Hot forming with a nonuniform temperature field using die partition cooling

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.

Термополяризационный эффект в линейном полиэтиленоксиде при кристаллизации из расплава

The 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.