Optimizing Material Parameters for Better Formability of DQ Steel Pipe

2019 ◽  
Author(s):  
Shabbir Memon ◽  
Obaidur Rahman Mohammed ◽  
D. V. Suresh Koppisetty ◽  
Hamid M. Lankarani
Keyword(s):  
Additive Model ◽  
Forming Limit Diagram ◽  
Strain Ratio ◽  
Forming Limit ◽  
Bulge Test ◽  
Optimum Process ◽  
Strain Hardening Exponent ◽  
Hydraulic Pressure ◽  
Plastic Strain Ratio ◽  
Material Parameters

Abstract As Pipelines are subjected to bursting failure, the prediction of the burst capacities of corroded pipelines is of significant relevance to the pipeline industry. The Single mode deformation processes, most commonly used in laboratory evaluations like tensile test, may not realistically predict formability performance. Therefore, limit strains tests that use multiple deformation stages would better simulate actual material performance hence bulge test is widely used in pipeline industry for analyzing formability. The tube bulge test is an advanced testing material in which the tube is placed in a die cavity and is sealed from both the ends, the water is injected from the hole inside the sealing punch and hydraulic pressure is increased and the tube gets deformed at the center. The objective of this work is to utilize Taguchi coupled finite element computational methodology to determine the optimum material parameters to attain better formability without necking-splitting failure. To evaluate the dependence of the slope of the forming limit diagram on the material parameters, the simulation under various combinations of strain-hardening exponent (n), plastic strain ratio (r) and thickness of tube (t) is carried out and using thickness gradient criterion, the occurrence of necking i. e. forming limit strains during tube bulging is examined. By observing the optimum condition obtained for maximum plain strain it is concluded that higher the n, r and t more the limit strains will be. It is also observed that among n, r and t, n is the most prominent factor contributing on limit strains followed by r and t. The verification of optimum process parameters obtained through Taguchi technique is carried out using additive model and it is found that the observed value is well in agreement with the predicted value, the extra validation simulation is carried out to validate the Taguchi results.

Determination of Optimal Coiling Temperature and Cold Reduction Ratio of 260MPa Grade High Strength Nb-IF Steel

2011 ◽  
Vol 399-401 ◽  
pp. 148-151
Author(s):  
Min Li Wang ◽  
Zhi Wang Zheng ◽  
Li Xiao
Keyword(s):  
High Strength ◽  
Strain Ratio ◽  
Reduction Ratio ◽  
Cold Reduction ◽  
Strain Hardening Exponent ◽  
If Steel ◽  
Coiling Temperature ◽  
Plastic Strain Ratio ◽  
N Value ◽  
R Value

Hot rolled 260MPa grade high strength Nb-IF steel sheet was used to study the effect of coiling temperature and cold reduction ratio on the microstructures and mechanical properties. The experimental results showed that the recrystallization has finished. Under 650°Ccoiling temperature and 75% cold reduction ratio, and under 600°C or 700°C coiling temperature and 65% cold reduction ratio, the plastic strain ratio r value and the strain hardening exponent n value were reached the maximum, and respectively, the r value was approximate 1.8, the n value was approximate 0.26. That obtains optimally match of high strength and punching property.

Effect of Cu Content on the Formability and Portevin-Le Chatelier Effect of Al-Mg Alloys

2015 ◽  
Vol 817 ◽  
pp. 150-157
Author(s):  
Peng Cheng Ma ◽  
Di Zhang ◽  
Lin Zhong Zhuang ◽  
Ji Shan Zhang
Keyword(s):  
Plastic Strain ◽  
Stress Drop ◽  
Strain Ratio ◽  
Mg Alloys ◽  
Dynamic Strain ◽  
Strain Hardening Exponent ◽  
Drawing Ratio ◽  
Plastic Strain Ratio ◽  
Cu Content ◽  
Al Mg Alloys

Al-Mg alloys developed for auto body sheets with different Cu contents were fabricated in the laboratory scale. The effects of Cu content on the microstructures, formability and Portevin–Le Chatelier(PLC) effect of the alloys were investigated by polarizied optical microscopy and room temperature tensile testing. It has been found that with increasing Cu content, there was little change of the strain hardening exponent, but the plastic strain ratio and limiting drawing ratio increased firstly and then decreased. A quantitative statistical analysis of the characteristics of the PLC effect was made, including the stress drop and the reloading time, which follow a common linear relationship with plastic strain, and the increase rate of stress drop and reloading time was bigger with more Cu content. A detailed discussion of the corresponding mechanism of Cu and Cu-containing precipitates on the dynamic strain aging(DSA) was made.

Formability and Correlation between Formability Indices of Al-0.9Mg-1.0Si-0.7Cu-0.6Mn Alloy for Automotive Body Sheets

2010 ◽  
Vol 638-642 ◽  
pp. 356-361 ◽  
Author(s):  
Ni Tian ◽  
Gang Zhao ◽  
Liang Zuo ◽  
Chun Ming Liu
Keyword(s):  
Solid Solution ◽  
Uniform Elongation ◽  
Annealing Treatment ◽  
Aging Treatment ◽  
Strain Ratio ◽  
Orientation Distribution ◽  
Distribution Functions ◽  
Strain Hardening Exponent ◽  
Plastic Strain Ratio ◽  
Automotive Body

The texture, the formability and the correlation between formability indices of Al-0.9Mg- 1.0Si-0.7Cu-0.6Mn alloy for automotive body sheets subjected to solid solution, T4, annealing treatment and artificial aging at 443k for different time were investigated by orientation distribution functions(ODF) analysis, tensile and cupping test, FLD measurement and regression analysis method. The results showed that the textures of cold rolled alloy sheets consist mainly of copper and brass orientations, which are transformed into the texture mainly containing {001}<310> orientation after recrystallization, and aging treatment has little influence on the recrystallization texture. The formability of alloy sheets subjected to solid solution, T4 and annealing treatment is similar, however, the formability was observably deteriorated after aging at 443k. The correlation between uniform elongation δu and FLD0 is the most remarkable in all the given formability indices, the correlation between strain-hardening exponent n and the FLD0 take second place, while there is no correlation between plastic strain ratio r and FLD0. The correlation between reduction of area ψ and cupping value IE is distinct, while ψ and IE have little correlation with FLD0.

Integrated Hydraulic Bulge and Forming Limit Testing Method and Apparatus for Sheet Metals

2014 ◽  
Vol 626 ◽  
pp. 171-177 ◽  
Author(s):  
Yan Yo Chen ◽  
Yu Chung Tsai ◽  
Ching Hua Huang
Keyword(s):  
Forming Limit Diagram ◽  
Close Correlation ◽  
Biaxial Stress ◽  
Forming Limit ◽  
Hydraulic Pressure ◽  
Sheet Metals ◽  
Stress Strain ◽  
Testing Method ◽  
Hydraulic Bulge ◽  
Strain Relationship

This paper proposes an integrated hydraulic bulge and forming limit testing method and apparatus for sheet metals. By placing a PU (Polyurethane) plate between molds and uniformly applying hydraulic pressure to sheet metals, a biaxial stress-strain relationship and forming limit diagram (FLD) displaying both left and right sides were acquired using the same apparatus. An uniaxial tension test and traditional drawing test were conducted to compare the results obtained from the proposed hydraulic bulge and forming limit testing methods, respectively. A close correlation between the results of the stress-strain relationship and FLD in both comparisons verified the feasibility and capability of this integrated hydraulic testing method and apparatus for use with sheet metals.

Forming limit diagram of aluminum/copper bi-layered tubes by bulge test

2017 ◽  
Vol 92 (5-8) ◽  
pp. 1539-1549 ◽  
Author(s):  
Mehran Mohammadi ◽  
Javad Shahbazi Karami ◽  
Seyed Jalal Hashemi
Keyword(s):  
Forming Limit Diagram ◽  
Forming Limit ◽  
Bulge Test

Analysis of Tube Hydroforming by Means of an Inverse Approach1

2003 ◽  
Vol 125 (2) ◽  
pp. 369-377 ◽  
Author(s):  
Ba Nghiep Nguyen ◽  
Kenneth I. Johnson ◽  
Mohammad A. Khaleel
Keyword(s):  
Tube Hydroforming ◽  
Forming Limit Diagram ◽  
Computational Time ◽  
Forming Limit ◽  
Hydraulic Pressure ◽  
Computational Tool ◽  
Incremental Method ◽  
Inverse Approach ◽  
Initial Geometry ◽  
Good Agreement

This paper presents a computational tool for the analysis of freely hydroformed tubes by means of an inverse approach. The formulation of the inverse method developed by Guo et al. [1] is adopted and extended to the tube hydroforming problems in which the initial geometry is a round tube submitted to hydraulic pressure and axial feed at the tube ends (end-feed). A simple criterion based on a forming limit diagram is used to predict the necking regions in the deformed workpiece. Although the developed computational tool is a stand-alone code, it has been linked to the Marc finite element code for meshing and visualization of results. The application of the inverse approach to tube hydroforming is illustrated through the analyses of the aluminum alloy AA6061-T4 seamless tubes under free hydroforming conditions. The results obtained are in good agreement with those issued from a direct incremental approach. However, the computational time in the inverse procedure is much less than that in the incremental method.

Research on Formability of AZ31B Magnesium Alloy at Room Temperature

2014 ◽  
Vol 886 ◽  
pp. 3-6
Author(s):  
Zu Jian Yu ◽  
Jian Hui Li ◽  
Yan Yang
Keyword(s):  
Magnesium Alloy ◽  
Room Temperature ◽  
Strain Ratio ◽  
Alloy Sheet ◽  
Strain Hardening Exponent ◽  
Drawing Ratio ◽  
Plastic Strain Ratio ◽  
Az31b Magnesium Alloy ◽  
Magnesium Alloy Sheet ◽  
Az31b Magnesium Alloy Sheet

Tensile tests and a cold deep drawing process were developed at room temperature to estimate the stamping formability of AZ31B magnesium alloy sheet. The results show that AZ31B magnesium alloy sheet has poor formability at room temperature with the total elongation of ~ 20%, the yield ratio is about 0.6 and the strain-hardening exponent is 0.18, while the plastic strain ratio is 1.58, and the earing ratio is-0.55.Thus, AZ31B magnesium alloy sheet can not suffer server plastic deformation. It was found that comparatively shallow magnesium alloy cups were satisfactorily formed at room temperature without heating when the punch fillet radius 6mm and the die fillet radius10mm with a 1mm thickness sheet with limit drawing ratio of 1.25.

Describing tube formability during pulsating hydroforming using forming limit diagrams

2017 ◽  
Vol 52 (4) ◽  
pp. 249-257 ◽  
Author(s):  
Lianfa Yang ◽  
Daofu Tang ◽  
Yulin He
Keyword(s):  
Deformation Behaviour ◽  
Forming Limit Diagram ◽  
Forming Limit ◽  
Hydraulic Pressure ◽  
Minor Strain ◽  
Steel Tubes ◽  
Periodic Oscillations ◽  
Forming Limit Diagrams ◽  
Uniform Wall ◽  
Forming Limit Curves

Pulsating hydroforming is a novel forming technique that applies pulsating hydraulic pressure to deform tubular materials. Larger expansions and more uniform wall thicknesses in tubes have reportedly been achieved using this technique. However, periodic oscillations of hydraulic pressure acting on the tubes during pulsating hydroforming make the tube deformation behaviour and formability unpredictable. Forming limit diagrams, which consist of two forming limit curves in a major–minor strain coordinate system, are widely used to indicate the formability of sheet materials in plastic deformation. The comparable use of forming limit diagrams to indicate the formability of tubular materials under the pulsating action of hydroforming has not been previously established. In this study, pulsating and non-pulsating hydro-bulging experiments were performed on SS304 stainless steel tubes. Under distinct tension–compression and tension–tension strain states with and without active axial feeding, the forming limit curves for the deformed tubes were constructed based on the experimental data. The effects of various hydraulic pressure pulsating parameters, including pulsating amplitude and frequency, on the forming limit curves were analysed and compared. The experimental results showed that each of the forming limit curves under pulsating hydro-bulging was higher than the forming limit curves under non-pulsating hydro-bulging, thereby confirming the influence of the pulsating parameters. In general, the height of the forming limit curves increased as the pulsating amplitude and frequency increased, largely independent of the tension–compression and tension–tension states. Overall, the results showed that the proposed method for determining the forming limit curves (and the subsequent forming limit diagram) for tubes during pulsating hydro-bulging is feasible.

Forming Limit Diagram of the AMS 5599 Sheet Metal

2013 ◽  
Vol 58 (4) ◽  
pp. 1213-1217
Author(s):  
W. Fracz ◽  
F. Stachowicz ◽  
T. Trzepieciński ◽  
T. Pieją
Keyword(s):  
Mechanical Properties ◽  
Sheet Metal ◽  
Plastic Anisotropy ◽  
Experimental Studies ◽  
Forming Limit Diagram ◽  
Forming Limit ◽  
Uniaxial Tensile ◽  
Strain Hardening Exponent ◽  
Uniaxial Tensile Test ◽  
Anisotropy Ratio

Abstract Formability of sheet metal is dependent on the mechanical properties. Some materials form better than others - moreover, a material that has the best formability for one stamping may behave very poorly in a stamping of another configuration. For these reasons, extensive test programs are often carried out in an attempt to correlate material formability with value of some mechanical properties. The formability of sheet metal has frequently been expressed by the value of strain hardening exponent and plastic anisotropy ratio. The stress-strain and hardening behaviour of a material is very important in determining its resistance to plastic instability. However experimental studies of formability of various materials have revealed basic differences in behaviour, such as the ”brass-type” and the ”steel-type”, exhibiting respectively, zero and positive dependence of forming limit on the strain ratio. In this study mechanical properties and the Forming Limit Diagram of the AMS 5599 sheet metal were determined using uniaxial tensile test and Marciniak’s flat bottomed punch test respectively. Different methods were used for the FLD calculation - results of these calculations were compared with experimental results

scholarly journals Calculation of Yield Surfaces and Determination of Forming Limit Diagrams of Aluminium Alloys

1993 ◽  
Vol 21 (2-3) ◽  
pp. 93-108 ◽  
Author(s):  
J. J. Fundenberger ◽  
M. J. Philippe ◽  
C. Esling ◽  
P. Lequeu ◽  
B. Chenal
Keyword(s):  
Aluminium Alloys ◽  
Expansion Method ◽  
Strain Ratio ◽  
Orientation Distribution ◽  
Forming Limit ◽  
Deformation Model ◽  
Plastic Strain Ratio ◽  
Yield Loci ◽  
Series Expansion Method

In order to point out the influence of the crystallographic texture on the formability of 2 aluminium alloys, the orientation distribution function (ODF) will be carried out using the series expansion method. Combining the ODF with a Taylor plastic deformation model we are able to calculate the yield loci and to predict the plastic strain ratio which is of high interest in the formability.

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