Hot forming with a nonuniform temperature field using die partition cooling

2019 ◽  
Vol 116 (6) ◽  
pp. 613
Author(s):  
Cai-yi Liu ◽  
Yan Peng ◽  
Ling Kong ◽  
Lu-han Hao ◽  
Ren Zhai
Keyword(s):  
Temperature Field ◽  
Material Properties ◽  
High Strength ◽  
Strengthening Mechanism ◽  
Hot Forming ◽  
Nonuniform Temperature ◽  
Forming Process ◽  
Gradient Distribution ◽  
Forming Technology ◽  
Nonuniform Temperature Field

High strength steel hot forming technology plays an important role in achieving lightweight vehicles, improving the safety of vehicles. The tensile strength of the blank formed by traditional hot forming process is as high as 1500–2000 MPa, the strength of the formed blank is high, but the elongation is usually low and comprehensive mechanical property is not high. In this article, the process control of material gradient properties hot forming technology is summarized through the analysis of strengthening mechanism of gradient distribution hot forming technology. Based on the traditional hot forming technology, a new hot forming technology based on partition cooling to achieve material property gradient distribution is proposed. By changing the cooling rate of blank in different zones is different, and the gradient distribution of material properties is finally obtained. The DEFORM is used to analyze the hot forming process of the blank under the nonuniform temperature field of the partition cooling. A set of partition cooling hot forming die was designed independently to verify the experimental results. The evolution mechanism of microstructure and its effect on material properties during hot forming under nonuniform temperature field with partition cooling were revealed.

Research on Synchronized Cooling Hot Forming Process of 6016 Aluminum Alloy

2012 ◽  
Vol 452-453 ◽  
pp. 81-85 ◽  
Author(s):  
Ming He Chen ◽  
Y.Y. Cao ◽  
W. Chen ◽  
Guo Liang Chen
Keyword(s):  
Aluminum Alloy ◽  
Process Parameters ◽  
High Strength ◽  
Strengthening Mechanism ◽  
Alloy Sheet ◽  
Hot Forming ◽  
Al Alloy ◽  
Forming Process ◽  
Process Step ◽  
6016 Aluminum Alloy

In order to improve formability of high strength Al-alloy sheet metal, in this paper, it come up with the synchronized cooling hot forming process. Taking the aluminum alloy of 6016 H18 aluminum alloy, which carried out its technology test by Gleeble3500 hot-mechanical simulator. The process parameters such as deformation temperature T, holding time t and cooling rate v is investigated by the orthogonal test and the microstructure is analyzed simultaneously. The results show that the synchronized cooling hot forming process can be applied to 6016 H18 aluminum alloy, it both improves the formability of 6016 H18 aluminum alloy significantly and obtains the high strength after forming, it can meet the purpose of implementing deformation and enhanced in one process step, the proper combination of process parameters are T=450 °C, t=210 s, v=60 °C/s. Strengthening mechanism is which there is a large number of strengthening phase precipitated from matrix in technology process, the strengthening phases are coarser and the dispersed uniformity is a bit worse compared with that of T4 state.

Wave-Front Stress Relaxation in a One-Dimensional Nonlinear Inelastic Material With Temperature and Position Dependent Properties

1971 ◽  
Vol 38 (1) ◽  
pp. 47-50 ◽  
Author(s):  
R. P. Shaw ◽  
F. A. Cozzarelli
Keyword(s):  
Temperature Field ◽  
Wave Front ◽  
Material Properties ◽  
Plastic Material ◽  
Nonuniform Temperature ◽  
Temperature Dependent ◽  
One Dimensional ◽  
Nonuniform Temperature Field ◽  
Nonlinear Viscoelastic ◽  
Inelastic Material

Analytical solutions are obtained for stress, velocity, and strain at the wave front in a suddenly loaded semi-infinite rod of a material with a linear instantaneous response and nonlinear inelastic response. The material properties are assumed to depend on position directly or through a dependence on a prescribed nonuniform temperature field. Detailed solutions are obtained for two examples—a nonlinear viscoelastic material with temperature dependent parameters and a rate-sensitive plastic material which may have temperature dependent parameters and yield point.

High-Strength Steel Hot Forming Mechanics Performance and Characteristic Experimental Study

2016 ◽  
Vol 693 ◽  
pp. 800-806
Author(s):  
You Dan Guo
Keyword(s):  
Yield Strength ◽  
High Strength Steel ◽  
High Strength ◽  
High Energy ◽  
Absorption Capacity ◽  
Hot Forming ◽  
Gas Content ◽  
Strength Increase ◽  
Gradual Change ◽  
Forming Process

In high-strength steel hot forming, under the heating and quenching interaction, the material is oxidized and de-carbonized in the surface layer, forming a gradual change microstructure composed of ferrite, ferrite and martensite mixture and full martensite layers from surface to interior. The experiment enunciation: Form the table to ferrite, ferrite and martensite hybrid organization, completely martensite gradual change microstructure,and make the strength and rigidity of material one by one in order lower from inside to surface, ductility one by one in order increment in 22MnB5 for hot forming;Changes depends on the hot forming process temperature and the control of reheating furnace gas content protection, when oxygen levels of 5% protective gas, can better prevent oxidation and decarburization;Boron segregation in the grain boundary, solid solution strengthening, is a major cause of strength increase in ;The gradual change microstructure in outer big elongation properties, make the structure of the peak force is relatively flat, to reduce the peak impact force of structure, keep the structure of high energy absorption capacity;With lower temperature, the material yield strength rise rapidly,when the temperature is 650 °C, the yield strength at 950 °C was more than 3 times as much.

Modeling and FE Simulation of Quenchable High Strength Steels Sheet Metal Hot Forming Process

2010 ◽  
Vol 20 (6) ◽  
pp. 894-902 ◽  
Author(s):  
Hongsheng Liu ◽  
Jun Bao ◽  
Zhongwen Xing ◽  
Dejin Zhang ◽  
Baoyu Song ◽  
...  
Keyword(s):  
Sheet Metal ◽  
Fe Simulation ◽  
High Strength Steels ◽  
High Strength ◽  
Hot Forming ◽  
Forming Process

Forming Response of Ultra High Strength Steel Sheet to Stamping Speed during Hot Forming

2010 ◽  
Vol 160-162 ◽  
pp. 123-129 ◽  
Author(s):  
Hai Yan Yu ◽  
Li Bao ◽  
You Zhi Deng ◽  
Wei Cao
Keyword(s):  
Temperature Field ◽  
Steel Sheet ◽  
Coupling Effect ◽  
High Strength ◽  
Hot Forming ◽  
Boron Steel ◽  
Cold Forming ◽  
22Mnb5 Steel ◽  
Ultra High Strength Steel ◽  
Shaped Part

Stamping speed is an important parameter in sheet metal forming especially in hot forming. In this study, hot forming of a U-shaped part made of ultra high strength boron steel (22MnB5) sheet is simulated with solid elements. The mechanical properties of 22MnB5 steel sheet and the key process parameters are introduced in detail. Emphasis is laid on the forming response of the boron steel sheet to stamping speeds of 3.25m/s, 0.325m/s and 0.0325m/s. The mechanism of stamping speed acting on hot formability and temperature field of the stamped part is analyzed. It is demonstrated that stamping speed affects both formability and the heat transferred from blank to tools and to environment during hot forming. And the coupling effect of material properties, the heat produced during plastic deformation and heat boundary condition decides the formability and temperature field. An appropriate stamping speed is more important for hot forming than that for common cold forming.

scholarly journals Термополяризационный эффект в линейном полиэтиленоксиде при кристаллизации из расплава

2018 ◽  
Vol 60 (10) ◽  
pp. 1911
Author(s):  
Н.Н. Матвеев ◽  
Н.И. Борисова ◽  
Н.С. Камалова ◽  
Н.Ю. Евсикова
Keyword(s):  
Molecular Weight ◽  
Temperature Field ◽  
Polyethylene Oxide ◽  
Crystallization Temperature ◽  
Structural Changes ◽  
Nonuniform Temperature ◽  
Nonuniform Temperature Field

AbstractThe correlation between crystallite structural changes and polarization properties of a linear crystallized [–CH_2CH_2O–]_ n polyethylene oxide polymer is studied. The average spherulite radius and polarization of polyethylene oxide are inspected as functions of molecular weight of polymer and crystallization temperature from melt in a nonuniform temperature field.

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