Papers by Keyword: Banding

Abstract: Comprehensive metallographic studies of steel forgings with different machinability by cutting with an edge tool were also completed. Structural features and properties of steel were revealed, having adversely influence on tool life and the process of chip formation during cutting. Metal Science criteria have been given for assessing the manufacturability of steel at machining operations. Microstructures of steel with satisfactory and unsatisfactory machinability are presented. The technological parameters of heat treatment of steel 18HGR have been established, causing a show of banding of ferrite-pearlite structure. The thermokinetic diagram shows an area of development of the segregation banding structure. An important role in assessing the manufacturability of steels is shown of the microhardness of individual structural components and the difference in values between them. The best results in machinability by cutting are observed when the microhardness of pearlite is not more than 350 HV, ferrite is not more than 210 HV and the difference in microhardness between these components is not more than 80 HV.

Abstract: In order to reduce banding and blurry edges produced by the conventional multilevel error diffusion algorithm in the digital halftone process, an improved multilevel error diffusion algorithm using neighborhood growing is proposed. According to human visual properties, the algorithm uses banding edge neighborhood alternately grow toward the center to revise halftone image. Experimental results show that the halftone image obtained by the improved algorithm eliminates banding and a better visual effect is achieved with the enhanced edges.

Abstract: The potential to utilize controlled thermal processing to minimize banding in a DP780 steel with 2 wt pct Mn was evaluated on samples processed on a Gleeble® 3500 thermomechanical processing simulator. All processing histories were selected to result in final dual-phase steel microstructures simulating microstructures achievable during annealing of initially cold rolled sheet. Strip samples were processed to evaluate the effects of heating rate, annealing time, annealing temperature, and cooling rate. The degree of banding in the final microstructures was evaluated with standard light optical microscopic techniques. Results are presented to illustrate that the extent of banding depended on control of both heating and cooling rates, and a specific processing history based on a two-stage heating rate can be used to minimize visible banding in selected final heat treated products.

Abstract: Recrystallization was investigated in the context of its effect on the roping phenomenon in a 6000 series Al alloy. The findings suggest that, in general, the recrystallized grain size affects the material's susceptibility to roping more than the actual area fraction of specific texture components. For example, bands of Cube grains were typically observed in the final processed samples in cases which had coarse, recrystallized grain sizes from the earlier stages of processing. In contrast, bands were not observed for cases having fine, intermediate recrystallized grain sizes. Although microstructure and texture are highly intertwined, these findings suggest that the microstructural characteristics, such as the recrystallized grain size, are more important than those related to the texture.