Room Temperature Forming of AA7075 Aluminum Alloys: W-Temper Process

2015 ◽  
Vol 651-653 ◽  
pp. 199-204 ◽  
Author(s):  
Eneko Sáenz de Argandoña ◽  
Lander Galdos ◽  
Rafael Ortubay ◽  
Joseba Mendiguren ◽  
Xabier Agirretxe
Keyword(s):  
Aluminum Alloys ◽  
Room Temperature ◽  
Hot Stamping ◽  
Dimensional Accuracy ◽  
Industrial Condition ◽  
High Strength ◽  
Industrial Applications ◽  
Hot Forming ◽  
High Yield ◽  
Industrial Designers

As important light-weight structure material, aluminum alloys have been widely used in automotive and aerospace industries. In the last years, the manufacturing of parts with high strength and good dimensional accuracy has become the main objective in industrial applications. Within the available aluminum alloys, the 7xxx series has attract the interest of the industrial designers due to the high yield strength and ultimate tensile strength they present. However, the formability of these alloys in as-received industrial condition is very poor at room temperature and various studies are being carried out to develop efficient warm and hot forming processes to form them industrially using heated tools. In the present paper, the W-Temper forming is studied as an alternative to the warm and hot forming processes. Heat treatment temperatures and critical times are presented and an industrial B-Pillar is formed to validate the new process. In the last chapter, the final mechanical properties of the part are reported, before and after a virtual e-coat process where the W-Temper forming is compared with a hot stamping process.

Effect of Heating Parameters on the Part’s Properties in Hot Stamping Process

2012 ◽  
Vol 557-559 ◽  
pp. 2417-2422
Author(s):  
Rui Ge ◽  
An Long ◽  
Yin Chen
Keyword(s):  
Hot Stamping ◽  
High Strength Steels ◽  
Dimensional Accuracy ◽  
High Strength ◽  
Hardness Measurement ◽  
Material Behavior ◽  
Hot Forming ◽  
Accuracy Test ◽  
Stamping Process ◽  
Proper Design

In the automotive industry, the hot forming of high strength steels offers the possibility to obtain significant reduction of weight without affecting the structural performances of final products. Compared with conventional sheet metal forming, the proper design of hot stamping process chain requires the deep knowledge of both interface phenomena and material behavior at high temperatures in order to obtain the desired properties of final products in terms of microstructure and strength characteristics. The work presented in this paper aims at accurately evaluate the effect of heating parameters on the properties of final sheet components produced in hot forming operations. Different from that in the lab, all the samples and parts used for the experimental test were produced in the production line, which can objectively show the manufacturing properties and microstructure character of products in mass. Microstructure evaluation, hardness measurement and dimensional accuracy test after hot stamping were performed and considered. The best heating parameters for the researched hot stamping B-Pillar’s production were obtained through the above research.

Investigation of the High Strength Steel Al-Si Coating during Hot Stamping Operations

2009 ◽  
Vol 410-411 ◽  
pp. 289-296 ◽  
Author(s):  
Francesca Borsetto ◽  
Andrea Ghiotti ◽  
Stefania Bruschi
Keyword(s):  
Surface Roughness ◽  
Cooling Rate ◽  
High Strength Steel ◽  
Room Temperature ◽  
Heating Temperature ◽  
Hot Stamping ◽  
High Strength ◽  
Tribological Behaviour ◽  
Metal Sheets ◽  
Coating Characteristics

To improve the low formability that HSS sheets exhibit at room temperature, innovative forming technologies like the hot stamping process are currently applied. In order to avoid scaling and decarburization during the heating step, metal sheets coated with a specially developed Al-Si coating are utilized. In the present work the coating characteristics in terms of morphology, surface roughness and tribological behaviour are investigated as function of heating temperature, holding time and cooling rate that are typical of hot stamping processes.

High Temperature Heat Transfer During Hot Forming Die Quenching of Boron Steel

2013 ◽  
Author(s):  
Etienne Caron ◽  
Kyle J. Daun ◽  
Mary A. Wells
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Cooling Rate ◽  
Hot Stamping ◽  
High Strength ◽  
Hot Forming ◽  
Boron Steel ◽  
Steel Blank ◽  
Die Quenching

Distributed mechanical properties can be obtained in ultra high strength steel parts formed via hot forming die quenching (HFDQ) by controlling the cooling rate and microstructure evolution during the quenching step. HFDQ experiments with variable cooling rates were conducted by quenching Usibor® 1500P boron steel blanks between dies pre-heated up to 600°C. The heat transfer coefficient (HTC) at the blank / die interface, which is used to determine the blank cooling rate, was evaluated via inverse heat conduction analysis. The HTC was found to increase with die temperature and stamping pressure. This heat transfer coefficient increase was attributed to macroscopic flattening of the boron steel blank as well as microscopic deformation of surface roughness peaks. At the end of the hot stamping process, the HTC reached a pressure-dependent steady-state value between 4320 and 7860 W/m2·K when the blank and die temperatures equalize.

Investigation of the Wear Behavior for Not Alloyed and Alloyed Hot Forming Tools

2016 ◽  
Vol 1140 ◽  
pp. 99-106
Author(s):  
Franziska Neubauer ◽  
Konstantin Hofmann ◽  
Kolja Andreas ◽  
Marion Merklein
Keyword(s):  
Wear Behavior ◽  
Hot Stamping ◽  
Base Material ◽  
High Strength ◽  
Hot Forming ◽  
Control Group ◽  
Laser Alloying ◽  
Shape Accuracy ◽  
Structural Parts ◽  
Forming Tools

Over the last few years, hot stamping has been established as a suitable manufacturing process to produce high-strength structural parts. A tensile strength up to 1500 MPa and a high shape accuracy of the hot stamping parts are achievable. The hot forming tools are thereby stressed by varying thermo-mechanical loads resulting in increased surface wear. In order to reduce expensive and time consuming rework of the forming tools, an analysis of the tribological conditions is required. Purpose of this work is to increase the wear resistance of the tool surface and to investigate the wear behavior. In this regard, a laser alloying process is developed to influence the properties of the base material. Firstly, the alloying elements are selected and the element concentration is determined. Results for the composition of NiCrMo90 are presented, which is added by a wire fed laser alloying process unlike the previously used and already researched methods of powder bed fusion. This wire fed method is engineered to ensure a higher material utilization and to simplify the material feeding. After the alloying process the wear behavior of the alloyed surfaces are examined and compared to a not alloyed control group of pins under similar thermo-mechanical conditions.

Effect of Dies Temperature on Mechanical Properties of Hot Stamping Square-Cup Part for Ultra High Strength Steel

2010 ◽  
Vol 129-131 ◽  
pp. 390-394
Author(s):  
Cheng Xi Lei ◽  
Zhong Wen Xing ◽  
Hong Ya Fu
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Hot Stamping ◽  
High Strength ◽  
Hot Forming ◽  
Forming Process ◽  
Stamping Process ◽  
Ultra High Strength Steel ◽  
Mechanical Properties Testing ◽  
Simulation Results

The numerical simulation of hot-stamping process was carried out for UHSS square-cup parts, and the influence of dies temperature on the hot-stamping process was anlysised. Besides, through the microstructure analysis and mechanical properties testing of the formed parts, effects of dies temperature on microstructures and mechanical properties of hot-stamping square-cup parts were obtained. The experiment and simulation results showed that the mechanical properties of the UHSS are strongly dependent on the temperature, so the dies temperature is one of the most important parameters that have to be taken into account in designing the hot-forming dies and the hot-forming process.

scholarly journals Investigation and Modeling of the Preheating Effects on Precipitation and Hot Flow Behavior for Forming High Strength AA7075 at Elevated Temperatures

2020 ◽  
Vol 4 (3) ◽  
pp. 76 ◽  
Author(s):  
Kailun Zheng ◽  
Yong Li ◽  
Song Yang ◽  
Kunning Fu ◽  
Jinghua Zheng ◽  
...  
Keyword(s):  
Aluminum Alloys ◽  
Heating Rate ◽  
Hot Deformation ◽  
Elevated Temperatures ◽  
Heating Temperature ◽  
Flow Behavior ◽  
Hot Stamping ◽  
High Strength ◽  
Mechanical Tests ◽  
Increasing Temperature

Preheating is the first but critical step for hot stamping high strength precipitate hardened aluminum alloys. To thoroughly understand the effects of preheating conditions—i.e., preheating rate and heating temperature—on the strength and hot deformation of aluminum alloys, a series of thermal–mechanical tests was performed to determine the post-hardness evolution and hot flow behaviors. Typical microstructures with different preheating conditions were also observed through transmission electron microscopy (TEM), with which a unified model of both hot flow and strength based on key microstructural variables was developed, enabling the successful prediction of macroscopic properties using different preheating strategies. The results have shown that for high strength AA7075 at the T6 condition, the dominant mechanism of precipitate evolution with increasing temperature is the coarsening of precipitates first, followed by dissolution when they exceed a critical temperature. A higher heating rate results in a slower coarsening and a relatively higher strength level. In addition, the flow stress of hot deformation is also higher using a quick heating rate, with more significant softening and reduced ductility.

scholarly journals A Simulation-Based Approach to Predict the Springback Behavior of Ultra-High Strength Spring Strips

2019 ◽  
Vol 949 ◽  
pp. 48-56 ◽  
Author(s):  
Karsten Richter ◽  
Franz Reuther ◽  
Roland Müller
Keyword(s):  
Process Design ◽  
Dimensional Accuracy ◽  
High Strength ◽  
Material Behavior ◽  
High Yield ◽  
Simulation Based ◽  
Bending Process ◽  
The Impact ◽  
Free Bending ◽  
Springback Behavior

One effect of high influence on the dimensional accuracy during bending is springback. It inevitably occurs due to the elastic proportion in the material behavior. The impact is notably high when producing springs made of ultra-high strength spring strips of the steel grade 1.4310 (X10CrNi18-8). The high yield ratio needed to fulfil the functionalities required during application leads to dimensional inaccuracies that have to be compensated during the production process. This paper reports a simulation-based approach to predict the springback behaviour of ultra-high strength spring strips with tensile strengths TS = 1500-1800 MPa. Based on the results of advanced material testing and modelling, the numerical prediction of the springback behavior of an exemplary bending process (free bending) has been investigated in detail. This helps to obtain deeper knowledge and understanding of the springback phenomenon and to achieve suitable strategies for a more efficient industrial tool and process design while processing ultra-high strength spring strips.

Umformung von höchstfesten Aluminiumlegierungen*/Forming of high-strength aluminum alloys - Influence of the forming temperature on the formability of 7xxx-aluminum alloys

2017 ◽  
Vol 107 (10) ◽  
pp. 695-699
Author(s):  
B.-A. Prof. Behrens ◽  
S. Hübner ◽  
H. Vogt
Keyword(s):  
Aluminum Alloys ◽  
Room Temperature ◽  
High Strength ◽  
Eine Hohe ◽  
Specific Strength ◽  
Automotive Body ◽  
High Specific Strength ◽  
Body Construction ◽  
Forming Temperature ◽  
High Strength Aluminum Alloys

Der Fachartikel befasst sich mit der Umformbarkeit von höchstfesten Aluminiumlegierungen der 7xxx-Reihe. Diese haben eine hohe spezifische Festigkeit, weshalb sie ein großes Leichtbaupotenzial besitzen. Eine Umformung bei Raumtemperatur ist allerdings nur bedingt möglich und somit ein Einsatz im Automobilkarosseriebau derzeit kaum umsetzbar. Daher werden für diese Legierungen verschiedene Prozessrouten untersucht, welche durch Erwärmung der Platinen und Werkzeuge die Umformbarkeit verbessern.   This study deals with the formability of high-strength aluminum alloys of the 7xxx-series. These alloys have a high specific strength and, therefore, a high lightweight potential. A limited formability at room temperature of these alloys, however, limits the use in automotive body construction. To increase the formability there are different approaches. In this study, the influence of the blank as well as the forming tool temperature is investigated.

Precipitation strengthening of aluminum alloys by room-temperature cyclic plasticity

Science ◽  
2019 ◽  
Vol 363 (6430) ◽  
pp. 972-975 ◽  
Author(s):  
Wenwen Sun ◽  
Yuman Zhu ◽  
Ross Marceau ◽  
Lingyu Wang ◽  
Qi Zhang ◽  
...  
Keyword(s):  
Aluminum Alloys ◽  
Room Temperature ◽  
High Strength ◽  
Cyclic Plasticity ◽  
Material Strength ◽  
Thermal Treatments ◽  
Dynamic Precipitation ◽  
Number Density ◽  
High Number Density ◽  
High Strength Aluminum Alloys

High-strength aluminum alloys are important for lightweighting vehicles and are extensively used in aircraft and, increasingly, in automobiles. The highest-strength aluminum alloys require a series of high-temperature “bakes” (120° to 200°C) to form a high number density of nanoparticles by solid-state precipitation. We found that a controlled, room-temperature cyclic deformation is sufficient to continuously inject vacancies into the material and to mediate the dynamic precipitation of a very fine (1- to 2-nanometer) distribution of solute clusters. This results in better material strength and elongation properties relative to traditional thermal treatments, despite a much shorter processing time. The microstructures formed are much more uniform than those characteristic of traditional thermal treatments and do not exhibit precipitate-free zones. These alloys are therefore likely to be more resistant to damage.

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