Study of the Microstructure and Mechanical Properties of a Medium Manganese Quenching and Partitioning (Q&P) Steel

2016 ◽  
Vol 850 ◽  
pp. 659-663
Author(s):  
Xiao Gang Li ◽  
Ai Min Zhao ◽  
Hong Hong Zheng ◽  
Shao Heng Sun ◽  
Hong Xiang Yin

The microstructure and mechanical properties of a medium manganese quenching and partitioning (Q&P) steel for automobile were investigated by optical microscope (OM), scanning electron microscope (SEM), X-ray diffraction (XRD) and mechanical property test. The grain size and recovery degree were greatly affected by annealing temperature normally. The result shows that the medium manganese steel after quenching and partitioning (Q&P) heat treatment exhibited good mechanical properties. The maximum tensile strength and yield strength was 1280MPa and 1421MPa at 600°C, respectively. Additionally, the product of strength and plasticity could reached to 40472MPa×% at 640°C. Annealing temperature also had a great influence on the volume of retained austenite which increases linearly with the rise of annealing temperature as well.

2021 ◽  
Vol 1035 ◽  
pp. 404-409
Author(s):  
Zhe Rui Zhang ◽  
Ren Bo Song ◽  
Nai Peng Zhou ◽  
Wei Feng Huo

In this study, a new Fe-6Mn-4Al-0.4C high strength medium manganese hot rolled steel sheet was designed. The influence mechanism of the intercritical annealing (IA) temperature on microstructure evolution and mechanical properties of experimental steel were studied by SEM and XRD. The experimental steel was held for 30 minutes at 640°C, 680°C, 720°C, 760°C, 800°C, respectively. When the annealing temperature was 640°C, cementite particles precipitated between the austenite and ferrite phase boundary. As the annealing temperature increased, the cementite gradually dissolved and disappeared, the fraction of lamellar austenite increased significantly. When the annealing temperature is 800°C, the coarse equiaxed austenite and ferrite appeared. The yield strength (YS) decreased, the product of strength and elongation (PSE) and total elongation (TE) both increased first and then decreased, while the ultimate tensile strength (UTS) showed the opposite trend. The experimental steel exhibited excellent comprehensive mechanical properties after held at 760°C for 30 min. The UTS was 870 MPa, the YS was 703 MPa, and the TE was 77 %, the PSE was 67 GPa·%.


2013 ◽  
Vol 303-306 ◽  
pp. 2524-2527 ◽  
Author(s):  
Lei Wang ◽  
Guang Hui Min ◽  
Pan Pan Gao ◽  
Xin Ying Wang ◽  
Hua Shun Yu ◽  
...  

The microstructure of magnesium alloy sheets (nominal composition Mg–6Zn–Y in at. %) was investigated with the Optical Microscope (OM), Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD) technique after the annealing treatment. Tensile test at room temperature was performed to show the influence of annealing treatment on mechanical properties. Experimental results indicate that there are a large number of twin crystals appearing in microstructure of the extruded Mg-Zn-Y alloy sheet at 350 °C. The distinct icosahedral phase appears on the α-Mg matrix in granular form and the strength gets largely improved to the maximum. The uniform distribution of isometric crystal contributes to the best elongation at the annealing temperature of 400 °C.


2018 ◽  
Vol 11 (05) ◽  
pp. 1850033 ◽  
Author(s):  
Shuanglei Li ◽  
Tae-Hyun Nam

In this study, the effect of annealing temperature on microstructure and mechanical properties of a Ti–18Zr–12.5Nb–2Sn (at.%) alloy was investigated by using optical microscopy (OM), X-ray diffraction (XRD) measurement and tensile test. The cold-rolled plate was annealed at temperatures between 773[Formula: see text]K and 1173[Formula: see text]K. Recrystallization occurred in the specimen annealed at 873[Formula: see text]K. Grain size increased from 8[Formula: see text][Formula: see text]m to 80[Formula: see text][Formula: see text]m with increasing temperature from 873[Formula: see text]K to 1173[Formula: see text]K. The ultimate tensile strength decreased from 1590[Formula: see text]MPa to 806[Formula: see text]MPa with increasing annealing temperature from 773[Formula: see text]K to 973[Formula: see text]K, and then showed similar value in the specimens annealed at temperatures from 973[Formula: see text]K to 1173[Formula: see text]K. The fracture strain increased from 3.8% to 41.0% with increasing annealing temperature from 773[Formula: see text]K to 1173[Formula: see text]K due to the recovery and recrystallization. The recovery strain increased with increasing of annealing temperature attributed to the evolution of recrystallization texture.


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