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Parameter analysis in the intensive quenching

Grant number: 11/19555-7
Support type:Scholarships in Brazil - Scientific Initiation
Effective date (Start): December 01, 2011
Effective date (End): November 30, 2012
Field of knowledge:Engineering - Materials and Metallurgical Engineering - Transformation Metallurgy
Principal Investigator:Lauralice de Campos Franceschini Canale
Grantee:Miguel Ribeiro Neto
Home Institution: Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil

Abstract

Heat treatment is an important topic for the national industries. Mechanical properties such as hardness, ductility and toughness can be modified using heat treatment processes. Although not very known in Brazil, Intensive quenching is a success heat treatment process because of the fatigue resistance increased associated to a low cracking risk during quenching. Intensive quenching uses water or aqueous solutions as quenchants, replacing mineral oils of the common use in the conventional quenching. Mineral oils have deleterious effect for the environment. Compared to the conventional quenching, intensive quenching generates high compressive stresses on the surface, which are responsible for the increase of the fatigue life. This current project proposes a sequence of intensive quenching studies that began in another IC FAPESP project (Processo Fapesp n°2009/50510-0). Original project proposed to study cooling behavior of an intensive quenching lab system using water as quenchant while this project intend to study heat transfer characteristics using NaNO3 aqueous solution at 4%. Samples made from 304 stainless steel at different diameters and equipped with thermocouples in the surface, ½ radius and center will be used in this experiment. Flow rate will be varied through the pump of the cooling system. Heat transfer coefficients will be calculated and compared with the original project data.There is also an intention to do experiments using plain carbon steel with the best set of conditions for the intensive quenching lab system. Additional measurements of residual stress and analysis of the obtained microstructure will be performed. Key words: Heat treatment, intensive quenching, quenchants.