Development of a Testing Procedure to Determine the Bond Strength in Joining-by-Forming Processes

2014 ◽  
Vol 966-967 ◽  
pp. 481-488 ◽  
Author(s):  
Alexander Mikloweit ◽  
Markus Bambach ◽  
Michael Pietryga ◽  
Gerhard Hirt
Keyword(s):  
Bond Strength ◽  
Surface Condition ◽  
Pure Aluminum ◽  
Experimental Parameter ◽  
Normal Pressure ◽  
Testing Procedure ◽  
Process Conditions ◽  
Parameter Study ◽  
Forming Process ◽  
Joining By Forming

Roll bonding is a joining-by-forming process, in which two or more metals are permanently joined through pressure and plastic deformation, which causes the creation of a metallic bond. The bond formation is a complex process based on various process conditions in the joining zone, such as strain, normal pressure, temperature, strain rate, shear strain and surface condition. Since an individual variation and analysis of the influencing parameters is usually not possible during the rolling process, a specific experimental setup for the investigation of the joining mechanisms is necessary. In this paper, a testing procedure has been developed to determine the bond strength in joining-by-forming processes. The material combination chosen was AA2024/AA1050 as used in aircraft applications. AA2024 sheets are cladded with pure aluminum to improve the corrosion resistance. The performed experimental parameter study confirms the expected influencing factors and is used to determine parameters of a bonding model, which can be integrated in a finite element simulation.

scholarly journals Mechanical properties of rotary swaged steel components

2021 ◽  
Author(s):  
Dhia Charni ◽  
Svetlana Ortmann-Ishkina ◽  
Marius Herrmann ◽  
Christian Schenck ◽  
Jérémy Epp
Keyword(s):  
Mechanical Properties ◽  
Residual Stresses ◽  
Strain Curve ◽  
Dynamic Mechanical Properties ◽  
Process Conditions ◽  
Forming Process ◽  
Rotary Swaging ◽  
Surface Residual Stresses ◽  
Near Net Shape ◽  
As Stress

AbstractThe radial infeed rotary swaging is widely used as a diameter reduction forming process of axisymmetric workpieces, improving the mechanical properties with excellent near net shape forming. In the present study, rotary swaging experiments with different parameter setups were performed on steel tubes and bars under different material states and several resulting property modifications were investigated such as stress-strain curve, hardness, fatigue strength and surface residual stresses. The results show a significant work hardening induced by the rotary swaging process and an improvement in the static and dynamic mechanical properties was observed. Furthermore, the hardness distribution was homogenous in the cross section of the rotary swaged workpieces. Moreover, depending on the process conditions, different residual stresses distribution were generated along the surface.

Experimental Parameter Study on Synthesis Gas Production by Steam-Oxygen Fluidized Bed Gasification of Sewage Sludge

2021 ◽  
Vol 11 (2) ◽  
pp. 579
Author(s):  
Max Schmid ◽  
Selina Hafner ◽  
Günter Scheffknecht
Keyword(s):  
Sewage Sludge ◽  
Fluidized Bed ◽  
Experimental Parameter ◽  
Space Velocity ◽  
Phosphate Fertilizer ◽  
Gas Production ◽  
Raw Material ◽  
Parameter Study ◽  
Syngas Production ◽  
Fuels And Chemicals

The conversion of biogenic residues to fuels and chemicals via gasification and synthesis processes is a promising pathway to replace fossil carbon. In this study, the focus is set on sewage sludge gasification for syngas production. Experiments were carried out in a 20 kW fuel input bubbling fluidized bed facility with steam and oxygen as gasification agent. In-situ produced sewage sludge ash was used as bed material. The sensitivity of the key operation parameters gasifier temperature, oxygen ratio, steam to carbon ratio, and the space velocity on the syngas composition (H2, CO, CO2, CH4, CxHy, H2S, COS, NH3, and tars) was determined. The results show that the produced syngas has high H2 and CO concentrations of up to 0.37 m3 m−3 and 0.18 m3 m−3, respectively, and is thus suitable for synthesis of fuels and chemicals. By adjusting the steam to carbon ratio, the syngas’ H2 to CO ratio can be purposely tailored by the water gas shift reaction for various synthesis products, e.g., synthetic natural gas (H2/CO = 3) or Fischer–Tropsch products (H2/CO = 2). Also, the composition and yields of fly ash and bed ash are presented. Through the gasification process, the cadmium and mercury contents of the bed ash were drastically reduced. The ash is suitable as secondary raw material for phosphorous or phosphate fertilizer production. Overall, a broad database was generated that can be used for process simulation and process design.

Joining by forming of metal–polymer sandwich composite panels

2018 ◽  
Vol 233 (10) ◽  
pp. 2089-2098 ◽  
Author(s):  
João PM Pragana ◽  
Tomás RM Contreiras ◽  
Ivo MF Bragança ◽  
Carlos MA Silva ◽  
Luis M Alves ◽  
...  
Keyword(s):  
Adhesive Bonding ◽  
Sandwich Composite ◽  
Composite Panels ◽  
Forming Process ◽  
Joining By Forming ◽  
Bulk Forming ◽  
New Concepts ◽  
Mechanical Fastening ◽  
Mortise And Tenon ◽  
Metal Polymer

This article presents new joining-by-forming processes to assemble longitudinally two metal–polymer sandwich composite panels perpendicular to one another. Process design draws from an earlier development of the authors for metal sheets to new concepts based on the combination of sheet-bulk forming with mortise-and-tenon joints. Selected examples obtained from experimentation and finite element modelling give support to the presentation. A new three-stage joining by the forming process is capable of producing mechanically locked joints with larger and stiffer flat-shaped heads than those fabricated by alternative single- or two-stage solutions. Failure in the new three-stage joining by the forming process is found to take place by cracking instead of disassembling after unbending the flat-shaped head of the joint back to its original shape. The required forming forces to produce the new metal–polymer joints are below 15 kN, allowing them to be an effective, easy-to-implement alternative to existing solutions based on adhesive bonding, welding and mechanical fastening.

Numerical Investigation of Size Effect on Dry Friction Behavior in Micro Upsetting Process

2014 ◽  
Vol 997 ◽  
pp. 321-324
Author(s):  
Wei Zheng ◽  
Guang Chun Wang ◽  
Bing Tao Tang ◽  
Xiao Juan Lin ◽  
Yan Zhi Sun
Keyword(s):  
Friction Coefficient ◽  
Size Effect ◽  
Dry Friction ◽  
Normal Pressure ◽  
Friction Model ◽  
Strain Hardening Exponent ◽  
Forming Process ◽  
Friction Behavior ◽  
Initial Yield Stress ◽  
Coulomb’S Friction

After modifying the Wahime/Bay friction model, a new friction model suitable for micro-forming process without lubrication is established. In this model, it is shows that the friction coefficient is a function of strain hardening exponent, the normal pressure and the initial yield stress of material. Based on the experimental data, the micro-upsetting process is simulated using the proposed friction model. The simulation results are used to investigate the size effect on the dry friction behavior. It is found that the Coulomb’s friction coefficient is dropping with miniaturization of specimens when the amount of reduction is not too large.

Surface Topography Influences on the Fatigue Behavior of Composite Joints

2019 ◽  
Vol 809 ◽  
pp. 341-346 ◽  
Author(s):  
Torsten Thäsler ◽  
Jens Holtmannspötter ◽  
Hans Joachim Gudladt
Keyword(s):  
Bond Strength ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Surface Condition ◽  
Atmospheric Pressure Plasma ◽  
Fatigue Tests ◽  
Stress Concentrations ◽  
Release Agent ◽  
Structured Surfaces ◽  
Lap Shear

The surface condition of carbon fibre reinforced plastic (CFRP) substrates is decisive to obtain high bond strength and lifetime of adhesively bonded parts. Those surfaces were adjusted in terms of their microscopic topography by means of peel plies and release foils. The subsequent surface treatment via atmospheric pressure plasma jet or vacuum blasting allowed the modification of the microscopic roughness as well as the surface chemistry. Those configuration were assessed using surface analytic methods as well as quasi-static and cyclic fracture tests on single lap shear specimens. The microscopic surface roughness, if at all, only showed a small influence on the bond strength. Despite release agent residues, fracture was found within the fiber-matrix interface, which caused difficulties in evaluating the effect of surface pretreatments on the adhesion strength. Fatigue tests revealed a lifetime reduction of uneven microscopic rough surfaces, which was assigned to stress concentrations at the tip of asperities. The crack propagation was accelerated in case of release agent residues. If surfaces were free of contaminations, no differences between microscopically smooth and slightly structured surfaces were found. Overall, fatigue testing on single lap shear specimens showed an increased sensitivity with regard to the assessment of surface morphology.

Investigation on Friction Coefficient Considering Al-Si Coating Layer Fracture of Boron Sheets in Hot and Cold Deep Drawing

2020 ◽  
Vol 846 ◽  
pp. 117-121
Author(s):  
Min Sik Lee ◽  
Jun Park ◽  
J.S.Suresh Babu ◽  
Chung Gil Kang
Keyword(s):  
Friction Coefficient ◽  
Deep Drawing ◽  
Deformation Behavior ◽  
Coating Layer ◽  
Surface Condition ◽  
Forming Limit ◽  
Boron Steel ◽  
Drawing Process ◽  
Forming Process ◽  
Deep Drawing Process

In this paper, hot and cold deep drawing processes are determined with direct deep drawing process and indirect deep drawing process. To predict the friction coefficient, the finite-element method, which can predict deformation behavior until the fracture of a blank sheet, was proposed using the forming limit diagram (FLD) curve. The effect of fracturing of the coating layer on the friction coefficient during the hot and cold deep drawing processes was investigated. The deformation behavior of the coating layer of the boron steel sheet that affects the friction coefficient in the hot and cold deep drawing processes was also proposed. A forming method that can control the surface condition of the formed product is further proposed by explaining the fracture of the coating due to the forming process.

Boss Forming, An Environment-Friendly Rotary Forming

2007 ◽  
Vol 344 ◽  
pp. 947-953 ◽  
Author(s):  
K. Kawai ◽  
H. Koyama ◽  
T. Kamei ◽  
W. Kim
Keyword(s):  
Experimental Study ◽  
Circular Plate ◽  
Working Conditions ◽  
Room Temperature ◽  
Pure Aluminum ◽  
Metal Flow ◽  
Forming Process ◽  
Environment Friendly ◽  
Commercially Pure ◽  
Technological Possibility

Boss forming, which is sometimes called hub forming, has attracted its attention as an environment-friendly rotary forming process to form a circular plate with a hole into a boss shape. An experimental study was conducted to survey the technological possibility of boss forming. Boss forming of A1050-O commercially pure aluminum plate of 10 mm thickness was carried out at room temperature under various working conditions. The effects of the working conditions on the metal flow in boss forming were clarified experimentally.

Flow Stress Experimental Determination for Warm-Forming Process

2011 ◽  
Author(s):  
Ting Fai Kong ◽  
Luen Chow Chan ◽  
Tai Chiu Lee
Keyword(s):  
Stainless Steel ◽  
Flow Stress ◽  
Room Temperature ◽  
Warm Forming ◽  
Recrystallization Temperature ◽  
Process Conditions ◽  
Compression Tests ◽  
Forming Process ◽  
Forming Temperature ◽  
Flow Stress Data

Warm forming is a manufacturing process in which a workpiece is formed into a desired shape at a temperature range between room temperature and material recrystallization temperature. Flow stress is expressed as a function of the strain, strain rate, and temperature. Based on such information, engineers can predict deformation behavior of material in the process. The majority of existing studies on flow stress mainly focus on the deformation and microstructure of alloys at temperature higher than their recrystallization temperatures or at room temperature. Not much works have been presented on flow stress at warm-forming temperatures. This study aimed to determine the flow stress of stainless steel AISI 316L and titanium TA2 using specially modified equipment. Comparing with the conventional method, the equipment developed for uniaxial compression tests has be verified to be an economical and feasible solution to accurately obtain flow stress data at warm-forming temperatures. With average strain rates of 0.01, 0.1, and 1 /s, the stainless steel was tested at degree 600, 650, 700, 750, and 800 °C and the titanium was tested at 500, 550, 600, 650, and 700 °C. Both materials softened at increasing temperatures. The overall flow stress of stainless steel was approximately 40 % more sensitive to the temperature compared to that of titanium. In order to increase the efficiency of forming process, it was suggested that the stainless steel should be formed at a higher warm-forming temperature, i.e. 800 °C. These findings are a practical reference that enables the industry to evaluate various process conditions in warm-forming without going through expensive and time consuming tests.

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