Tribological Issues in the Tube Hydroforming Process—Selection of a Lubricant for Robust Process Conditions for an Automotive Structural Frame Part

2003 ◽  
Vol 125 (3) ◽  
pp. 484-492 ◽  
Author(s):  
Muammer Koc¸
Keyword(s):  
Process Design ◽  
Tube Hydroforming ◽  
Process Conditions ◽  
Process Selection ◽  
The Coefficient Of Friction ◽  
Hydroforming Process ◽  
Critical Regions ◽  
Robust Process ◽  
Lubricant Performance ◽  
Selection Of

In this paper, an overall review of tribological issues in the tube hydroforming process is presented. Guidelines for the selection of lubricants under the hydroforming process conditions are summarized following a description of existing testing methods and apparatus. A methodology of combined experiments and FEA was presented to determine the coefficient of friction in the hydroforming process in addition to selecting a proper lubricant for a given part and process design. Experimental results showed that thickness of the final part at critical regions, amount of axial feeding and axial force are strong indicators of lubricant performance whereas effect of lubrication on the part flatness, corner radius formation and box dimensions are found to be negligible.

Experimental Researches upon Changes of a Pipe's Roughness after Hydroformation

2013 ◽  
Vol 371 ◽  
pp. 111-115
Author(s):  
Bogdan Constantin Vaceanu ◽  
Gheorghe Nagit ◽  
Vasile Huian
Keyword(s):  
Surface Roughness ◽  
Tube Hydroforming ◽  
Work Piece ◽  
Copper Pipe ◽  
Work Area ◽  
The Coefficient Of Friction ◽  
Hydroforming Process ◽  
Aluminum Pipe ◽  
Experimental Researches

Surface roughness was studied in the tube hydroforming process, considering the quality of the material and the coefficient of friction between the work piece and die. Other researchers have studied the surface roughness to the front of an aluminum pipe [. The aim of this work was to analyze changes in a copper pipe roughness occurred after hydroforming process with fluid. Effects of changing roughness were studied, following the deformation of the material in the work area and roughness changes occurring in the material flow. After achieving hydroforming process, the surface roughness was measured by electron microscopy SEM in different areas of the hydro formed tube. After hydroforming process, an increase of surface roughness in connection areas of the mold to the curvature and the transverse direction of the pipe.

Corner Fill Modeling of Tube Hydroforming

2000 ◽  
Author(s):  
J. Y. Chen ◽  
Z. C. Xia ◽  
S. C. Tang
Keyword(s):  
Numerical Experiment ◽  
Internal Pressure ◽  
Process Design ◽  
Tube Hydroforming ◽  
Design Guidelines ◽  
Structural Components ◽  
Round Tube ◽  
Fundamental Understanding ◽  
Hydroforming Process ◽  
Square Box

Abstract Hydroforming process provides important advantages for automotive structural components over conventional stamp-and-weld parts, but it also brings unique challenges in process design. This paper attempts to obtain fundamental understanding of the process through corner fill modeling. A round tube is pressurized to expand into a square box with tight radius in the numerical experiment. Several parameters are identified and investigated during the process, namely, the internal pressure, end feed, and the lubricant. Their effects on the deformation profiles are presented, and their importance in process design is discussed. The established design guidelines from the study can be a valuable tool for hydroforming process engineers and part designers.

Preform Design for Tube Hydroforming Based on Wrinkle Formation

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
Chen Yang ◽  
Gracious Ngaile
Keyword(s):  
Circular Cylinder ◽  
Axial Compression ◽  
Process Design ◽  
Tube Hydroforming ◽  
Preform Design ◽  
Two Stage ◽  
Evolution Characteristics ◽  
Hydroforming Process ◽  
Ss 304 ◽  
Thinning Rate

A two-stage preforming process based on wrinkle formation is developed for the tube hydroforming process to accumulate material in the forming zone, thus reducing the thinning rate and improving the formability. In preforming stage one, the wrinkle onset is triggered with limited axial compression. In preforming stage two, the wrinkle grows stably and uniformly to a certain height. Then, the preformed wrinkles are flattened to conform to the die shape in the final tube hydroforming process. An analytical model based on bifurcation analysis and postbuckling analysis of the elastic-plastic circular cylinder under axial compression and internal pressure is used to study the wrinkle evolution characteristics in tube hydroforming. The analytical results offer valuable guidance to the process design of the two-stage preforming process. To validate this methodology, preform die sets for two axisymmetric parts were designed and tube hydroforming experiments were carried out on SS 304 tubing. Through this methodology, an expansion rate of 71% was achieved.

Process design and experimental verification of hydroforming for flanged tubular part

2011 ◽  
Vol 225 (11) ◽  
pp. 2015-2023
Author(s):  
B D Joo ◽  
M K Choi ◽  
C J Van Tyne ◽  
Y H Moon
Keyword(s):  
Process Design ◽  
Vehicle Body ◽  
Tool Geometry ◽  
Process Conditions ◽  
Hydraulic Pressure ◽  
Specific Target ◽  
Tubular Part ◽  
Hydroforming Process ◽  
Flange Forming ◽  
Forming Characteristics

Tube hydroforming is a technology that utilizes hydraulic pressure to form a tube into desired shapes inside die cavities. It is widely used in the automotive industry because of its various advantages, such as weight reduction, increased strength, improved quality, and reduced tooling cost. Hydroformed automotive parts used as structural components in the vehicle body frame or the subframe must often be structurally joined at certain locations, and it is useful if these parts can be manufactured with a localized attachment flange. This study proposes a flange hydroforming process, which consists of pre-bulging, flange forming, and conform shaping. The numerical process design by finite element (FE) analysis was performed with Dynaform 5.5. To accomplish a successful flange hydroforming process design, investigations on the proper combination of process parameters such as tool geometry, tube diameter, and internal hydraulic pressure were performed. To fabricate a flange of a specific target length on hydroformed tubular parts, an analytical model that predicts the flange length for a given set of process conditions is proposed. Hydroforming experiments to fabricate a flanged tubular part were performed, and the forming characteristics at various pressure conditions were analysed. The results show that the proposed hydroforming process can successfully produce flanged parts of a specific target length.

Reliability Analysis of the Tube Hydroforming Process Based on Forming Limit Diagram

2003 ◽  
Author(s):  
Bing Li ◽  
Don R. Metzger ◽  
T. J. Nye
Keyword(s):  
Tube Hydroforming ◽  
Forming Limit Diagram ◽  
Alternative Methods ◽  
Forming Limit ◽  
Process Conditions ◽  
Forming Process ◽  
Element Simulation ◽  
Hydroforming Process ◽  
Free Bulging ◽  
The Relationship

Tube hydroforming has become an increasingly attractive manufacturing process in automotive industry due to it having several advantages over alternative methods. The forming limit diagram has been extensively used in metal forming as the criteria of formability. A method to assess the probability of failure of the process based on reliability theory and the forming limit diagram is proposed in this paper. The tube hydroforming process is affected by many parameters such as geometry, material properties, and process conditions. Finite element simulation was used to predict the relationship between the strain and these parameters, and a numerical method was applied to get the statistical distribution of the strain. Based on the forming limit band in the forming limit diagram, the reliability of the forming process can be evaluated. A tube hydroforming process of free bulging is then introduced as an example to illustrate the approach. The results show this reliability evaluation technique to be an innovative approach for product designers and process engineers to avoid failure during tube hydroforming.

Research on Friction Behavior in Tube Hydroforming Process

2012 ◽  
Vol 217-219 ◽  
pp. 1774-1778
Author(s):  
Zai Xiang Zheng ◽  
Jing Xu ◽  
Guo Xian Liu
Keyword(s):  
Material Flow ◽  
Tube Wall ◽  
Thickness Distribution ◽  
Tube Hydroforming ◽  
Experimental Tests ◽  
Friction Model ◽  
Friction Behavior ◽  
Hydroforming Process ◽  
Tooling Design ◽  
Selection Of

In the tube hydroforming process, the friction behavior between the tube blank and the die is very complex. As a result, it is very difficult to build a precise friction model in accordance with the actual working conditions by fully taking into account the various factors. In this paper, the friction behaviors between the tube blank and the die in the guided, transition and expansion zones have been studied with the help of numerical simulation and experimental tests. The influences of the different friction conditions in the three zones as well as the uneven friction behavior in the expansion zone on the thickness distribution of tube wall and the characteristics of material flow have been analyzed and experimental tests have been carried out for the verification. The conclusions have provided theoretical references for the process planning, selection of lubrication and tooling design in the actual production process of tube hydroforming.

Study on the Chemical Modification Process of Jute Fiber

TAPPI Journal ◽  
2010 ◽  
Vol 9 (2) ◽  
pp. 23-29 ◽  
Author(s):  
Wei-ming Wang ◽  
Zai-sheng Cai ◽  
Jian-yong Yu
Keyword(s):  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Treatment Time ◽  
Jute Fiber ◽  
Process Conditions ◽  
Silicate Concentration ◽  
Sodium Hydroxide Concentration ◽  
Liquor Ratio ◽  
Degumming Process ◽  
Selection Of

Degumming of pre-chlorite treated jute fiber was studied in this paper. The effects of sodium hydroxide concentration, treatment time, temperature, sodium silicate concentration, fiber-to-liquor ratio, penetrating agent TF-107B concentration, and degumming agent TF-125A concentration were the process conditions examined. With respect to gum decomposition, fineness and mechanical properties, sodium hydroxide concentration, sodium silicate concentration, and treatment time were found to be the most important parameters. An orthogonal L9(34) experiment designed to optimize the conditions for degumming resulted in the selection of the following procedure: sodium hydroxide of 12g/L, sodium silicate of 3g/L, TF-107B of 2g/L, TF-125A of 2g/L, treatment time of 105 min, temperature of 100°C and fiber to liquor ratio of 1:20. The effect of the above degumming process on the removal of impurities was also examined and the results showed that degumming was an effective method for removing impurities, especially hemicellulose.

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