scholarly journals Analysis of Springback Behaviour in Micro Flexible Rolling of Crystalline Materials

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Feijun Qu ◽  
Zhengyi Jiang ◽  
Xiaogang Wang ◽  
Cunlong Zhou
Keyword(s):  
Stainless Steel ◽  
Voronoi Tessellation ◽  
Constitutive Modelling ◽  
Combined Loading ◽  
304 Stainless Steel ◽  
Isotropic Hardening ◽  
Stress Strain ◽  
Finite Element Program ◽  
Hardening Model ◽  
Average Grain Size

This paper presents a constitutive modelling of the polycrystalline thin metal strip under a state of combined loading in microflexible rolling. The concept of grained inhomogeneity is incorporated into the classic Chaboche hardening model that accounts for the Bauschinger effect, in order to provide more precise description and analysis of the springback mechanism in the particular forming operation. The model is first implemented in the finite element program ABAQUS to numerically predict the stress-strain relationship of 304 stainless steel specimens over a range of average grain sizes. After validation of the developed model by comparison of predicted curves and actual stress-strain data points, it is further applied to predict the thickness directional springback in microflexible rolling of 304 stainless steel strips with initial thickness of 250 µm and reduction changing from 5 to 10%. The model predictions show a reasonable agreement with the experimental measurements and have proven to be more accurate than those obtained from the conventional multilinear isotropic hardening model in combination with the Voronoi tessellation technique. In addition, the variation of thickness directional springback along with the scatter effect is compared and analysed in regard to the average grain size utilising both qualitative and quantitative approaches in respect of distinct types of data at different reductions.

Analysis of the Redundant Deformation Factor in the Axisymmetric Drawing of AISI 304 Stainless Steel Bars through Experimental Techniques

2010 ◽  
Vol 638-642 ◽  
pp. 3170-3175
Author(s):  
Elaine Carballo Siqueira Corrêa ◽  
Maria Teresa Paulino Aguilar ◽  
Paulo Roberto Cetlin
Keyword(s):  
Stainless Steel ◽  
Structural Features ◽  
304 Stainless Steel ◽  
Aisi 304 Stainless Steel ◽  
Stress Strain ◽  
Aisi 304 ◽  
Steel Bars ◽  
Deformation Features ◽  
Superposition Technique ◽  
The Relationship

One of the most significant aspects of the axisymmetric drawing operation is the occurrence of non-homogeneous deformation in the cross section of the metal. This phenomenon is associated with an internal distortion process that takes place in the bar as it flows through the die, leading to the development of higher drawing forces and affecting the subsequent mechanical behavior of the material. An adequate analysis of the process and of the work hardening of the drawn metal, therefore, must involve a detailed study of the deformation features in the forming operation. In the present work, the deformation in the single-pass drawing of AISI 304 stainless steel bars was investigated through the evaluation of the relationship between the redundant deformation factor and the parameter . Two experimetal procedures were employed in the study: the visioplasticity and the stress-strain curves superposition techniques. The first one, previously considered as the method leading to the most realistic solutions to various forming processes, allowed the establishment of an increasing linear relationship between de redundant deformation factor and the parameter . A similar behavior was observed through the stress-strain curves superposition technique. In this case, however, the redundant deformation factor values were lower or higher than those obtained through visioplasticity according to the drawing conditions and more sensitive to variations of the parameter . The results were compared to those exhibited by the AISI 420 stainless steel, revealing the influence of the structural features on the behavior of the metal.

Strain Hardening of Annealed 304 Stainless Steel by Creep

1993 ◽  
Vol 115 (4) ◽  
pp. 345-350 ◽  
Author(s):  
Han-Chin Wu ◽  
Chin-Cheng Ho
Keyword(s):  
Stainless Steel ◽  
Strain Hardening ◽  
Kinematic Hardening ◽  
Constant Strain Rate ◽  
Transient Creep ◽  
304 Stainless Steel ◽  
Isotropic Hardening ◽  
Loading Surface ◽  
Before And After ◽  
Strain Hardening Behavior

Combined axial-torsional experiments have been conducted at room temperature on thin-walled tubes to investigate the strain hardening behavior of annealed 304 stainless steel due to creep. The constant strain-rate dynamic loading (or SCISR) surfaces representing the state of material before and after creep have benn determined. It has been found that transient creep essentially causes the loading surface to undergo kinematic hardening with insignificant amount of isotropic hardening for this material. A conclusion is drawn that the loading surface hardened by transient creep is the same as that hardened by plastic deformation. This is true both for specimens with pure tension and pure torsion loading paths. The results confirm assumptions of the overstress theory of viscoplasticity.

Mechanical Behavior of Constrained Groove Pressed Stainless Steel and Pure Zinc

2021 ◽  
Vol 882 ◽  
pp. 28-34
Author(s):  
Zeynel Guler ◽  
Guney Guven Yapici
Keyword(s):  
Stainless Steel ◽  
Mechanical Behavior ◽  
304 Stainless Steel ◽  
Pure Zinc ◽  
Aisi 304 ◽  
Remarkable Improvement ◽  
Commercially Pure ◽  
Average Grain Size ◽  
Viable Method ◽  
Hardness Values

Constrained groove pressing (CGP), which is a severe plastic deformation technique, has been implemented on AISI 304 and commercially pure zinc samples in the present work. Four CGP passes were successfully applied to both materials providing a remarkable improvement in both strength and hardness values, despite reduced ductility. Average grain size values were diminished by around 45% for 304 stainless steel and 47% for commercially pure zinc. The highest levels of strengthening due to severe deformation were displayed after the initial passes for both materials. CGP was shown to be a viable method for strengthening based on deformation processing, whereby similar trends in microstructure and mechanical behavior were observed for both crystal structures.

High-Cycle Fatigue Behavior of Solution-Annealed and Thermally-Aged Type 304 Stainless Steel

1980 ◽  
Vol 102 (1) ◽  
pp. 141-146 ◽  
Author(s):  
P. Soo ◽  
J. G. Y. Chow
Keyword(s):  
Stainless Steel ◽  
High Cycle Fatigue ◽  
Fatigue Behavior ◽  
Cyclic Stress ◽  
304 Stainless Steel ◽  
Strain History ◽  
Cycle Fatigue ◽  
Stress Strain ◽  
Type 304 ◽  
Type 304 Stainless Steel

High-cycle, load-controlled fatigue data have been obtained for solution-annealed and thermally-aged Type 304 stainless steel, for temperatures between 22 and 593°C (72-1100°F) at a cycling rate of 40 Hz. Although these data are principally used to assess fatigue failure in components subjected to rapid stress cycling, it has been shown that they may be correlated with available low-cycle data if cyclic stress-strain curves are used for converting the high-cycle stresses to effective strains. Differences in initial stress-strain history and cycling rates for the high- and low-cycle data evaluated are found to be unimportant. For the thermally-aged material there is an initial enhancement of the high-cycle-fatigue strength but, after long aging times, the strength decreases to a value close to that for unaged material. The carbide precipitates formed during aging appear to influence fatigue life through changes they impart in the cyclic work-hardening rates.

Ratcheting Simulation of Z2CN18.10 Austenitic Stainless Steel under Pre-Strain Conditions

2016 ◽  
Vol 853 ◽  
pp. 112-116
Author(s):  
Yong Wang ◽  
You Gang Peng ◽  
Xu Chen
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Kinematic Hardening ◽  
Isotropic Hardening ◽  
Good Prediction ◽  
Strain Accumulation ◽  
Modified Model ◽  
Hardening Model ◽  
Ratcheting Strain ◽  
Independent Model

Uniaxial ratcheting behaviors of Z2CN18.10 austenitic stainless steel under both tensile pre-strain (TP) and compressive pre-strain (CP) were experimentally studied at room temperature. The experimental results show that: TP restrains ratcheting strain accumulation of subsequent cycling with positive mean stress; lower level of CP is found to accelerate ratcheting strain accumulation while higher level of CP retards the accumulation. Based on the Ohno-Wang II kinematic hardening rule, rate-independent model, viscoplastic model, isotropic hardening model and a modified model were constructed to describe the ratcheting behaviors under various pre-strain conditions. All the four models gave fairly good prediction on ratcheting strains for various TP. The isotropic hardening model and modified model predicted acceptable ratcheting strain though still showed slight tendency of over prediction.

A Simple Model for Stable Cyclic Stress-Strain Relationship of Type 304 Stainless Steel Under Nonproportional Loading

1999 ◽  
Vol 122 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Takamoto Itoh ◽  
Xu Chen ◽  
Toshimitsu Nakagawa ◽  
Masao Sakane
Keyword(s):  
Stainless Steel ◽  
Cyclic Stress ◽  
304 Stainless Steel ◽  
Surface Model ◽  
Stress Strain ◽  
Nonproportional Loading ◽  
Strain Relationship ◽  
Strain Paths ◽  
Type 304 ◽  
Type 304 Stainless Steel

This paper proposes a simple two-surface model for cyclic incremental plasticity based on combined Mroz and Ziegler kinematic hardening rules under nonproportional loading. The model has only seven material constants and a nonproportional factor which describes the degree of additional hardening. Cyclic loading experiments with fourteen strain paths were conducted using Type 304 stainless steel. The simulation has shown that the model was precise enough to calculate the stable cyclic stress-strain relationship under nonproportional loadings. [S0094-4289(00)00101-8]

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