Research On Maximizing Critical And Reducing Initial Heat Flux Densities To Eliminate Any Film Boiling And Minimize Distortion During Quenching

In the paper the results of testing three types of FUCHS oils: Thermisol QH 120, Thermisol QH 10 and Thermisol QB 46 are discussed. The main attention is paid to critical heat flux densities evaluation because they create a basis for optimizing cooling intensity of any liquid quenchant. In the paper is underlined that any film boiling during quenching is undesirable since it is a reason for big distortion and non-uniform surface harness. It is shown that intensive quenching decreases distortion of steel parts during quenching. To eliminate film boiling during quenching in mineral oils, optimal temperature of oil should be chosen which maximize the first critical heat flux density and special additives should be used to decrease initial heat flux by creating surface micro-coating. Along with the evaluation of heat transfer coefficients, critical heat flux densities inherent to liquid quenchant must be measured first to optimize quenching processes. International DATABASE on cooling characteristics of liquid quenchants must include critical heat flux densities, initial heat flux densities, and heat transfer coefficients allowing optimizing and governing quenching processes

New Era in Designing and Governing Cooling Intensity of Liquid Quenchants to Decrease Distortion During Hardening of Steel Parts

It was proved in last decade that very intensive and uniform cooling eliminates quench crack formation and significantly decreases distortion of quenched steel parts as compared with their slow cooling in mineral oils. That opened a new era in design ing and governing cooling intensity of liquid quenchants for strengthening steel parts and decrease their distortion after quenching. The new approaches were developed by authors to provide accelerated and uniform cooling steel parts during quenching by creation on their surface thin insulating layers. For this purpose low concentration of water polymer solutions of inverse solubility are used as a quenchant. More information on cooling intensity of Poly (Alkylene Glycol) polymers (PAG) solutions one can find in a well known book (Totten et al., 1993). Along with decreasing distortion of steel parts, such approach decreases cost of bath’s coolant which less affects environment. It is shown in presentation that accelerated cooling should be interrupted at proper time to provide self tempering, fix compressive residual stresses, decrease more distortion and prevent quench crack formation. To govern process of quenching and make cooling interruption, software IQCalc2 was developed

New Era in Designing and Governing Cooling Intensity of Liquid Quenchants to Decrease Distortion During Hardening of Steel Parts

It was proved in last decade that very intensive and uniform cooling eliminates quench crack formation and significantly decreases distortion of quenched steel parts as compared with their slow cooling in mineral oils. That opened a new era in design ing and governing cooling intensity of liquid quenchants for strengthening steel parts and decrease their distortion after quenching. The new approaches were developed by authors to provide accelerated and uniform cooling steel parts during quenching by creation on their surface thin insulating layers. For this purpose low concentration of water polymer solutions of inverse solubility are used as a quenchant. More information on cooling intensity of Poly (Alkylene Glycol) polymers (PAG) solutions one can find in a well known book (Totten et al., 1993). Along with decreasing distortion of steel parts, such approach decreases cost of bath’s coolant which less affects environment. It is shown in presentation that accelerated cooling should be interrupted at proper time to provide self tempering, fix compressive residual stresses, decrease more distortion and prevent quench crack formation. To govern process of quenching and make cooling interruption, software IQCalc2 was developed