A proposed coal-fired power plant at Rampal, Bangladesh will produce over 38 million tons of ash during 60 years of operation at 90% electric load generation capacity. The ash disposal pond would b...

Environmental hazard assessment of coal ash disposal at the proposed Rampal power plant

Effect of laser shock peening on ratcheting strain accumulation, fatigue life and bulk texture evolution in HSLA steel

Effect of Laser Shock Peening on Microstructure and Micro-texture Evolution in High-Strength Low-Alloy Steel upon Electrochemical Interaction

Microstructure, strength, and fiber texture evolutions in arc-based casting using low-carbon steel wire

The analysis of the modern state of wear-resistant metallic material production showed that one of the promising directions for improving their quality is the use of bimetallic steel-cast iron castings, which have a complex of properties differentiated over the volume and surface of the products. However, the problem of obtaining a high-quality joint of the steel base and the working cast iron layers is not completely solved at present. So, the research aims to determine the quality criterion of a good diffusion joint and to study the selected technological factor influence on the formation process of bimetallic castings using the developed mathematical model. The paper examines the effect of the steel base temperature at liquid cast iron pouring over it, the temperature of pouring cast iron, as well as the ratio of liquid cast iron mass to the unit surface of the steel base on the contact surface temperature as selected quality criteria, and the structure of the transition diffusion layer of bimetallic castings. It was determined that a high-quality joint is realized when this temperature is larger than the solidus temperature of the cast iron. Moreover, the results of the mathematical model application showed maximum contribution of the liquid cast iron mass/steel unit surface ratio, less effect of the pouring iron temperature and minimum influence of the solidified steel base temperature onto the quality criteria. The metallographic analysis established the diffusion joint formation in the transition steel-cast iron layer consisting of pearlite on the side of the steel base and without the carbide matrix area on the side of the working iron layer. The results obtained are of great importance for the designing bimetallic machine parts worked under intensive wear conditions.

Influence of technological factors on formation process of bimetallic castings

Ratcheting deformation in association with bulk texture evolution in HSLA steel is studied in this investigation. The cyclic deformation behaviors and damage modes of the specimens are obtained at room temperature, employing asymmetric stress-controlled tests under various combinations of mean stress and stress amplitudes. Bulk texture measurements of the specimens are done adopting an X-ray diffraction analysis. The results exhibit an increase in strain accumulation from 0.23 to 30.61% associated with a sharp reduction in ratcheting life from 3320 to 880 cycles by the increment in mean stress/stress amplitude. A continuous cyclic softening until the final failure is observed for all the ratcheting tests. It is noticed that variation of mean stress is more detrimental than stress amplitude in controlling strain accumulation while the effect of stress amplitude is more pronounced than mean stress for the reduction of ratcheting life. The fracture surface morphology indicates typical striation formation in the crack propagation region along with overload failure. The bulk texture studies indicate that there is a transition between ‘ϒ’ fiber and ‘ζ’ fiber during all loading conditions. The texture intensity is increased from 5.71 to 11.68 with progressive ratcheting strain accumulation. Here also, influence of stress amplitude is more significant than the mean stress. 

https://link.springer.com/content/pdf/10.1007/s12540-021-01107-2.pdf

Investigation on the Effect of Asymmetric Cyclic Loading on Ratcheting Deformation and Bulk Texture Development in HSLA Steel

Electric power generation in India has stepped up to numerous times in last decade and major portion of this power generation is coming from the coal based thermal plants. The chief by-product of thermal power plants are fly and bottom ashes. Transportation of ash slurry is a key problem in its efficient disposal. The foremost difficulty linked with ash slurry is that the particles settle down earlier than preferred. Lately, high concentrated slurry disposal (HCSD) structure has been hosted to get over of these problems. In this transportation system, ash slurry doesn’t only flow till it reaches the destination, but also settles down on the ash pond. This study describes the geotechnical properties of ash slurry of HCSD system in terms of densities, specific gravity, moisture content, and permeability. Change in properties of field tests with time are also shown in graphs. These studies and comparison with traditional mode of transportation will provide thorough understanding to the slurry disposal organization.

Susovan Kumar Sahoo

Papers

Investigation on the Effect of Asymmetric Cyclic Loading on Ratcheting Deformation and Bulk Texture Development in HSLA Steel

Geotechnical Study on Behaviour of High Concentrated Ash Slurry