Designing of Advanced and Original Austempering Processes Based on Thermal Science and Engineering Physics Approaches

Abstract

In the paper, a small concentration of inverse solubility polymers in water and other liquid media is recommended to eliminate film boiling by means of reducing initial heat flux density. Quenching steel parts and tools in a small concentration of water solutions under pressure allows performing austempering process just using cold liquids. Its essence consists in coinciding martensite start temperature MS with the average temperature of self-regulated thermal process during nucleate boiling mode and further immediate transferring steel parts for tempering at the temperature which exceeds value MS. The new technology increases the service life of austempered workpieces by more than two times, saves alloy elements, is suitable for larger metallic components, improves environmental conditions, since instead of melted salts and alkali, plain water and water salt solutions can be used. The new austempering process can be used in forging shops to obtain super-strengthened materials in order to switch from alloy steel to plain carbon steels. And it can be also widely used for obtaining nano - bainitic structure in plain carbon steels resulting in saving alloy elements and improving mechanical characteristics of materials.

Liscic/Petrofer Probe to Investigate Real Industrial Hardening Processes and Some Fundamentals During Quenching of Steel Parts in Liquid Media

“…In this paragraph an austempering process in cold liquids, developed in Ukraine, is considered [8,9]. The idea is very simple and understandable.…”

An Effect of Pib Additives to Mineral Oil Resulting in Elimination of Film Boiling During Steel Parts Quenching

“…4. The proposed approach for additions of PIB by the authors [2][3][4], for decreasing initial heat flux densities by creating a surface insulating layer to limit the process of film boiling, is a very promising method to decrease distortion taking place during quenching of steel parts in liquid media.…”

“…In 1987 authors proposed an original idea [2] on the possibility of eliminating film boiling during quenching by creating an insulating layer on the surface of steel parts to be hardened. The invented process was rather costly that is why the author [3,4] proposed to use small concentration of inverse solubility polymers in water which create micro layer on the surface during the beginning of the quench cooling process. In this case technology becomes significantly cheaper resulting in decreased distortion of the steel parts after quenching.…”

“…After discussion of the problem, authors decided to find out whether additive could create an insulating layer on the surface of Inconel 600 probe which could be a reason for such unusual behavior. Thus, the aim of this paper is to find out a reason for elimination of film boiling when PIB-2400 in oil is present by exploring the previous studies of the authors [2][3][4]. Fig.…”

“…It is counter-intuitive that film boiling disappears with the addition of the PIB additive when surface tension and dynamic viscosity remain unchanged. Based on early investigations [3,4], the authors believed that one reason for the absence of film boiling is an insulating layer of the additive formed immediately after immersion of the heated high temperature probe into the oil I-20A containing PIB. In the present paper, the authors provide additional support for their thesis by providing appropriate calculations and direct video observation.…”