Effect of Continuous Annealing Temperature on the Microstructure, Mechanical Properties and Texture of Annealed Drawn and Ironed Plate

Zhiying Mo,Haixu Li,Xiaohong Chu,Zhengzhi Zhao,Dengcui Yang,Yuan Fang,Xiandong Yin,Pengfei Gao,Heng Cui

doi:10.3390/cryst11121569

Abstract

To improve the production process and produce high-quality annealed drawn and ironed (DI) plate, continuous annealing experiments were carried out at 620 °C, 640 °C, 680 °C, and 720 °C, and the effect of continuous annealing temperature on the microstructure, mechanical characteristics, and texture of annealed DI plate were clarified. The microstructure was tested with a scanning electron microscope (SEM); the mechanical properties and weighted average of the plastic strain ratio (r¯) were measured using a tension test; and the texture characterizations were tested by X-ray powder diffractometer (XRD) and electron backscatter diffraction (EBSD). The results reveal that, with the increase of the annealing temperature, the average grain size grew from 5.14 μm to 6.56 μm, the yield strength and tensile strength decreased, and the elongation increased. The rolling textures drastically reduced after annealing. When annealed at a lower temperature of 620 °C, the texture content of {111} <110> was the highest. When the annealing temperature increased to 640 °C, 680 °C and 720 °C, the texture content of {111} <112> was higher than that of {111} <110>. The mechanical properties of the DI plate that was annealed at 640 °C are the best, with a higher r¯ value and a lower planar anisotropy value.

Highlights

The drawn and ironed (DI) plate is regarded as one of the three finest carbon steel sheets and is one of the most technically complex high-end tinplate products
Microstructures of the annealed grains gradually grow upwhich with the increase of the annealing temperature,but and are the average samples are ferrite, have undergone recrystallization still elongated along grain size changes greatly
With the increase of the annealing temperature, the degree of recrystallization increased, the proportion of equiaxed grains improved and the average grain size grew from 5.14 μm to 6.56 μm

Summary

Introduction

The DI plate is regarded as one of the three finest carbon steel sheets and is one of the most technically complex high-end tinplate products. DI plate is primarily used in the production of high-quality food packaging for food and beverage cans, and it has high compressive strength and is easy to recycle. In order to improve the competitiveness of the products, users have higher requirements for thinner thickness, higher hardness, greater strength, and good deep drawability [1]. On the basis of achieving the required thickness and mechanical properties, the texture component is a crucial indicator, as it affects the drawing performance and ear formation [2]. As a deep drawing sheet, the DI plate needs a higher r value and a smaller planar anisotropy value (∆r), because the larger the r value, the greater the sheet’s ability to resist instability and thinning, and the more advantageous it has for stamping. The larger |∆r| value will produce larger ears

Methods

Results

Conclusion