Structure and Microhardness of Steel Samples after Pulse Plasma Flows Processing

Abstract

The phase structure of surfaces of steel samples, modified by pulse plasma processing, was analyzed using XRD and metallographic methods. It has been shown, that after pulse plasma processing under different conditions a modified structure consisting of three new phases, including austenite, iron nitride and carbide, is formed. The dependence of phase transition and microhardness on plasma flow parameters has been studied. A sharp decrease in the dimensions of ferrite crystallites after the impact of plasma flow is observed. The main purpose of hardening of common steel samples is formation of nano-dimension ferrite with oriented iron carbide on grains.

The Improvement of Stainless Steel Properties after Pulse Plasma Processing

“…For common (carbon) steel samples the single time treatment by plasma flow is enough for significant modification of properties [8]. The studies have shown that for stainless steel samples repeated treatment is more effective.…”

“…One of the reasons for the increase in microhardness, apparently, are the structural changes, including the formation of hardening nitride and carbide phases. As known, when implanted iron-based alloys with nitrogen ions increase the radiation dose to 4 · 10 16 cm -2 at room temperature leads to the appearance of the martensite phase, which when heated to temperatures of 426 K into a tetragonal BCC grid iron nitride [8]. And as in the experiment, surface treatment of steel 12X18N10T done repeatedly, as the plasma gas was used by the air that N2 is one of the main components, and the results of X-ray analysis showed the presence of nitride phase, we can assume that these conditions impulse excitation can initiate similar phase transformation.…”

Расчет Теплофизических Процессов И Особенности Модификации Поверхности Стали Импульсными Потоками Плазмы

“…В настоящей работе сделана попытка связать воедино теплофизическую задачу на поверхности твердого тела и результаты экспериментальных исследований структуры материалов, модифицированных на плазменном ускорителе КПУ-30. Ранее в наших работах [7][8] были проанализированы изменения структуре обычных и нержавеющих сталей, обработанных на ускорителе КПУ-30. Если в обычных углеродистых сталях обнаружено сильное уменьшение размеров кристаллитов при возрастании энергии, то в нержавеющих сталях этого не происходит.…”