Research on Intercritical Rolling of 0.2C-1.5Si-1.5Mn TRIP Steels by Thermo-Mechanical Simulation

2005 ◽  
Vol 297-300 ◽  
pp. 1223-1228
Author(s):  
Zuo Cheng Wang ◽  
Sung Joon Kim ◽  
Chang Gil Lee ◽  
Tae Ho Lee
Keyword(s):  
Grain Size ◽  
Volume Fraction ◽  
Intercritical Annealing ◽  
Rolling Process ◽  
Isothermal Treatment ◽  
Trip Steels ◽  
Mechanical Simulation ◽  
Size Refinement ◽  
Multi Phase ◽  
Hot Rolled

In order to simplify the production routine and to save cost of hot-rolled TRIP steels, the intercritical rolling process was investigated using thermo-mechanical simulation technology. Both 0.2C-1.5Mn-1.5Si and 0.2C-1.5Mn-1.5Si-0.5Cu TRIP steels were chosen so as to study the effect of 0.5 pct Cu addition on microstructure and retained austenite volume fraction of 0.2C-1.5Mn-1.5Si TRIP steel. It is found that grain size refinement happened during intercritical deformation, and multi-phase microstructure could be achieved after isothermal treatment, so intercritical annealing can be eliminated to avoid grain size coarse and to keep the refine grain size in intercritical-deformed TRIP steels.

scholarly journals Finite Element Analysis of Dynamic Recrystallization of Casting Slabs during Hot-Core Heavy Reduction Rolling Process

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 181
Author(s):  
Haijun Li ◽  
Tianxiang Li ◽  
Meina Gong ◽  
Zhaodong Wang ◽  
Guodong Wang
Keyword(s):  
Grain Size ◽  
Dynamic Recrystallization ◽  
Volume Fraction ◽  
Rolling Process ◽  
Reduction Ratio ◽  
Secondary Development ◽  
Innovative Technology ◽  
Element Analysis ◽  
The Core ◽  
Average Grain Size

Hot-core heavy reduction rolling (HHR2) is an innovative technology, where a two-high rolling mill is installed after the solidification end of a strand, which can significantly eliminate the core defects of the slab. The mill exhibits a heavy reduction ratio, which promotes the dynamic recrystallization (DRX) of the slab. This study aims to optimize the parameters of the HHR2 process considering the effect of DRX on microstructure homogeneity. The secondary development of commercial software DEFORM-3D is conducted to calculate the deformation and DRX behavior of HHR2 for different reduction ratios. The parameters of DRX volume fraction and DRX grain size are compared, and finer DRX grains are obtained when the greater reduction ratios are conducted in HHR2. Then, corresponding to the deformation conditions in the HHR2, the thermal–mechanical simulations are conducted on the Gleeble3800 to obtain the average grain sizes before and after this process. When the reduction amount increases from 20 mm to 50 mm, the difference of average grain size between the core and the surface reduces by 52%. In other words, appropriately enhancing the reduction ratio is helpful to reduce the average austenite grain and promote the microstructure uniformity of the slab. These results provide some valuable information on the design of deformation parameters for HHR2.

The Production Technology in High-Performance and Economical Hot-Rolled Ribbed Wire Rod

2013 ◽  
Vol 746 ◽  
pp. 539-542
Author(s):  
Fei Ming Xie ◽  
Yang Liu ◽  
Yan Lin Wang ◽  
Qing Zhang
Keyword(s):  
Grain Size ◽  
High Performance ◽  
Alloy Composition ◽  
Rolling Process ◽  
National Standard ◽  
Size Scale ◽  
Wire Rod ◽  
Limit Value ◽  
Steel Technology ◽  
Hot Rolled

According to the production actual situation of the hot-rolled ribbed wire rod in Fangda special steel technology Co., Ltd, Through optimizing the rolling process to improve rolling organization , and with low alloy composition, which can greatly save resources and production cost. The results show that the yield strength of hot-rolled ribbed wire rod is 510MPa, the tensile strength is 622MPa, and the elongation is 23.35%, but the content of Mn can be decreased 58.13%, the content of Si can be decreased 67.50% compared with the national standard upper limit value in HRB400; The grain size scale of edge microstructure is 9.0 at the 1# flying shear in the rolling process, the grain size scale of core microstructure is 8.5, and the edge microstructure of hot-rolled ribbed wire rod after rolling is the tempered sorbite, the grain size scale is 13.5, the core microstructure is the ferrite-pearlite, the grain size scale is 12.0, and the depth of hardening is 0.50mm.

scholarly journals Effect of Carbon Content and Intercritical Annealing on Microstructure and Mechanical Tensile Properties in FeCMnSiCr TRIP-Assisted Steels

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1546
Author(s):  
Enzo Tesser ◽  
Carlos Silva ◽  
Alfredo Artigas ◽  
Alberto Monsalve
Keyword(s):  
Carbon Content ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Intercritical Annealing ◽  
Bainitic Ferrite ◽  
Ferrite Matrix ◽  
Polygonal Ferrite ◽  
Isothermal Treatment ◽  
Ferrite Steel ◽  
Mechanical Tensile

Four TRIP (Transformation Induced Plasticity) assisted steels, three TBF (TRIP Bainitic Ferrite) steels and one TPF (TRIP Polygonal Ferrite) steel, were manufactured from three different carbon contents (0.2, 0.3 and 0.4 wt.% C), to study the evolution of their microstructure and tensile mechanical properties in 15 mm thick plates. TBF steels were subjected to the same austenitization heat treatment and subsequent bainitization isothermal treatment. The TPF steel was subjected to an intercritical annealing and subsequent isothermal bainitization treatment. All were microstructurally characterized by optical, scanning electron and atomic force microscopy, as well as X-ray diffraction. Mechanically, they were characterized by the ASTM E8 tensile test and fractographies. For the TBF steels, the results showed that when the carbon content increased, there were an increase in volume fraction of retained austenite, of the microconstituent “martensite/retained austenite” and in the tensile strength; and a decrease in the volume fraction of bainitic ferrite matrix and elongation; with an improvement in TRIP behavior due to the increase in retained austenite. The TPF steel presented around 50% ductile polygonal ferrite developing better TRIP behavior than the TBF steels. The evolution of the fractographies was ductile to brittle for TBF steels with an increase in carbon content, and for TPF, the appearance of the fracture surface was ductile.

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.

Finite Element Analysis on Microstructure Evolution of Hot Ring Rolling Process

2008 ◽  
Vol 575-578 ◽  
pp. 1455-1460 ◽  
Author(s):  
Zhi Chao Sun ◽  
He Yang ◽  
Xin Zhe Ou
Keyword(s):  
Grain Size ◽  
Microstructure Evolution ◽  
Volume Fraction ◽  
Small Deformation ◽  
Local Area ◽  
Rolling Process ◽  
Ring Rolling ◽  
Rigid Plastic ◽  
Element Analysis ◽  
Average Grain Size

Hot ring rolling (HRR) is a 3D unsteady-state and coupled thermo-mechanical process, the metal undergoes complicated unequal deformation and microstructure evolution. In this paper a 3D rigid-plastic and coupled thermo-mechanical FEM model for hot ring rolling was developed based on DEFORM3D platform, taking dynamic recrystallization (DRX) volume fraction, DRX grain size, recystallization volume fraction and average grain size as objects, the mechanism of material microstructure evolution and distributions in HRR process are thoroughly studied. The results show that: with the HRR progressing, the DRX volume fraction, volume fraction, DRX grain size and average grain size have the similar distributing characteristic, and the distribution zones expand from a small local area into the whole ring strip, then diffuse to the mid-layer of ring with small deformation, their distributions become more uniform. Meanwhile with increase of deformation, the values of the DRX volume fraction and recrystallization volume fraction augment, i.e. the degree of recystallization increases. The DRX grain size also augments due to local high temperature, while the average grain size decreases. In general during HRR process the distributions of DRX volume fraction, recrystallization volume fraction, DRX grain size, and average grain size are ununiform due to unequal deforming in HRR process.

Ultra Fine-Grained 6wt% Manganese TRIP Steel

2010 ◽  
Vol 654-656 ◽  
pp. 286-289 ◽  
Author(s):  
Sea Woong Lee ◽  
Kyoo Young Lee ◽  
Bruno C. De Cooman
Keyword(s):  
Mechanical Properties ◽  
Retained Austenite ◽  
Annealing Temperature ◽  
Volume Fraction ◽  
Intercritical Annealing ◽  
High Volume ◽  
Magnetic Saturation ◽  
Trip Steels ◽  
Fine Grained ◽  
Annealing Temperatures

Ultra-fine grained TRIP steels (UFG-TRIP) containing 6wt%Mn were produced by intercritical annealing. An ultra-fine grained microstructure with a grain size less than 1μm was obtained. The formation mechanism of the high volume fraction of retained austenite was investigated by dilatometry, XRD and magnetic saturation. The fraction of retained austenite was strongly dependent on the annealing temperature. The tensile properties were also found to be strongly influenced by the annealing temperature with poorer mechanical properties being observed at higher annealing temperatures. It was found that the stabilization of the retained austenite was both a composition and size-effect, made possible by the grain refinement due to the reversely transformed martensite.

Microstructures and Strength of Hot-Rolled Mg-Zn-Y Alloys

2011 ◽  
Vol 291-294 ◽  
pp. 137-140
Author(s):  
Yao Min Zhu ◽  
Qiu Ran Gao ◽  
Feng Zhang Ren ◽  
Shi Jie Fang
Keyword(s):  
Grain Size ◽  
Tensile Strength ◽  
Hot Rolling ◽  
Rolling Process ◽  
Recrystallization Process ◽  
Fine Grained ◽  
Hot Rolling Process ◽  
Fine Grained Structure ◽  
Cast Alloys ◽  
Hot Rolled

The effects of the hot-rolling process on microstructures and strength were investigated for two kinds of magnesium alloy Mg-Zn-Y and Mg-Zn-Y-Nd. In comparison with the as-cast alloys, the tensile strength of Mg-Zn-Y and Mg-Zn-Y-Nd both increases 45%, whereas their elongation decreases 73%, 60% via hot-rolling process, respectively. The results show that the dynamic recrystallization process and the pining effect of I-phase during hot rolling contribute to the fine-grained structure formation. The hot-rolling process has refined the grain size greatly.

Precipitation Behavior and Microstructure Evolution of Mg-Zn-Zr-Er Alloy Processed by Secondary Deformation and Heat Treatment

2013 ◽  
Vol 747-748 ◽  
pp. 377-382
Author(s):  
Bao Xiang Zhang ◽  
Jing Zhang
Keyword(s):  
Microstructure Evolution ◽  
Hot Rolling ◽  
Volume Fraction ◽  
Rolling Direction ◽  
Hardness Test ◽  
Secondary Phase ◽  
Rolling Process ◽  
Second Phase ◽  
Precipitation Behavior ◽  
Hot Rolled

Preheated at 673K for 3h and 6h respectively, as-extruded Mg-9Zn-0.6Zr-2Er (wt.%) slabs with starting thickness of 8mm were hot-rolled at 673K to 2mm. The hot-rolled alloys were then solution treated at 673K for1.5h and aged at 473K for 10h. Microstructure evolution and second phase precipitation behavior during hot rolling and subsequent heat treatments were examined by optical microscopy (OM), scan electron microscopy (SEM) and micro hardness test. Mg-9Zn-0.6Zr-2Er alloy were fully recrystallized with fine equiaxed grains after preheating for 3 hours, prolonging heating time leads to a higher degree of dissolution of secondary phase into Mg matrix but a coarsening of the microstructure. During hot rolling process, the volume fraction of the DRX grains increased gradually with increasing reduction ratio, shearing bands became visble in the final pass. Thermal stable Mg-Zn-Er intermetallic compounds distributed along rolling direction at the first rolling passes and became more homogenous in the final pass. More nanosized MgZn2 precipitated during hot rolling in the alloy preheated for 6h than that for 3h, leading to an enhanced precipitation hardening effect in the former.

scholarly journals Effect of Reduction in Thickness and Rolling Conditions on Mechanical Properties and Microstructure of Rolled Mg-8Al-1Zn-1Ca Alloy

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Yuta Fukuda ◽  
Masafumi Noda ◽  
Tomomi Ito ◽  
Kazutaka Suzuki ◽  
Naobumi Saito ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
High Strength ◽  
Rolling Process ◽  
Rolled Sheet ◽  
Roll Temperature ◽  
Mean Grain Size ◽  
Thick Rolled Sheet ◽  
Hot Rolled ◽  
Strength And Ductility

A cast Mg-8Al-1Zn-1Ca magnesium alloy was multipass hot rolled at different sample and roll temperatures. The effect of the rolling conditions and reduction in thickness on the microstructure and mechanical properties was investigated. The optimal combination of the ultimate tensile strength, 351 MPa, yield strength, 304 MPa, and ductility, 12.2%, was obtained with the 3 mm thick Mg-8Al-1Zn-1Ca rolled sheet, which was produced with a roll temperature of 80°C and sample temperature of 430°C. This rolling process resulted in the formation of a bimodal structure in the α-Mg matrix, which consequently led to good ductility and high strength, exclusively by the hot rolling process. The 3 mm thick rolled sheet exhibited fine (mean grain size of 2.7 μm) and coarse grain regions (mean grain size of 13.6 μm) with area fractions of 29% and 71%, respectively. In summary, the balance between the strength and ductility was enhanced by the grain refinement of the α-Mg matrix and by controlling the frequency and orientation of the grains.

FE Analysis of Microstructure Evolution during Ring Rolling Process of a Large-Scale Ti-6Al-4V Alloy Ring

2010 ◽  
Vol 638-642 ◽  
pp. 223-228 ◽  
Author(s):  
Jong Taek Yeom ◽  
Jeoung Han Kim ◽  
Jae Keun Hong ◽  
Nho Kwang Park ◽  
Chong Soo Lee
Keyword(s):  
Grain Size ◽  
Prediction Model ◽  
Microstructure Evolution ◽  
Large Scale ◽  
Volume Fraction ◽  
Rolling Process ◽  
Ring Rolling ◽  
Forming Process ◽  
Microstructure Prediction ◽  
Ring Rolling Process

Microstructure evolution during ring rolling process of a large-scale Ti-6Al-4V ring was investigated with the combined approaches of three dimensional finite element method (FEM) simulation and microstructure prediction model. A microstructure prediction model was established by considering the volume fractions and grain size of  and  phases varying with process variables, and grain growth. In order to perform FE simulation for ring rolling process of Ti-6Al-4V alloy, a constitutive equation was generated by utilizing the flow stress data obtained from hot compression tests at different temperature and strain rate conditions. The volume fraction and grain size of  and  phases during ring rolling were calculated by de-coupled approach between FEM analysis and microstructure prediction model. The prediction results were compared with the experimental ones. Our proposed microstructure simulation module was useful for designing hot forming process of Ti-6Al-4V alloy

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