A Study on the Formability of IF and Plain Carbon Mild Steels

2010 ◽  
Author(s):  
Mohamadreza Nourani ◽  
Hossein Aliverdilu ◽  
Hossein Monajati Zadeh ◽  
Hamid Khorsand ◽  
Ali Shokuhfar ◽  
...  
Keyword(s):  
Uniaxial Tension ◽  
Steel Sheet ◽  
Raw Material ◽  
Forming Limit ◽  
Interstitial Free ◽  
If Steel ◽  
Sheet Metals ◽  
Original Design ◽  
Engineering Strain ◽  
Stamping Process

Steel sheet metals are widely used in different industries due to their high strength, good weldability, availability, moderate cost, and the ability to form to complex 3D parts. The study of the formability of sheet metals is often done by means of Forming Limit Diagram (FLD) which presents the major and minor engineering strain thresholds under different deformation states. In this article, the formability parameters of three different steel sheet metals with the same thickness have been determined by uniaxial tension test and their FLDs have been produced by Hecker method: RRSt14O3, Zinc coated IF (Interstitial Free) steel and uncoated IF steel. Also the materials’ formability during the stamping process of a car door inner panel has been investigated as a case study to substitute the original design of raw material, coated IF steel, with a cheaper alternative. Among the tested materials to form the part, the uniaxial tension results showed that the formability parameters of uncoated IF steel was higher than the coated IF steel and the parameters of RRSt14O3 sheet metal was the lowest. The FLD of coated IF steel sheet was the highest (best formability). Differences among the formability parameters in uniaxial tension, the FLDs, and the stamping behavior of the part with different steel sheet metals have been explained by their surface roughnesses and the friction coefficients that affect the material flow during the FLD test as well as the stamping process.

Forming limit strains of interstitial free-IF steel sheet

2016 ◽  
Author(s):  
José Divo Bressan ◽  
Luciano Pessanha Moreira ◽  
Maria Carolina dos Santos Freitas
Keyword(s):  
Steel Sheet ◽  
Forming Limit ◽  
Interstitial Free ◽  
If Steel ◽  
If Steel Sheet

Strain-Path Effects on the Formability Behavior of Interstitial-Free Steel

2015 ◽  
Vol 651-653 ◽  
pp. 126-131
Author(s):  
Jetson Lemos Ferreira ◽  
José Osvaldo Amaral Tepedino ◽  
Marco Antonio Wolff ◽  
Luciano Pessanha Moreira
Keyword(s):  
Uniaxial Tension ◽  
Plane Strain ◽  
Strain Path ◽  
Steel Sheet ◽  
Interstitial Free ◽  
If Steel ◽  
Biaxial Stretching ◽  
Nominal Thickness ◽  
Strain Paths ◽  
If Steel Sheet

In this work, the formability behavior of Interstitial-Free (IF) steel sheet, grade DC07 with 0.65 mm of nominal thickness, was evaluated by means of both linear and bi-linear strain-paths to define the Forming Limit Curve (FLC) at the onset of necking according to ASTM E22182 standard. In the first strain-path, flat-bottomed punch with 200 mm diameter and 10 mm corner die radius was adopted together with counter-blanks of an IF steel sheet grade DC07 with 0.80 mm nominal thickness in order to yield two equal amounts of plastic work under uniaxial tension and under equibiaxial stretching strain-paths. Afterwards, Nakajima’s 100 mm hemispherical punch stretching procedure and bulge tests were adopted to determine the FLC of both as-received and strained DC07 blanks with the help of an automated digital image correlation system to define the linear and bi-linear limit strains. Increasing the straining level (5 and 10%) of the first strain-path in uniaxial tension improved the limit strains of the DC07 steel sheet between the plane-strain intercept (FLC0) and the biaxial stretching region of the FLC. On the other hand, blanks which were firstly pre-strained in equibiaxial stretching mode (4.8 and 9%) provided better formability in the FLC drawing region and reduced limit strains in plane-strain and biaxial stretching regions.

Evolution of Roughness on Straining of Interstitial Free – IF Steel Sheet

2012 ◽  
Vol 504-506 ◽  
pp. 83-88 ◽  
Author(s):  
Ricardo Kirchhof Unfer ◽  
José Divo Bressan
Keyword(s):  
Plastic Strain ◽  
Tensile Test ◽  
Steel Sheet ◽  
Material Behavior ◽  
Uniaxial Tensile ◽  
Interstitial Free ◽  
If Steel ◽  
Local Necking ◽  
Incremental Step ◽  
If Steel Sheet

This study aims to assess the evolution of surface roughness and waviness parameters with plastic strain in Interstitial Free – IF steel sheet. For the achievement of this study, it was considered various roughness and waviness profile parameters such as: arithmetic average roughness (Ra), maximum distance peak-valley (Rt), average waviness (Wa) and waviness of the total height peak-valley (Wt). Tensile test specimens of IF steel at 0º, 45º and 90º to the direction of rolling were fabricated. After preparing the sheet proof specimens, it was performed simple tensile tests and measurements of roughness and waviness of the specimen surface at various strain stages resulting in a large quantity of data. During the tensile test, it has been measured the following plastic strain to indicate the incremental step: (e1) longitudinal strain and (e2) transverse strain. From these data, it was possible to obtain points needed to plot the curves of roughness and waviness parameters versus strain and to determine the material behavior using equations of the equivalent strain. From the curves drawn it was possible to see how the material roughness and waviness behaves during the straining in the uniaxial tensile state, with the possibility to predict the influence of plastic strain on roughness and waviness parameters and the onset of local necking of IF steel sheet. The waviness parameters Wt is the best for characterizing the onset of local necking.

Work-Hardening Behavior of Cold Rolled Interstitial-Free Steel Sheet and Dual Phase High Strength Steel Sheets Subjected to Two-Stage, Coaxial and Non-Coaxial Tension/Compression

2015 ◽  
Vol 651-653 ◽  
pp. 83-88 ◽  
Author(s):  
Satoshi Shirakami ◽  
Shigeru Yonemura ◽  
Tohru Yoshida ◽  
Noriyuki Suzuki ◽  
Toshihiko Kuwabara
Keyword(s):  
Work Hardening ◽  
Steel Sheet ◽  
High Strength ◽  
Dual Phase ◽  
Interstitial Free ◽  
If Steel ◽  
Two Stage ◽  
Work Hardening Behavior ◽  
Hardening Behavior ◽  
Cold Rolled

In-plane tension/compression tests of a cold rolled interstitial-free (IF) steel and sheet a 980MPa dual phase high strength steel sheet (980DP) were carried out to investigate the work-hardening behavior under two-stage loading paths. The two-stage loading paths consist of the uniaxial tension/compression for the rolling direction (RD) followed by unloading and subsequent uniaxial tension/compression in the 0°, 45° and 90° directions from the first loading direction (0°-, 45°- and 90°-loading). The work hardening behavior in the second loading was different between the 980DP and the IF steel. It was found that the work hardening behaviors were significantly affected by the inner product of the strain rate mode tensors for the first and second loading and that the effect of the deformation mode (tension/compression) was small.

Microstructure and Texture Evolution in Cold Rolled Interstitial Free (IF) Steel Sheet during Annealing under AC Magnetic Field

2010 ◽  
Vol 638-642 ◽  
pp. 2781-2786
Author(s):  
Chang Shu He ◽  
Sadahiro Tsurekawa ◽  
Hiroyuki Kokawa ◽  
Xiang Zhao ◽  
Liang Zuo
Keyword(s):  
Magnetic Field ◽  
Steel Sheet ◽  
Texture Evolution ◽  
Rolling Direction ◽  
Recrystallization Annealing ◽  
Interstitial Free ◽  
If Steel ◽  
Ac Magnetic Field ◽  
Cold Rolled ◽  
If Steel Sheet

An AC magnetic field (0.5Tesla) is applied with the field direction perpendicular to the rolling direction during annealing of a 76% cold-rolled IF steel sheet. Microstructure and texture evolution in the as-annealed specimens were determined using SEM based OIM technique. It is found that the recrystallization is noticeably retarded by AC magnetic field annealing. At the early stage of recrystallization (annealing at 650°C for 30min), the development of (111) <123> orientations was favored by the AC magnetic field. With progress of recrystallization (annealing at 700°C and 750°C for 30min), the applied AC magnetic field suppressed the development of γ-fiber recrystallization textures to some extent.

Study on the Micro Mechanism of Recrystallization Texture Formation in Cold-Rolled IF Steel Sheet

2005 ◽  
Vol 495-497 ◽  
pp. 417-422
Author(s):  
T. He ◽  
Y.D. Liu ◽  
Yan Wu ◽  
Q.W. Jiang ◽  
Gang Wang ◽  
...  
Keyword(s):  
Recrystallization Texture ◽  
Steel Sheet ◽  
Salt Bath ◽  
Experimental Setup ◽  
Interstitial Free ◽  
If Steel ◽  
Back Scattering ◽  
Cold Rolled ◽  
Steel Foils ◽  
Kinetics Of

An experimental setup was designed to study the recrystallization kinetics of Interstitial Free (IF) steel in this work. The 80% cold rolled IF steel foils are heated rapidly to 680°C, 730°C and 780°C by a salt bath. The recrystallization kinetic curves were obtained by the quantitative analysis of texture components, microstructures and EBSP (electron back-scattering patterns) measurements. With the help of EBSD, the orientations of the recrystallization nuclei are determined. The growth rule of the recrystallization nuclei was analyzed statistically. The effect of nucleus orientation on the formation of the recrystallization texture was investigated.

Characteristics of Recrystallization Texture Evolution in High Magnetic Field for Interstitial Free (IF) Steel Sheet

2005 ◽  
Vol 495-497 ◽  
pp. 465-470 ◽  
Author(s):  
Chang Shu He ◽  
Yu Dong Zhang ◽  
X. Zhao ◽  
Liang Zuo ◽  
Claude Esling
Keyword(s):  
Magnetic Field ◽  
High Magnetic Field ◽  
Recrystallization Texture ◽  
Steel Sheet ◽  
Texture Evolution ◽  
Interstitial Free ◽  
If Steel ◽  
Direction Parallel ◽  
The Magnetic Field ◽  
If Steel Sheet

High magnetic field is applied with the field direction parallel to the rolling direction during annealing of a cold rolled IF steel sheet. Results of X-ray ODF analysis show that, magnetic field annealing retards the normal recrystallization texture evolution for the IF steel sheet. It is worth noting that an abnormal increase of orientation intensity at {100}<110> is found after magnetic annealing for 25min at 650°C. When the magnetic field strength is increased from 10 Tesla to 14 Tesla, the a-fiber is further strengthened, especially the {100}<110> component. Combined with EBSD analysis results, it is considered that the magnetic field does not change the mechanism of recrystallization texture evolution for the IF steel sheet in the present case.

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