scholarly journals Plasticity and failure behavior modeling of high-strength steels under various strain rates and temperatures: microstructure to components

2018 ◽  
Vol 13 ◽  
pp. 1421-1426 ◽  
Author(s):  
Junhe Lian ◽  
Wenqi Liu ◽  
Ioanna Papadioti ◽  
Ilias Bellas ◽  
Sarath Chandran ◽  
...  
Keyword(s):  
High Strength Steels ◽  
High Strength ◽  
Behavior Modeling ◽  
Failure Behavior ◽  
Strain Rates

Application of Advanced Multiphase Steels in Crashworthiness Structures: Experimental Study and Constitutive Equations

2006 ◽  
Vol 514-516 ◽  
pp. 579-583 ◽  
Author(s):  
Nuno Peixinho ◽  
António Pinho
Keyword(s):  
Constitutive Equations ◽  
Tensile Testing ◽  
High Strength Steels ◽  
High Strength ◽  
Experimental Program ◽  
Dual Phase ◽  
Strain Rates ◽  
Trip Steels ◽  
Advanced High Strength Steels ◽  
Steel Grades

This work presents results of tensile testing of advanced high strength steels of interest for crashworthy structures: Dual-Phase and TRIP (Transformation Induced Plasticity) steels. The improvements in vehicle crashworthiness observed in recent years have been closely linked to advanced high-strength steels that are currently being produced or in process of development. Amongst these, Dual-Phase and TRIP steels have presented excellent properties for use in crashworthy structures. For these steel grades an understanding of material behaviour at relevant strain rates is needed as well as constitutive equations suitable for use in analytic and numerical calculations. For that purpose an experimental program of tensile testing was performed in a range of strain rates of interest for crashworthiness problems: 0.0001 /s to 1000 /s. The test results were used to compare material properties and to evaluate the Cowper-Symonds constitutive equation and a modified version. Crush tests were performed at different speeds for top-hat and hexagonal tubes manufactured using laser welding and the results discussed in view of energy absorption.

The Effect of Strain Rate on Yielding in High Strength Steels

1966 ◽  
Vol 88 (1) ◽  
pp. 37-44 ◽  
Author(s):  
D. P. Kendall ◽  
T. E. Davidson
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Power Law ◽  
High Strength Steels ◽  
Rate Sensitivity ◽  
High Strength ◽  
Strain Rates ◽  
Alloy Steels ◽  
Strength Alloy ◽  
Continuous Power

The effect of strain rates ranging from 10−4 to 10 in/in/sec on the yield strengths of several high strength alloy steels is investigated. Quenched and tempered-type alloys exhibit two regions of strain-rate sensitivity with the strain rate dividing the sensitive and insensitive regions varying from 0.5 to greater than 10 in/in/sec, depending on composition, microstructure and grain size. At the higher rates a power-law relationship is found which is consistent with a yielding model involving breakaway of dislocations from solute atmospheres. Maraging steel exhibits a continuous power law-strain rate sensitivity over the entire range.

scholarly journals Temperature Dependence of the Static and Dynamic Behaviour in a Quenching and Partitioning Processed Low-Si Steel

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 509 ◽  
Author(s):  
Florian Vercruysse ◽  
Carola Celada-Casero ◽  
Bernd M. Linke ◽  
Patricia Verleysen ◽  
Roumen H. Petrov
Keyword(s):  
Mechanical Properties ◽  
Retained Austenite ◽  
High Strength Steels ◽  
High Strength ◽  
Dynamic Strain ◽  
Strain Rates ◽  
Trip Effect ◽  
Quenching And Partitioning ◽  
Advanced High Strength Steels ◽  
Wide Range

Because of their excellent combination of strength and ductility, quenching and partitioning (Q & P) steels have a great chance of being added to the third generation of advanced high strength steels. The large ductility of Q & P steels arises from the presence of 10% to 15% of retained austenite which postpones necking due to the transformation induced plasticity (TRIP) effect. Moreover, Q & P steels show promising forming properties with favourable Lankford coefficients, while their planar anisotropy is low due to a weak texture. The stability of the metastable austenite is the key to obtain tailored properties for these steels. To become part of the newest generation of advanced high strength steels, Q & P steels have to preserve their mechanical properties at dynamic strain rates and over a wide range of temperatures. Therefore, in the present study, a low-Si Q & P steel was tested at temperatures from −40 °C to 80 °C and strain rates from 0.001 s−1 to 500 s−1. Results show that the mechanical properties are well-preserved at the lowest temperatures. Indeed, at −40 °C and room temperature, no significant loss of the deformation capacity is observed even at dynamic strain rates. This is attributed to the presence of a large fraction of austenite that is so (thermally) stable that it does not transform in the absence of deformation. In addition, the high stability of the austenite decreases the elongation at high test temperatures (80 °C). The additional adiabatic heating in the dynamic tests causes the largest reduction of the uniform strain for the samples tested at 80 °C. Quantification of the retained austenite fraction in the samples after testing confirmed that, at the highest temperature and strain rate, the TRIP effect is suppressed.

Application of Dual-Phase and TRIP Steels on the Improvement of Crashworthy Structures

2005 ◽  
Vol 502 ◽  
pp. 181-188 ◽  
Author(s):  
Nuno Peixinho ◽  
N. Jones ◽  
António Pinho
Keyword(s):  
High Strength Steels ◽  
High Strength ◽  
Tensile Tests ◽  
Dual Phase ◽  
Strain Rates ◽  
Trip Steels ◽  
Advanced High Strength Steels ◽  
Steel Grades ◽  
Determination Of Parameters

The improvements in vehicle crashworthiness observed in recent years have been closely linked to advanced high-strength steels that are currently being produced or in process of development. Amongst these, Dual-Phase and TRIP (Transformation Induced Plasticity) steels have presented excellent properties for use in crashworthy structures. For these steel grades an understanding of material behaviour at relevant strain rates is needed as well as constitutiv eequations suitable for use in analytic and numerical calculations. In this study the crashworthiness of thin-walled sections made of Dual-Phase and TRIP steels was investigated. Tensile tests were performed at different strain rates in a range of interest for crashworthiness problems. The results allowed the determination of parameters of Cowper-Symonds equation. Crush tests were performed at different speeds for top-hat and hexagonal tubes manufactured using laser welding. The experimental results were compared with numerical simulations obtained with LS-DYNA software. The influence of different material parameters on the accuracy of the simulations was examined.

Compression Tests of High Strength Steels

2008 ◽  
Vol 59 ◽  
pp. 293-298
Author(s):  
Vaclav Mentl ◽  
Josef Bystricky
Keyword(s):  
Mechanical Properties ◽  
Mechanical Testing ◽  
High Speed ◽  
Dynamic Compression ◽  
Testing Machine ◽  
High Strength Steels ◽  
High Strength ◽  
Strain Rates ◽  
Compression Tests ◽  
Impact Compression

Mathematical modelling and virtual testing of components and structures represent a useful and economic tool for design and safety assessment. The basic mechanical properties which can be found in material standards are not relevant in cases where the real service conditions differ from those applied during standardised testing. Thus e.g. mechanical behaviour at higher strain rates can be interesting for the car components when the simulation of crash situations is used during structure development. The dynamic compression tests are usually performed by means of drop towers, by means of high speed hydraulic testing machines or Hopkinson bar method. At the Mechanical Testing Laboratory of the SKODA Research Inst. in Pilsen, Czech Republic, an instrumentation of Charpy pendulum testing machine was realised in order that it was possible to perfom dynamic compression tests, [1], and the compatibility of obtained results in comparison with traditional impact compression tests was verified within the round–robin carried out by TC5 ESIS Sub-Committee on “Mechanical Testing at Intermediate Strain Rates“, [2]. A new striking tup and load measurement system were designed and callibrated. At the same time, a new software was developed which makes it possible to evaluate the test force-deformation record. The goal of this study was 1. to check the possibility of compression testing of high strength materilas by mens of Charpy pendulum, and 2. to study the strain rate influence on basic mechanical properties.

scholarly journals Soldering of steel sheets and zinc-coated aluminum by hybrid composite forging

2020 ◽  
Author(s):  
T. Bick ◽  
K. Treutler ◽  
V. Wesling
Keyword(s):  
High Strength Steels ◽  
High Strength ◽  
Intermetallic Phases ◽  
Single Step ◽  
Failure Behavior ◽  
Forming Process ◽  
Contact Corrosion ◽  
Static Tensile ◽  
Solid Part ◽  
Mathematical Relationships

Abstract In lightweight construction, light metals like aluminum are used in addition to high-strength steels. However, a welded joint of aluminum and steel leads to the precipitation of brittle, intermetallic phases and contact corrosion. Nevertheless, to use the advantages of this combination in terms of weight saving, composite hybrid forging has been developed. In this process, an aluminum solid part and a steel sheet were formed in a single step and joined at the same time with zinc as brazing material. For this purpose, the zinc was applied by hot dipping on the aluminum in order to produce a Brazing via these layers in a forming process, under pressure and heat. Due to the formed intermediate layer of zinc, the formation of the Fe-Al intermetallic phases and the contact corrosion are excluded. By determining the mathematical relationships between joining parameters and the mechanical properties of the joint, the strength of a specific joint geometry could be adjusted to reach the level of conventional joining techniques. In addition to the presentation of the joint properties, the influence of the joining process on the structure of the involved materials will be shown. Furthermore, the failure behavior under static tensile and shear stress will be shown.

scholarly journals Static and dynamic response of ultra-fast annealed advanced high strength steels

2018 ◽  
Vol 183 ◽  
pp. 03017
Author(s):  
Florian Vercruysse ◽  
Felipe M. Castro Cerda ◽  
Roumen Petrov ◽  
Patricia Verleysen
Keyword(s):  
Strain Rate ◽  
Retained Austenite ◽  
High Strain ◽  
High Strength Steels ◽  
High Strength ◽  
Strain Rates ◽  
Low Carbon ◽  
Heating Rates ◽  
High Strain Rates ◽  
Advanced High Strength Steels

Ultra-fast annealing (UFA) is a viable alternative for processing of 3rd generation advanced high strength steels (AHSS). Use of heating rates up to 1000°C/s shows a significant grain refinement effect in low carbon steel (0.1 wt.%), and creates multiphase structures containing ferrite, martensite, bainite and retained austenite. This mixture of structural constituents is attributed to carbon gradients in the steel due to limited diffusional time during UFA treatment. Quasi-static (strain rate of 0.0033s-1) and dynamic (stain rate 600s-1) tensile tests showed that tensile strength of both conventional and UFA sample increases at high strain rates, whereas the elongation at fracture decreases. The ultrafast heated samples are less sensitive to deterioration of elongation at high strain rates then the conventionally heat treated ones. Based on metallographic studies was concluded that the presence of up to 5% of retained austenite together with a lower carbon martensite/bainite fraction are the main reason for the improved tensile properties. An extended stability of retained austenite towards higher strain values was observed in the high strain rate tests which is attributed to adiabatic heating. The extension of the transformation induced plasticity (TRIP) effect towards higher strain values allowed the UFA-samples to better preserve their deformation capacity resulting in expected better crashworthiness.

Hot Deformation Behavior of a 3rd Generation Advanced High Strength Steel with a Medium-Mn Content

2015 ◽  
Vol 651-653 ◽  
pp. 120-125 ◽  
Author(s):  
Katharina Steineder ◽  
Martina Dikovits ◽  
Coline Beal ◽  
Christof Sommitsch ◽  
Daniel Krizan ◽  
...  
Keyword(s):  
Hot Deformation ◽  
Deformation Behavior ◽  
High Strength Steels ◽  
Rate Sensitivity ◽  
High Strength ◽  
Strain Rates ◽  
Compression Tests ◽  
Hot Deformation Behavior ◽  
Present Contribution ◽  
Mn Content

Medium-Mn steels are one of the promising candidates to achieve the desired mechanical properties in the 3rd generation of cold rolled advanced high strength steels (AHSS) for automotive applications. Their duplex microstructure consists of a ferritic matrix with a substantial amount of metastable retained austenite, which transforms to strain-induced martensite upon forming. This strengthening mechanism, well known as the TRansformation Induced Plasticity (TRIP) effect, provides the steel an excellent combination of high strength and elongation with a product of RmxA80 up to 30.000 MPa%. As hot rolling is one of the crucial steps during their production, the hot deformation behavior of Medium-Mn steels has to be thoroughly evaluated during their development stage.Therefore, the present contribution studied the hot deformation response of a 0.1 %C 5.5 %Mn steel by means of hot compression tests using a Gleeble® 3800 device. The influence of different deformation temperatures (900-1100 °C) and strain rates (0.1-10 s-1) on the stress-strain behavior was investigated. The flow curves were analyzed and corrected by the effects of adiabatic heating.Furthermore, the strain rate sensitivity m of the material was determined by evaluating stress values at different strain rates for given temperatures and strains. The m-values can be used to predict the deformation behavior of the material within the investigated range of parameters.Lastly, the hot working behavior of an alternative steel concept for a 3rd Generation AHSS with significantly lower Mn-content was comparatively investigated.

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