Rapid Determination of the Fracture Toughness of Metallic Materials Using Circumferentially Notched Bars

Newly developed polyvinyl pyrrolidone (PVP)-based quenchants have more oil-like cooling characteristics and thus can replace oil for quenching high alloy steel with complicated sections. The factors influencing the cooling rate are studied in this paper using the method of orthogonal regression. The regression equations show that concentration, bath temperature, and agitation are highly significant factors in the maximum cooling rate. For the cooling rate at 300 °C, concentration is critical, temperature is related, but agitation is not related. Based on the regression equation, suggestions regarding the better control of cooling rate in practice are given.