Microestructural and hardness evaluation of SAE 1020 and SAE 8620 steels quenched in high severity quenchants

• Grant number: 19/24225-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2020
• End date: January 31, 2021
• Field of knowledge: Engineering - Materials and Metallurgical Engineering
• Principal Investigator: Lauralice de Campos Franceschini Canale
• Grantee: Marina Eichemberger Martinez Mergulhão
• Host Institution: Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil

Abstract

High hardenability of steels during quenching requires low severity quenchants since the presence of alloying elements can promote martensitic transformation. However, those alloying elements increase the cost of the steel and the use of high severity quenchants can give good properties even for plain carbon steels. So, this work is proposing the use of very high severity quenchant to quench low carbon steels, considered with low hardenability, since they demand higher heat extraction to the achievement of good hardness values. Therefore, the search seeks to compare quenchants with different severities in low carbon steel and an alloyed steel low carbon, verifying the quenchant effect on the microstructure and hardness. Among the quenchants, a formulation with surfactants and ionic additives called fast quench will be available. As complementary fluids, water, aqueous sodium chloride solution (brine), nanofluid and oil will be used only for comparative purposes, once the oil is not considered a high severity medium. Cooling curves will be performed, and the quench will be done in samples with 25 mm in diameter by 100 mm in length. Thereby, it is expected to verify the quenchants that will promote the higher hardness among the evaluated steels. (AU)