Effect of Nb on the stability of retained austenite in hot-rolled TRIP steels based on dynamic transformation

2014 ◽  
Vol 603 ◽  
pp. 169-175 ◽  
Author(s):  
Qingxiao Feng ◽  
Longfei Li ◽  
Wangyue Yang ◽  
Zuqing Sun
Keyword(s):  
Retained Austenite ◽  
Trip Steels ◽  
Dynamic Transformation ◽  
The Stability ◽  
Hot Rolled

Effect of Different Coiling Temperature on Mechanical Properties in Hot Rolled TRIP Steel

2011 ◽  
Vol 239-242 ◽  
pp. 1092-1095
Author(s):  
Xu Tao Gao ◽  
Ai Min Zhao ◽  
Zheng Zhi Zhao ◽  
Ming Ming Zhang ◽  
Di Tang
Keyword(s):  
Mechanical Properties ◽  
Retained Austenite ◽  
X Ray Diffraction ◽  
Coiling Temperature ◽  
Experimental Steel ◽  
Transformation Induced Plasticity ◽  
X Ray ◽  
Trip Steels ◽  
Hot Rolled ◽  
Scanning Electron

By means of optical microscopy(OM), scanning electron microscopy(SEM),X-ray diffraction(XRD),And tensile test, Mechanical Properties of hot rolled transformation -induced plasticity (TRIP) steels which were prepared through three different coiling temperature was investigated. Result reveals that the formability index of the experimental steel descends when the coiling temperature becomes low. Different coiling temperature has greater impact on retained austenite. Amount and carbon content of retained austenite in the experimental steel get less with lower coiling temperature.

Hot-Rolled TRIP Steels Based on Dynamic Transformation of Undercooled Austenite

2010 ◽  
Vol 654-656 ◽  
pp. 250-253 ◽  
Author(s):  
Wang Yue Yang ◽  
Long Fei Li ◽  
Yun Yang Yin ◽  
Zu Qing Sun ◽  
Xi Tao Wang
Keyword(s):  
Volume Fraction ◽  
High Volume ◽  
Test Machine ◽  
Compression Tests ◽  
Controlled Cooling ◽  
Thermomechanical Process ◽  
Trip Steels ◽  
Dynamic Transformation ◽  
Hot Rolled ◽  
Undercooled Austenite

A novel thermomechanical process to manufacture hot-rolled transformation-induced plasticity (TRIP) steels was developed based on dynamic transformation of undercooled austenite (DTUA). Between DTUA and the isothermal bainitic treatment, only one-step controlled-cooling was required. The microstructure evolution of hot-rolled C-Mn-Si and C-Mn-Al-Si TRIP steels based on DTUA was investigated by hot uniaxial compression tests using a Gleeble1500 simulation test machine. The results indicated that during DTUA, the kinetics of ferrite formation was fast, the volume fraction of ferrite formed was determined by applied strain. In comparison with the process based on static transformation of austenite, a more uniform multiphase microstructure with fine ferrite grains was formed, the bainite packets were small and had relatively random orientations, the retained austenite distributed uniformly and had relatively high volume fraction. Hot-rolled TRIP steels based on DTUA demonstrated better mechanical properties, especially for C-Mn-Al-Si TRIP steel.

Temperature Development during Step-Wise Tensile Tests on a TRIP Steel

2010 ◽  
Vol 638-642 ◽  
pp. 3579-3584
Author(s):  
Lie Zhao ◽  
Corinna Thomser ◽  
Kirsten Schneider ◽  
Wolfgang Bleck ◽  
Jilt Sietsma
Keyword(s):  
Trip Steel ◽  
Retained Austenite ◽  
Room Temperature ◽  
Longitudinal Direction ◽  
Tensile Tests ◽  
Transformation Induced Plasticity ◽  
Trip Steels ◽  
Loading Process ◽  
Temperature Development ◽  
The Stability

Temperature development during plastic deformation affects the stability of retained austenite and thus the mechanical properties in transformation-induced plasticity (TRIP) steels. In this work, we used a thermo-camera to monitor the temperature development during a step-wise tensile test of an Al-containing multiphase TRIP steel. The tensile tests were performed by loading the specimen at six straining rates ranging from 5 to 30 s-1 to a stress of 700 MPa and then holding for 15 min, followed by further loading at 50 s-1 until fracture. It is found that temperature increases about 13 – 18 °C during the first loading process and drops back to room temperature with a time-constant of around 2 min. The increment of temperature increases with increasing straining rate. The temperature increases around 30 °C during the second loading process. The distribution of temperature over the specimen surface is found to be rather homogeneous along the longitudinal direction in most cases, except for the ending points of two loading processes. The measurement of temperature development is found to be consistent with previous numerical simulation on the temperature development under constant stress in TRIP steels.

Effect of Phosphorus on Microstructure, Mechanical Properties, and Formation of Retained Austenite in TRIP Steels

2012 ◽  
Vol 508 ◽  
pp. 128-132 ◽  
Author(s):  
Eui Pyo Kwon ◽  
Shun Fujieda ◽  
Kozo Shinoda ◽  
Shigeru Suzuki
Keyword(s):  
Mechanical Properties ◽  
Carbon Concentration ◽  
Trip Steel ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Transformation Induced Plasticity ◽  
Trip Steels ◽  
The Stability

In this Study, Influences of P on the Microstructure, Mechanical Properties, and Retained Austenite Characteristics in Transformation Induced Plasticity (TRIP) Steels Were Investigated. Microstructure of 0.2mass%P Containing TRIP Steel Was Inhomogeneous and it Resulted in Deterioration of the Mechanical Properties. Retained Austenite Characteristics such as Volume Fraction and Carbon Concentration Were Also Affected by P. The Stability of Retained Austenite in P Containing TRIP Steel Was Different from that in P-Free TRIP Steel. Such Difference in the Stability of Retained Austenite Was Attributed to the Effect of the Carbon Concentration in Retained Austenite as Well as their Different Microstructure.

Effect of Retained Austenite Stability on Mechanical Properties of 590MPa Grade TRIP Sheet Steels

2010 ◽  
Vol 638-642 ◽  
pp. 3374-3379 ◽  
Author(s):  
Hiroshi Matsuda ◽  
Hisata Noro ◽  
Yasunobu Nagataki ◽  
Yoshihiro Hosoya
Keyword(s):  
Mechanical Properties ◽  
Carbon Content ◽  
Retained Austenite ◽  
High Strain ◽  
Sheet Steels ◽  
Trip Steels ◽  
Austenite Stability ◽  
Retained Austenite Stability ◽  
The Stability ◽  
High Work

Industrial low alloy TRIP sheet steels contain blocky and lath-shaped retained austenite. In the present study, transformation behaviour of blocky and lath-shaped retained austenite during straining was investigated to clarify its effect on mechanical properties. Two types of TRIP steels containing almost the same amount but the different morphology of retained austenite were used. A steel containing large amount of lath-shaped retained austenite exhibits superior ductility, and sustains high work-hardenability in a high strain region. On the contrast, a steel containing large amount of blocky retained austenite exhibits low ductility. 　The work-hardenability increased steeply to the maximum at a low strain region, and then reduced in a high strain region. The stability of the blocky austenite has been found to be poor with respected to martensite transformation. The lath-shaped retained austenite remains until a high strain region whereas the blocky retained austenite transformed into martensite in a low strain region. Carbon content was higher in the lath-shaped retained austenite than in the blocky retained austenite. Stability of retained austenite is, however, inexplicable only by the carbon content, and would be affected by the different morphology and the resulting restraint conditions.

The Effect of Texture on the Stability of Retained Austenite in Al-Alloyed TRIP Steels

2011 ◽  
Vol 1296 ◽  
Author(s):  
Kemal Davut ◽  
Stefan Zaefferer
Keyword(s):  
Retained Austenite ◽  
Electron Backscatter Diffraction ◽  
High Strength ◽  
Trip Steels ◽  
Tension And Compression ◽  
Stable Austenite ◽  
Ebsd Technique ◽  
Face Centered ◽  
The Stability ◽  
Backscatter Diffraction

ABSTRACTSteels with transformation induced plasticity (TRIP) offer an excellent combination of high strength and ductility. The transformation of meta-stable austenite into martensite during straining leads to strong local hardening and prevents early localization of strain. Therefore, the mechanical properties of TRIP steels, including the damage resistance depend to a significant extent on the stability of retained austenite. The aim of this study was to evaluate the effect of texture on the stability of retained austenite. In order to compare the changes in both tension and compression the steel was deformed by a micro 3-point-bending device. The texture development upon bending was followed by electron backscatter diffraction (EBSD) technique. Based on a simple analysis using the relation between face centered cube (FCC) and body centered cube (BCC) shear geometries theoretically expected changes of texture components due to deformation are proposed. Using the results of this analysis the observed changes of the austenite texture due to deformation could be distinguished from those due to transformation, by comparing the experimental results with the theoretically expected behavior. From this comparison, austenite grains with “Brass (B) {011} <211>” and “Goss (G) {110} <100>” texture components were found to transform into martensite much easier than differently oriented grains.

The Influence of the Substitution of Si by Al on the Properties of Hot Rolled C-Mn-Si TRIP Steel

2017 ◽  
Vol 896 ◽  
pp. 198-201 ◽  
Author(s):  
Zhan Shan Wei ◽  
Zhuang Li ◽  
Wei Lv ◽  
Zhen Yao Shao
Keyword(s):  
Mechanical Properties ◽  
Trip Steel ◽  
Retained Austenite ◽  
Polygonal Ferrite ◽  
Granular Bainite ◽  
Trip Effect ◽  
Al Substitution ◽  
The Stability ◽  
Hot Rolled

The influence of the substitution of Si by Al on the properties of hot rolled C-Mn-Si TRIP steel was investigated by TMCP. The results have shown that the microstructures of the present steels consist of polygonal ferrite, granular bainite and retained austenite. The Al substitution of Si in a conventional C-Mn-Si TRIP steel leads to excellent mechanical properties (UTS>714MPa, A50>31%). TMCP led to the stability of the remaining austenite and a satisfactory TRIP effect. Excellent mechanical properties were obtained through tmcp for the hot rolled TRIP steel.

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