scholarly journals Automatic Multi-Stage Cold Forging of an SUS304 Ball-Stud with a Hexagonal Hole at One End

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5300
Author(s):  
Jong Bok Byun ◽  
Mohd Kaswandee Razali ◽  
Chang Ju Lee ◽  
Il Dong Seo ◽  
Wan Jin Chung ◽  
...  
Keyword(s):  
Flow Stress ◽  
Room Temperature ◽  
Cold Forging ◽  
Material Strength ◽  
Element Analysis ◽  
Multi Stage ◽  
Plastic Deformation Behavior ◽  
Die Stress ◽  
Hexagonal Hole ◽  
Good Strain

SUS304 stainless steel is characterized by combined tensile and compression testing, with an emphasis on flow stress at higher strain and temperature. The plastic deformation behavior of SUS304 from room temperature to 400 °C is examined and a general approach is used to express flow stress as a closed-form function of strain, strain rate, and temperature; this is optimal when the strain is high, especially during automatic multi-stage cold forging. The fitted flow stress is subjected to elastothermoviscoplastic finite element analysis (FEA) of an automatic multi-stage cold forging process for an SUS304 ball-stud. The importance of the thermal effect during cold forging, in terms of high material strength and good strain-hardening, is revealed by comparing the forming load, die wear and die stress predictions of non-isothermal and isothermal FEAs. The experiments have shown that the predictions of isothermal FEA are not feasible because of the high predicted effective stress on the weakest part of the die.

scholarly journals Multi-Stage Cold Forging Process for Manufacturing a High-Strength One-Body Input Shaft

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 532
Author(s):  
A Jo ◽  
Myeong Jeong ◽  
Sang Lee ◽  
Young Moon ◽  
Sun Hwang
Keyword(s):  
High Strength ◽  
Microstructural Characterization ◽  
Fatigue Tests ◽  
Machining Process ◽  
Cold Forging ◽  
Element Analysis ◽  
Forging Process ◽  
Input Shaft ◽  
Multi Stage ◽  
The One

A multi-stage cold forging process was developed and complemented with finite element analysis (FEA) to manufacture a high-strength one-body input shaft with a long length body and no separate parts. FEA showed that the one-body input shaft was manufactured without any defects or fractures. Experiments, such as tensile, hardness, torsion, and fatigue tests, and microstructural characterization, were performed to compare the properties of the input shaft produced by the proposed method with those produced using the machining process. The ultimate tensile strength showed a 50% increase and the torque showed a 100 Nm increase, confirming that the input shaft manufactured using the proposed process is superior to that processed using the machining process. Thus, this study provides a proof-of-concept for the design and development of a multi-stage cold forging process to manufacture a one-body input shaft with improved mechanical properties and material recovery rate.

scholarly journals Generalized optimizations of two-stage forging of micro/meso copper fastener

2018 ◽  
Vol 185 ◽  
pp. 00002
Author(s):  
Shih-Hsien Lin ◽  
Un-Chin Chai ◽  
Gow-Yi Tzou ◽  
Dyi-Cheng Chen
Keyword(s):  
Simulation Analysis ◽  
Effective Strain ◽  
Cold Forging ◽  
Two Stage ◽  
Forming Simulation ◽  
Multi Stage ◽  
Element Simulation ◽  
Die Stress ◽  
Stress Optimization ◽  
Forging Force

Three are generalized simulation optimizations considering the forging force, the die stress, and the dual-goals in two-stage forging of micro/meso copper fastener. Constant shear friction between the dies and workpiece is assumed to perform multi-stage cold forging forming simulation analysis, and the Taguchi method with the finite element simulation has been used for mold-and-dies parameters design simulation optimizations considering the forging force, die stress, and dual-goals. The die stress optimization is used to explore the effects on effective stress, effective strain, velocity field, die stress, forging force, and shape of product. The influence rank to forging process of micro/meso copper fastener for three optimizations can be determined, and the optimal parameters assembly consider die stress can be obtained in this study. It is noted that the punch design innovation can reduce the forging force and die stress.

Fully Coupled Finite Element Analysis of an Automatic Multi-Stage Cold Forging Process

2020 ◽  
Vol 311 ◽  
pp. 88-93
Author(s):  
Jong Bok Byun ◽  
Hyun Joon Lee ◽  
Jong Bok Park ◽  
Il Dong Seo ◽  
Man Soo Joun
Keyword(s):  
High Strength ◽  
Material Model ◽  
Die Design ◽  
Cold Forging ◽  
Complete Analysis ◽  
Analysis Model ◽  
Element Analysis ◽  
Forging Process ◽  
Multi Stage ◽  
Analysis Scheme

In this paper, non-isothermal analysis of an automatic multi-stage cold forging process of a ball-stud is conducted using a new material model which is a closed form function of strain, temperature and strain rate covering low and warm temperatures for high-strength stainless steel SUS304. An assembled die structural analysis scheme is employed for revealing the detailed die stresses, which is of great importance for process and die design for metal forming of the materials with high strengths. Die elastic deformation is dealt with to predict final geometries of material with higher accuracy. A complete analysis model is proposed to be used for optimal design of process and die designs in automatic multi-stage cold forging of high-strength materials.

Finite Element Prediction of Temperature Variation of Material and Dies in Aluminum Forging

2020 ◽  
Vol 830 ◽  
pp. 93-100
Author(s):  
Jae Dong Yoo ◽  
Tae Min Hwang ◽  
Man Soo Joun
Keyword(s):  
Aluminum Alloy ◽  
Temperature Rise ◽  
High Speed ◽  
Room Temperature ◽  
High Strain ◽  
Cold Forging ◽  
Multi Stage ◽  
Aluminum Forging ◽  
The Right ◽  
Finite Element Prediction

Investigation into behaviors of aluminum alloy to be metal formed at the room temperature is conducted in this study. An index is used to evaluate the sensitivity of temperature, that is, index of relative normalized temperature rise to steel called normalized temperature rise index per steel which helps researchers to obtain some insight on new materials based on experiences of steel forging. An investigation to an aluminum alloy shows that the index is quite high, implying that temperature effect as well as rate-dependence effect on the forming processes of aluminum alloy at the room temperature cannot be neglected. Some details of thermomechanical predictions of a relatively high-speed automatic multi-stage forging process of a yoke with highly deformed region are given to reveal the importance of temperature and/or strain rate even in cold forging of aluminum alloy parts with high speed and high strain. All manuscripts must be in English, also the table and figure texts, otherwise we cannot publish your paper. Please keep a second copy of your manuscript in your office. When receiving the paper, we assume that the corresponding authors grant us the copyright to use the paper for the book or journal in question. Should authors use tables or figures from other Publications, they must ask the corresponding publishers to grant them the right to publish this material in their paper. Use italic for emphasizing a word or phrase. Do not use boldface typing or capital letters except for section headings (cf. remarks on section headings, below).

Plastic Deformation Behavior of Micro-Alloyed Cold Forging Steel

2007 ◽  
Vol 26-28 ◽  
pp. 61-64
Author(s):  
Yong Nam Kwon ◽  
Young Seon Lee ◽  
Jung Hwan Lee
Keyword(s):  
Plastic Deformation ◽  
Work Hardening ◽  
Cold Working ◽  
Cold Forging ◽  
Element Analysis ◽  
Die Life ◽  
Heat Treated ◽  
Plastic Deformation Behavior ◽  
Save Energy ◽  
Life Predictions

Micro-alloyed cold forging steel has been developed to rule out heat treatment process before forging in order to save energy consumption. These non heat-treated cold forging steels utilize the work hardening during cold working to ensure the mechanical properties. In other words, the required strength of forged part is achieved by work hardening with the accumulation of plastic strain during the cold working. Therefore, the plastic deformation characteristics should be carefully understood for successful process design. Evolution of both microstructure and plastic characteristics of micro-alloyed cold forging steel has been investigated in the present study. For the optimization of forging processes, finite element analysis and die life predictions were carried out.

Analysis of Cold Preforming Process for Hollow Fasteners with Thin Flange

2013 ◽  
Vol 418 ◽  
pp. 246-249
Author(s):  
Ting Ping Chang ◽  
Shyh Chour Huang ◽  
Te Fu Huang ◽  
Thanh Phong Dao
Keyword(s):  
Finite Element Analysis ◽  
Deformation Behavior ◽  
Cold Forging ◽  
Forming Process ◽  
Element Analysis ◽  
Forging Process ◽  
Plastic Deformation Behavior ◽  
The Finite Element Analysis ◽  
Simulation Results ◽  
Future Work

This paper aims to study and detect the imperfects of the hollow fasteners with thin flange during cold forging process. In this study, the finite element analysis (FEA) based on 3-D DEFORMTM software to investigate the plastic deformation behavior of the hollow fasteners with thin flange. The simulation results showed that there is a folding phenomenon, which is occurring in the forming process. As a result, it revealed that with using FEA, the imperfects of forming hollow fasteners with the thin flange can be correctly predicted. From that, the occurrence of defects can be effectively prevented in the actual fabricating process. Future work will include an investigation into the optimization of the mold geometric parameters during cold pre-forming process for hollow fasteners with thin flange by comparing the simulative and experimental results.

Testing Extrusion Flow Stress and Friction Factor via Inverse Analysis

2011 ◽  
Vol 381 ◽  
pp. 128-134
Author(s):  
Xin Ping Dai ◽  
Yun Ni
Keyword(s):  
Finite Element ◽  
Flow Stress ◽  
Friction Factor ◽  
Inverse Analysis ◽  
Accurate Determination ◽  
Material Strength ◽  
Strain Hardening Exponent ◽  
Element Analysis ◽  
Pure Lead ◽  
Simulation And Experiment

Accurate determination of flow stress and friction factor is the guarantee of accuracy for finite element analysis of metal extrusion. Firstly, flow stress equation parameters for materials test were initially decided in order to perform finite element analogy. Then, the simulation values and experiment values were compared and the iterative optimization algorithm was used to amend the parameters. The objective was that value error of simulation and experiment values was controlled within tolerance. Finally, accurate flow stress and friction factor were determined. In rod-rod composite extrusion experiment of pure lead,it is determined by inverse analysis that the material strength coefficient is 11.9, strain hardening exponent is 0.127,and friction factor is 0.18. The comparison of the load-stroke curve between simulation and experiment and pure lead upsetting test contribute to confirm that the measured data is accurate. The results show that inverse analysis is a precise, simple and practical method for measuring flow stress and friction factor.

Dislocation structures around SiO2 Particles in aged Cu-Cr-SiO2

1978 ◽  
Vol 36 (1) ◽  
pp. 594-595
Author(s):  
N.J. Long ◽  
M.H. Loretto ◽  
C.H. Lloyd
Keyword(s):  
Flow Stress ◽  
Single Crystals ◽  
Room Temperature ◽  
Thin Foil ◽  
Age Hardening ◽  
Dispersion Strengthening ◽  
Accurate Picture ◽  
The Matrix ◽  
Very High ◽  
Good Agreement

IntroductionThere have been several t.e.m. studies (1,2,3,4) of the dislocation arrangements in the matrix and around the particles in dispersion strengthened single crystals deformed in single slip. Good agreement has been obtained in general between the observed structures and the various theories for the flow stress and work hardening of this class of alloy. There has been though some difficulty in obtaining an accurate picture of these arrangements in the case when the obstacles are large (of the order of several 1000's Å). This is due to both the physical loss of dislocations from the thin foil in its preparation and to rearrangement of the structure on unloading and standing at room temperature under the influence of the very high localised stresses in the vicinity of the particles (2,3).This contribution presents part of a study of the Cu-Cr-SiO2 system where age hardening from the Cu-Cr and dispersion strengthening from Cu-Sio2 is combined.

scholarly journals A numerical approach for the modelling of forming limits in hot incremental forming of AZ31 magnesium alloy

2021 ◽  
Author(s):  
Davide Campanella ◽  
Gianluca Buffa ◽  
Ernesto Lo Valvo ◽  
Livan Fratini
Keyword(s):  
Room Temperature ◽  
Incremental Forming ◽  
Material Model ◽  
Numerical Approach ◽  
Forming Limit ◽  
Material Strength ◽  
Wall Angle ◽  
Analytical Expression ◽  
The Poor ◽  
Specific Material

AbstractMagnesium alloys, because of their good specific material strength, can be considered attractive by different industry fields, as the aerospace and the automotive one. However, their use is limited by the poor formability at room temperature. In this research, a numerical approach is proposed in order to determine an analytical expression of material formability in hot incremental forming processes. The numerical model was developed using the commercial software ABAQUS/Explicit. The Johnson-Cook material model was used, and the model was validated through experimental measurements carried out using the ARAMIS system. Different geometries were considered with temperature varying in a range of 25–400 °C and wall angle in a range of 35–60°. An analytical expression of the fracture forming limit, as a function of temperature, was established and finally tested with a different geometry in order to assess the validity.

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