scholarly journals Experimental Investigation of the Effects of Irradiating Schemes in Laser Tube Bending Process

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1123
Author(s):  
Mehdi Safari ◽  
Ricardo J. Alves de Sousa ◽  
Jalal Joudaki
Keyword(s):  
Laser Beam ◽  
Contact Process ◽  
Steel Tube ◽  
Thickness Variation ◽  
Tube Bending ◽  
Lateral Bending ◽  
Bending Angle ◽  
Laser Tube ◽  
Bending Process ◽  
Thickness Variations

The laser tube bending process (LTBP) process is a thermal non-contact process for bending tubes with less springback and less thinning of the tube. In this paper, the laser tube bending process will be studied experimentally. The length of irradiation and irradiation scheme are two main affecting process parameters in the LTBP process. For this purpose, different samples according to two main irradiation schemes (Circular irradiating scheme (CIS) and axial irradiating scheme (AIS)) and different lengths of laser beam irradiation (from 4.7 to 28.2 mm) are fabricated. The main bending angle of laser-bent tube, lateral bending angle, ovality, and thickness variations is measured experimentally, and the effects of the irradiating scheme and the length of irradiation are investigated. An 18 mm diameter, 1 mm thick mild steel tube was bent with 1100 Watts laser beam. The results show that for both irradiating schemes, by increasing the irradiating length of the main and lateral bending angle, the ovality and thickness variation ratio of the bent tube are increased. In addition, for a similar irradiating length, the main bending angle with AIS is considerably higher than CIS. The lateral bending angle by AIS is much less than the lateral bending angle with CIS. The results demonstrate that the ovality percentage and the thickness variation ratio for the laser-bent tube obtained by CIS are much more than the values associated with by AIS laser-bent tube.

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.

scholarly journals Improve the material absorption of light and enhance the laser tube bending process utilizing laser softening heat treatment

2018 ◽  
Vol 99 ◽  
pp. 15-18 ◽  
Author(s):  
Khalil Ibraheem Imhan ◽  
B.T.H.T. Baharudin ◽  
Azmi Zakaria ◽  
Mohd Idris Shah B. Ismail ◽  
Naseer Mahdi Hadi Alsabti ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Tube Bending ◽  
Laser Tube ◽  
Bending Process ◽  
Absorption Of Light ◽  
Softening Heat

scholarly journals An Analytical and Experimental Investigation of Average Laser Power and Angular Scanning Speed Effects on Laser Tube Bending Process

2017 ◽  
Vol 95 ◽  
pp. 05008 ◽  
Author(s):  
Khalil Ibraheem Imhan ◽  
B.T.H.T. Baharudin ◽  
Azmi Zakaria ◽  
Mohd Idris Shah b. Ismail ◽  
Nasser Mahdi Hadi Alsabti ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Laser Power ◽  
Scanning Speed ◽  
Tube Bending ◽  
Laser Tube ◽  
Average Laser Power ◽  
Bending Process ◽  
Angular Scanning ◽  
Average Laser

The Effect of Nonconventional Laser Beam Geometries on Stress Distribution and Distortions in Laser Bending of Tubes

2006 ◽  
Vol 129 (3) ◽  
pp. 592-600 ◽  
Author(s):  
Shakeel Safdar ◽  
Lin Li ◽  
M. A. Sheikh ◽  
Zhu Liu
Keyword(s):  
Laser Beam ◽  
Laser Scanning ◽  
Thermal Stresses ◽  
Laser Forming ◽  
Beam Diameter ◽  
Hydraulic Systems ◽  
Tube Bending ◽  
Laser Bending ◽  
Scanning Velocity ◽  
Laser Tube

Laser forming is a spring-back-free noncontact forming method that has received considerable attention in recent years. Compared to mechanical bending, no hard tooling, dies, or external force is used. Within laser forming, tube bending is an important industrial activity with applications in critical engineering systems such as heat exchangers, hydraulic systems, boilers, etc. Laser tube bending utilizes the thermal stresses generated during laser scanning to achieve the desired bends. The parameters varied to control the process are usually laser power, beam diameter, scanning velocity, and the number of scans. The thermal stresses generated during laser scanning are strongly dependent upon laser beam geometry. The existing laser bending methods use either circular or rectangular beams. These beam geometries sometimes lead to undesirable effects such as buckling and distortion in tube bending. This paper investigates the effects for various laser beam geometries on laser tube bending. Finite element modeling has been used for the study of the process with some results also validated by experiments.

On the Three-Dimensional Laser Bending of Metal Tubes

2012 ◽  
Vol 197 ◽  
pp. 297-301
Author(s):  
Nan Hai Hao ◽  
Yu Ling Gai
Keyword(s):  
Three Dimensional ◽  
Tube Bending ◽  
Laser Bending ◽  
Bending Angle ◽  
Laser Tube ◽  
Systematic Scheme ◽  
Helical Tube ◽  
Plastic Forming ◽  
High Flexibility ◽  
Adjacent Segments

Laser tube bending is a kind of plastic forming method with high flexibility, and is suitable for the low ductility material and thin thickness tube. This paper proposes a systematic scheme for three-dimensional tube bending, which forms the tube by varying the bending position and bending direction continuously. The bending part is simplified as a three-dimensional curve and then the curve is divided into segments and substituted with line sections. The scheme takes the angle between two adjacent segments as the laser bending angle at each bending position and the angle between two adjacent bending plane as the variation of bending direction. The effectiveness of proposed scheme is verified with the forming of a helical tube experimentally. The dimension errors of the formed helical tube are 6.25% in diameter and 7.59% in pitch respectively.

Study on 3D Strain Distribution Characteristics Using Etched Grid Method in Tube Bending

2012 ◽  
Vol 184-185 ◽  
pp. 505-509
Author(s):  
Heng Li ◽  
He Yang ◽  
Kai Peng Shi
Keyword(s):  
Strain Distribution ◽  
Three Dimensional ◽  
Grid Method ◽  
Thickness Variation ◽  
Distribution Characteristics ◽  
Tube Bending ◽  
Thickness Strain ◽  
Bending Angle ◽  
Maximum Value ◽  
Wall Thickness Variation

Strain distribution is crucial for understanding tube bending and preventing defects. In this paper, taking 321 stainless steel as the objective, via etched grid method, the strain distribution characteristics during tube bending are studied, the effects of the bending velocity and the bending angle on the strain distribution are analyzed, and the consistency of thickness strain with wall thickness variation is verified. The results show that: (1) three-dimensional (3D) strain is symmetrically distributed about bending plane and reaches the maximum value at wall extrados and intrados; (2) absolute value of the 3D strain increases at first, then decreases in tube bending; (3) compared with bending angle, bending velocity has greater effect on spatial strain, and compared with tangent strain, thickness strain is more sensitive to bending velocity; (4) thickness strain distribution characteristics are generally consistent with distribution characteristics of wall thinning degree.

Durability of Tube Bends Made of the 14MoV6-3 Steel under Low-Cycle Fatigue Conditions and Creep at a Temperature of 500°C

2015 ◽  
Vol 226 ◽  
pp. 79-86
Author(s):  
Marek Cieśla ◽  
Rafal Findziński ◽  
Grzegorz Junak
Keyword(s):  
Numerical Analysis ◽  
Wall Thickness ◽  
Low Cycle Fatigue ◽  
Steel Tube ◽  
Cycle Fatigue ◽  
Tube Bending ◽  
Creep Tests ◽  
Pipe Bend ◽  
Supply Condition ◽  
Bending Process

The paper contains the results of theoretical and experimental research on tube bending process used in manufacturing of 14MoV6-3 steel tubes. The innovative tube bending process using local induction heating and the results of finite-element numerical analysis of tube bends using Symufact Forming 11.0 software were presented. Numerical analysis covered the changes in pipe bend geometry (ovalization of cross section, wall thickness) and the results were compared with those obtained in industrial conditions. Basic mechanical properties of bended tube (diameter 323.9 mm, wall thickness 40 mm) in the supply condition and after heat treatment were determined using tensile, hardness, impact, low-cycle fatigue and creep tests. It has been shown that 14MoV6-3 steel tube bends manufactured using proposed technology meet the requirements of the PN-EN 10216-2 standard.

Characteristics of Rotary Draw-Bent Tubes for the Hydroforming

2011 ◽  
Vol 213 ◽  
pp. 320-324
Author(s):  
Byeong Don Joo ◽  
Jeong Hwan Jang ◽  
Hyun Jong Lee ◽  
Young Hoon Moon
Keyword(s):  
Cross Section ◽  
Structural Strength ◽  
Dimensional Accuracy ◽  
Thickness Variation ◽  
Important Process ◽  
Rotary Draw Bending ◽  
Higher Dimensional ◽  
Bending Process ◽  
Geometric Size ◽  
Draw Bending

Hydroformed parts have higher dimensional accuracy, structural strength, and dimensional repeatability. The pre-bending process is an important process for the successful hydroforming in the case where the perimeter of the blank is nearly the same as that of final product. At initial pre-bending stage, the variations of wall thickness and cross-section have effects on the accuracy of final products and quality. Because of a relatively excellent productive velocity, geometric size precision and reliance of product qualities, rotary draw bending is widely used. This study shows the bendability such as cross-section ovality, springback ratio and thickness variation in the various conditions of materials.

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