Numerically modeling spring back and spring go amounts and bending deformations of Cr-Mo alloyed sheet material

2020 ◽  
Vol 62 (12) ◽  
pp. 1265-1272
Author(s):  
Mustafa Özdemir ◽  
Hakan Dilipak ◽  
Bülent Bostan
Keyword(s):  
Heat Treatment ◽  
Mathematical Models ◽  
Deformation Zone ◽  
Sheet Material ◽  
Analysis Program ◽  
Spring Back ◽  
Forming Process ◽  
Bending Angle ◽  
Heat Treated ◽  
Bending Process

Abstract In the study conducted for this contribution, sheet material 4 mm thick, non-heat treated (II), normalized (NH) and tempering heat treatment implemented (TH), were formed at a bending angle of 90°. As a result of the forming process, the effects of the R2, R3, R4, R5, and R6 mm punch tip radii on spring back and spring go values were investigated. The bending operations were carried out by waiting for the punch in the material bending zone for 30 sec and then lifting. The samples were extracted from the middle deformation zone of the II, NH and TH applied sheet material, to which the bending process was applied, following which their ferrite phase, pearlite and martensite structures were microstructurally analyzed. A Minitab analysis program was used to investigate the effect of the bending parameters on the sheet material’s spring-back and spring-go behavior. Moreover, the effects of bending parameters were investigated by creating numerical and mathematical models. Thus, it was determined that spring-go behavior occurred on the II and NH applied sheet material, while spring-back behavior occurred on the TH applied material.

scholarly journals Effect of Spring Back on Formation Process of Sheet Metal Bending Plates

Teknomekanik ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 28-35
Author(s):  
Purwantono Purwantono ◽  
Nelvi Erizon ◽  
Nofri Helmi ◽  
Muhammad Akhbar ◽  
Muhibuddin Muhibuddin
Keyword(s):  
Sheet Metal ◽  
Room Temperature ◽  
Steel Plate ◽  
Metal Plate ◽  
Spring Back ◽  
Forming Process ◽  
Bending Angle ◽  
Small Deviations ◽  
Bending Process ◽  
Bending Plates

This study aims to observe the amount of deviation that occurs due to the influence of spring back on the forming process. spring back in question is the back force when the plate undergoes a forming process, but when the load is released, the plate condition will reverse or return to its initial condition. This reversal is due to the factor of the elasticity of the material that is owned. Other factors that influence the bending process include thickness, width, angle of bending and others. object of this research is a sheet metal plate with a thickness of 1 mm - 4 mm. Forming process is done by bending process. This bending process is widely used in the plate forming process, namely to bend the sides of the plate to make it stiffer. This bending process is carried out in cold conditions where the process is carried out at room temperature. This research was conducted by preparing slices of the same width and length and then the process of bending them to form an angle of 20 ° to 120 °. results of this test indicate that the thicker the bent material has the tendency to produce small deviations. This means that the value of the spring back ratio also decreases. The value of the spring back ratio in this study ranges from 1% to 9%. This means that if the bending process is carried out on a steel plate with the resulting bending angle of 90 °, the bending angle of the shoe must be more than 90 °, the excess is 1 ° - 9 °. So that when the load is released, the position of the susdut bends closer to 90 °.

Effects of Part Geometry on Spring-Back/Spring-Go Feature in U-Bending Process

2013 ◽  
Vol 549 ◽  
pp. 100-107 ◽  
Author(s):  
Wiriyakorn Phanitwong ◽  
Arkarapon Sontamino ◽  
Sutasn Thipprakmas
Keyword(s):  
Laboratory Experiments ◽  
Fem Simulation ◽  
Work Piece ◽  
Spring Back ◽  
Forming Process ◽  
Bending Angle ◽  
Part Geometry ◽  
Bending Process ◽  
Metal Forming Process ◽  
Simulation Results

The U-bending process is a common sheet-metal forming process widely employed to fabricate sheet parts like channels, beams, and frames of various sizes applied in almost all industrial fields. In recent years, the precision requirements are increased on the U-bent parts. To achieve these requirements, in this study, the effects of part geometry on the spring-back/spring-go feature including work piece length, U-channel width, punch and die radii, and work piece thickness, were investigated by using the finite element method (FEM) and laboratory experiments. The FEM simulation results clearly revealed the influence of part geometry on spring-back/spring-go feature via the changes of stress distribution analyses on the bending allowance zone, the bottom of bent part, and the U-leg of bent part. Specifically, the part geometry affected on the bending characteristic on the bending allowance zone, as well as it affected on the spring-back feature. In addition, the part geometry also affected on the formation of reversed bending characteristic on the bottom and U-leg of bent parts, as well as it affected on the spring-go feature. The bending angle could be achieved by compensating these bending and reversed bending characteristics. Therefore, to meet the required bending angle, the suitable design of part geometry was strongly considered to maintain the balancing of the bending and reversed bending characteristics. The laboratory experiments were carried out to validate the accuracy of the FEM simulation results. The FEM simulation results showed good agreement with the experimental results with reference to the bending angle and bending force.

Application of Tailored Heat Treated Blanks under Quasi Series Conditions

2007 ◽  
Vol 344 ◽  
pp. 383-390 ◽  
Author(s):  
Marion Merklein ◽  
Uwe Vogt
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Local Heat ◽  
Strength Distribution ◽  
Process Window ◽  
Short Term ◽  
Forming Process ◽  
Heat Treated ◽  
Set Up ◽  
The Impact

Tailored Heat Treated Blanks (THTB) are blanks that exhibit locally different strength specifically optimized for the succeeding forming process. The strength distribution is set by a local, short-term heat treatment modifying the mechanical properties of the material. Hence, THTB allow enhancing forming limits significantly leading to shorter and more robust manufacture process chains. In order to qualify the use of THTB under quasi series conditions, the interdependencies of the blank’s local heat treatment and the entire process chain of the car body manufacture have to be analyzed. In this respect, the impact of a short-term heat treatment on the mechanical properties of AA6181PX, a commonly used aluminum alloy in today’s car bodies, was studied. Also the influence of a short-term heat treatment on the coil lubricant, usually already applied by the material supplier, was given a closer look. Based on these experiments process restrictions for the application of THTB in an industrial automotive environment were derived and a process window for the THTB design was set up. In conclusion, strategies were defined how to enhance the found process boundaries leading to a more robust process window.

Calculating Salmonella Inactivation in Nonisothermal Heat Treatments from Isothermal Nonlinear Survival Curves

2001 ◽  
Vol 64 (5) ◽  
pp. 606-613 ◽  
Author(s):  
K. L. MATTICK ◽  
J. D. LEGAN ◽  
T. J. HUMPHREY ◽  
M. PELEG
Keyword(s):  
Differential Equation ◽  
Heat Treatment ◽  
Mathematical Models ◽  
Survival Curve ◽  
Survival Ratio ◽  
Survival Curves ◽  
Time Intervals ◽  
Heat Treated ◽  
Rich Media ◽  
Nonisothermal Conditions

Salmonella cells in two sugar-rich media were heat treated at various constant temperatures in the range of 55 to 80°C and their survival ratios determined at various time intervals. The resulting nonlinear semilogarithmic survival curves are described by the model log10S(t) = −b(T)tn(T), where S(t) is the momentary survival ratio N(t)/N0, and b(T) and n(T) are coefficients whose temperature dependence is described by two empirical mathematical models. When the temperature profile, T(t), of a nonisothermal heat treatment can also be expressed algebraically, b(T) and n(T) can be transformed into a function of time, i.e., b[T(t)] and n[T(t)]. If the momentary inactivation rate primarily depends on the momentary temperature and survival ratio, then the survival curve under nonisothermal conditions can be constructed by solving a differential equation, previously suggested by Peleg and Penchina, whose coefficients are expressions that contain the corresponding b[T(t)] and n[T(t)] terms. The applicability of the model and its underlying assumptions was tested with a series of eight experiments in which the Salmonella cells, in the same media, were heated at various rates to selected temperatures in the range of 65 to 80°C and then cooled. In all the experiments, there was an agreement between the predicted and observed survival curves. This suggests that, at least in the case of Salmonella in the tested media, survival during nonisothermal inactivation can be estimated without assuming any mortality kinetics.

Effect of Heat Treatment on Tensile Strength and Microstructure of AZ61A Magnesium Alloy

2014 ◽  
Vol 606 ◽  
pp. 55-59 ◽  
Author(s):  
R. Senthil ◽  
A. Gnanavelbabu
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Mg Alloys ◽  
Forming Process ◽  
Microstructural Parameters ◽  
Heat Treated ◽  
Mutual Relations

Magnesium alloys are the very progressive materials whereon is due to improve their end-use properties. Especially, wrought Mg alloys attract attention since they have more advantageous mechanical properties than cast Mg alloys. Investigations were carried out the effects of heat treatment on tensile strength and microstructure of AZ61A magnesium alloy. The AZ61A Mg alloy is solution heat treated at the temperature of 6500F (343°C) for various soaking timing such as 120 min, 240 min and 360 minutes and allowed it cool slowly in the furnace itself. Magnesium alloys usually are heat treated either to improve mechanical properties or as means of conditioning for specific fabrication operations. Special attention had been focused on the analysis of mutual relations existing between the deformation conditions, microstructural parameters, grain size and the achieved mechanical properties. The result after the solution heat treatment, showed remarkably improved hardness, tensile strength and yield strength. It would be appropriate for a forming process namely isostatic forming process.

Study of NC Cold Tube Bending Spring-Back Characteristics

2010 ◽  
Vol 154-155 ◽  
pp. 202-208 ◽  
Author(s):  
Yi Nan Lai ◽  
Sheng Le Ren ◽  
Zeng Lou Li ◽  
Jun Tao Gu ◽  
Guang Fei Wu
Keyword(s):  
High Reliability ◽  
Prediction Equation ◽  
Strong Nonlinearity ◽  
Spring Back ◽  
Tube Bending ◽  
Bending Angle ◽  
Bending Process ◽  
Elasto Plasticity ◽  
Bending Radius ◽  
Back Angle

The unloading spring-back of tubes during its manufacturing process shows a strong nonlinearity, which greatly influences the precision of parts. In this paper, the strain distribution of bending tubes was analyzed based on the elasto-plasticity theory, and the theoretical equation for spring-back of tubes was derived. The numerical simulation model for cold tube-bending process was developed with prediction error of 9% compared with experimental results, indicating high reliability of the model. The 12Cr1MoV and 20G tubes were used to analyze the effects of bending angle, bending radius and bending speed on the spring-back of tubes. The prediction equation of spring-back was built, which shows that the spring-back tendency was in accordance with theoretical analysis results. The simulated results show that the spring-back angle is linearly proportional to the bending angle within a certain range. In addition, it is proportional to the relative bending radius and the bending speed.

Technological features of autoclave molding of parts of complex configuration from В95оч alloy sheets

2021 ◽  
Author(s):  
Keyword(s):  
Heat Treatment ◽  
Technological Process ◽  
Aging Process ◽  
Sheet Material ◽  
High Strength ◽  
Spring Back ◽  
Corrosion Properties ◽  
Strength Alloy ◽  
Mechanical And Corrosion Properties ◽  
Wing Skin

The development is shown with the use of modeling the technological process of autoclave molding, combined with the aging process, for the manufacture of upper wing skins from sheets of "В95оч" high-strength alloy taking into account the spring back of the workpiece. The results of studies of indicators of mechanical and corrosion properties of the resulting product are presented. Keywords: autoclave molding, heat treatment, springback, upper wing skin, sheet material, "В95оч". [email protected]

Process Optimization of Laser Micro-Bending Using iSIGHT

2008 ◽  
Vol 575-578 ◽  
pp. 408-415
Author(s):  
Jie Liu ◽  
Yan Jin Guan ◽  
Sheng Sun ◽  
Guang Chun Wang
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Laser Power ◽  
Geometrical Parameters ◽  
Beam Diameter ◽  
Forming Process ◽  
Bending Angle ◽  
Scanning Velocity ◽  
Stainless Steel Foil ◽  
Bending Process

There are many factors, such as the laser and geometrical parameters, which influence greatly on the laser bending process. So it is of great importance to determine these variables properly. Considering the relationship of material properties and temperature, a 3-D thermal-mechanical finite element analysis model for laser micro-bending of stainless steel foil is developed based on the software MSC.Marc, and the laser micro-bending process of 0.1mm thick stainless steel foil is implemented. The finite element method simulation process is integrated with the optimization software package iSIGHT through secondary development. The objective function is to realize the maximum bending angle after single laser scan, and laser power, beam diameter and scanning velocity are regarded as the design variables. The forming process is optimized by using genetic algorithm. The optimal result shows the bending angle can be got to the maximum 1.0332°when the laser power, beam diameter and scanning velocity are 32W, 0.17mm and 132mm/s respectively. The experiment results are in good agreement with optimal results.

Numerical Study on Influences of Process Parameters on Laser Tube Bending

2010 ◽  
Vol 148-149 ◽  
pp. 590-594
Author(s):  
Yan Jin Guan ◽  
Hong Mei Zhang ◽  
Sheng Sun ◽  
Guo Qun Zhao
Keyword(s):  
Numerical Study ◽  
Laser Spot ◽  
Forming Process ◽  
Laser Bending ◽  
Bending Angle ◽  
Scanning Velocity ◽  
Bending Process ◽  
Wrap Angle ◽  
Flexible Forming Process ◽  
External Forces

Laser bending process of tubes is a new flexible forming process without rigid tools and external forces. The tube is formed by internal thermal stress induced by laser irradiation. The process simulation of laser bending of tubes is realized numerically. When the other parameters remain invariable, the laser bending angle augments with the increase of the laser power. The laser bending angle decreases with the increase of the scanning velocity. Meanwhile, the bending angle varies with the diameter of the laser spot. The angle begins to decrease when the laser spot diameter get to an optimum value. The bending angle enlarges if the scanning wrap angle augments. The bending angle is largest when the scanning wrap angle is 180°. When the scanning wrap angle is over 180°, the bending angle decreases with the increase of the scanning wrap angle. The relationship between the number of scans and the bending angle is about in direct ratio. The bending angle induced by the first irradiated time is the largest.

Spring-Back Evaluation of Stretch Bending Process Based on Chaboche Combined Isotropic-Kinematic Hardening Laws

2011 ◽  
Vol 204-210 ◽  
pp. 1745-1750 ◽  
Author(s):  
Jing Hu ◽  
Xiao Xing Li ◽  
Kwan Soo Chung ◽  
Rao Yao
Keyword(s):  
Kinematic Hardening ◽  
Spring Back ◽  
Stretch Forming ◽  
Forming Process ◽  
Hardening Law ◽  
Stretch Bending ◽  
User Subroutine ◽  
Bending Process ◽  
Chaboche Model ◽  
Simulation Results

We present a study on spring-back prediction in the stretching bending process using the Chaboche model combined isotropic-kinematic hardening law and Mises yielding criterion, and a material user subroutine (VUMAT, UMAT) program was developed base on the ABAQUS interface for the model. The effects of different hardening law on the spring-back in the stretch forming process was also analyzed and compared. The simulation results show that the combined isotropic-kinematic hardening law has the better spring-back prediction compared with the pure isotropic and kinematic hardening law in the stretch forming process, which is verified by the experimental results.

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