Progress on High Pressure Pneumatic Forming and Warm Hydroforming of Titanium and Magnesium Alloy Tubular Components

2014 ◽  
Vol 783-786 ◽  
pp. 2456-2461 ◽  
Author(s):  
Gang Liu ◽  
Yong Wu ◽  
Jian Long Wang ◽  
Wen Da Zhang
Keyword(s):  
High Pressure ◽  
Temperature Field ◽  
Magnesium Alloy ◽  
Thickness Distribution ◽  
Expansion Ratio ◽  
Mg Alloy ◽  
Ti Alloy ◽  
Warm Hydroforming ◽  
Corner Filling ◽  
Tubular Components

Complex structural tubular components of Titanium and Magnesium alloy can be obtained at a certain temperature by high pressure pneumatic forming (HPPF) with gas medium or warm hydroforming with pressurized liquid medium. At 800°C, through experimental research on HPPF of TA18 Ti-alloy tube with expansion ratio of 50%, the influence of axial feeding on thickness distribution of the workpiece was studied. Using reasonable loading curve, the component with large ratio can be formed with a small thinning ratio as 13% with total axial feeding amount of 40mm. At 850°C, HPPF experiments of TA18 Ti-alloy component with square section were carried out. The influence of gas pressure on thickness distribution and corner filling process were analyzed. The larger the pressure, the sooner the displacement changes at the corner, and the shorter corner filling term. At pressure of 30 MPa, small corner with the relative corner radius of 2.0 can be obtained within 168s. For Mg-alloy tubular part, warm hydroforming with non-uniform temperature field was studied. By using reasonable axial temperature field and loading path, the maximum thinning ratio of Mg-alloy tubular component with expansion ratio of 35% was reduced from 21.6% to 11.6%.

Effects of Nonconstant Strain Rate on Forming Limit and Efficiency in High Pressure Pneumatic Forming of Ti-Alloy Components

2014 ◽  
Vol 622-623 ◽  
pp. 347-352
Author(s):  
Gang Liu ◽  
Jian Long Wang ◽  
Ze Jun Tang ◽  
Yong Wu
Keyword(s):  
High Pressure ◽  
Strain Rate ◽  
High Energy ◽  
Expansion Ratio ◽  
Forming Limit ◽  
Ti Alloy ◽  
Alloy Tube ◽  
Large Expansion ◽  
Deformation State ◽  
Free Bulging

A process with gas pressure up to 70MPa is introduced, which is called High Pressure Pneumatic Forming (HPPF), comparing to superplastic forming (SPF) with pressure lower than 5MPa. HPPF process can be used to form tube blank at lower temperature with high energy efficiency and also at higher strain rate than SPF. With Ti-3Al-2.5V Ti-alloy tube, the potential of HPPF was studied through experiment in the temperature range of 700~850°C. To know the formability of the Ti-alloy tube, HPPF experiments of a large expansion tube and a square cross-section tube were carried out at different temperature and pressure. The limit expansion ratio and limit radius were measured to evaluate the forming limit of Ti-3Al-2.5V tube within HPPF. The results show that the lower the pressure, the better formability and the lower efficiency. At a constant pressure, the strain rate increases exponentially with bulging time during the free bulging procedure, but decreases exponentially during the small corner calibration. Through EBSD pictures, the deformation mechanism of the corner forming process in HPPF was analyzed. Because of a nonconstant strain rate deformation state and complicated stress and strain state during HPPF, the microstructure at the transition zone of the components are also nonhomogenous, but the grains are refined to a certain extent. Key words: HPPF, Ti-3Al-2.5V, limit expansion ratio, corner forming

Warm hydroforming of magnesium alloy tube with large expansion ratio

2010 ◽  
Vol 20 (11) ◽  
pp. 2071-2075 ◽  
Author(s):  
Gang LIU ◽  
Ze-jun TANG ◽  
Zhu-bin HE ◽  
Shi-jian YUAN
Keyword(s):  
Magnesium Alloy ◽  
Expansion Ratio ◽  
Alloy Tube ◽  
Large Expansion ◽  
Warm Hydroforming

Simulation and Experiment on Warm Hydroforming of AZ31 Magnesium Alloy Tube

2013 ◽  
Author(s):  
Shijian Yuan ◽  
Zejun Tang ◽  
Gang Liu
Keyword(s):  
Magnesium Alloy ◽  
Internal Pressure ◽  
Axial Direction ◽  
Sine Wave ◽  
Expansion Ratio ◽  
State Graph ◽  
Alloy Tube ◽  
Different Temperatures ◽  
Simulation And Experiment ◽  
Warm Hydroforming

The wrinkling behavior of an AZ31B magnesium alloy tube was investigated by simulation at different loading paths and at different temperatures. The effects of strain rate, internal pressure and temperature on the wrinkles were studied. Stressstrain track was analyzed in the quasi-static strain state graph of the plane stress processing to explain the changing of the wrinkles’ shape, radius and wall thickness. It is shown that shape of the wrinkles wave along the axial direction keeps the sine wave character. The radius and thinning at the top zone of the wrinkles and the width of the wrinkles increased with the temperature, the internal pressure or the axial feeding. Moreover, hydro-formability of wrinkled parts was investigated and the improvement was observed. Finnally, as an application of using wrinkled parts as preform prior to the final calibration, a magnesium alloy tubular part with 50% expansion ratio was formed.

Effect of Gas Pores on Mechanical Properties of High-Pressure Die-Casting AM50 Magnesium Alloy

2016 ◽  
Vol 22 (4) ◽  
pp. 814-819
Author(s):  
Wei Jiang ◽  
Zhanyi Cao ◽  
Liping Liu ◽  
Bo Jiang
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
Magnesium Alloy ◽  
3D Reconstruction ◽  
Die Casting ◽  
Mg Alloy ◽  
Uniaxial Tensile ◽  
High Pressure Die Casting ◽  
Areal Fraction ◽  
Pressure Die Casting

AbstractHigh-pressure die-casting (HPDC) AM50 tensile specimens were used to investigate characteristics of gas pores and its effect on mechanical properties of HPDC AM50 magnesium alloy. Combining microstructure morphology gained from optical microscopy, scanning electron microscopy (SEM), and three-dimensional (3D) reconstruction with the experimental data from uniaxial tensile testing, we pursued the relationship between gas pores and the mechanical properties of HPDC AM50 Mg alloy. Results indicate that comparing with 3D reconstruction models, 2D images like optical metallography images and SEM images have one-sidedness. Furthermore, the size and maximum areal fraction of gas pores have negative effects on the mechanical properties of HPDC AM50 Mg alloy. With increase of the maximum size of gas pores in the specimen, the ultimate tensile strength (UTS) and elongation decrease. In addition, with the maximum areal fraction becoming larger, both the UTS and elongation decrease linearly.

scholarly journals Warm Hydroforming Process under Non-Uniform Temperature Field for Magnesium Alloy Tubes

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 901
Author(s):  
Toshiji Morishima ◽  
Ken-Ichi Manabe
Keyword(s):  
Temperature Distribution ◽  
Magnesium Alloy ◽  
Thickness Distribution ◽  
Tube Hydroforming ◽  
Fuzzy Model ◽  
Fe Analysis ◽  
Experimental Result ◽  
Loading Path ◽  
Analysis Model ◽  
Warm Hydroforming

The warm tube hydroforming (WTHF) process of lightweight materials such as magnesium alloy contributes to a remarkable weight reduction. The success of the WTHF process strongly depends on the loading path with internal pressure and axial feeding and other process variables including temperature distribution. Optimization of these process parameters in this special forming technique is a great issue to be resolved. In this study, the optimization of the symmetrical temperature distribution and process loading path for the warm T-shape forming of magnesium alloy AZ31B tube was carried out by finite element (FE) analysis using a fuzzy model. As a result, a satisfactory good agreement of the wall thickness distribution of the samples formed under the optimum loading path condition can be obtained between the FE analysis result and the experimental result. Based on the validity validation of FE analysis model, the optimization method was applied to other materials and forming shapes, and applicability was discussed.

Study on Nitridation Behavior of Mg-Ca Alloy under Nitrogen

2011 ◽  
Vol 415-417 ◽  
pp. 1127-1131
Author(s):  
Xiao Xia Yang ◽  
Dun Qiang Tan ◽  
Dong Fei Xiao ◽  
Yi Jie Zhan
Keyword(s):  
Magnesium Alloy ◽  
Profile Analysis ◽  
Surface Film ◽  
Spray Forming ◽  
Holding Time ◽  
Mg Alloy ◽  
Nitride Film ◽  
Forming Process ◽  
Small Cracks

To study the ignition-proof behavior in the spray deposited magnesium alloy with nitrogen as atomizing gas, SEM and XRD were employed to study the morphology and elements profile of nitride film formed on the Mg-5Ca alloy melt in different conditions, and the ignition proof principle was also analyzed preliminarily. The results indicated that under ordinary nitrogen (99.5%), a layer of smooth and continuous nitride film was formed on the surface of Mg-5Ca alloy after sintered at 740°C for 2 hours, and with the increasing of temperature and holding time, small cracks and cavities appeared locally on the surface film. The surface film was mainly composed of CaO、MgO、Ca3N2and Mg3N2.The profile analysis of the nitride film indicated that Ca element collected on the surface of the nitride film, and a multiple film was formed which filled the loose and holes of single film, avoided the burning of Mg alloy during spray forming process.

Study on the leakage of plunger pair under static condition in high-pressure common rail injector considering deformation effect

2021 ◽  
pp. 095440702110656
Author(s):  
Zhenbo Gao ◽  
Yong Zhang ◽  
Dandan Wang
Keyword(s):  
High Pressure ◽  
Physical Properties ◽  
Thickness Distribution ◽  
Physical Property ◽  
Static Condition ◽  
Flow Equation ◽  
Common Rail ◽  
Plunger Pair ◽  
Common Rail Injector ◽  
High Pressure Common Rail

Plunger pair is the key component of high pressure common rail injector and its sealing performance is very important. Therefore, it is of great significance to study the leakage mechanism of plunger pair. Under static condition, the high-pressure fuel flow in the gap of the plunger pair caused the deformation of the plunger pair structure and the temperature rise of fuel. For a more comprehensive and accurate study, the effect of deformation, including elastic deformation and thermal expansion, the physical properties of fuel, including density, viscosity and specific heat capacity, as well as the influence of plunger posture in the plunger sleeve, including concentric, eccentric, and inclination condition, are considered in this paper. Firstly, the mathematical models including Reynolds equation, film thickness equation, non-isothermal flow equation, parametric equation of fuel physical property, and section velocity equation are established. The numerical analysis based on finite difference method for the solution of these models is given, which can simultaneously solve for the fuel film pressure distribution, temperature distribution, thickness distribution, distribution of fuel physical properties, and leakage rate. The models are validated by comparing the calculated leakage rates with the measurements. The effects under different posture of plunger are discussed too. Some of the conclusions provided good guidance for the design of high-pressure common rail injector.

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