Callister

The Jominy End-Quench TestOne standard procedure that is widely utilized to determine hardenability is the Jominy end-quench test.

With this procedure, except for alloy composition, all factors that may influence the depth to which a piece hardens (i.e., specimen size and shape,and quenching treatment) are maintained constant. A cylindrical specimen 25.4 mm (1.0 in.) in diameter and 100 mm (4 in.) long is austenitized ata prescribed temperature for a prescribed time. After removal from the furnace, it is quickly mounted in a fixture as diagrammed in Figure 14.5a.The lower end is quenched by a jet of water of specified flow rate and temperature. Thus, the cooling rate is a maximum at the quenched end anddiminishes with position from this point along the length of the specimen. After the piece has cooled to room temperature, shallow flats 0.4mm(0.015 in.) deep are ground along the specimen length and Rockwell hardness measurements are made for the first 50 mm (2 in.) along eachflat (Figure 14.5b); for the first 12.8 mm (1/2 in.), hardness readings are taken at 1.6 mm (1/16 in.) intervals, and for the remaining 38.4 mm (11/2 in.),every 3.2 mm (1/8 in.). A hardenability curve is produced when hardness is plotted as a function of position from the quenched end.

http://www.journalamme.org/papers_vol37_2/37236.pdf

For quantitative estimation of hardenability for steel and cast steels the Jominy end quench test is used [1]. The other method is Grossmann’sanalytical method [2] in which for Di calculation the multiplying hardenability coefficients for alloying elements, presented in the graphical formare applied. The main advantage of calculation method is short time and low cost of obtained results. But the disadvantage of method is, thatpublished data on multiplying hardenability coefficients show scatter and the effect of alloying element on the hardenability may depend on thechemical composition of steel. A comprehensive review of published data on the multiplying hardenability coefficients was presented by Doane[3]. Steel is the iron alloy after plastic deformation and shows difference with cast steel, not deformed. It is interesting if data used forestimation of the steel hardenability provide the accuratehardenability parameters of cast steel. The aim of the investigation was to verify if published data applied for calculation of the hardenability ofconstructional steels enable accurate estimation of cast steel hardenability and selection of data for obtaining the best agreement betweenexperimental and calculated hardenability parameters.

CCTs y TTTs