Development of anisotropy and strain hardening in damaged stamped parts made of IF steel

Schmidová, Eva; Klejch, Filip; M.R, Sunilkumar

doi:10.1016/j.engfailanal.2022.107015

Cited by 7 publications

(5 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Maximum thickness reduction leading to the failure was found to be more than 60% compared to the initial thickness of the sheet. According to Schmidová et al, (2023), the limiting thickness reduction leading to plasticity degradation was found to be over 28%. The state in the figure shows the stage slightly over this critical value, steep thickness distribution is visible from the gradient.…”

Section: Resultsmentioning

confidence: 99%

“…This was studied by Ghosh (1977), who demonstrated the critical influence of strain hardening on sheet metal forming under uniaxial and biaxial deformation. The localization leads to microstructure deformation, where in the critical state, the interaction of dislocations leading to the formation of subgrains with low-angle boundaries occurs (Schmidová et al, 2023). The effect of localization and its influence on further deformation is also dependent on the geometry of the part.…”

Section: Discussionmentioning

confidence: 99%

“…All these inputs must be correctly set and controlled for the given material so that the resulting stamped parts get the required quality. However, even with an apparently correctly set stamping process and its inputs, sometimes undesirable phenomenon in the form of unacceptable local thinning or crack occurs (Schmidová et al, 2023). The reason may be the part's complex shape leading to a complicated stress-strain state in combination with the effect of different friction in contact of the stamping tool and the coating.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Limit State of Bake Hardened Stamped Interstitial-free Steel Automotive Parts Caused by Local Thickness Reduction

Klejch,

Schmidová

2024

Period. Polytech. Transp. Eng.

View full text Add to dashboard Cite

Current trends in the complex shapes of modern automobiles lead to the need for extremely formable materials for deep drawing applications. In general Interstitial–Free (IF) steels present the solution for this purpose. In addition, the cold stamping process is influenced by a variety of input factors that must be correctly adjusted. An imperfection in one of the inputs may cause stamping defects even with deep drawing materials. Limit states may then appear in the form of cracks or unacceptable thinning in the critically stressed areas of the stamped parts. For this reason, a general focus is placed on the use of non-destructive methods and inspection of stamped parts after stamping for potential subsequent modification of the stamping process. The presented work deals with the material analyses of stamped parts made of Bake-Hardened Interstitial-Free steel, including the local thickness reduction of the material, leading to the occurrence of crack propagation. The focus of the work was placed on the critical influencing factors resulting from the limit states presented. The evaluation of the material flow and the local plastic response was carried out using a cylindrical indentation method. In addition, the SEM analyses showed the importance of the deformation capacity of the surface coating which proved to be one of the decisive parameters for the occurrence of limit states.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Limit State of Bake Hardened Stamped Interstitial-free Steel Automotive Parts Caused by Local Thickness Reduction

Klejch,

Schmidová

2024

Period. Polytech. Transp. Eng.

View full text Add to dashboard Cite

show abstract

“…The coiling temperatures were set at 480 °C and 520 °C, and the coiling time was 1 h. After the end of coiling, it was cooled to ambient temperature with the furnace. Rolled plate due to preferred orientation, resulting in the anisotropy of its macroscopic mechanical properties, mainly manifested in the anisotropy of strengthening and yielding [15,16]. Anisotropy dramatically affects the distribution of stress and strain in the plate deformation process, the thickness of the thinning, and the formability of the plate.…”

Section: Methodsmentioning

confidence: 99%

Effect of Coiling Temperature on Microstructure and Properties of Ferritic-Bainitic Dual-Phase Steels

Li,

Zhou,

Liu

et al. 2024

Metals

View full text Add to dashboard Cite

In this study, a 780 MPa grade ferritic-bainitic dual-phase steel with excellent matching of strength-plasticity and formability was developed using thermomechanical control processing. Optical microscopy, Scanning electron microscopy, and Electron Backscatter Diffraction techniques were used to characterize the microstructure comprehensively, and the effects of coiling temperature on the microstructure, the strength-plasticity, and hole-expansion ratio of the test steels were thoroughly investigated. The results showed that the test steel had an excellent combination of ferrite and bainite at the coiling temperature of 520 °C, 23.7 and 76.3%, respectively, with a hole expansion ratio of 58.5 ± 2.8%. The uniformity of the microstructure was the key to obtaining a high expansion ratio in ferrite-bainite dual-phase steels. The test steels formed granular bainite at low-temperature coiling, while polygonal ferrite was promoted at high-temperature coiling. The effect of coiling temperature on grain size is small. Dislocations were redistributed during high-temperature coiling, resulting in a decrease in dislocation density. The higher elongation and hole expansion rate at higher coiling temperatures were attributed to increased polygonal ferrite content, reduced grain size, and enhanced TRIP effect. When coiling at low temperatures, the agglomeration of polygonal ferrite or granular bainite tends to result in a non-uniform distribution of the soft and hard phases of the matrix. At the same time, the strong texture parallel to the rolling direction has a significant difference in plasticity in different directions, leading to non-uniform deformation, which is liable to stress concentration, causing crack nucleation and extension in the hole expanding process, thus reducing the hole expansion performance.

show abstract

“…The potential imperfections can be divided into two main types: geometric imperfections and material imperfections. The former mainly includes out-of-roundness [54] and thickness deviation [55], while the latter mainly includes material anisotropy [56] and residual stress [57,58]. These two sets of factors interact with each other.…”

Section: Geometric Parameter Measurementsmentioning

confidence: 99%

Failure Behavior of Corrugated Pressure Cylindrical Shells with Variable Wall Thickness under Uniform External Pressure

Sun,

Zhang,

Zhang

et al. 2024

JMSE

View full text Add to dashboard Cite

The main load-bearing structure of submarines is the pressure shell. Shell failures are usually caused by high hydrostatic pressure and its own potential geometric imperfections. This paper proposes a cylindrical shell with a strong corrugated stiffening structure. Two theoretically geometrically identical shells are fabricated using CNC machining to ensure the reproducibility and reasonableness of the results. Firstly, the point cloud data of all the geometric parameters of the corrugated pressure cylindrical shells were obtained using a 3D scanner. Geomagic Control X 3D inspection software was used to determine the geometric deviations of the shells. Geometric reconstruction was performed using Geomagic Design X reverse modeling software to capture potential imperfections of the shells. The aluminum shells were then welded and placed in the pressure chamber. Failure loads were obtained for all shells by constant water injection and pressurization. Considering the confined nature of the pressure chamber, a nonlinear finite element analysis of the corrugated pressure cylindrical shell was carried out using Abaqus/Riks, taking into account actual fabrication imperfections. Finally, the failure behavior of the shells under uniform external pressure was determined. The results show that both corrugated pressure cylindrical shells have high machining accuracy. The numerical simulation results of the critical buckling load of the corrugated pressure cylindrical shells were in good agreement with the test results. The corrugated structure has additional advantages in retarding the generation and expansion of shell surface defects. The equilibrium path of the corrugated pressure cylindrical shell can be maintained in a smooth and continuous state, showing stable buckling behavior. This study will provide new inspiration for the structural design and failure prediction of the submarine pressure shell.

show abstract

Development of anisotropy and strain hardening in damaged stamped parts made of IF steel

Cited by 7 publications

References 30 publications

Limit State of Bake Hardened Stamped Interstitial-free Steel Automotive Parts Caused by Local Thickness Reduction

Limit State of Bake Hardened Stamped Interstitial-free Steel Automotive Parts Caused by Local Thickness Reduction

Effect of Coiling Temperature on Microstructure and Properties of Ferritic-Bainitic Dual-Phase Steels

Failure Behavior of Corrugated Pressure Cylindrical Shells with Variable Wall Thickness under Uniform External Pressure

Contact Info

Product

Resources

About