Temperature Controlled Forming of 7075-T6 Aluminum Using Linearly Decaying Direct Electric Current

2016 ◽  
Author(s):  
Brandt J. Ruszkiewicz ◽  
Laine Mears
Keyword(s):  
Flow Stress ◽  
Fuel Efficiency ◽  
High Strength ◽  
Cold Forming ◽  
Direct Electric Current ◽  
Wave Forms ◽  
Continuous Current ◽  
Tension Testing ◽  
Material Forming ◽  
Sawtooth Waveform

The push in the automotive industry towards lightweighting to meet new stricter fuel efficiency standards has driven the need to research lightweight material forming. This requires research into forming high strength materials, as well as lower strength lightweight materials that may typically have poor formability characteristics. 7075-T6 aluminum suffers from limited elongation during tensile forming; electrically-assisted forming, which uses direct current to improve formability, is a viable candidate process to improve formability. In past electrical tension testing by various authors, two types of wave forms have been examined: continuous current and square waveforms. For tension it was shown that applying current using square waveforms was able to extend formability beyond what continuous current could produce, due to reducing the overheating in the necking region. This paper examines the effect of a non-decaying and linearly globally decaying saw tooth wave on the formability and flow stress of 7075-T6 aluminum in tension. It is shown that EAM using a sawtooth waveform can result in further elongation than cold forming, with similar elongation to previously-investigated square waves. An existing temperature model is adapted to the saw tooth waveform and used to calculate the change in material properties to find the flow stress using a theoretical strength equation.

Temperature-Controlled Forming of 7075-T6 Aluminum Using Linearly Decaying Direct Electric Current

2016 ◽  
Vol 138 (9) ◽  
Author(s):  
Brandt J. Ruszkiewicz ◽  
Laine Mears
Keyword(s):  
Flow Stress ◽  
Stress Model ◽  
Temperature Prediction ◽  
Direct Electric Current ◽  
Stress Effects ◽  
Electrically Assisted ◽  
Continuous Current ◽  
Tension Testing ◽  
Temperature Controlled ◽  
Flow Stress Model

7075-T6 aluminum suffers from limited elongation during tensile forming; electrically assisted forming (EAF), which uses direct current to improve formability, is a viable candidate process to improve this effect. In past electrical tension testing by various authors, two types of waveforms have been examined: continuous current and square waveforms. For tension, it was shown that the applying current using square waveforms was able to extend formability beyond what continuous current could do, due to reducing the overheating in the necking region. The goal of this paper is to model the temperature and flow stress effects of saw tooth waves by modifying an existing square wave temperature prediction model and combining it with a theoretical flow stress model. Nondecaying and linearly globally decaying saw tooth waveforms are used in an attempt to control the temperature of the necking zone to allow for increased strain at fracture. Comparisons between saw tooth waveforms and square waveforms are exhibited, and it is found that the saw tooth waveforms are inferior to square waves for increasing strain at fracture for 7075-T6.

Effect of Pulsed Electric Current on the Tensile Properties of DP Type Ultra-High Strength Steel Sheets

2013 ◽  
Vol 389 ◽  
pp. 284-288
Author(s):  
Jung Han Song ◽  
J. Lee ◽  
I. Hwang ◽  
Y.B. Kim ◽  
S. Choi ◽  
...  
Keyword(s):  
Flow Stress ◽  
Electric Current ◽  
High Strength Steel ◽  
Fuel Efficiency ◽  
High Strength ◽  
Test System ◽  
Steel Sheets ◽  
Ultra High Strength Steel ◽  
Pulsed Electric Current ◽  
Main Factors

Although ultra-high strength steel (UHSS) sheets with tensile stress above 1.0 GPa have a great attention in the automotive industries for reducing the weight and improving fuel efficiency of auto-body, the poor formability of UHSS sheets is one of the main factors hindering their industrial application. Enhancing the formability is a very important and challenging problem to both automotive and manufacturing engineers. In this study, the electro-plastic effect, which is first discovered in 1960s, of ultra-high strength steel sheets is investigated to improve the formability. To begin with, a test system is built up to carry out the tensile test with heavy electric current flowing through the specimen. The evolutions of the flow stress and the electric resistivity are obtained using this test system. The significant decrease in the flow stress caused by the heavy flowing through current is observed.

DOMEX 550MC

Alloy Digest ◽  
2009 ◽  
Vol 58 (3) ◽  
Keyword(s):  
Physical Properties ◽  
Hsla Steel ◽  
Steel Structures ◽  
High Strength ◽  
Heat Treating ◽  
Bend Strength ◽  
Cold Forming ◽  
Wide Range ◽  
Hot Rolled ◽  
Earthmoving Machines

Abstract Domex 550MC is a hot-rolled, high-strength low-alloy (HSLA) steel for cold forming operations. It is available in thicknesses of 2.00-12.80 mm. The alloy meets or exceeds the requirements of S550MC in EN 10149-2. Applications include a wide range of fabricated components and steel structures, including truck chassis, crane booms, and earthmoving machines. This datasheet provides information on composition, physical properties, tensile properties, and bend strength as well as fatigue. It also includes information on forming, heat treating, and joining. Filing Code: SA-594. Producer or source: SSAB Swedish Steel Inc.

Effect of Cold Machining Process on the Property and Microstructure of Ti-5Mo-5V-8Cr-3Al Strip

2014 ◽  
Vol 788 ◽  
pp. 134-137 ◽  
Author(s):  
Pei Tong Ni ◽  
Li Peng Zhou ◽  
Bao Liang Bai ◽  
Ming Chen Han ◽  
Mei Sheng Zhu
Keyword(s):  
Solution Treatment ◽  
Aging Treatment ◽  
High Strength ◽  
Machining Process ◽  
Beta Titanium Alloy ◽  
Cold Forming ◽  
Corrugated Shell ◽  
Beta Titanium ◽  
Gas Quenching ◽  
Metastable Beta

Metastable beta titanium alloy Ti-5Mo-5V-8Cr-3Al, with high-strength, favorite ductility and outstanding capacity of cold forming and welding, has been found the applications in sheet metal component, pressure vessel, corrugated shell and cold heading rivet at the temperature lower than 350°C. In the present paper, the effect of cold machining deformation rate and heat treatment process on the properties and microstructures of Ti-5Mo-5V-8Cr-3Al strip were investigated. The results revealed that excellent comprehensive mechanical properties could be achieved with the alloy by reasonable cold machining process and with solution treatment at 800°C followed by gas quenching. Upon a solution and aging treatment at 480°C, the alloy performed favorite plasticity and high ultimate tensile strength of 1250MPa.

scholarly journals Enhancement of Road Freight Vehicle Fuel Efficiency Using Lightweight Flat-Bed Trailers Made of High-Strength Steel Plates

2015 ◽  
Vol 22 (2) ◽  
pp. 65-82 ◽  
Author(s):  
Hong-Seung Roh ◽  
민연주 ◽  
장소영 ◽  
신승진 ◽  
YU, Byeong-Jae ◽  
...  
Keyword(s):  
High Strength Steel ◽  
Fuel Efficiency ◽  
High Strength ◽  
Steel Plates ◽  
Road Freight ◽  
Vehicle Fuel Efficiency

Laser Assisted Cold Bending of High Strength Steels

2014 ◽  
Author(s):  
Erica Liverani ◽  
Alessandro Ascari ◽  
Alessandro Fortunato ◽  
Adrian Lutey
Keyword(s):  
Heat Treatment ◽  
High Strength Steels ◽  
High Strength ◽  
Processing Parameters ◽  
Cold Forming ◽  
Steel Sheets ◽  
Phase Lead ◽  
Cold Bending ◽  
Bending Process ◽  
Definition Of

This paper presents the feasibility of an innovative application of laser-assisted bending process. The high strength steel sheets bending, carried out after a laser heat treatment, is studied. Several strategies aimed at obtaining a ductile structure along the bending line, suitable for cold forming, are investigated. The influence of laser processing parameters on the microstructure, hardness and strength of the sheets are discussed and analyzed. In order to predict the temperature and ensure the repeatability and reliability of the process, a model for heat treatment simulation is developed. The study of the experimental data and the integration with the simulation of the heating phase lead to the definition of specific process parameters suitable for achieving a crack-free cold bending of high strength steels.

Application of Deformation to Improve Hot Ductility in the Peritectic Steel

2005 ◽  
Vol 500-501 ◽  
pp. 203-210 ◽  
Author(s):  
Ahmad Rezaeian ◽  
Faramarz Zarandi ◽  
D.Q. Bai ◽  
Steve Yue
Keyword(s):  
Flow Stress ◽  
High Strength ◽  
Microalloyed Steels ◽  
Hot Strip Mill ◽  
Mean Flow ◽  
Hot Strip Rolling ◽  
Strip Rolling ◽  
Slip Ratio ◽  
Hot Strip ◽  
Mean Flow Stress

The hot strip rolling of advanced microalloyed high strength steels still represents a new task to many mills due to the lack of data on the hot deformation resistance. With the aid of processing data from the Ispat-Inland hot strip mill, the “measured mean flow stresses” are calculated from the mill force using the Sims analysis and taking into account roll flattening, slip ratio and the redundant strain. A modification of the Misaka mean flow stress equation is proposed for C – Mn – Si – Al steels microalloyed with up to 0.02 % Nb. The effects of alloying and microalloying are then estimated. A new fitting parameter shows excellent agreement with the mean flow stress data from industrial processing of advanced high strength microalloyed steels. However, during the second half of the rolling schedule (lower temperature region), indications of austeniteto- ferrite transformation were found.

A Review of Electrically-Assisted Manufacturing With Emphasis on Modeling and Understanding of the Electroplastic Effect

2017 ◽  
Vol 139 (11) ◽  
Author(s):  
Brandt J. Ruszkiewicz ◽  
Tyler Grimm ◽  
Ihab Ragai ◽  
Laine Mears ◽  
John T. Roth
Keyword(s):  
Fuel Economy ◽  
Elastic Recovery ◽  
Fuel Efficiency ◽  
High Strength ◽  
Carbon Steels ◽  
Metallic Materials ◽  
Low Carbon ◽  
Electroplastic Effect ◽  
Electrically Assisted ◽  
Electrically Assisted Manufacturing

Increasingly strict fuel efficiency standards have driven the aerospace and automotive industries to improve the fuel economy of their fleets. A key method for feasibly improving the fuel economy is by decreasing the weight, which requires the introduction of materials with high strength to weight ratios into airplane and vehicle designs. Many of these materials are not as formable or machinable as conventional low carbon steels, making production difficult when using traditional forming and machining strategies and capital. Electrical augmentation offers a potential solution to this dilemma through enhancing process capabilities and allowing for continued use of existing equipment. The use of electricity to aid in deformation of metallic materials is termed as electrically assisted manufacturing (EAM). The direct effect of electricity on the deformation of metallic materials is termed as electroplastic effect. This paper presents a summary of the current state-of-the-art in using electric current to augment existing manufacturing processes for processing of higher-strength materials. Advantages of this process include flow stress and forming force reduction, increased formability, decreased elastic recovery, fracture mode transformation from brittle to ductile, decreased overall process energy, and decreased cutting forces in machining. There is currently a lack of agreement as to the underlying mechanisms of the electroplastic effect. Therefore, this paper presents the four main existing theories and the experimental understanding of these theories, along with modeling approaches for understanding and predicting the electroplastic effect.

scholarly journals Process chain for the fabrication of hardenable aluminium-zirconium micro-components by deep drawing

2018 ◽  
Vol 190 ◽  
pp. 15013 ◽  
Author(s):  
Anastasiya Toenjes ◽  
Julien Kovac ◽  
Bernd Koehler ◽  
Axel von Hehl ◽  
Andreas Mehner ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Magnetron Sputtering ◽  
Deep Drawing ◽  
High Strength ◽  
Tensile Tests ◽  
Process Chain ◽  
Production Chain ◽  
Cold Forming ◽  
Industrial Sectors ◽  
Material State

Today, micro components are used in various industrial sectors such as electronics engineering and medical applications. The final quality of such parts depends on each individual step of the production chain from the manufacturing of semi-finished parts to the post-processing. In this study, magnetron sputtering is used to manufacture thin (15-30 μm) aluminium-zirconium alloy foils for the deep drawing of high strength and hardenable micro cups, which can be, for example, employed as micro valve caps. The development of a novel process chain for the production of these parts includes four different steps, beginning with the production of Al-Zr foils by magnetron sputtering. Secondly, tensile tests are performed with the foils in order to estimate their mechanical properties. Subsequently, micro deep drawing is used to produce the cup’s shape, and finally, a heat treatment in a drop-down tube furnace adjusts the cup’s hardness during fall. It is shown in particular that Al-Zr foils produced by magnetron sputtering have an attractive cold forming and hardening potential due to a microstructure consisting essentially of an oversaturated solid solution of zirconium in the aluminium matrix. This material state enables adequate formability and simplifies the heat treatment process since no solution annealing is required.

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