Electrolytic plasma is an emerging, environmentally friendly surface engineering technology that can be used for cleaning of metal surfaces and removing several coating. The present work was concerned with cleaning of corrosion products (oxides and contamination) on steel surfaces for corrosion protection. The effects of processing parameters on cleaning steel surfaces were investigated. The results show that electrolytic plasma can effectively produce clean surfaces and remove iron oxides. Also the arc spray coatings deposited on steel was removed by electrolytic plasma.
Plasma electrolysis is an electrolytic-chemical-thermal technique that can be used for local hardening of the different type of steels. The feasibility of hardening the 1.2333 cold work tool steel by applying a single-stage-local surface treatment, which combines the methods of plasma electrolysis, is discussed. The effects of treatment durations of plasma electrolytic hardening on the surface microstructural, mechanical, and tribological characteristics of 1.2333 cold work steel substrates are studied. The major advantage of the plasma electrolytic hardening is shown to be hardened layer (maximum 900 Hv - minimum 500 Hv) of the substrates consisting of martensitic phase in very short treatment durations, approximately 7 mm thick/0.5 min. Reciprocating-sliding friction and wear tests against an alumina ball counter face have shown that the application of a plasma electrolysis promotes a change in wear mechanism of the friction pair from relatively severe adhesion-abrasion to mild deformation. This results in simultaneous reduction of the volumetric wear rate from 0.18-0.2 mm^3 to 0.04 mm^3.
The determination of prior-austenite grain size has been the subject of metallurgical research efforts for many years. Metallurgical laboratories are often required to perform prior-austenite grain size determinations on martensitic steel components that have been heat treated. Although these methods may occasionally be mandated by material or procedural specifications, they are typically not preferred because they have a tendency of altering the as-received microstructure. These processes can also be labour-intensive and costly. The goal of this work is to chemically etch and identify the prior austenite grain size and martensitic structure of AISI 4140 steel treated by plasma electrolysis. Polished samples were immersed in 60% HCl, 30% HNO_3, 5% HF, 5% H_2O for 5 seconds then immersed in 5% picric acid, 5% HCl, 90% ethanol to reveal microstructures. Finally, the grain boundary and lath martensitic structure were revealed.
High-pressure die casting offers reduced costs due to its small tolerances and smooth surface finish. Casting parts produced are consumed by the automotive industry in millions. In this study, the use of computer aided engineering applications on design of high-pressure die-casting was studied. The influence of casting process steps in die design was studied and analyzed. The casting simulation software was used to improve design and solve problems. By using the simulation software in analyses of die design, the final design was reached in a few hours and thus the design process of pre-production was shortened and mold production was carried out with no revision on die material. Radiographic test was applied on the casting parts and the result shows good correlation between simulations of solidification result data. Also the results proved that the application of squeeze pressure in the intensification phase of high-pressure die casting process could be examined in the casting simulation.
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