scholarly journals Strain Hardening and Stretch Formability Behavior of Triple Phase (TP) Steel Strips

2021 ◽  
Vol 27 (3) ◽  
pp. 152-156
Author(s):  
Maha ElMeligy ◽  
Taher El-Bitar
Keyword(s):  
Strain Hardening ◽  
Volume Fraction ◽  
Salt Bath ◽  
Holding Time ◽  
Forming Limit ◽  
Stretch Forming ◽  
Steel Strips ◽  
Stretch Formability ◽  
Rolled Condition ◽  
Hot Rolled

The current work explores the strain hardening and stretches formability behaviour of the developed Triple Phase (TP) steel. Double quenched TP steel strips posse three distinguished stages of strain hardening on tensile forming. 1st stage represents the highest n-value reflecting resistance to homogeneous deformation, where steel can be safely stretched. 2nd and 3rd stage reveals lower n-values, where localized thinning exist. On Erichsen testing, the relationship between punch forming force and punch stroke exhibits two forming regions. The 1st region is delineated by a straight line showing an ultra-high strain-hardening rate, which represents a reversible elastic stretch forming.  The 2nd forming region continues to a higher Erichsen punch stroke than that of the 1st region and presents the permanent plastic stretch forming behaviour.  It is found that bainite and martensite clusters created, by double quenching, in TP-steel exaggerated the elastic stretch forming limit 10 times higher than the as-hot rolled condition. 7 min. holding time of strips in the salt bath is considered the most effective for the creation of a useful volume fraction of the bainite phase. However, 21 min. holding time in salt bath grows martensite laths through the bainite aggregates, affecting negatively on stretch formability.

Evolution of Hot Rolling and Phase Transformation Textures in an α″ (Orthorhombic) Phase in Ti-Nb Alloys

2011 ◽  
Vol 702-703 ◽  
pp. 872-875
Author(s):  
S. Banumathy ◽  
Rajiv Kumar Mandal ◽  
A.K. Singh
Keyword(s):  
Hot Rolling ◽  
Volume Fraction ◽  
Solution Treatment ◽  
Orthorhombic Phase ◽  
Moderate Intensity ◽  
Large Volume Fraction ◽  
Β Phase ◽  
Rolled Condition ◽  
Textural Changes ◽  
Hot Rolled

This work describes the development of texture during hot rolling of two alloys namely, Ti-12Nb and Ti-16Nb. The alloys have been unidirectionally hot rolled to 80 % reductions at 800°C and air cooled. Both the alloys show the presence of a² (orthorhombic) and small volume fraction of b (bcc) phases in hot rolled condition. The alloy Ti-12Nb exhibit moderate intensity texture while the alloy Ti-16Nb displays quite strong texture. The high overall intensity of texture in alloy Ti-16Nb in 80 % HR specimen can be attributed to the presence of large volume fraction of b phase in comparison to that of the alloy Ti-12Nb. This has been extended to study the textural changes after b solution treatment. This heat treatment consists of two types of phase transformations that are a² ® b ® a² and a² ® b ® a after water quenching and furnace cooling from β phase field.

scholarly journals Microstructure Evolution during Recrystallization in Dual-Phase Steels

2012 ◽  
Vol 715-716 ◽  
pp. 13-22 ◽  
Author(s):  
Nicola Peranio ◽  
Franz Roters ◽  
Dierk Raabe
Keyword(s):  
Plane Strain ◽  
Volume Fraction ◽  
Salt Bath ◽  
Dip Coating ◽  
Time Range ◽  
Dual Phase ◽  
Dual Phase Steels ◽  
Heating And Cooling ◽  
Temperature Regimes ◽  
Hot Rolled

The microstructure and texture of rolled and annealed dual-phase steels with 0.147 wt. % C, 1.868 wt. % Mn, and 0.403 wt. % Si were analyzed using SEM, EDX, and EBSD. Hot rolled sheets showed a ferritic-pearlitic microstructure with a pearlite volume fraction of about 40 % and ferrite grain size of about 6 µm. Ferrite and pearlite were heterogeneously distributed at the surface and distributed in bands at the center of the sheets. The hot rolled sheets revealed a through-thickness texture inhomogeneity with a plane-strain texture with strong α-fiber and γ-fiber at the center and a shear texture at the surface. After cold rolling, the ferrite grains showed elongated morphology and larger orientation gradients, the period of the ferrite-pearlite band structure at the center of the sheets was decreased, and the plane-strain texture components were strengthened in the entire sheet. Recrystallization, phase transformation, and the competition of both processes were of particular interest with respect to the annealing experiments. For this purpose, various annealing techniques were applied, i.e., annealing in salt bath, conductive annealing, and industrial hot-dip coating. The sheets were annealed in the ferritic, intercritical, and austenitic temperature regimes in a wide annealing time range including variation of heating and cooling rates.

REPUBLIC X-80-W

Alloy Digest ◽  
1980 ◽  
Vol 29 (5) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Yield Strength ◽  
Physical Properties ◽  
Surface Treatment ◽  
High Strength ◽  
Heat Treating ◽  
Low Alloy Steel ◽  
Rolled Condition ◽  
Hot Rolled ◽  
Minimum Yield

Abstract REPUBLIC X-80-W is a high-strength, low-alloy steel developed to achieve a minimum yield strength of 80,000 psi in the as-hot-rolled condition. It also exhibits good fatigue performance, good bendability, and good weldability. It is available as bars and can be used in various automotive and machinery applications. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SA-372. Producer or source: Republic Steel Corporation.

scholarly journals Forming Limit Stress Diagram Prediction of Pure Titanium Sheet Based on GTN Model

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1783 ◽  
Author(s):  
Tao Huang ◽  
Mei Zhan ◽  
Kun Wang ◽  
Fuxiao Chen ◽  
Junqing Guo ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Pure Titanium ◽  
Void Volume Fraction ◽  
Void Volume ◽  
Forming Limit ◽  
Stress And Strain ◽  
Gtn Model ◽  
Stress Diagram ◽  
Limit Stress ◽  
Hemispherical Punch

In this paper, the initial values of damage parameters in the Gurson–Tvergaard–Needleman (GTN) model are determined by a microscopic test combined with empirical formulas, and the final accurate values are determined by finite element reverse calibration. The original void volume fraction (f0), the volume fraction of potential nucleated voids (fN), the critical void volume fraction (fc), the void volume fraction at the final failure (fF) of material are assigned as 0.006, 0.001, 0.03, 0.06 according to the simulation results, respectively. The hemispherical punch stretching test of commercially pure titanium (TA1) sheet is simulated by a plastic constitutive formula derived from the GTN model. The stress and strain are obtained at the last loading step before crack. The forming limit diagram (FLD) and the forming limit stress diagram (FLSD) of the TA1 sheet under plastic forming conditions are plotted, which are in good agreement with the FLD obtained by the hemispherical punch stretching test and the FLSD obtained by the conversion between stress and strain during the sheet forming process. The results show that the GTN model determined by the finite element reverse calibration method can be used to predict the forming limit of the TA1 sheet metal.

Shape Measurement for Hot Rolled Steel Strips

1979 ◽  
Author(s):  
P. Petit ◽  
G. Tourscher ◽  
M. Machet ◽  
M. Kassel
Keyword(s):  
Shape Measurement ◽  
Rolled Steel ◽  
Steel Strips ◽  
Hot Rolled ◽  
Hot Rolled Steel

scholarly journals Iron-chromium-carbon-vanadium white cast irons: Microstructure and properties

2014 ◽  
Vol 68 (4) ◽  
pp. 413-427 ◽  
Author(s):  
Mirjana Filipovic
Keyword(s):  
Fracture Toughness ◽  
Strain Hardening ◽  
Volume Fraction ◽  
Dynamic Fracture Toughness ◽  
M23c6 Carbide ◽  
Cast Irons ◽  
Repeated Impact ◽  
Secondary Carbides ◽  
The Matrix ◽  
Microstructure Parameters

The as-cast microstructure of Fe-Cr-C-V white irons consists of M7C3 and vanadium rich M6C5 carbides in austenitic matrix. Vanadium changed the microstructure parameters of phase present in the structure of these alloys, including volume fraction, size and morphology. The degree of martensitic transformation also depended on the content of vanadium in the alloy. The volume fraction of the carbide phase, carbide size and distribution has an important influence on the wear resistance of Fe-Cr-C-V white irons under low-stress abrasion conditions. However, the dynamic fracture toughness of Fe-Cr-C-V irons is determined mainly by the properties of the matrix. The austenite is more effective in this respect than martensite. Since the austenite in these alloys contained very fine M23C6 carbide particles, higher fracture toughness was attributed to a strengthening of the austenite during fracture. Besides, the secondary carbides which precipitate in the matrix regions also influence the abrasion behaviour. By increasing the matrix strength through a dispersion hardening effect, the fine secondary carbides can increase the mechanical support of the carbides. Deformation and appropriate strain hardening occur in the retained austenite of Fe-Cr-C-V alloys under repeated impact loading. The particles of precipitated M23C6 secondary carbides disturb dislocations movement and contribute to increase the effects of strain hardening in Fe-Cr-C-V white irons.

scholarly journals Nanoparticle amount, and not size, determines chain alignment and nonlinear hardening in polymer nanocomposites

2017 ◽  
Vol 114 (16) ◽  
pp. E3170-E3177 ◽  
Author(s):  
H. Samet Varol ◽  
Fanlong Meng ◽  
Babak Hosseinkhani ◽  
Christian Malm ◽  
Daniel Bonn ◽  
...  
Keyword(s):  
Strain Hardening ◽  
Polymer Nanocomposites ◽  
Nonlinear Elasticity ◽  
Volume Fraction ◽  
Uniaxial Tensile ◽  
Large Strains ◽  
Chain Alignment ◽  
Strain Hardening Behavior ◽  
Polymer Chain Alignment ◽  
Nonlinear Hardening

Polymer nanocomposites—materials in which a polymer matrix is blended with nanoparticles (or fillers)—strengthen under sufficiently large strains. Such strain hardening is critical to their function, especially for materials that bear large cyclic loads such as car tires or bearing sealants. Although the reinforcement (i.e., the increase in the linear elasticity) by the addition of filler particles is phenomenologically understood, considerably less is known about strain hardening (the nonlinear elasticity). Here, we elucidate the molecular origin of strain hardening using uniaxial tensile loading, microspectroscopy of polymer chain alignment, and theory. The strain-hardening behavior and chain alignment are found to depend on the volume fraction, but not on the size of nanofillers. This contrasts with reinforcement, which depends on both volume fraction and size of nanofillers, potentially allowing linear and nonlinear elasticity of nanocomposites to be tuned independently.

Hot Deformation Behavior of Al-Cu-Li-Mg-Zn-Zr-Sc Alloy in As-Cast and Hot-Rolled Condition

2018 ◽  
Vol 920 ◽  
pp. 244-249 ◽  
Author(s):  
Yaroslav Erisov ◽  
Sergey Surudin ◽  
Fedor Grechnikov
Keyword(s):  
Strain Rate ◽  
Hot Deformation ◽  
Rheological Model ◽  
Physical Simulation ◽  
Constant Strain Rate ◽  
Rolled Plate ◽  
Hollomon Parameter ◽  
Aluminum Lithium ◽  
Rolled Condition ◽  
Hot Rolled

The results of physical simulation of hot compression of semi-finished products, selected from a cast ingot and hot-rolled plate from aluminum-lithium alloy V-1461, in the temperature range of 400-460°C and strain rates of 1-60 s-1are presented. It is established that at a constant strain rate the flow stresses decrease with increasing test temperature, an increase in the strain rate leads to an increase in flow stresses at a constant temperature. The parameters of the hot deformation rheological model, including the Zener-Hollomon parameter and the hyperbolic sine law, are determined. It is established that the parameters of the rheological model for the cast and hot-rolled state differ insignificantly.

Fast Position and Accurate Segmentation Algorithms for Detecting Surface Defects of the Thermal-State Heavy Rail Based on Machine Vision

2013 ◽  
Vol 5 (4) ◽  
pp. 40-60
Author(s):  
Xue Wang ◽  
Yiran Chen ◽  
Tao Cheng ◽  
Zhijiang Xie
Keyword(s):  
Nearest Neighbor ◽  
Surface Defects ◽  
Thermal State ◽  
Mean Shift ◽  
Sampling Point ◽  
Positioning Method ◽  
Rolled Condition ◽  
Novel Algorithms ◽  
Hot Rolled ◽  
Heavy Rail

Color imaging in the hot rolled condition provides the better reaction of heavy rail on surface defects. In this paper, it proposes a series of novel algorithms of accurate position and segmentation of surface defects of heavy rail. An image acquisition device is designed on the adjustable camera bracket with the linear array CCD, and based on the correlation among pixels at the image level, a fast positioning method is developed for searching the Region Of Interesting (ROI) of the surface defects. Using the Mean-Shift image filtering algorithm which features multi-parameter kernel function, amendments to the sampling point weights and regional search with the nearest neighbor sampling points, accurate segmentation of the identification character is easily achieved by K-means clustering. Experiments show that this algorithm for the identification of the heavy rail surface defects is proven to be more rapid in testing the inclusions, cracks and oxide skin defects with a good promotional value.

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