scholarly journals The Performance of CR180IF and DP600 Laser Welded Steel Sheets under Different Strain Rates

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1553
Author(s):  
Mária Mihaliková ◽  
Kristína Zgodavová ◽  
Peter Bober ◽  
Anna Špegárová
Keyword(s):  
Sheet Steel ◽  
Testing Machine ◽  
Dynamic Test ◽  
Tensile Tests ◽  
Joint Surface ◽  
Strain Rates ◽  
Interstitial Free ◽  
Welded Steel ◽  
Steel Sheets ◽  
Static Tensile

The presented research background is a car body manufacturer’s request to test the car body’s components welded from dissimilar steel sheets. In view of the vehicle crew’s protection, it is necessary to study the static and dynamic behavior of welded steels. Therefore, the influence of laser welding on the mechanical and dynamical properties, microstructure, microhardness, and welded joint surface roughness of interstitial free CR180IF and dual-phase DP600 steels were investigated. Static tensile tests were carried out by using testing machine Zwick 1387, and dynamic test used rotary hammer machine RSO. Sheet steel was tested at different strain rates ranging from 10−3 to 103 s−1. The laser welds’ microstructure and microhardness were evaluated in the base metal, heat-affected zone, and fusion zone. The comprehensive analysis also included chemical analysis, fracture surface analysis, and roughness measurement. The research results showed that the strain rate had an influence on the mechanical properties of base materials and welded joints. The dynamic loading increases the yield stress more than the ultimate tensile strength for the monitored steels, while the most significant increase was recorded for the welded material.

IMPACT TENSILE PROPERTIES OF YAG LASER WELDED BUTT JOINTS MADE BY DIFFERENT STEEL SHEETS FOR VEHICLES

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1712-1717
Author(s):  
Y. TAKAHASHI ◽  
M. DAIMARUYA ◽  
H. KOBAYASHI ◽  
H. TSUDA ◽  
H. FUJIKI
Keyword(s):  
Tensile Properties ◽  
Welded Joints ◽  
Testing Machine ◽  
High Strength ◽  
Tensile Tests ◽  
Butt Joints ◽  
Yag Laser ◽  
Steel Sheets ◽  
Static Tensile ◽  
The Impact

The tensile properties of YAG laser welded butt joints using different high strength steel sheets with a tensile strength of 270 MPa, 590 MPa and 980 MPa (denoted HR270, HR590 and HR980, respectively) were investigated at static and dynamic rates, together with the three kinds of laser welded joints made by the same steel sheets. The impact tensile tests were performed by using the vertical type of split Hopkinson tension bar apparatus, while the static tensile tests were carried out using a universal testing machine INSTRON5586. The impact tensile strengths were significantly increased in comparison with the static ones due to the effect of strain rate, which might be the contribution of the part of HR270 base metal. And in both of static and impact tests, the fracture strains of HR270-HR590 joint, HR270-HR980 joint and HR590-HR980 joint were about one half of the fracture strains observed in the same steel welded joints of HR270-HR270, HR270-HR270 and HR590-HR590, respectively.

Effect of Loading Rate on Tensile Properties of Automotive Steel Sheet

2013 ◽  
Vol 690-693 ◽  
pp. 211-217
Author(s):  
Jin Gui Qin ◽  
Fang Yun Lu ◽  
Yu Liang Lin ◽  
Xue Jun Wen
Keyword(s):  
Strain Rate ◽  
Testing Machine ◽  
Structural Response ◽  
Tensile Tests ◽  
Dynamic Tests ◽  
Static Tests ◽  
Split Hopkinson Tensile Bar ◽  
Axial Tensile ◽  
Static Tensile ◽  
Cook Model

Results of uni-axial tensile loading of three automotive steels at different strain rates (0.0011–3200s-1) are reported here. Quasi-static tensile tests were performed under the strain rate of 1.1×10-3 s-1 using an electromechanical universal testing machine, whereas dynamic tests were carried out under the strain rate in the range of 1100 to 3200 s-1 using a Split Hopkinson Tensile Bar apparatus. Based on the experimental results, the material parameters of widely used Johnson–Cook model which described the strain rate and temperature-dependent of mechanical behaviour were determined. The experiments show that strain-rate hardening is superior to thermal softening: yield stresses, tensile strength, deformation, and energy dissipation increase with the strain rate from quasi-static tests to dynamic tests. The Johnson–Cook model can describe the behaviour of these steels and provides the opportunity to study the material and structural response.

New Structures and Techniques for Easy Axial Loading Test of Static and Fatigue Properties of MEMS Materials

2005 ◽  
Vol 297-300 ◽  
pp. 545-550 ◽  
Author(s):  
Jun Hyub Park ◽  
Chung Youb Kim ◽  
Sung Hoon Choa ◽  
Chang Seung Lee ◽  
Woo Seong Che ◽  
...  
Keyword(s):  
Microelectromechanical Systems ◽  
Testing Machine ◽  
Axial Loading ◽  
Tensile Tests ◽  
Fatigue Properties ◽  
Mems Devices ◽  
Loading Test ◽  
Static Tensile ◽  
Materials Used ◽  
Electro Magnetic

Mechanical property evaluation of micrometer-sized structures is necessary to help design reliable microelectromechanical systems (MEMS) devices. Most material properties are known to exhibit dependence on specimen size and such properties of microscale structures are not well characterized. This paper describes techniques developed for tensile testing of materials used in MEMS. Epi-polycrystalline silicon is currently the most widely used material, and its tensile strength has been measured as 1.52GPa. We have developed an axial testing machine for testing microscale specimen using electro-magnetic actuator. The field magnet and the moving coil taken from an audio-speaker were utilized as the components of the actuator. Structure of specimen was designed and manufactured for easy handling and alignment. In addition to the static tensile tests, new techniques and procedures for measuring strength are described.

scholarly journals The investigation on the ideal spot weld numerical model in resistance welding

2020 ◽  
Vol 111 (3-4) ◽  
pp. 895-907
Author(s):  
Zygmunt Mikno ◽  
Bogusław Grzesik ◽  
Mariusz Stępień
Keyword(s):  
Numerical Model ◽  
Spot Welding ◽  
Base Material ◽  
Spot Weld ◽  
3D Fem ◽  
Welded Steel ◽  
Steel Sheets ◽  
Static Tensile ◽  
Different Dimensions ◽  
The Ideal

Abstract The paper presents investigation on the ideal spot weld numerical model. The weld discussed in the paper was made by the resistance spot welding of two overlapping steel sheets. The ideal weld contained three parts, i.e. two welded steel sheets and an intermediate component (connector) made of the same material. The connector was placed between the sheets, assembled mechanically and fixed. A numerical model of the ideal weld enables the elimination of all welding imperfections, including, among other things, an indent left by the electrode as well as stresses and deformations of materials present in the actual welded joint. The ideal weld was intentionally not subjected to the thermal cycle. As a result, the heat-affected zone and the molten nugget were eliminated from the model (welding area). Consequently, the entire tested (analysed) weld specimen only had the properties of the base material. The analysis presented in the paper is based on 3D FEM numerical modelling and experimental validation. The numerical model of the ideal weld (nugget surface) was investigated in relation to various shapes of the nugget (e.g. circular, square and rectangular) as well as in relation to different dimensions. The research also involved the performance of a comparative analysis including various welding conditions. The analysis was carried out to determine the highest possible value of shear force generated during a static tensile test. The results of the numerical tests were compared with the results of selected laboratory tests.

Dynamic Tensile Characteristics of DP600 Steel Sheets for Automotive Applications

2012 ◽  
Vol 509 ◽  
pp. 40-45
Author(s):  
Dan Yang Dong ◽  
Yang Liu ◽  
Lei Wang ◽  
Chang Sheng Liu
Keyword(s):  
Strain Rate ◽  
Tensile Testing ◽  
High Speed ◽  
Greenhouse Gas Emission ◽  
Testing Machine ◽  
Fracture Mechanisms ◽  
Strain Rates ◽  
Automotive Applications ◽  
Tensile Testing Machine ◽  
Steel Sheets

To reduce fuel consumption and greenhouse gas emission, dual phase (DP) steels have been considered for automotive applications due to their higher tensile strength, better initial work hardening along with larger elongation compared to conventional grade of steels. In such applications, which would create potential safety and reliability issues under dynamic loading, the mechanical behavior of DP steel considering the strain rate must be examined. In the present study, the dynamic tensile behavior of DP600 steel sheets was investigated using a high-speed tensile testing machine at various strain rates. And the quasi-static tensile testing was also conducted on the steel to understand the effect of the strain rate on the tensile property. The fracture mechanisms of the steel were also analyzed. The results show that the mechanical properties of DP600 steel are noticeably influenced by the strain rates. As the strain rate increases, the strength of the steel increases and the obvious yield phenomenon can be observed when the strain rate is above 0.01 s-1. The fracture elongation of DP600 steels decreases with increasing strain rate from 0.001 to 1 s-1, then increases up to the strain rate of 100 s-1 and reaches the lowest value at the strain rate of 1000 s-1. DP600 steel sheet exhibit typical ductile fracture characteristics with dimples morphology of the facture surface when tensile deformed at various strain rates.

Static and Dynamic Tensile Behavior of Unidirectional Glass/Epoxy Composites

2014 ◽  
Vol 1016 ◽  
pp. 298-301 ◽  
Author(s):  
Pedro Correia ◽  
Nuno Peixinho
Keyword(s):  
Tensile Tests ◽  
Hydraulic Testing ◽  
Strain Rates ◽  
Dynamic Tests ◽  
Widespread Application ◽  
Glass Fiber Reinforced ◽  
Unidirectional Glass ◽  
Static Tensile ◽  
Transportation Applications ◽  
Static And Dynamic Loading

A widespread application of composite materials requires proper knowledge of both static and dynamic loading properties, particularly for automotive and transportation applications. In this study the behavior of unidirectional glass fiber reinforced polymeric composites under uniaxial loading is determined at quasi-static and intermediate strain rates in the range 0.6–500/s. The tensile tests were performed using different servo-hydraulic testing apparatus. Dynamic tests results are compared with the results of static tensile tests carried out on specimens with identical geometry. Experimental results show a significant increase of the tensile strength with increasing strain rate. The strain to failure is also observed to increase slightly for higher strain rates.

Thermal Deformation Behavior and Formability of High Temperature with Corrosion Resistance Alloy

2019 ◽  
Vol 794 ◽  
pp. 142-150
Author(s):  
Gyeong Uk Jeong ◽  
Jun Park ◽  
Chul Kyu Jin ◽  
Young Hoon Moon ◽  
Chung Gil Kang
Keyword(s):  
High Temperature ◽  
Base Alloy ◽  
Testing Machine ◽  
Tensile Tests ◽  
High Temperature Deformation ◽  
Inconel 625 ◽  
Temperature Deformation ◽  
Strain Rates ◽  
Rigid Plastic ◽  
Compression Process

The aim of present wor is, therfore, to investigated the effect of the damage value prediction equation on the formability of compression specimen and find the optimize forming condition.Although Inconel 625 alloys are excellent materials, Ni-base alloy cannot be formed at room temperature owing to limitation of formability. To improve the formability of Inconel 625, it is necessary to investigate the formability at a high temperature range.A high temperature compression test is performed with a Gleeble 3500 testing machine at various temperatures (approximately 900 1200°C) and strain rates (10/s and 30/s) to obtain high temperature deformation characteristics of Inconel 625. Furthermore, high temperature tensile tests results are used to measure elongations and reductions in the area of Inconel 625.A rigid-plastic finite element simulation is applied to the high temperature compression process to obtain the damage valueThe results of the hot deformation experiment and analysis are presented for various conditions of temperatures and strain rates, and it is expected that damage value will be used in hot forming processes such as hot extrusion and rolling process.

scholarly journals Stress-Strain Behavior – Deformation Degree Relationship Investigation of Alloy CrNi60WTi

2021 ◽  
Vol 65 (1) ◽  
pp. 105-107
Author(s):  
Yaroslav Kosmatskiy ◽  
Nikolai Fokin ◽  
Kseniya Yakovleva ◽  
Vladislav Nikolenko ◽  
Boris Barichko ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cold Deformation ◽  
Testing Machine ◽  
Tensile Tests ◽  
Outer Diameter ◽  
Test Results ◽  
Deformation Degree ◽  
Tensile Testing Machine ◽  
Strain Behavior ◽  
Static Tensile

The article presents the results of a research of the dependence of the mechanical properties of the CrNi60WTi alloy on the degree of cold deformation. As part of the study, five samples were taken from a pipe with an outer diameter of 89.0 mm and a wall thickness of 11.0 mm. The samples were cold-deformed to varying degrees and static tensile tests were performed on an SSI MTSInsight tensile testing machine. Based on the test results, the dependences of the mechanical properties on the degree of cold deformation were calculated.

scholarly journals Strain rate sensitivity of the aluminium-magnesium-scandium alloy - Scalmalloy®

2021 ◽  
Vol 250 ◽  
pp. 05014
Author(s):  
Puneeth Jakkula ◽  
Georg Ganzenmüller ◽  
Florian Gutmann ◽  
Stefan Hiermaier
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Testing Machine ◽  
Rate Sensitivity ◽  
Tensile Tests ◽  
Image Correlation ◽  
Strain Rates ◽  
Rate Dependency ◽  
Strain Rate Dependency ◽  
Scandium Alloy

This work investigates the strain rate sensitivity of the aluminiummagnesium-scandium alloy Scalmalloy, which is used extensively for additive manufacturing of lightweight structures. This high strength aluminium alloy combines very good weldability, machinability and mechanical strength: it can be heat-treated to reach nominal ultimate tensile strengths in excess of 500 MPa. We report tensile tests at strain rates ranging from 10−3 /s to 103 /s at room temperature. It is well known that Al-Mg alloys exhibit a negative strain rate dependency in combination with serrated flow caused by the Portevin-Le Chatelier effect, which describes the interaction of Mg solutes with dislocation propagations. In contrast, in Al-Sc alloys, the flow stress increases with increasing strain rate and displays positive strain rate dependency. Additionally, the presence of Sc in the form of Al3-Sc provides a fine-grained microstructure which allows higher tensile and fatigue strength. This research shows how these combined effects interact in the case of Scalmalloy, which contains both Mg and Sc. Tests are performed at quasi-static, intermediate and high strain rates with a servohydraulic testing machine and a Split-Hopkinson tension bar. Local specimen strain was performed using 2D Digital Image Correlation.

Flow Stress and Damage Behavior of C45 Steel Over a Range of Temperatures and Loading Rates

2017 ◽  
Vol 139 (2) ◽  
Author(s):  
Farid H. Abed ◽  
Mohammad H. Saffarini ◽  
Akrum Abdul-Latif ◽  
George Z. Voyiadjis
Keyword(s):  
Coupling Effect ◽  
Damage Model ◽  
Ductile Failure ◽  
Tensile Tests ◽  
Dynamic Strain ◽  
Strain Rates ◽  
Sem Images ◽  
Proposed Model ◽  
Static Tensile ◽  
Structural Responses

This research aims to describe the behavior of C45 steel and provide better understanding of the thermomechanical ductile failure that occurs due to accumulation of microcracks and voids along with plastic deformation to enable proper structural design, and hence provide better serviceability. A series of quasi-static tensile tests are conducted on C45 steel at a range of temperatures between 298 K and 923 K for strain rates up to 0.15 s−1. Drop hammer dynamic tests are also performed considering different masses and heights to study the material response at higher strain rates. Scanning electron microscopy (SEM) images are taken to quantify the density of microcracks and voids of each fractured specimens, which are needed to define the evolution of internal defects using an energy-based damage model. The coupling effect of damage and plasticity is incorporated to accurately define the constitutive relation that can simulate the different structural responses of this material. Good correlation was observed between the proposed model predictions and experiments particularly at regions where dynamic strain aging (DSA) is not present.

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