the best experts on this subject based on the ideXlab platform.

  • formability of austenitic and ferritic stainless steels at warm Forming Temperature
    International Journal of Mechanical Sciences, 2013
    Co-Authors: Hyuk Jong Bong, Frederic Barlat
    Abstract:

    Abstract The warm Temperature drawability of austenitic (STS 304) and ferritic stainless (STS 430) steel sheet samples was evaluated using the cup drawing test. The measured limiting drawing ratios (LDRs) increased about 44% and 25% for STS 304 and STS 430, respectively, compared to the isothermal case by introducing optimal Temperature gradients between punch and die/blank holder. The drawability improvement was more drastic with STS 304 than with STS 430 using this Temperature gradient approach. Fully coupled thermo-mechanical finite element (FE) analyses of the warm cup drawing tests were also carried out and validated using experimental data. For an accurate FE modeling, the mechanical properties measured in uniaxial and balanced biaxial tension tests were accounted for. For STS 304, an isotropic, Temperature-dependent, yield function led to a reasonable prediction of the cup drawing performance at all Temperature conditions. However, for STS 430, an anisotropic yield function was necessary to achieve good accuracy, in particular, for the prediction of the fracture location and cup height. Besides drawability, the earing profiles of the STS 430 cups were also simulated using three different yield functions, namely, von Mises, Hill48 and the non-quadratic anisotropic Yld2000-2d. Comparisons with experimental measurements indicated that the latter resulted in the best earing profile predictions for various Temperature conditions.