scholarly journals Effects of composition and strain rate on hot ductility of Cr–Mo-alloy steel in the two-phase region

2021 ◽  
Vol 40 (1) ◽  
pp. 228-240
Author(s):  
Yaxu Zheng ◽  
Wei Shen ◽  
Liguang Zhu ◽  
Zhihong Guo ◽  
Qi Wang ◽  
...  
Keyword(s):  
Strain Rate ◽  
Alloy Steel ◽  
Tensile Tests ◽  
Phase Region ◽  
Hot Ductility ◽  
Strain Rates ◽  
Sufficient Time ◽  
Two Phase ◽  
Obvious Effect ◽  
Ferrite Transformation

Abstract The hot tensile tests were conducted in this study to investigate the effects of Nb, B, Mo, and V on hot ductility of 25CrMo alloy steel in a temperature range of 650–850°C with strain rates of 0.005 and 0.5 s−1. Besides, the influences of ferrite transformation and precipitates on hot ductility were also investigated by the use of SEM and TEM. Thermo-Calc and J Mat Pro were used for calculating equilibrium precipitates and CCT curves, respectively. The results indicated that the hot ductility is deteriorated with the addition of 0.04% Nb due to Nb(C,N) particles and ferrite transformation. The addition of B inhibits ferrite transformation and improves hot ductility. The hot ductility is improved with increasing strain rate from 0.005 to 0.5 s−1 due to the nucleation and growth behavior of ferrite. The fast strain rate promotes nucleation of ferrite; however, the ferrite has no sufficient time to grow up. The addition of Mo inhibits ferrite transformation and improves hot ductility. The addition of 0.12% V has no obvious effect on ferrite transformation. The hot ductility has deteriorated a little with the addition of 0.12% V due to the solution V that increases stress during hot deformation.

Relevance of Hot Ductility Tests to Crack Sensitivity during Continuous Casting of Steel

2014 ◽  
Vol 922 ◽  
pp. 201-206
Author(s):  
Simon Großeiber ◽  
Christian Gusenbauer ◽  
Sergiu Ilie ◽  
Guillermo C. Requena ◽  
Ernst Kozeschnik
Keyword(s):  
Strain Rate ◽  
Tensile Tests ◽  
Phase Region ◽  
Austenite Phase ◽  
Hot Ductility ◽  
Strain Rates ◽  
X Ray ◽  
X Ray Computed ◽  
Reduction Of Area ◽  
Critical Reduction

Hot tensile tests are performed on a Ni-alloyed steel after solution treating and cooling to test temperatures ranging between 600 and 950°C at strain rates of 3∙10-4and 3∙10-3/s. The critical reduction of area (RA) for damage formation is determined by means of laboratory X-ray computed tomography. The results are compared with the corresponding RA at fracture traditionally used for assessing hot ductility and crack sensitivity during straightening of the slab. We demonstrate that using RA at fracture is inadequate for evaluating hot ductility in the austenite phase region at temperatures varying with the strain rate. Hot ductility curves more relevant for slow strain rate deformation are determined.

scholarly journals Effect of Vanadium and Strain Rate on Hot Ductility of Low-Carbon Microalloyed Steels

Metals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 14
Author(s):  
Siying Song ◽  
Junyu Tian ◽  
Juan Xiao ◽  
Lei Fan ◽  
Yuebiao Yang ◽  
...  
Keyword(s):  
Strain Rate ◽  
Tensile Tests ◽  
Vanadium Content ◽  
Microalloyed Steels ◽  
Hot Ductility ◽  
Low Carbon ◽  
Temperature Range ◽  
Ferrite Transformation ◽  
Ductility Trough ◽  
Carbon Microalloyed

Hot tensile tests were conducted in this study to investigate the effect of strain rate (10−3 and 10 s−1) and vanadium content (0.029 and 0.047 wt.%) on the hot ductility of low-carbon microalloyed steels. The results indicate that a hot ductility trough appears at a low strain rate (10−3 s−1) because of the sufficient time for ferrite transformation and the growth of second particles, but it disappears at a high strain rate (10 s−1). The hot ductility is improved with the increase in strain rate at 700 °C or higher temperatures. In addition, with the increase in vanadium content, the large amounts of precipitate and increased ferrite transformation result in poor hot ductility of steels fractured at a low temperature range (600~900 °C). However, when the steel is fractured at a high temperature range (1000~1200 °C), more vanadium in the solid solution in the austenite inhibits the growth of parental austenite grains and results in grain refinement strengthening, slightly improving the hot ductility.

scholarly journals New Approach In The Properties Evaluation Of Ultrafine-Grained OFHC Copper

2015 ◽  
Vol 60 (2) ◽  
pp. 605-614 ◽  
Author(s):  
T. Kvačkaj ◽  
A. Kováčová ◽  
J. Bidulská ◽  
R. Bidulský ◽  
R. Kočičko
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Tensile Tests ◽  
Coarse Grained ◽  
Wear Behaviour ◽  
Ofhc Copper ◽  
Strain Rates ◽  
Ultrafine Grained ◽  
Reduction Of Area ◽  
Pin On Disk

AbstractIn this study, static, dynamic and tribological properties of ultrafine-grained (UFG) oxygen-free high thermal conductivity (OFHC) copper were investigated in detail. In order to evaluate the mechanical behaviour at different strain rates, OFHC copper was tested using two devices resulting in static and dynamic regimes. Moreover, the copper was subjected to two different processing methods, which made possible to study the influence of structure. The study of strain rate and microstructure was focused on progress in the mechanical properties after tensile tests. It was found that the strain rate is an important parameter affecting mechanical properties of copper. The ultimate tensile strength increased with the strain rate increasing and this effect was more visible at high strain rates$({\dot \varepsilon} \sim 10^2 \;{\rm{s}}^{ - 1} )$. However, the reduction of area had a different progress depending on microstructural features of materials (coarse-grained vs. ultrafine-grained structure) and introduced strain rate conditions during plastic deformation (static vs. dynamic regime). The wear behaviour of copper was investigated through pin-on-disk tests. The wear tracks examination showed that the delamination and the mild oxidational wears are the main wear mechanisms.

The Effects of Physical Ageing and of Prior Immersion on the Esc Behaviour of Polycarbonate in Ethanol

1993 ◽  
Vol 305 ◽  
Author(s):  
J. C. Arnold ◽  
A. R. Eccott
Keyword(s):  
Strain Rate ◽  
Immersion Time ◽  
Constant Strain Rate ◽  
Tensile Tests ◽  
Strain Rates ◽  
Physical Ageing ◽  
Diffusion Effects ◽  
Craze Initiation ◽  
Comparison Of Tests

AbstractThe effects of physical ageing and prior immersion time on the ESC behaviour of polycarbonate in ethanol were studied. Constant strain rate tensile tests were performed at a range of strain rates for samples with ageing times varying from 100 hours to 3000 hours and for prior immersion times of between 1 hour and 500 hours. Comparison of tests performed in ethanol and in air gave a good indication of the point of craze initiation. The results showed that there was a reduction in strain to crazing as the strain rate decreased, apart from with the lowest strain rate used. A longer prior immersion time also promoted craze formation. Both of these results are attributable to diffusion effects. Physical ageing had little effect on the ESC behaviour, due to the large amounts of deformation encountered in this system.

scholarly journals Effect of strain rate on α-lath thickness of TC17 alloy after deformation and subsequent heat treatment

2020 ◽  
Vol 321 ◽  
pp. 13003
Author(s):  
Zimin Lu ◽  
Jiao Luo ◽  
Miaoquan Li
Keyword(s):  
Heat Treatment ◽  
Strain Rate ◽  
Electron Backscatter Diffraction ◽  
Phase Region ◽  
Subsequent Heat Treatment ◽  
Strain Rates ◽  
Optical Micrograph ◽  
Β Phase ◽  
Electron Backscatter ◽  
Backscatter Diffraction

Effect of strain rate on α-lath thickness of TC17 alloy with a basketweave microstructure was studied in the present work. For this purpose, this alloy was deformed in the β phase region and subsequently soluted and aged in α+β phase region. Moreover, optical micrograph (OM) and electron backscatter diffraction (EBSD) were applied to analyze the change of lath thickness at different strain rates. The result showed that α-lath thickness increased with increasing strain rate. This phenomenon was possibly attributed to the higher degree of variant selection (DVS) at higher strain rate (0.1 s-1). The higher DVS was beneficial for the formation of parallel α-lath colonies during cooling after deformation. And, these parallel α-lath colonies would more easily grow up and coarsen during subsequent heat treatment. Therefore, α-lath at higher strain rate is more thick.

scholarly journals Influence of strain rate and heat treatments on tensile and creep properties of Zn-0.15Cu-0.07Ti alloys

DYNA ◽  
2016 ◽  
Vol 83 (195) ◽  
pp. 77-83 ◽  
Author(s):  
María José Quintana Hernández ◽  
José Ovidio García ◽  
Roberto González Ojeda ◽  
José Ignacio Verdeja
Keyword(s):  
Strain Rate ◽  
Room Temperature ◽  
Rolling Direction ◽  
Tensile Tests ◽  
Strain Rates ◽  
Creep Tests ◽  
Design Problems ◽  
Creep Properties ◽  
Heat Treated ◽  
Zn Alloys

The use of Cu and Ti in Zn alloys improves mechanical properties as solid solution and dispersoid particles (grain refiners) may harden the material and reduce creep deformation. This is one of the main design problems for parts made with Zn alloys, even at room temperature. In this work the mechanical behavior of a Zn-Cu-Ti low alloy is presented using tensile tests at different strain rates, as well as creep tests at different loads to obtain the value of the strain rate coefficient m in samples parallel and perpendicular to the rolling direction of the Zn strip. The microstructure of the alloy in its raw state, as well as heat treated at 250°C, is also analyzed, as the banded structure produced by rolling influences the strengthening mechanisms that can be achieved through the treatment parameters.

Tensile Stress-Strain Curves Modeling of Four Kinds of Solders with Temperature and Rate Dependence

2005 ◽  
Vol 297-300 ◽  
pp. 905-911 ◽  
Author(s):  
Xu Chen ◽  
Li Zhang ◽  
Masao Sakane ◽  
Haruo Nose
Keyword(s):  
Tensile Stress ◽  
Constitutive Model ◽  
Strain Rate ◽  
Constant Strain Rate ◽  
Tensile Tests ◽  
Strain Rate Range ◽  
Rate Dependence ◽  
Strain Rates ◽  
Stress Strain ◽  
Rate Range

A series of tensile tests at constant strain rate were conducted on tin-lead based solders with different Sn content under wide ranges of temperatures and strain rates. It was shown that the stress-strain relationships had strong temperature- and strain rate- dependence. The parameters of Anand model for four solders were determined. The four solders were 60Sn-40Pb, 40Sn-60Pb, 10Sn-90Pb and 5Sn-95Pb. Anand constitutive model was employed to simulate the stress-strain behaviors of the solders for the temperature range from 313K to 398K and the strain rate range from 0.001%sP -1 P to 2%sP -1 P. The results showed that Anand model can adequately predict the rate- and temperature- related constitutive behaviors at all test temperatures and strain rates.

Stress-Strain Equations for Some Near-Eutectic Tin-Lead Solders

1991 ◽  
Vol 113 (4) ◽  
pp. 475-484 ◽  
Author(s):  
K. P. Jen ◽  
J. N. Majerus
Keyword(s):  
Strain Rate ◽  
Printed Circuit Boards ◽  
Volume Fraction ◽  
Total Error ◽  
Tensile Tests ◽  
Elastic Behavior ◽  
Plastic Behavior ◽  
Strain Rates ◽  
Stress Strain ◽  
Engineering Strain

This paper presents the evaluation of the stress-strain behavior, as a function of strain-rate, for three tin-lead solders at room temperature. This behavior is critically needed for reliability analysis of printed circuit boards (PCB) since handbooks list minimal mechanical properties for the eutectic solder used in PCBs. Furthermore, most handbook data are for stable eutectic microstructure whereas PCB solder has a metastable microstructure. All three materials were purchased as “eutectics.” However, chemical analysis, volume fraction determination, and microhardness tests show some major variations between the three materials. Two of the materials have a eutectic composition, and one does not. The true stress-strain equations of one eutectic and the one noneutectic material are determined from compressive tests at engineering strain-rates between 0.0002/s and 0.2/s. The second eutectic material is evaluated using tensile tests with strain-rates between 0.00017/s and 0.042/s. The materials appear to exhibit linear elastic behavior only at extremely small strains, i.e., less than 0.0005. However, this “elastic” behavior showed considerable variation, and depended upon the strain rate. In both tension and compression the eutectic alloy exhibits nonlinear plastic behavior, i.e., strain-softening followed by strain-hardening, which depends upon the strain rate. A quadratic equation σy = σy(ε˚/ε˚0) + A(ε˚/ε˚0)ε + B(ε˚/ε˚0)ε2 fit to the data gives correlation coefficients R2 > 0.91. The coefficients σy(ε˚/ε˚0), A(ε˚/ε˚0), B(ε˚/ε˚0) are fitted functions of the normalized engineering strain rate ε˚/ε˚0. Replicated experiments are used at each strain-rate so that a measure of the statistical variation could be estimated. Measures of error associated with the regression analysis are also obtained so that an estimate of the total error in the stress-strain relations can be made.

Coupling effect of strain rate and temperature on tensile damage mechanism of polyphenylene sulfide reinforced by glass fiber (PPS/GF30)

2020 ◽  
pp. 089270572094422
Author(s):  
Mohammadali Shirinbayan ◽  
Joseph Fitoussi ◽  
Farid Kheradmand ◽  
Arash Montazeri ◽  
Peiyuan Zuo ◽  
...  
Keyword(s):  
Strain Rate ◽  
Glass Fiber ◽  
High Strain ◽  
Coupling Effect ◽  
Damage Mechanism ◽  
Tensile Tests ◽  
Ultimate Stress ◽  
Polyphenylene Sulfide ◽  
Stress And Strain ◽  
Strain Rates

Influence of loading temperature on the damage mechanism of polyphenylene sulfide (PPS) reinforced by glass fiber (PPS/GF30) under tension was experimentally studied from quasi-static (QS) to high strain rates. Two kinds of PPS/GF30 samples were prepared: PPS-0° and PPS-90° (correspond to fibers oriented parallel and perpendicular to the injection direction, respectively). After microscopic observation and thermomechanical characterizations by dynamic mechanical analysis, tensile tests up to failure with strain rates varying from 10−3 s−1 to 100 s−1 have been carried out at 25°C and 120°C with regard to PPS/GF30 glass transition temperature. To achieve the coupling effect of high strain rate and high temperature, a special chamber was designed to install on the servo-hydraulic machine. The results of QS tensile tests confirm the significant effect of fiber orientation and temperature on the Young’s modulus, the ultimate stress, and strain. High strain tensile test results showed that the PPS/GF30 composite is strain rate dependent at both temperatures. The results indicated that Young’s modulus remains constant by strain rate increasing at both temperatures while ultimate stress and strain are increased. No significant damage has been observed at 25°C in QS loading, whereas the macroscopic damage variable is increased to 20% at 120°C. Debonding at the fiber–matrix interface is the main damage mechanism at 120°C.

scholarly journals Strain Rate-Dependent Constitutive and Low Stress Triaxiality Fracture Behavior Investigation of 6005 Al Alloy

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Yong Peng ◽  
Xuanzhen Chen ◽  
Shan Peng ◽  
Chao Chen ◽  
Jiahao Li ◽  
...  
Keyword(s):  
Flow Stress ◽  
Plastic Strain ◽  
Strain Rate ◽  
Fracture Behavior ◽  
Equivalent Plastic Strain ◽  
Stress Triaxiality ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Strain Rates ◽  
Stress States

In order to study the dynamic and fracture behavior of 6005 aluminum alloy at different strain rates and stress states, various tests (tensile tests at different strain rates and tensile shearing tests at five stress states) are conducted by Mechanical Testing and Simulation (MTS) and split-Hopkinson tension bar (SHTB). Numerical simulations based on the finite element method (FEM) are performed with ABAQUS/Standard to obtain the actual stress triaxialities and equivalent plastic strain to fracture. The results of tensile tests for 6005 Al show obvious rate dependence on strain rates. The results obtained from simulations indicate the feature of nonmonotonicity between the strain to fracture and stress triaxiality. The equivalent plastic strain reduces to a minimum value and then increases in the stress triaxiality range from 0.04 to 0.30. A simplified Johnson-Cook (JC) constitutive model is proposed to depict the relationship between the flow stress and strain rate. What is more, the strain-rate factor is modified using a quadratic polynomial regression model, in which it is considered to vary with the strain and strain rates. A fracture criterion is also proposed in a low stress triaxiality range from 0.04 to 0.369. Error analysis for the modified JC model indicates that the model exhibits higher accuracy than the original one in predicting the flow stress at different strain rates. The fractography analysis indicates that the material has a typical ductile fracture mechanism including the shear fracture under pure shear and the dimple fracture under uniaxial tensile.

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